Materials, Their Properties and Uses 800 RHODIUM molybdenite, which contains 0.0001 to 0.05% of the metal But the usual source is from the flue dusts and from the sublimed rhenium oxide, Re2O7, of stack gases in the smelting of copper and other ores It is precipitated from the flue dust of molybdenum-bearing copper ores in the form of potassium perrhenate, KReO4, or of ammonium perrhenate, NH4ReO4 The Russians also obtain some rhenium from the Ural platinum ores The stable rhenia, used in alloying, is rhenium trioxide, ReO3, which comes as a red powder The metal is obtained as a dense, silvery powder which can be compacted, sintered, and cold-rolled with frequent annealing It is marketed in the form of rod, strip, foil, and wire At the Technical University of Munich in Germany, pure, electrically conductive ReO3 ceramic films have been made by heating the polymer methyl-trioxorhenium Ch3ReO3, above 460°F (240°C), causing it to lose its methyl groups and water Rhenium has a higher electrical resistivity than tungsten, has high arc resistance, and does not become brittle after prolonged heating, as tungsten does Rhenium is used as an undercoat for tungsten coatings on graphite nozzles to prevent the formation of tungsten carbide and thus give the full heat resistance of the tungsten Rhenium and rhenium-tungsten alloys used for electric contacts give very long service life Rhenium-tungsten versus tungsten thermocouples are good for service to 5072°F (2800°C) Substantial amounts of rhenium are used in select tungsten- and molybdenum-base alloys RHODIUM A rare metal, symbol Rh, found in platinum ores such as the nickel-copper ores of Canada and pyroxenite of South Africa It is very hard and is one of the most infusible of the metals The melting point is 3565°F (1963°C) It is insoluble in most acids, including aqua regia, but is attacked by chlorine at elevated temperatures and by hot fuming sulfuric acid Liquid rhodium dissolves oxygen, and ingots are made by argon-arc melting At temperatures above 2192°F (1200°C), rhodium reacts with oxygen to form rhodium oxide, Rh2O3 The specific gravity is 12.44 Rhodium is used to make the nibs of writing pens, to make resistance windings in high-temperature furnaces, for high-temperature thermocouples, as a catalyst, and for laboratory dishes As a catalyst, it is used with platinum and palladium in auto catalytic converters to convert nitrogen oxide emission to nitrogen gas It is the hardest of the platinum-group metals, the annealed metal having a Brinell hardness of 135 Rhodium also has considerable strength and rigidity, ultimate tensile strengths ranging from 138,000 to 300,000 lb/in2 (952 to 2,068 MPa), and tensile modulus from 42 ϫ 106 to 55 ϫ 106 lb/in2 (290,000 to 379,000 MPa), depending on condition or hardness Rhodium is also valued for electroplating jewelry, Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses RICE 801 electric contacts, hospital and surgical instruments, and especially reflectors For electrodepositing rhodium, an electrolyte of rhodium sulfate, Rh (SO ) , is used The coatings are wear-resistant and tarnish-resistant The plated metal has a pinkish-white luster of high corrosion resistance and a light reflectivity of 80% Decorative finishes are seldom more than 0.0002 in (0.0005 cm) thick, but plates for electric contacts may be up to 0.005 in (0.013 cm) Rhodium carbonyl has the general formula Rh(CO), but with several variations in the number of CO groups They are used for depositing rhodium coatings The most important alloys of rhodium are rhodium-platinum They form solid solutions in any proportion, but alloys of more than 40% rhodium are rare Rhodium is not a potent hardener of platinum but increases its high-temperature strength It is easily workable and does not tarnish or oxidize at high temperatures These alloys are used for thermocouples and in the glass industry A rhodium-iron alloy with equiatomic proportions of the metal has an ordered crystal structure and changes from antiferromagnetic to ferromagnetic in an electric field Rhodium is sold by the troy ounce (31 g), in3 (16 cm3) weighing 6.56 troy oz (204 g) RICE The white seed of the large annual grass Oryza sativa, grow- ing to a height of to ft (0.6 to 1.2 m) It is a tropical plant native to Asia, but grows in hot, moist regions well into the temperate zones and is cultivated in many parts of the world Rice fields are flooded after planting to control weeds The rice seed grows in an inflorescence composed of a number of fine branches, each terminating in a single grain enclosed in a brown husk Rice forms the staple food of more than half the populations of the world Wild rice was used by the Indians of North America before the first Asiatic rice was brought to South Carolina in 1694 Rice is high in starch and low in proteins It is used as a direct food, also as flour, as cereal, in puddings, and for the manufacture of starch and for alcoholic beverages Rice hulls are used as stock feed, and rice straw is used for packing, hats, and other articles Maxflo and Profix, of EnviroGuard, Inc., are filtration aids made from rice hull ash, a by-product of rice milling The textured surface of the ash speeds solids separation from wastestreams A low-ash version has some caloric value so that it can be used to sop up waste oils during filtering and produce a recyclable waste fuel Rice in the husk before hulling is known by the Hindu name of paddy Brown rice is rice that has been cleaned but not polished Broken grains are sold in the India trade as coodie or khood, and about 20% of the rice produced from paddy is broken Patna rice does not refer to the Patna district of India, but to a variety of rice Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 802 ROSEWOOD with bold and hard grains especially suited for soups, as it holds its shape in boiling Malekized rice, developed by General American Transportation Co., is produced by steaming unpolished rice to force the soluble part of the bran and the vitamins into the core of the grain, and then sealing the rice kernal by gelatinization, after which it is polished The treated rice holds its shape and does not become gummy when cooked, and the nutritional value is improved The beverage known in Japan as saké is rice wine containing 14% alcohol, made by fermenting rice with the mold tané koji Rice bran oil, used as a salad and cooking oil and in lubricants, is produced from rice bran By wet-milling whole rice in a rice oil solutions, a higher yield of oil and wax is obtained together with a yield of proteins It is clear, odorless, and neutral, with a pleasant flavor, and is resistant to oxidation and rancidity Rice wax is produced from rice bran by hot hexane extraction after cold extraction of the oil It is a hard, brown, lustrous wax with a melting point of 174°F (79°C) used in polishes Synthetic rice, used in Japan as a rice extender, is made from wheat flour, potato starch, and powdered rice The wood of several species of Dalbergia of northern South America, but chiefly from the jacaranda tree, D nigra It is used for fine cabinetwork, pianos, novelties, and expensive furniture It should not be confused with the wood of the tree Physocalymma floridum, which also comes from Brazil and is there called pao rosa or rosewood The color of rosewood is dark brown to purple, and it takes a beautiful polish It has a characteristic fragrance Very hard with a coarse, even grain, it has a density of 54 lb/ft3 (865 kg/m3) The tree grows to a height of 125 ft (38 m) Brazilian rosewood is the preferred wood for guitar bodies, but its use was banned in 1969 by the Convention on International Trade in Endangered Species Another Brazilian wood, caroba, from the large tree Jacaranda copaia, is also called jacaranda and is sometimes confused with rosewood The tree has purple flowers while the true rosewood has white flowers Caroba wood is chocolate-colored and is used for fine furniture and knife handles Indian rosewood is from the tree D sissoo of India It is also called sissoo and is a beautiful, brown hardwood employed for carvings In Europe it is used for parquet floors Borneo rosewood, also known as ringas, is the wood of several species of trees of genus Melanorrhoea of Borneo The wood has a deep-red color with light and dark streaks It has a close texture suitable for carving Satinee is a type of rosewood from the tree Ferolia guianensis of the order Rosaceae, native to tropical America, particularly the Guianas The wood is reddish brown, has a density of 54 lb/ft3 (865 kg/m3), is fairly hard, has a fine grain, and takes a lustrous polish It is used for cabinetwork Bois de rose oil, or rosewood oil, ROSEWOOD Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses ROSIN 803 is not from rosewood, but is extracted from the heartwood of the tree Aniba panurensis of Brazil and the Guianas, though the wood of this tree is also used as a cabinet wood The oil is also called Cayenne linaloe, or Cayenne oil It has a delicate rose odor with a suggestion of orange and mignonette valued in perfumes It contains a high percentage of linalol, a colorless