Materials Handbook 15th ed - G. Brady_ H. Clauser_ J. Vaccari (McGraw-Hill_ 2002) Episode 4 docx

lard and pork products. The clove tree attains a height up to 40 ft (12.2 m), bearing in 7 or 8 years, and continuing to bear for a century, yielding 8 to 10 lb (3.6 to 4.5 kg) of dried cloves annually. Clove stems are also aromatic, but contain only 5 to 6% oil of interior value. Clove was one of the most valued spices of medieval times. It grew origi- nally only on five small islands, the Moluccas, in a volcanic-ash soil, and was carried by Chinese junks and Malayan outriggers to India from whence the Arabs controlled the trade, bringing the tree also to Zanzibar. The Victoria of Magellan’s fleet returned to San Lucar with 26 tons (24 metric tons) of cloves, enough to pay for the loss of the other four ships and the expenses of the voyage around the world. COAL. A general name for a black mineral formed of ancient vegetable matter, and employed as a fuel and for destructive distillation to obtain gas, coke, oils, and coal-tar chemicals. Coal is composed largely of car- bon with smaller amounts of hydrogen, nitrogen, oxygen, and sulfur. It was formed in various geological ages and under varying conditions, and it occurs in several distinct forms. Peat is the first stage, followed by lignite, bituminous coal, and anthracite, with various intermediate grades. The mineral is widely distributed in many parts of the world. The value of coal for combustion purposes is judged by its fixed carbon content, volatile matter, and lack of ash. It is also graded by the size and percentage of lumps. The percentage of volatile matter declines from peat to anthracite, and the fixed carbon increases. A good grade of coal for industrial powerplant use should contain 55 to 60% fixed car- bon and not exceed 8% ash. The heating value should be 13,500 to 14,000 Btu/lb (31,400 to 33,700 kJ/kg). Finely ground coal, or pow- dered coal, is used for burning in an air blast like oil, or it may be mixed with oil. Coal in its natural state absorbs large amounts of water and also, because of impurities and irregular sizes, is not so efficient a fuel as the reconstructed coal made by crushing and briquetting lig- nite or coal and waterproofing with a coating of pitch. Anthracite powder is used as a filler in plastics. Carb-O-Fil, of Shamokin Filler Co., is powdered anthracite in a range of particle sizes used as a car- bonaceous filler. It has a plasticizing effect. It can also be used to replace carbon black in phenolic resins. Low-sulfur coal burns cleaner than regular coal, but its heating value is much less so that it is uneconomical as a fuel. A conversion process developed by SGI International Inc., however, can raise the heating value of a 8,300 Btu/lb (19,000 kJ/kg) low-sulfur coal to about 12,000 Btu/lb (28,000 kJ/kg). The process involves crushing the coal, removing its moisture, drying, and pressurizing at 1000°F (538°C). Pressurizing at this temperature releases volatile gaseous material, which can be condensed to coal liquids and sold as industrial fuel. 240 COAL 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 Increasing amounts of coal are being used for the production of gas and chemicals. By the hydrogenation of coal much greater quantities of phenols, cresols, aniline, and nitrogen-bearing amines can be obtained than by means of by-product coking, and low grades of coal can be used. The finely crushed coal is slurred to a paste with oil, mixed with a catalyst, and reacted at high temperature and pressure. Synthesis gas, used for producing gasoline and chemicals, is essen- tially a mixture of carbon monoxide and hydrogen. It is made from low-grade coals. The pulverized coal is fed into a high-temperature reactor with steam and a deficiency of oxygen, and the gas produced contains 40% hydrogen, 40 carbon monoxide, 15 carbon dioxide, 1 methane, and 4 inert materials. It is made by passing steam through a bed of incandescent coke to form a water gas of about equal propor- tions of carbon monoxide and hydrogen. It is made from natural gas. COATED FABRICS. The first coated fabric was a rubberized fabric produced in Scotland by Charles Mackintosh in 1823 and known as Mackintosh cloth for rainwear use. The cloth was made by coating two layers of fabric with rubber dissolved in naphtha and pressing them together, making a double fabric impervious to water. Rubberized fabrics are made by coating fabrics, usually cotton, with compounded rubber and passing between rollers under pressure. The vulcanized coating may be no more than 0.003 in (0.008 cm) thick, and the resultant fabric is flexible and waterproof. But most coated fabrics