alcohol with a soft, sweet odor, also found in the rose, lilac, lily, lavender, petitgrain, and other plants It also contains geraniol Linaloe oil, or Mexican linaloe, is distilled from the heartwood of the trees Bursera delpechianum and B aloeoxylon It contains less linalol and also terpineol and geraniol Linalol is closely related to geraniol and nerol Bois de rose is also made synthetically from geraniol Oriental linaloe is distilled from selected, highly perfumed parts of the wood of the large tree Aquilaria agollocha of eastern India, Burma, and Java The odor of the oil is like rose, ambergris, and sandalwood Like the linaloes of the American continent, the oil is a pathological product and comes only from old trees It is also called aloe wood oil and agar attar, and is a very ancient perfume The beautifully figured and fragrant, reddish wood of this tree, called aloes wood, eagle wood, and paradise wood, is used for ornamental articles True original rosewood oil known as rhodium oil was distilled from the wood of the plant Convolvulus scoparius of the Canary Islands The common resin of several varieties of pine tree, found widely distributed in North America and Europe It is obtained by cutting a longitudinal slice in the tree and allowing the exudation to drip into containers The liquid resin is then distilled to remove the turpentine, and the residue forms what is known as gum rosin, or pine gum Wood rosin is obtained by distillation of old pine stumps It is darker than gum rosin and is inferior for general use Rosin contains seven acids with very similar characteristics, but consists chiefly of abietic acid, C19H29COOH Normally, when gum rosin is heated, the natural pimaric acid isomerizes to form abietic acid; but in the production of turpentine and rosin from pine sap, the turpentine is removed by steam distillation, and various acids are then extracted Pimaric acid is closely related to abietic acid It reacts with maleic and anhydride, and maleopimaric acid is used in printing inks and coatings Rosin has a specific gravity of about 1.08 and a melting point of about 180°F (82°C), and it is soluble in alcohol, turpentine, and alkalis It is used in varnishes, paint driers, soluble oils, paper sizing, and belt dressings; for compounding with rubber and other resins; and for producing many chemicals Rosin is generally graded commercially by letters according to color The darkest grade is B, and the lightest is W Extra grades are A, nearly black, and WW, water-white Thirteen color grades are ROSIN Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 804 ROSIN designated under the Naval Stores Act The dark grades of wood rosin are considered inferior They have a high melting point and low acid number and are used for making rosin oil; for battery wax, thermoplastics, and dark varnish; and for linoleum manufacture The ruby-red wood rosin, obtained by extraction from fat pine wood, has high acid number, 155, and low melting point, 175°F (79°C) It is used for printing inks, paper size, and adhesives Rosin is usually marketed in barrels of 280 lb (127 kg) Naval stores is an old name for rosin and turpentine Pexite and Pamite are rosin grades from Hercules Inc that cover the various color standards set by the U.S Department of Agriculture Pelletized rosin consists of free-flowing, dustless pellets produced by coating droplets of molten rosin with inert powder Colophony is an old pharmacy name for rosin before distillation of rosin oil Rosin was referred to by early writers as Greek pitch, but the ancient incendiary known as Greek fire was tow or pine sawdust impregnated with rosin, pitch, and sulfur Burgundy pitch was originally the resin of the Norway spruce, Picea abies, used in medicine, but the name was later applied to a rosin, rubber, and mineral oil compound used for friction tape Hardened rosin is a weak resinate made by adding to 8% high-calcium lime to melted rosin It is used in some varnishes Fosfo rosin, of Newport Industries, Inc., is a lime-hardened rosin It is an FF rosin treated with 4.75% calcium hydrate, which raises the melting point, decreases the free rosin acids, and decreases the tendency to crystallize It is used in paints, varnishes, and molded products Soda-treated rosins, with about 1% Na2O, but no free alkali, are used for soap, paper size, and disinfectants Rosin size is alkali-treated rosin in dry powder or emulsion form for sizing paper Dresinite is such a sodium or potassium salt of rosin Cyfor, of American Cyanamid Co., is a rosin size fortified with a synthetic resin to give increased water and acid resistance to paper Rosin ester, or ester gum, is prepared by heating rosin with glycerin It is lighter in color than rosin, has a higher softening point, and has a much lower acid number, usually to It is used with tung oil in enamels and varnishes and in adhesives Resin V is a rosin glycerin ester gum Rosin esterified with glycerin has lower molecular weight and is not as stable as rosin esterified with pentaerythritol or other tetrahydric alcohol; but modified rosin ester gums develop hardness quickly in nitrocellulose and are used for such purposes as furniture lacquers Cellolyn 102, of Hercules Inc., is a modified ester gum of this type, and Lewisol 28 is a maleic alkyd modified rosin ester used for hard, glossy furniture lacquers Hydroabietyl alcohol, used as a plasticizer and tackifier for rubber and for sizing textiles, is a colorless, tacky liquid made by reduction of rosin The 85% alcohol has a Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses ROSIN 805 specific gravity of 1.008 and a flash point of 369°F (187°C) It is also used for making rosin esters Abitol, of Hercules, is this material Abalyn is a methyl ester of abietic acid, methyl abietate, made by treating rosin with methyl alcohol It is a liquid rosin used as a plasticizer Hydrogenated rosin has greater resistance to oxidation than common rosin, has less odor and taste, and has a pale color that is more stable to light It is used in protective coatings, in paper size, in adhesives, in soaps, and as a tackifier and plasticizer in rubber Because of its saturated nature, it cannot be used for rosin-modified plastics The average acid number is 162, saponification value 167, and softening point 157°F (69°C) Staybelite resin, of Hercules, may be glycerol ester or ethylene glycol ester of hydrogenated rosin Another modified rosin, a perhydrogenated variety, is Foral Ax And a disproportionated rosin from the same company is Rosin 731 Vinsol resin is a hard, high-melting-point, dark resin produced from the distillation of wood, or is the black residue left after rosin is extracted with petroleum solvents It is soluble in alcohols, has a melting point of 239°F (115°C), and is used for insulating varnishes where light color is not essential, and for compounding in thermoplastics Hercolyn is Abalyn hydrogenated to saturate the double bonds with hydrogen Flexalyn, of the same company, is a pale-colored, very tacky, semisolid resin produced by the esterification of rosin acids with diethylene glycol, and it has a complex chemical structure It is used in adhesives to give added tack and strength Although rosin should be considered a natural resin, it is used primarily in coatings as a synthetic ester The principal materials are the glycerol ester of rosin, or ester gum, and the pentaerythritol ester, or PE ester gum The Pentalyn resins of Hercules are pentaerythritol esters Pentalyn M is a phenol-formaldehyde-modified pentaerythritol ester; it has a melting point of 329°F (165°C), and when used in linseed oil varnishes, it gives a tough coating Maleic modified ester gums have higher melting points and show better color retention in varnishes than simple rosin esters Ester gum varnishes are used primarily in low-cost, interior finishes that are not exposed to the weather Rosin is hardened by polymerization to form a dipolymer of abietic acid The product is then pale in color, and has a lower acid number and a higher melting point than rosin Poly-pale resin, of Hercules, is a polymerized rosin with melting point of 208 to 217°F (98 to 103°C), acid number 152 to 156, and saponification value 157 to 160 It can be substituted for natural copals in paints, and in gloss oil it gives water resistance and high viscosity In the making of metallic resinates, it gives higher melting points, higher viscosity, and better Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 806 ROUGE solubility than natural rosin Another modified rosin of this company is Dymerex resin It consists chiefly of dimeric rosin acids, is highly soluble, is resistant to oxidation, and has a high softening point at 282°F (139°C) It is used in synthetic resins and protective coatings Rosin amine D, of the same company, is a primary amine made from rosin It is a yellow, viscous liquid that wets glass and siliceous materials It is soluble in most organic solvents and emulsifies in water It is used in cutback asphalts, in road asphalts, in asphalt cements, in ceramic inks, in foundry core binders, and in paper pulp to improve adhesion of resins Nuroz is a polymerized rosin with a melting point of 169°F (76°C) and acid value 161 It has high resistance to oxidation and is used in varnishes and soaps Rosin oil is an oil produced by the dry distillation of rosin at a temperature of 392 to 680°F (200 to 360°C) There are two qualities of the oil: a light spirit, pinolin, which forms from to 5% of the rosin, and a bluish, heavy oil, which forms 80 to 84% It contains abietic acid and has an acid value of about 28 The commercial oil has a specific gravity of 1.020 with a flash point of 320 to 338°F (160 to 170°C) The refined oil is a yellow liquid with a pleasant odor and is used for blending with turpentine It is also employed as a plasticizer in rubber, as a tack producer in rubber cements, and in synthetic molding resins When treated with lime, it may be used to mix with lubricating oils The light distillate is used sometimes in pharmacy under the name of oil of amber Blended rosin oil is a mixture with mineral oils A hydrated iron oxide used for polishing metals and in break-in lubricants for aluminum bronze bearings It has a Mohs hardness of 5.5 to 6.5 and is made by calcining ferrous sulfate and driving off the sulfur The color is varying shades of red; the darker the color, the harder the rouge The grains are rounded, unlike the grains of crocus The pale-red rouge is used for finishing operations; the other grades are used for various polishing of metal surfaces Stick rouge is made of finely crushed powder Although the word rouge means red, materials of other colors are used for buffing and are called rouge Black rouge, also called Glassite, is magnetic iron oxide made by precipitating ferrous sulfate with caustic soda It is used for buffing but is not popular because it stains the skin Green chrome rouge is chromium oxide, CrO, made by the strong heating of chromic hydroxide It is used for buffing stainless steels When used as a paint pigment, it is called Guignet’s green Satin rouge is a name applied to lampblack when used as a polishing medium in the form of brick for polishing silverware Crocus is a name applied to mineral powders of a deep-yellow, brown, or red color made into cakes with grease for polishing Polishing crocus is usually red fer- ROUGE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses RUBBER 807 ric oxide used for a buffing glass and jewelry Crocus cloth is a fabric coated with red iron oxide, marketed in sheets and used for polishing metals A gum resin exudation of a wide variety of trees and plants, but especially of the tree Hevea brasiliensis and several other species of Hevea growing in all tropical countries and cultivated on plantations in southern Asia, Indonesia, Sri Lanka, Zaire, and Liberia, from which natural rubber elastomers are made The gum resin was formerly referred to as India rubber, and the name given it by Charles Goodyear was gum elastic The first highly compounded rubber for insulation, developed in 1867, was called Kerite Brazilian rubber is sometimes called Pará rubber Caoutchouc was an early name for the crude rubber then cured over a fire into a dark, solid mass for shipment Castilla rubber, or castilloa, is from the large tree Castilla elastica, and was the original rubber of the Carib and Mayan Indians, but was cultivated only in Mexico and in Panama where it was called Panama rubber The latex and rubber are identical with heavea rubber after purification Euphorbia rubber is from vines of the genus Euphorbia, of which there are 120 species in tropical Africa Much mangabeira rubber was formerly produced in the Amazon Valley It is the latex of the mangabeira tree which comprises various species of the genus Hancoria and yields the edible fruit mangaba The latex is coagulated with alum or sodium chloride, but the native Indians coagulated it with the latex of the caxiguba tree, Ficus anthelmintica, giving a better rubber The rubber is softer than hevea rubber, but ages better The low-grade Assam rubber is from a species of ficus tree, F elastica, of India and Malaya Ceara rubber comes from the small, rapid-growing tree, Manihot glaziovii, native to the semidesert regions of Brazil but now grown in India and Sri Lanka The rubber is of good grade Rubber latex is a colloidal emulsion of the gathered sap, containing about 35% of rubber solids, blended from various sources to give average uniformity The latex is coagulated with acid and milled into ribbed sheets called crepe rubber, or into sheets exposed to wood smoke to kill bacteria and called smoked sheet rubber These sheets constitute the commercial crude rubber, although much rubber latex is used directly, especially for dipped goods such as gloves, toys, and balloons; for coatings; and for making foam rubber Rubber has the property of being vulcanized with sulfur and heat, removing the tackiness and making it harder and more elastic in the low-sulfur compounds All natural rubber except adhesive rubbers is thus vulcanized rubber Ordinary soft rubber contains only to 6% sulfur, RUBBER Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 808 RUBBER but usually also contains softeners, fillers, antioxidants, or other compounding agents, giving varying degrees of elasticity, strength, and other qualities When as much as 30% sulfur is added, the product is called hard rubber Vapor-cured rubber is rubber vulcanized by sulfur chloride fumes and neutralized with magnesium carbonate It is used for thin goods only Acid-cured rubber is rubber cured in a bath of sulfur chloride in a solvent The tensile strength of rubber of low vulcanization is 800 to 1,200 lb/in2 (6 to MPa) of the original cross section A good soft rubber can be stretched as much as 1,000% without rupture and will return to close to the original length with little permanent set The specific gravity is about 1.05, but with fillers may be as high as 1.30 When the term vulcanized rubber is now used, it generally refers to hard rubber vulcanized to a rigid but resilient solid, used for electrical parts and tool handles Ace hard rubber has a specific gravity of 1.27, a tensile strength of 8,700 lb/in2 (60 MPa), dielectric strength of 485 V/mil (19 ϫ 106V/m), heat distortion temperature of 172°F (78°C), and water absorption 0.04% Vulcanite and Ebonite are old names for hard rubber Reclaimed rubber is produced largely from old tires and factory scrap It is usually lower in cost than new rubber, but it is easier to process and is employed in large quantities even when the price is higher It is sold in sheets, slabs, pellets, and powder, but much of the rubber powder, or granulated rubber, used for adhesives and molding is not reclaimed rubber but is made by spray-drying latex In a reclamation system developed by American Resource Recovery Corp., waste tires depolymerized in a high-temperature vacuum chamber are converted into oil, carbon black, steel, and ash Several types of modified natural rubber are used in the production of coatings, protective films, and adhesives These types are chlorinated rubber, rubber hydrochloride, and cyclized rubber or isomerized rubber Chlorinated rubber, for example, modified with any one of a number of plastic resins, provides maximum protection against a wide range of chemicals, and the coatings are widely used in chemical plants, in gas works, and as tank-car linings Red rubber is now simply rubber colored red, but was originally rubber vulcanized with antimony pentasulfide which broke down with the heat of vulcanization, yielding sulfur to the rubber and coloring it red with the residual antimony trisulfide Many trade-name accelerators, fillers, and stiffeners are marketed for rubber compounding Crumb rubber is any rubber in the form of porous particles that can be dissolved easily without milling, cutting, or pelletizing It is used in adhesives and plastics Magnetic rubbers, produced in sheets and strips of various magnetic strengths, are made of synthetic rubbers compounded with magnetic metal powders Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses RUBY 809 RUBIDIUM A rare metallic element, symbol Rb, atomic weight 85.45, belonging to the group of alkali metals The chief occurrence of rubidium is in the mineral lepidolite There is no real rubidium ore, but the element is widely disseminated over the earth in tiny quantities It is a necessary element in plant and animal life and is found in tea, coffee, tobacco, and other plants It is a silvery-white metal, with a specific gravity of 1.53, melting point, of 102°F (39°C), and boiling at 1270°F (688°C) It takes fire easily in air and decomposes water Of all the alkali metals it is next to cesium in highest chemical activity It can be obtained by electrolysis, but has few industrial applications owing to its rarity Its chief use is in electronics For photoelectric cells it is preferred to cesium, and a very thin film is effective Like potassium, it has a weak radioactivity by the emission of beta particles, the beta emission being only about one-thousandth that of an equal weight of uranium Rubidium titanyl arsenate (RTA), a derivative of potassium titanyl phosphate (KTP), is a nonlinear