are now made with synthetic rubbers or plastics, and the base fabric may be of synthetic fibers, or a thin plastic film may be laminated to the fabric. Coated fabrics now have many uses in industrial applications, and the number of variations with different resins and backing materials is infinite. They are usually sold under trade names and are used for upholstery, linings, rainwear, bag covers, book covers, tarpaulins, out- erwear, wall coverings, window shades, gaskets, and diaphragms. Vinyl-type resins are most commonly used, but for special purposes other resins are selected to give resistance to wear, oils, or chemicals. The coated fabric of Reeves Bros., Inc., called Reevecote, for gaskets and diaphragms, is a Dacron fabric coated with Kel-F fluorocarbon resin. An industrial sheeting of Auburn Mfg. Co. is a cotton fabric coated with urethane rubber. It is tough, flexible, and fatigue-resistant, and it gives 10 times better wear resistance than natural rubber. Vinyl-coated fabrics are usually tough and elastic and are low- cost, but unless specially compounded are not durable. Many plastics in the form of latex or emulsion are marketed especially for coating textiles. Rhoplex WN-75 and WN-80, of Rohm & Haas Co., are water dispersions of acrylic resins for this purpose. Coatings cure at room temperature, have high heat and light stability, give softness and COATED FABRICS 241 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 flexibility to the fabric, and withstand repeated dry cleaning. A water emulsion of a copolymer of vinyl pyrrolidone with ethyl acrylate forms an adherent, tough, and chemical-resistant coating. Geon latex, of Geon Co., is a water dispersion of polyvinyl chloride resin. Polyvinyl chloride of high molecular weight is resistant to staining, abrasion, and tearing and is used for upholstery fabrics. The base cloth may be of various weights from light sheetings to heavy ducks. They may be embossed with designs to imitate leather. The Boltaflex cape vinyl, of DiversiTech General, is a rayon fabric coated with a vinyl resin embossed with a leatherlike grain. It has the appearance, feel, and thickness of a split leather and, when desired, is impregnated with a leather odor. One of the first upholstery fabrics to replace leather was Fabrikoid, of Du Pont. It was coated with a cellulose plastic and came in various weights, colors, and designs, especially for automo- bile seating and book covers. Armalon is twill or sateen fabric coated with ethylene plastic for upholstery. For some uses, such as for draperies or industrial fabrics, the fabric is not actually coated, but is impregnated, either in the fiber or in the finished cloth, to make it water-repellent, immune to insect attack, and easily cleaned. Tontine, of Stauffer Chemical Co., is a plastic-impregnated fabric for window shades. The Fairprene fabrics, also of Du Pont, are cotton fabrics coated with chloroprene rubber or other plastics. Corfam, of the same company, used as a leather substitute, is a nonwoven sheet of urethane fibers reinforced with polyester fibers, with a porous tex- ture. The fabric can be impregnated or coated. Terson voile, of Athol Mfg. Co., for umbrellas, rainwear, and industrial linings, is a sheer-weight rayon coated with a vinyl resin. It weighs 2 oz/yd 2 (0.07 kg/m 2 ). Coated fabrics may also be napped on the back, or coated on the back with a flock, to give a more resilient backing for upholstery. Impregnated fabrics may have only a thin, almost undetectable surface coating on the fibers to make them water-repellent and immune to bacterial attack, or they may be treated with fungicides or with flame-resistant chemicals or waterproofing resins. Stabilized fabrics, however, are not waterproofed or coated, but are fabrics of cotton, linen, or wool that have been treated with a water solution of a urea formaldehyde or other thermosetting resin to give them greater resiliency with resistance to creasing and resistance to shrinking in washing. Shrinkproof fabrics are likewise not coated fabrics, but have a light impregnation of resin that usually remains only in the core of the fibers. The fabric retains its softness, texture, and appearance, but the fibers have increased stability. Various resin materials are marketed under trade names for creaseproofing and 242 COATED FABRICS 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 shrinkproofing fabrics, such as Lanaset, a methylomelamine resin of American Cyanamid Co., and Synthrez, a methylourea resin of Synthron, Inc. Under the general name of protective fabrics, coated fabrics are now marketed by use characteristics rather than by coating designa- tion