optical crystal material for improved optical parametric oscillators (OPOs), modulators, and Q-switches OPOs are used to tune laser frequency; Q-switches are used to control release of laser energy Because RTA crystals retain clarity with increasing laser power, they can extend a laser’s operating transmission range 15% into the infrared Developed at Wright Laboratory’s Materials Directorate and Crystal Associates Inc., RTA will increase the tunable range of solid-state lasers in industrial, medical, and military applications RUBY A red variety of the mineral corundum which ranks with the best grades of precious stones as a gemstone, while the off-color stones are used for watch and instrument bearings Most of the best rubies come from upper Burma, Thailand, and Cambodia, but the center of natural-ruby cutting is near Bombay Some deep-red rubies are found in east Africa, and they also occur in western North Carolina The carmine-red, or pigeon’s-blood, stones are the most highly prized Before the advent of the synthetic ruby, the larger stones were more valuable than diamond The pink to deep-red colors of the ruby are due to varying percentages of chromic oxide Star rubies contain also a small amount of titania which precipitates along crystallographic planes of the hexagonal crystal and shows as a movable six-ray star when the gem is cut with the axis normal to the base of the stone Spinel ruby is not corundum but magnesium aluminate and is a spinel, often occurring in the same deposits Synthetic rubies are equal in all technical qualities to the natural, and synthetic star rubies surpass the natural stones in perfection and quality Most of the ruby used for instrument bearings is synthetic Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SOAP 865 unless a phosphate is added Many industrial cleansers, therefore, may be balanced combinations of soaps, synthetic detergents, phosphates, or alkalies, designed for particular purposes About half of all soap is made with tallow, 25% with coconut oil, and the remainder with palm oil, greases, fish oils, olive oil, soybean oil, or mixtures A typical soap contains 80% mixed oils and 20 coconut oil, with not over 0.2 free alkali Auxiliary ingredients are used in soap to improve the color, for perfuming, as an astringent, or for abrasive or harsh cleaning purposes Phenol or cresylic acid compounds are used in antiseptic soap The soft soaps and liquid soaps of USP grade have a therapeutic value and may be sold under trade names Solvents are added to industrial soaps for scouring textiles or when used in soluble oils in the metal industry Zinc oxide, benzoic acid, and other materials are used in facial soaps with the idea of aiding complexion Excessive alkalinity in soaps dries and irritates the skin, but hand grit soap usually has to 5% alkaline salts such as borax or soda ash and 10 to 25% abrasive materials Softer hand soap may contain marble flour Silicate of soda, used as a filler, also irritates the skin Face soaps, or toilet soaps, contain coloring agents, stabilizers, and perfuming agents For special purposes, cosmetic soaps contain medications Deodorant soaps contain antibacterial chemicals, such as triclosan, which inhibit the production of bacteria on the skin Experts disagree on whether antibacterial ingredients are harmful to the skin Some, such as Dove, are a blend of detergents and soap Castile soap is a semitransparent soap made with olive oil Marseilles soap and Venetian soap are names for castile soap with olive oil and soda Ordinary soft soaps used as bases for toilet soap are made with mixtures of linseed oil and olive oil Linseed oil, however, gives a disagreeable odor Soybean oil, corn oil, and peanut oil are also used, although peanut oil, unless the arachidic acid is removed, makes a hard soap Tall oil soaps are sodium soaps made from the fatty acids of tall oil They are inferior to sodium oleate in detergency, but superior to sodium rosinate Many toilet soaps contain excess unsaponified oil, fatty acid, or lanolin and are known as superfatted Saddle soap is any soap used for cleaning leather goods which has the property of filling and smoothing the leather as well as cleaning The original saddle soaps were made of palm oil, rosin, and lye, with glycerin and beeswax added Oils for the best soaps are of the nondrying type High-grade soft soap for industrial use is made with coconut or palm kernel oil with caustic potash But soft soap in paste form is generally made of low-titer oils with caustic soda, usually linseed, soybean, or corn oil The lauric acid of coconut oil gives the coconut-oil soaps their characteristic of profuse lathering, but lauric Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 866 SOAPSTONE acid affects some skins by causing itching, and soaps with high coconut-oil content and low titer are also likely to break down in hot water and wash ineffectively Palm-kernel oil develops free acids, and upon aging the soap acquires the odor of the oil Palm oil produces a crumbly soap It does not lather freely, but is mild to the skin Olive oil is slow-lathering, but has good cleansing powers It is often used in textile soaps Cottonseed oil is used in some laundry soaps, but develops yellow spots in the soap Corn oil with potash makes a mild soft soap Soybean oil also makes a soft soap Rosin is used to make yellow laundry soaps ASTM standards for bar soap permit up to 25% rosin Sulfonated oils not give as good cleansing action as straight oils, but are used in shampoos where it is desirable to have some oil or greasiness Blending of various oils is necessary to obtain a balance of desired characteristics in a soap Hand soaps may be made with trisodium phosphate or with disodium phosphate, or sodium perborate, NaBO3 и H2O, known as perborin, all of which are crystalline substances which are dissolved in water solution Soap powder is granular soap made in a vacuum chamber or by other special processes It usually contains 15 to 20% soap and the balance sodium carbonate Scouring powder is an intimate mixture of soap powder and an insoluble abrasive such as pumice Floating soaps are made light by blowing air through them while in the vats Soapless shampoos and tooth powders contain saponin or chemical detergents Liquid soaps are made by saponification with potassium and ammonium hydroxide, or triethanolamine, to produce more-soluble products The floating soaps, such as Ivory from Procter & Gamble Co., are made by injecting air into the molten soap A massive variety of impure talc employed for electric panels, gas-jet trips, stove linings, tank linings, and as an abrasive It can be cut easily and becomes very hard when heated because of the loss of its combined water The waste product from the cutting of soapstone is ground and used for the same purposes as talc powder Steatite is a massive stone rich in talc that can be cut readily, while soapstone may be low in talc When free of iron oxide and other impurities, block steatite is used for making spacer insulators for electronic tubes and for special electrical insulators Block steatite suitable for electrical insulation is mined in Montana, India, and Sardinia Steatite is also ground and molded into insulators It can be purified of iron and other metallic impurities by electrolytic osmosis When fluxed with alkaline earths instead of feldspar, the molded steatite ceramics have a low loss factor at high frequencies, and have good electrical properties at high temperatures The white-burning refractory steatite of the SOAPSTONE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SODA ASH 867 Red Sea coast of Egypt averages 60% silica and 30.5 magnesia, with iron oxide and 1.5 CaO Alberene stone, quarried in Virginia, is blue-gray The mediumhard varieties are used for building trim and for chemical laboratory tables and sinks, and the hard varieties are employed for stair treads and flooring Alberene stone marketed by the Alberene Stone Corp as a basic refractory substitute for chrome or magnesite for medium temperatures has a fusion point of 2400°F (1316°C) Virginia greenstone is a gray-green soapstone resistant to weathering, used as a building stone Talc crayons for marking steel are sticks of soapstone The common name for anhydrous sodium carbonate, Na2CO3, which is the most important industrial alkali It is a grayishwhite, lumpy material which loses any water of crystallization when heated For household use in hydrous crystallized form, Na2CO3 и 10H2O, it is called washing soda, soda crystals, or sal soda, as distinct from baking soda, which is sodium hydrogen carbonate, or sodium bicarbonate, NaHCO3 Sal soda contains more than 60% water Another grade, with one molecule of water, Na2CO3 и H2O, is the standard product for scouring solutions Federal specifications call for this product to have a total alkalinity not less than 49.7% Na2O Commercial high-quality soda ash contains 99% minimum Na2CO3, or 58 minimum Na2O It varies in size of particle and in bulk density, being marketed as extra-light, light, and dense The extralight has a density of 23 lb/ft3 (368 kg/m3) and the dense has a density of 63 lb/ft3 (1,009 kg/m3) Laundry soda is soda ash mixed with sodium bicarbonate, with 39 to 43% Na2O Modified sodas, used for cleansing where a mild detergent is required, are mixtures of sodium carbonate and sodium bicarbonate They are used in both industrial and household cleaners Tanners’ alkali, used in processing fine leathers, and textile soda, used in fine wool and cotton textiles, are modified sodas Flour bland, used by the milling industry in making free-flowing, self-raising food flours, is a mixture of sodium bicarbonate and tricalcium phosphate Soda ash is made by the Solvay process, which consists of treating a solution of common salt with ammonia and with carbon dioxide and calcining the resulting filter cake of sodium bicarbonate to make light soda ash Dense soda ash is then made by adding water and recalcining Soda ash is less expensive than caustic soda and is used for cleansing, for softening water, in glass as a flux and to prevent fogging, in the wood-pulp industry, for refining oils, in soapmaking, and for the treating of ores Caustic ash, a strong cleaner for metal scouring and for paint removal, is a mixture of about 70% caustic soda and SODA ASH Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 868 SODIUM 30 soda ash Flake alkali, of PPG Industries, contains 71% caustic soda and 29 soda ash Soda ash is also used as a flux in melting iron to increase the fluxing action of the limestone, as it will carry off 11% sulfur in the slag Soda briquettes, used for desulfurizing iron, are made of soda ash formed into pellets with a hydrocarbon bond Hennig purifier is soda ash combined with other steel-purifying agents made into pellets The natural hydrous sodium carbonate of Egypt and Libya is called nitron Natural soda ash is obtained in Wyoming from beds to 10 ft (1.5 to 3.0 m) thick located 1,200 ft (366 m) underground, which contain 47% Na2CO3 and 36 NaHCO3, designated as trona, Na2CO3 и NaHCO3 и 2H2O By calcination the excess CO2 is driven off, yielding soda ash The salt brine of Owens Lake, California, is an important source of soda ash The brine, which contains 10.5% Na2CO3 and 2.5 sodium borate decahydrate, is concentrated and treated to precipitate the trona The Salt Lake area of Utah is a source of trona Soda ash and sodium carbonate may be sold under trade names Purite is a sodium carbonate Tronacarb is an industrial grade, and Tronalight, as the name suggests, is a light soda ash Both products are made by Kerr-McGee Chemical Corp SODIUM A metallic element, symbol Na and atomic weight 23, occur- ring naturally only in the form of its salts The most important mineral containing sodium is the chloride, NaCl, which is common salt It also occurs as the nitrate, Chile saltpeter, as a borate in borax, and as a fluoride and a sulfate When pure, sodium is silvery white and ductile, and it melts at 208°F (97.8°C) and boils at 1620°F (882°C) The specific gravity is 0.97 It can be obtained in metallic form by the electrolysis of salt When exposed to the air, it oxidizes rapidly, and it must therefore be kept in airtight containers It has a high affinity for oxygen, and it decomposes water violently It also combines directly with the halogens, and is a good reducing agent for the metal chlorides Sodium is one of the best conductors of electricity and heat The element has five isotopes, and sodium 24, made by neutron irradiation of ordinary sodium, is radioactive It has a half-life of 15 h and decays to stable magnesium 24 with the emission of one beta particle and two gamma rays per atom The metal is a powerful desulfurizer of iron and steel even in combination For this purpose it may be used in the form of soda-ash pellets or in alloys Desulfurizing alloys for brasses and bronzes are sodium-tin, with 95% tin and sodium, or sodium-copper Sodium-lead, used for adding sodium to alloys, contains 10% sodium and is marketed as small, spheroidal shot It is also marketed as sodium marbles, which are spheres of pure sodium up to in (2.54 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SODIUM CYANIDE 869 cm) in diameter coated with oil to reduce handling hazards Sodium bricks contain 50% sodium metal powder dispersed in a paraffin binder They can be handled in air and are a source of active sodium Sodium in combination with potassium is used as a heat-exchange fluid in reactors and high-temperature processing equipment A sodium-potassium alloy, containing 56% sodium and 44 potassium, has a melting point of 66°F (19°C) and a boiling point of 1517°F (825°C) It is a silvery, mobile liquid High-surface sodium is sodium metal absorbed on common salt, alumina, or activated carbon to give a large surface area for use in the reduction of metals or in hydrocarbon refining Common salt will adsorb up to 10% of its weight of sodium in a thin film on its surface, and this sodium is 100% available for chemical reaction It is used in reducing titanium tetrachloride to titanium metal Sodium vapor is used in electric lamps When the vapor is used with a fused alumina tube, it gives a golden-white color A 400-W lamp produces 42,000 lm and retains 85% of its efficiency after 6,000 h Sodium compounds are widely used in industry, particularly sodium chloride, sodium hydroxide, and soda ash Sodium bichromate, Na2Cr2O7 и 2H2O, a red, crystalline powder, is used in leather tanning, textile dyeing, wood preservation, and pigments When heated, it changes to the anhydrous form which melts at 673°F (356°C) and decomposes at about 752°F (400°C) In a hot water solution with sulfuric acid, sodium bichromate gives a golden-brown, brasslike finish to zinc parts The sodium bichromate liquor from alkali production is used for making pigments When combined with lead compounds, the bichromate precipitate is yellow The addition of iron blue, or ferric cyanide, develops greens Sodium metavandate, NaVO3, is used as a corrosion inhibitor to protect some chemical-processing piping It dissolves in hot water, and a small amount in the water forms a tough, impervious coating of magnetic iron oxide on the walls of the pipe Sodium iodide crystals are used as scintillation probes for the detection and analysis of nuclear energies Sodium oxalate is used as an antienzyme to retard tooth decay In the drug industry, sodium is used to compound with pharmaceuticals to make them water-soluble salts Gas-generating pellets or wafers of sodium azide are used as a propellant in auto airbag inflators Upon ignition, the gas burns and liberates large amounts of nitrogen gas, inflating the bag Sodium is a plentiful element, easily available, and is one of the most widely used A salt of hydrocyanic acid of composition NaCN, used for carbonizing steel for case hardening, for heat-treating baths, for electroplating, and for the extraction of gold and silver SODIUM CYANIDE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 870 SODIUM HYDROXIDE from their ores For carburizing steel it is preferred to potassium cyanide because of its lower cost and its higher content of available carbon It contains 53% CN, as compared with 40% in potassium cyanide The nitrogen also aids in forming the hard case on the steel The 30% grade of sodium cyanide, melting at 1156°F (679°C), is used for heat-treating baths instead of lead, but it forms a slight case on the steel Sodium cyanide is very unstable, and on exposure to moist air it liberates the highly poisonous hydrocyanic acid gas, HCN For gold and silver extraction it easily combines with the metals, forming soluble double salts, NaAu(CN)2 Sodium cyanide is made by passing a stream of nitrogen gas over a hot mixture of sodium carbonate and carbon in the presence of a catalyst It is a white, crystalline powder, soluble in water The white copper cyanide used in electroplating has composition Cu2(CN)2, containing 70% copper It melts at 887°F (475°C) and is insoluble in water, but is soluble in sodium cyanide solution Sodium ferrocyanide, or yellow prussiate of soda, is a lemon-yellow, crystalline solid of composition Na4Fe(CN)6 и 10H2O, used for carbonizing steel for case hardening It is also employed in paints, in printing inks, and for the purification of organic acids; in minute quantities, it is used in salt to make it free-flowing It is soluble in water Calcium cyanide in powder or granulated forms is used as an insecticide It liberates 25% of hydrocyanic acid gas Cyanogas, of American Cyanamid Co., is gaseous HCN from calcium cyanide SODIUM HYDROXIDE Known commonly as caustic soda, and also as sodium hydrate Lye is an old name used in some industries and in household uses It is a white, massive, crystalline solid of composition NaOH used for scouring and cleaning baths, for etching aluminum, in quenching baths for heat-treating steel, in cutting and soluble oils, in making soaps, and in a wide variety of other applications It is usually a by-product in the production of chlorine from salt The specific gravity is 2.13 and melting point 604°F (318°C) It is soluble in water, alcohol, and glycerin Sodium hydroxide is sold in liquid and in solid or powder forms on the basis of its Na2O