since resin formulations vary greatly in quality. For example, the low-cost grades of vinyl resins may be hard and brittle at low temper- atures and soft and rubbery in hot weather, and thus unsuitable for all-weather tarpaulins. Special weaves of fabric are used to give high tear strength with light weight, and the plastic may be impregnated, coated on one side or both, bonded with an adhesive or electronically bonded, or some combination of all these. Flame resistance and static- free qualities may also be needed. Many companies have complete lines to meet definite needs. The Coverlight fabrics of Reeves Bros., Inc., which come in many thicknesses and colors, are made with coat- ings of neoprene, Hypalon, or vinyl chloride resin, with weights from 6 to 22 oz/yd 2 (0.18 to 0.67 kg/m 2 ) and widths up to 72 in (1.8 m). The H.T.V. Coverlight is a high-tear-resistant nylon fabric with specially formulated vinyl coating. The 22-oz (0.62-kg) grade for such heavy- duty, all-weather uses as truck-trailer covers and concrete-curing cov- ers remains flexible at temperatures down to Ϫ50°F (Ϫ46°C). COBALT AND COBALT ALLOYS. A white metal, Co, resembling nickel but with a bluish tinge instead of the yellow of nickel. It is rarer and costlier than nickel, and its price has varied widely in recent years. Although allied to nickel, it has distinctive differences. It is more active chemically than nickel. It is dissolved by dilute sulfuric, nitric, or hydrochloric acid and is attacked slowly by alkalies. The oxidation rate of pure cobalt is 25 times that of nickel. Its power of whitening copper alloys is inferior to that of nickel, but small amounts in nickel- copper alloys will neutralize the yellowish tinge of the nickel and make them whiter. The metal is diamagnetic like nickel, but has nearly 3 times the maximum permeability. Like tungsten, it imparts red-hardness to tool steels. It also hardens alloys to a greater extent than nickel, especially in the presence of carbon, and can form more chemical compounds in alloys than nickel. Cobalt has a specific gravity of 8.756, a melting point of 2723°F (1495°C), Brinell hardness 85, and an electrical conductivity about 16% that of copper. The ultimate tensile strength of pure cast cobalt is 34,000 lb/in 2 (234 MPa), but with 0.25% carbon it is increased to 62,000 lb/in 2 (427 MPa). Strength can be increased slightly by anneal- ing and appreciably by swaging or zone refining. The metal is used in tool-steel cutters, in magnet alloys, in high-permeability alloys, and as a catalyst; and its compounds are used as pigments and for producing many chemicals. The metal has two forms: a close-packed hexagonal COBOLT AND COBALT ALLOYS 243 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 crystal form, which is stable below 782°F (417°C), and a cubic form stable at higher temperatures to the melting point. Cobalt has valences of 2 and 3, while nickel has only a valence of 2. The natural cobalt is cobalt 59, which is stable and nonradioactive, but the other isotopes from 54 to 64 are all radioactive, emitting beta and gamma rays. Most have very short life, except cobalt 57 which has a half-life of 270 days, cobalt 56 with a half-life of 80 days, and cobalt 58 with a half-life of 72 days. Cobalt 60, with a half-life of 5.3 years, is used for radiographic inspection. It is also used for irradiat- ing plastics and as a catalyst for the sulfonation of paraffin oils, since gamma rays cause the reaction of sulfur dioxide and liquid paraffin. Cobalt 60 emits gamma rays of 1.1- to 1.3-MeV energy, which gives high penetration for irradiation. The decay loss in a year is about 12%, the cobalt changing to nickel. Cobalt metal is marketed in rondels, or small cast slugs, in shot and anodes, and as a powder. Powders with low nickel content for making cobalt salts and catalysts are in particle sizes down to 39 ␮in (1 ␮m). About one-quarter of the supply of cobalt is used in the form of oxides and salts for driers, ceramic frits, and pigments. Cobalt carbonyls are used for producing cobalt powder for use in powder metallurgy, as catalysts, and for producing cobalt chemicals. Dicobalt octacarbonyl, Co 2 (CO) 8 , or cobalt tetracarbonyl, is a brownish powder melting at 123°F (51°C) and decomposing at 140°F (60°C) to tetracobalt dodecacarbonyl, (CoCO 3 ) 4 , a black powder which oxidizes in the air. The best-known cobalt alloys are the cobalt-base superalloys used for aircraft-turbine parts. The desirable high-temperature proper- ties of low creep, high stress-rupture strength, and high thermal-shock resistance are attributed to cobalt’s allotropic change to a face-centered cubic structure at high temperatures. Besides containing 36 to 65% cobalt, usually more than 50%, most of these alloys also contain about 20 chromium for oxidation resistance and substantial amounts of nickel, tungsten, tantalum, molybdenum, iron and/or aluminum, and small amounts of still other ingredients. Carbon content is in the 0.05 to 1% range. These alloys include L-605; S-816; V-36; WI-52; X-40; J-1650; Haynes 21 and 151; AiResist 13, 213, and 215; and MAR-M 302, 322, and 918. Their 1,000-h stress-rupture strengths range from about 40,000 lb/in 2 (276 MPa) to 70,000 lb/in 2 (483 MPa) at 1200°F (649°C) and from about 4,000 lb/in 2 (28 MPa) to 15,000 lb/in 2 (103 MPa) at 1800°F (982°C). Cobalt is also an important alloying element in some nickel-base superalloys, other high-temperature alloys, and alloy steels. Besides tool steels, the maraging steels are a good example. Although cobalt-free grades have been developed, due to the scarcity of this metal at times, most maraging steels contain cobalt, as much as 12%. Cobalt 244 COBALT AND COBALT ALLOYS 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 is also a key element in magnet steels, increasing residual magnetism and coercive force, and in nonferrous-base magnetic alloys. An important group of cobalt alloys is the Stellites. These alloys include the relatively low-carbon Stellite 21 with 28% chromium, 5.5 molybdenum, 2.5 nickel, 2 iron, 2 silicon, 1 manganese, and 0.25 carbon; and Stellite 306 with 25 chromium, 6 columbium, 5 nickel, 2 tungsten, and 0.4 carbon. There are also high-carbon (1 to 3.3) alloys Stellite 1, 3, 6, 12, 190, and F, which contain 25 to 31% chromium, 4 to 14.5 tungsten, 3 iron, 2.5 to 3 nickel (22 in Stellite F), 1 to 1.5 molybdenum, 1 to 1.4 manganese, and 0.7 to 2 silicon. Stellite 3 also has 0.1% boron. These alloys excel in resistance to abrasion, corrosion, and heat and are used for weld overlays, or hardfacings, and cast parts in the power-generating, steel-produc- ing, chemical processing, and petroleum industries. Ultimet, 54 cobalt, 26 chromium, 9 nickel, 5 molybdenum, 3 iron, 2 tungsten, 0.8 manganese, 0.3 silicon, 0.08 nitrogen, and 0.06 carbon, combines the wear resistance of the Stellites and the corrosion resistance of the Hastelloys. Solution-heat-treated sheet, 0.063 in (1.6 mm) thick has an ultimate tensile strength of 138,000 lb/in 2 (952 MPa), 72,000 lb/in 2 (496 MPa) yield strength, and 42% elongation at room temper- ature and 120,000 lb/in 2 (827 MPa), 41,000 lb/in 2 (283 MPa), and 76% respectively, at 800°F (427°C). Room-temperature V-notch impact strength is 130 ft . lb (176 J). The interesting properties of cobalt-containing permanent, soft, and constant-permeability magnets are a result of the electronic configu- ration of cobalt and its high curie temperature. In addition, cobalt in well-known Alnico magnet alloys decreases grain size and increases coercive force and residual magnetism. Cobalt is a significant element in many glass-to-metal sealing alloys and low-expansion alloys. One iron-base alloy containing 31% nickel and 5 cobalt provides a lower coefficient of thermal expan- sion than the iron–36% nickel alloy called Invar and is less sensitive to variations in heat treatment. Cobalt-chromium alloys are used in dental and surgical applications because they are not attacked by body fluids. Alloys named Vitallium are used as bone replacements and are ductile enough to permit anchoring of dentures on neighbor- ing teeth. They contain about 65% cobalt. BioDur CCM alloy, of Carpenter Technology, is a wrought version of the cast ASTM F75 cobalt alloy and is used for surgical implants. It is a vacuum-melted and electroslag-remelted product containing 26 to 30% chromium, 5 to 7 molybdenum and maximum amounts of 1 nickel, 1 silicon, 1 man- ganese, 0.75 iron, 0.25 nitrogen, and 0.1 carbon. BioDur CCM Plus alloy is a wrought powder-metallurgy product with the same COBALT AND COBALT ALLOYS 245 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 chromium and molybdenum contents, 0.2 to 0.3 carbon, and 0.15 to 0.2 nitrogen for similar applications. However, it is a more forgeable and machinable alloy. Cobalt is a necessary material in human and animal metabolism, and it is used in fertilizers in the form of cobaltous carbonate, CoCO 3 , in which form it is easily assimilated. This form occurs in nature in the mineral cobalt spar and is mixed with magnesium and iron carbonates. Cobaltous citrate, Co(C 6 H 5 O 7 ) и 2H 2 O, is a rose-red powder soluble in water, used in making pharmaceuticals. Cobaltous fluorosilicate, CoSiF 6 и H 2 O, is an orange-red, water-soluble powder used in toothpastes. It furnishes fluorine and