content A high-grade commercial caustic soda contains 98% minimum NaOH equivalent to 76 minimum Na2O The liquid contains 50% minimum NaOH Pels, of PPG Industries, is a caustic soda in bead form It is less irritating to the skin when used in detergents Phosflake, of PPG Industries, used in washing machines, is a mixture of caustic soda and trisodium phosphate Caustic potash is potassium hydroxide, KOH, which has the same uses but is more expensive Caustic potash is a white, lumpy solid It is soluble in water and makes a powerful cleansing bath for scouring metals It is marketed as solid, flake, granular, or Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SODIUM SILICATE 871 broken, and also is 40 to 50% liquid solutions It is used in soaps and for bleaching textiles When used in steel-quenching baths, it gives a higher quenching rate than water alone and does not corrode the steel as a salt solution does Also called soda niter and Chile saltpeter A mineral found in large quantities in the arid regions of Chile, Argentina, and Bolivia, where the crude nitrate with iodine and other impurities is called caliche It is used for making nitric and sulfuric acids, for explosives, as a flux in welding, and as a fertilizer The composition is NaNO3 It is usually of massive, granular, crystalline structure with a Mohs hardness of 1.5 to and specific gravity of 2.29 It is colorless to white, but sometimes colored by impurities It is readily soluble in water In other parts of the world it occurs in beds with common salt, borax, and gypsum Sodium nitrate is also made by nitrogen fixation and is marketed granulated, in crystals, or in sticks It is colorless and odorless, and it has a specific gravity of 2.267 and a melting point of 601°F (316°C) It has a bitter, saline taste Sodan, used for spraying on soils, is a clear liquid solution of sodium nitrate and ammonium nitrate containing 20% nitrogen Norway saltpeter, used in fertilizers and explosives, is calcium nitrate, Ca(NO3)2, in colorless crystals soluble in water Calcium nitrate of fine crystal size is used as a coagulant for rubber latex SODIUM NITRATE SODIUM SILICATE A water-soluble salt commonly known as water glass or soluble glass Chemically, it is sodium metasilicate of composition Na2SiO3 or NaSiO3 и 9H2O Two other forms of the silicate are also available, sodium sequisilicate, 3Na2O и 2SiO2, and sodium orthosilicate, 2Na2O и SiO2 All of these are noted for their powerful detergent and emulsifying properties and for their suspending power The material has good adhesion, and large quantities are used in water solutions for industrial adhesives It is also used to inhibit corrosion in potable- and industrial-water systems, forming an oxidation-resistant film on pipe walls If corrosion has begun, pH-neutral reconditioning solutions can remove the rust or scale without pH adjustment of flush water When solid, sodium silicate is glassy in appearance and dissolves in hot water It melts at 1864°F(1018°C) It is obtained by melting sodium carbonate with silica, or by melting sand, charcoal, and soda The fused product is ground and dissolved in water by long boiling Potassium silicate is made in the same way, or a complex soluble glass is made by using both sodium and potassium carbonates Potassium silicate is more soluble than sodium silicate Kasil, of Philadelphia Quartz Co., is a potassium silicate in fine powder containing 71% SiO2 and 28.4 K2O It is used in ceramic coatings Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 872 SOLDER and refractory cements Corlok is potassium silicate free of fluorides and sodium compounds It is resistant to strong oxidizing acids, has good bond strength, and is used as a cement for acid tanks Ammonium silicate has an ammonium group instead of the sodium Quram 220, of Philadelphia Quartz Co., is this material in the form of white powder or in opalescent solution The intermediate silica grades act like sodium silicates and are used as binders for refractory ceramics Sodium silicate is marketed as a viscous liquid or in powder form It is used as a detergent, as a protection for wood and porous stone, as a fixing agent for pigments, for cementing stoneware, for lute cements for such uses as sealing lightbulbs, for waterproofing walls, for greaseproofing paper containers, for coating welding rods, as a filler for soaps, and as a catalyst for high-octane gasoline It increases the cleansing power of soaps but irritates the skin However, it is used in cleansing compounds because it is a powerful detergent Brite Sil is a spray-dried sodium silicate powder which dissolves more easily and more uniformly Sodium silicate is also used for insulating electric wire It is applied in solution, and the coated wire is then heated, leaving a flexible coating Mixed with whiting, it is used as a strong cement for grinding wheels Sodium metasilicate marketed by Philadelphia Quartz Co as a cleaner of metals is a crystalline powder Hot solutions of this salt in water are caustic and will clean grease readily from metals Drymet is the anhydrous sodium metasilicate It is a fine, white powder with total alkalinity of 51% Na2O It is easily soluble in water and is used as a detergent in soap powders to give free-flowing, noncaking properties The anhydrous material for a given detergent strength weighs little more than half the weight of the hydrous powder Dryorth is the anhydrous material of 60% alkalinity It is a powerful detergent and grease remover Crystamet is the material with 42% water of crystallization It is a free-flowing white powder Penchlor is an acidproof cement made by mixing cement powder with a sodium silicate solution It is used for lining chemical tanks and drains Aquagel, of Silica Products Co., is a hydrous silicate of alumina, used in the same manner for waterproofing concrete SOLDER An alloy of two or more metals used for joining other met- als together by surface adhesion without melting the base metals as in welding and without requiring as high a temperature as in brazing However, there is often no definite temperature line between soldering alloys and brazing alloys A requirement for a true solder is that it have a lower melting point than the metals being joined and an affinity for, or be capable of uniting with, the metals to be joined Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SOLDER 873 A common solder is called half-and-half, or plumbers’ solder, and is composed of equal parts of lead and tin It melts at 360°F (182°C) The density is 0.318 lb/in3 (8,802 kg/m3), the tensile strength is 5,500 lb/in2 (38 MPa), and the electrical conductivity is 11% that of copper SAE solder No has 49.5 to 50.0% tin, 50 lead, 0.12 maximum antimony, and 0.08 maximum copper It melts at 359°F (181°C) Much commercial half-and-half, however, usually contains larger proportions of lead and some antimony, with less tin These mixtures have higher melting points, and solders with less than 50% tin have a wide melting range and not solidify quickly Sometimes a wide melting range is desired, in which case a wiping solder with 38 to 45% tin is used A narrow-melting-range solder, melting at 362 to 365°F (183 to 185°C), contains 60% tin and 40 lead A 42% tin and 58 lead solder has a melting range of 362 to 448°F (183 to 231°C) Slicker solder is the best quality of plumbers’ solder, containing 63 to 66% tin and the balance lead The earliest solders were the Roman solders called argentarium, containing equal parts of tin and lead, and tertiarium, containing part tin and lead Both alloys are still in use, and throughout early industrial times tertiarium was known as tinman’s solder Good-quality solders for electrical joints should have at least 40% tin, as the electrical conductivity of lead is only about half that of tin, but conductivity is frequently sacrificed for better wiping ability, and the wiping solders are usually employed for electrical work Soft solders should not contain zinc because of poor adhesion from the formation of oxides Various melting points to suit the work are obtained with solders by varying the proportions of the metals The low-melting solders are those that melt at 446°F (230°C) or lower, and the high-melting solders melt at higher temperatures The flow point, at which the solder is entirely liquid, is often considerably above the melting point Tin added to lead lowers the melting point of the lead until, at 356°F (180°C), at 68% tin, the melting point rises as the tin content increases until the melting point of pure tin is reached A standard solder with 48% tin and 52 lead melts at 360°F (182°C) A 45–55 solder melts at 440°F (227°C) Cheap solders may contain much less tin, but they have less adhesion SAE solder No contains 22.5 to 23.5% tin, 75 lead, and maximum antimony It melts at 370°F (188°C) A tin-silver-copper alloy, developed at the University of Iowa (Ames), is lead-free and intended to replace tin-lead solders Made by blending spherical powder particles with a fluxing agent, the lead-free solder melts at 421°F (216°C) and wets similarly to tin-lead solders The silver and copper form hard, intermetallic phases, reinforcing the tin and strengthening the solder The toxicity of lead has been the impetus in Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 874 SOLDER the quest for its elimination in solder, especially for printed circuits in the electronics industry where the 63tin-37lead eutectic alloy has dominated for many years Five promising tin-based, lead-free alloys and their eutectic or melting temperatures are: tin-3.5silver (430°F, 221°C), tin-3silver-2bismuth (428°F, 220°C), tin-2.6silver-0.8 copper-0.5antimony (412°F, 211°C), tin-3.4silver-4.8bismuth (410°F, 210°C) and tin-3.5silver-0.5copper-1zinc (430°F, 221°C) With an ultimate tensile strength of about 8,000 lb/in (55 MPa) and a shear strength of about 4,600 lb/in2 (32 MPa), the tin-3.5 silver alloy is stronger than the tin-37lead alloy; it is also more creep resistant Solders with low melting points are obtained from mixtures of lead, tin, cadmium, and bismuth Bismuth solder is also more fluid, as bismuth lowers surface tension Bismuth, however, hardens the alloy, although to a lesser extent than antimony A bismuth solder containing equal parts of lead, tin, and bismuth melts at 284°F (140°C) Cerrolow alloys, of Cerro Metal Products Co., are bismuth solders containing sufficient indium to be designated as indium solders Cerrolow 147, which melts at 142°F (61°C), contains 48% bismuth, 25.6 lead, 12.8 tin, 9.6 cadmium, and indium Cerrolow 105, melting at 100°F (38°C), contains 42.9% bismuth, 21.7 lead, tin, cadmium, 18.3 indium, and mercury Cadmium solders have low melting points, are hard, and are usually cheaper than tin solders; but they have the disadvantage of blackening and corroding, and the fumes are toxic Cadmium-zinc solders were used in wartime because of the scarcity of tin A solder containing 80% lead, 10 tin, and 10 cadmium has about the same strength as a 50–50 tin-lead solder and has greater ductility, but is darker in color Cadmium-tin solder, with high cadmium, is used to solder magnesium alloys Soft solders for soldering brass and copper, especially for electric connections, may be of tin hardened with antimony Solder wire for this purpose contains 95% tin and antimony Thallium may be used in high-lead solders to increase strength and adhesion Hard solder may be any solder with a melting point above that of the tin-lead solders; more specifically, hard solders are the brazing solders, silver solders, or aluminum solders Aluminum solders may contain up to 15% aluminum A solder prepared by the National Bureau of Standards contains 87% tin, zinc, and aluminum It has good strength and ductility Alcoa solder 805, for joining aluminum to steel or other metals, has 95% zinc and aluminum The melting range is 715 to 725°F (379 to 385°C) For soldering aluminum to aluminum, an alloy of 91% tin and zinc is used The solder known as Richard’s solder is a yellow brass with 3% aluminum and phosphor tin Solders containing nickel are used for soldering nickel silver, and silver and gold solders are used for jewelry Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SOLVENT 875 work Silver solder in varying proportions is also used as a high-melting-point solder for general work, and small amounts of silver are sometimes used in lead-tin solders to conserve tin, but the melting point is high Lead-tin solders with more than 90% lead and some silver, in use during war emergency, had high melting points and poor spreading qualities Indium improves these solders, and a solder with 96% lead, silver, and indium has a melting point of 590°F (310°C) and a tensile strength of 4,970 lb/in2 (34 MPa) Cerroseal 35, of Cerro Metal Products Co., contains 50% tin and 50 indium It melts at 240°F (116°C), has low vapor pressure, and will adhere to ceramics Alkali-resistant solders are indium-lead alloys A solder with 50% lead and 50 indium melts at 360°F (182°C) and is very resistant to alkalies, but lead-tin solders with as little as 25% indium are resistant to alkaline solutions, have better wetting characteristics, and are strong Indium solders are expensive Adding 0.85% silver to a 40% tin soft solder gives equivalent wetting on copper alloys to a 63% tin solder, but the addition is not effective on low-tin solders A gold-copper solder used for making high-vacuum seals and for brazing difficult metals such as iron-cobalt alloys contains 37.5% gold and 62.5 copper The silver-palladium solders have high melting points, 2246°F (1232°C) for a 30% palladium alloy, and good flow, and corrosion resistance A palladium-nickel alloy with 40% nickel has a melting point of about 2258°F (1237°C) The brazing alloys containing palladium are useful for a wide range of metals and metal-to-ceramic joints Cold solder, used for filling cracks in metals, may be a mixture of a metal powder in a pyroxylin cement with or without a mineral filler, but the strong cold solders are made with synthetic resins, usually epoxies, cured with catalysts, and with no solvents to cause shrinkage The metal content may be as high as 80% Devcon F, of Devcon Corp., for repairing holes in castings, has 80% aluminum powder and 20 epoxy resin It is heat-cured at 150°F (66°C), giving high adhesion Epoxyn solder is aluminum powder in an epoxy resin in the form of a putty for filling cracks or holes in sheet metal It cures with a catalyst The metal-epoxy mixtures give a shrinkage of less than 0.2%, and they can be machined and polished smooth A material, usually a liquid, having the power of dissolving another material and forming a homogeneous mixture called a solution The mixture is physical, and no chemical action takes place A solid solution is such a mixture of two metals, but the actual mixing occurs during the liquid or gaseous state Some materials are soluble in certain other materials in all proportions, while others are soluble only up to a definite percentage and the residue is precipitated out of solution Homogeneous mixtures of gases may SOLVENT Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 876 SOLVENT technically be called solutions, but are generally referred to only as mixtures The usual industrial applications of solvents are for putting solid materials into liquid solution for more convenient chemical processing, for thinning paints and coatings, and for dissolving away foreign matter as in dry-cleaning textiles But they may have other uses, such as absorbing dust on roadways and killing weeds They have an important use in separating materials, for example, in the extraction of oils from seeds In such use, a clathrate is a solid compound added to the solution containing a difficult-to-extract material, but which is trapped selectively by the clathrate The solid clathrate is then filtered out and processed by heat or chemicals to separate the desired compound Antifoamers are chemicals, such as the silicones, added to solvents to reduce foam so that processing equipment can be used to capacity without spillover Antifoam 71, of General Electric, is a silicone emulsion that can be used in foodstuffs in proportions up to 100 parts per million Solvent-solvents are solvents used for second-stage extraction of difficult-to-extract metals such as gold, uranium, and thorium Tributyl phosphine oxide, (C4H9)3PO, a white, crystalline powder, is such a material used in benzene or kerosene solution for extracting metals from the acids employed in ore extraction The usual commercial solvents for organic substances are the alcohols, ether, benzene, and turpentine, the latter two being common solvents for paints and varnishes containing gums and resins The so-called coal-tar solvents are light oils from coal tar, distilling off between 293 and 356°F (145 and 180°C), with specific gravity 0.850 to 0.890 Solvent oils, from coal tar, are amber to dark liquids with distillation ranges from about 302 to 644°F (150 to 340°C), with specific gravity 0.910 to 0.980 They are used as solvents for asphalt varnishes and bituminous paints Shingle stains are amber to dark grades of solvent oils of specific gravity 0.910 to 0.930 A valuable solvent for rubbers and many other products is carbon bisulfide, CS , also called carbon disulfide, made by heating together carbon and sulfur It is flammable and toxic When pure, it is nearly odorless The specific gravity is 1.2927 and boiling point 116°F (46.5°C) Ethyl acetate, CH3COOC2H5, made from ethyl alcohol and acetic acid, is an important solvent for nitrocellulose and lacquers It is liquid, boiling at 171°F (77°C) Ashland Chemical Co makes it in three grades, containing 85 to 88, 99, and 99.5% ethyl acetate Some producers offer ethyl acetate solvent grades for urethanes One of the best solvents for cellulose is cuprammonium hydroxide Amyl and other alcohols, amyl acetate, and other volatile liquids are used for quick-drying lacquers, but many synthetic chemicals are available for such use Dioxan, a water-white liquid of specific gravity 1.035 and Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SOLVENT 877 composition CH2CH2OCH2CH2O, is a good solvent for cellulose compounds, resins, and varnishes, and is used also in paint removers, which owe their action to their solvent power Dow Chemical Co makes a similar material, called diethylene ether Ferro Corp.’s brand is an uninhibited variety, 1,4-dioxane, that has a purity of 99.97% and comes packed under nitrogen Ethyl lactate, used as a solvent for cellulose nitrate, is a liquid with boiling point of 150°C and specific gravity of 1.03 Octyl alcohol, a liquid of composition CH3(CH2)6CH2OH, specific gravity 1.429, and boiling point of 383°F (195°C), has a high solvent power for nitrocellulose and resins Diafoam is a secondary octyl alcohol used as a defoaming agent in plastics and lacquers Methyl hexyl ketone, CH3(CH2)5COCH3, is a powerful, high-boiling-point solvent which also acts as a dispersing agent in inks, dyestuffs, and perfumes It is a water-white liquid boiling at 343°F (173°C) It is made by Penta Manufacturing Co The chlorinated hydrocarbons have powerful solvent action on fats, waxes, and oils and are used in degreasing Of major commercial significance are perchloroethylene (PCE), trichloroethylene (TCE), and 1,1,1-trichloroethane (1,1,1-TCA) The biggest industrial use of PCE, also known as tetrachloroethylene and Perc, is as a dry-cleaning solvent because of its nonflammability, and high solvency, vapor pressure, and stability The largest applications of TCE and 1,1,1-TCA have been in metal cleaning, which also consumes significant quantities of PCE Because 1,1,1-TCA has been implicated in ozone depletion of the stratosphere, its use is being discontinued Hydrofluoroether-based solvents have similar boiling points to 1,1,1-TCA and CFC-113 and are possible alternatives to 1,1,1-TCA Actrel ED, of Exxon Chemical, is a line of non-ozonedepleting solvents for cleaning electronics These specially processed hydrocarbons are effective in removing resin residues from printedcircuit boards and other organic and ionic contaminants from electronic components Water is a solvent for most acids and alkalies and for many organic and inorganic materials Acids or alkalies that decompose the material are not solvents for the material Solvents are used to produce a solution that can be applied, as in the case of paints, and the evaporation of the solvent then leaves the material chemically unchanged They may also be employed to separate one substance from another, by the selection of a solvent that dissolves one substance but not the other Dichlorethyl ether, a yellowish liquid with a chloroformlike odor, of composition ClCH2CH2OCH2CH2Cl, is a good solvent for fats and greases and is used in scouring solutions and in soaps Dichlorethylene is a liquid of composition C2H2Cl2, specific gravity 1.278, and boiling point Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 878 SOLVENT about 126°F (52°C) It is used as a solvent for the extraction of fats and for rubber Dichloromethane, known also as methylene chloride and carrene, is a colorless, nonflammable liquid of composition CH2Cl2, boiling at 104°F (39.8°C) It is soluble in alcohol and is used in paint removers, as a dewaxing solvent for oils, for degreasing textiles, and as a refrigerant A low-boiling solvent for oils and waxes is butyl chloride, CH3CH2CH2CH2Cl It is a water-white liquid of specific gravity 0.8875, boiling at 173°F (78.6°C) Isocrotyl chloride is a liquid of composition CH3:C(CH2)2 и CHCl, with specific gravity 0.919 and boiling point 154°F (68°C), used for cleaning and degreasing Cyclohexane, (CH2)6, made by the hydrogenation of benzene, is a good solvent for rubbers, resins, fats, and waxes It is a water-white, highly flammable liquid of specific gravity 0.777, boiling point 177°F (80.8°C), and flash point 10°F (Ϫ12°C) This solvent is marketed in England as Sextone Nadene of Allied-Signal Co is cyclohexanone, CH2(CH2)4C и O It is a powerful general solvent, and is used as a coupling agent for immiscible compounds The Sulfolanes of Shell Oil Co are selective solvents for separating mixtures having different degrees of saturation, and they can be removed easily by water wash Dimethyl sulfolane is produced from pentadiene by reacting with SO2 and hydrogenation Cyclohexanol, also called hexalin and hexahydrophenol, C6H11OH, is a solvent for oils, gums, waxes, rubber, and resins It is made by the hydrogenation of phenol, and is a liquid, boiling at 316°F (158°C) Dichlorethyl, CH2(OCH2 и CH2 и Cl)2, is a water-insoluble highboiling solvent for cellulose, fats, oils, and resins The boiling point is 424°F (218°C), and specific gravity 1.234 The nitroparaffins constitute a group of powerful solvents for oil, fats, waxes, gums, and resins Blended with alcohols, they are solvents for cellulose acetate, producing good flow and hardening properties for nonblushing lacquers Nitromethane, CH3NO2, is a water-white liquid, with specific gravity 1.139, boiling point 214°F (101°C), and freezing point Ϫ20°F (Ϫ29°C) It is also used as a rocket fuel At 500°F (260°C) it explodes into a hot mixture of nitrogen, hydrogen, carbon monoxide, carbon dioxide, and water vapor, but with a catalyst the disintegration can be controlled into a smooth, continuous explosion Nitrofuel is an industrial grade used in automobile racing and in model engines It is also a raw material for chemical synthesis and a stabilizer for halogenated alkanes Nitrofuel is made by Angus Chemical Co Nitroethane, CH3CH2NO2, has a specific gravity 1.052, boiling point 237°F (114°C), and freezing point Ϫ130°F (Ϫ90°C) Because of the ozone depletion potential and health and environmental concerns regarding chlorine solvents, various compounds for Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses SOLVENT 879 cleaning with aqueous and semiaqueous solvents have come about NST, a low-temperature polyethylene glycol ether with sodium pyrophosphate, of Oakite Products Inc., is used for ultrasonic cleaning of aluminum, copper, and brass parts Micro, a high-temperature sulfonated compound with ethylenediamine tetracetic acid, of International Products Corp., is applied in ultrasonic cleaning of iron and steel parts A blend of Solvent 140, a high-flash-point hydrocarbon mineral spirit, and 5% dipropylene glycol methyl ether (DPM) is effective in manually cleaning 304L stainless steel Adding DPM makes the water-immiscible solvent miscible with water, enhancing its ability to displace waterborne machining coolants Both the 140 and blend are flammable and slow to evaporate, however, necessitating special precautions Zestron solvents, of Dr O K Wack Chemie GmbH of Germany, use propylene glycol ether, have a boiling point of about 338°F (170°C), and are used to clean circuit boards in electronics production A semiaqueous system of Dow Europe uses modified propylene glycol ethers for this application In the United States, Dow offers semiaqueous solvent Dowanol PX-165, which contains polar and nonpolar molecules, is nontoxic and biodegradable, and has no ozone depletion potential BASF AG of Germany offers semiaqueous cleaning solvents based on n-methyl pyrrolidine, a nonhalogenated solvent with a boiling point of 395°F (201°C) said to be a suitable alternative to methyl chloroform for degreasing and to methylene chloride for paint stripping Oxsol, from Occidental Chemical, combines benzotrifluorides, monochlorotoluene, and perchloroethylene It is not ozone depleting and seems suitable for various cleaning tasks Dow Chemical’s Invert solvents 1000, 2000, and 5000 feature reduced solvent and volatile organic compounds, and can serve as replacements for many chlorinated solvents The 1000 and 5000 are based on aliphatic hydrocarbons, and the 2000 is turpene-based Not being boilable, however, they are not suitable for vapor degreasing Purasolv solvents, from Purac America, are lactate esters derived from natural lactic acid and alcohols They are biodegradable, toxicologically and environmentally safe, not ozone depleting, and recyclable by vacuum distillation for reuse in degreasing They are strong solvents for polar and nonpolar substances, leave no residue on drying, and are effective for removal of high-solids coatings, photoresists, and rosin-containing fluxes Grades include ML methyl lactate, EL and ELS ethyl lactates, and BL butyl lactates, with boiling points of 291 to 372°F (144 to 189°C) and flash points of 131 to 174°F (55 to 79°C) A plasticizer is a liquid or solid that dissolves in or is compatible with a resin, gum, or other material and renders it plastic, flexible, or easy to work A sufficient quantity of plasticizer will result in a viscous Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website ... a 10-mesh and be retained on a 28-mesh screen; No through a 6-mesh and be retained on a 14-mesh screen; No should pass through a 4-mesh and be retained on an 8-mesh screen Number sand is used... is added, the product is called hard rubber Vapor-cured rubber is rubber vulcanized by sulfur chloride fumes and neutralized with magnesium carbonate It is used for thin goods only Acid-cured rubber... made into a foil and then welded, brazed, or adhesive-bonded can be made into a cellular core A number of materials are used, including aluminum, glass-reinforced plastics, and paper Tubulam