silica as well as cobalt. Cobaltous hydroxide, Co(OH) 2 , has a high cobalt content, 61.25%, is stable in storage, and is used for paint and ink driers and for mak- ing many other compounds. Cobaltous chloride, CoCl 2 , a black pow- der, is an important cobalt chemical. It is used as a humidity indicator for silica gel and other desiccants. As the desiccant becomes spent, the blue of the cobaltous chloride changes to the pink color of the hexahydrate; but when the material is regenerated by heating to drive off the moisture, the blue reappears. Cobalt metal may be obtained from the sulfur and arsenic ores by melting and then precipitating the cobaltous hydroxide powder which is high in cobalt, has high stability in storage, and is readily converted to the metal or the oxide or used directly for driers and other applications. The chief cobalt ores are cobalite and smaltite. Cobalite, or cobalt glance, from Ontario and Idaho, is a sul- farsenide, CoAsS, and occurs with gersdorffite, NiAsS. Another sul- fide is linnaeite, Co 3 S 4 , containing theoretically 58% cobalt, but usually containing also nickel and iron. Cobalt is also found with pyrites as the mineral bieberite, which is cobaltous sulfate, CoSO 4 и 7H 2 O, but combined with iron sulfate. Some cobalt is extracted from the iron pyrites of Pennsylvania, the concentrated pyrite containing 1.41% cobalt, 42 iron, and 0.28 copper. Erythrite is a hydrous cobalt arsenate occurring in the smaltite deposits of Morocco. Skutteru-dite also occurs in Morocco. It is a silvery-gray, brittle mineral of composition (CoNiFe)AS 3 , with a specific gravity of 6.5 and Mohs hardness of 6. Asbolite, an important ore in Shaba and New Caledonia, is a soft mineral, hardness Mohs 2, consisting of varying mixtures of cobaltif- erous manganese and iron oxides. A number of minerals classified as heterogenite, black and containing only cobalt and copper, occur in copper deposits, especially in Shaba. Among these are mindigite, 2Co 2 O 3 и CuO и 3H 2 O, and trieuite, 2Co 2 O и CuO и 6H 2 O. Carrollite, CuS и Co 2 S 3 , a steel-gray mineral with a specific gravity of 4.85 and hardness of 5.5, is an important ore in Zimbabwe. The copper ores of 246 COBALT AND COBALT ALLOYS 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 Congo and Zimbabwe form one of the chief sources of commercial cobalt. Some of the metal is exported as white alloy, containing 40% cobalt, 9 copper, and the balance iron. Cobalt occurs naturally in many minerals, and the metal may be considered as a by-product of other mining. Small quantities are produced regularly as a by-product of zinc production in Australia, although the cobalt content of the con- centrate is only 0.015%. Some cobalt is obtained from the lead and zinc ores of Missouri. Its relative scarcity is a matter of cost of extraction. High-purity cobalt can be produced from lower-grade cobalt, such as that containing copper, iron, and zinc impurities, by an electrolytic process developed by the U.S. Bureau of Mines. The lower-grade cobalt is dissolved at the anode, generating a cobalt-chloride anolyte, while the high-purity metal plates out at the cathode. An ionic double membrane in the cell allows only chloride ions to migrate to the cath- ode. The anolyte is continuously removed, impurities are separated by cementation and solvent extraction, and the purified solution flows to the cathode side of the cell. The process is aimed at upgrading lower-grade material in the U.S. stockpile to Grade A cobalt, which is at least 99.85% pure. COBALT OXIDE. A steel-gray to blue-black powder employed as a base pigment for ceramic glazes on metal, as a colorant for glass, and as a chemical catalyst. It gives excellent adhesion to metals and is valued as an undercoat for vitreous enamels. It is the most stable blue, as it is not changed by ordinary oxidizing or reducing conditions. It is also one of the most powerful colorants for glass, 1 part in 20,000 parts of a batch giving a distinct blue color. Cobalt oxide is produced from the cobalt-nickel and pyrite ores, and the commercial oxide may be a mixture of the three oxides. Cobaltous oxide, CoO, is called gray cobalt oxide but varies from greenish to reddish. It is the easi- est to reduce to the metal, and it reacts easily with silica and alumina in ceramics. Cobaltic oxide, Co 2 O 3 , occurs in the mixture only as the unstable hydrate, and it changes to the stable black cobalt oxide, or cobalto-cobaltic oxide, Co 3 O 4 on heating. Above about 1652°F (900°C) this oxide loses oxygen to form cobaltous oxide. Cobalt dioxide, CoO 2 , does not occur alone, but the dioxide is sta- ble in combination with other metals. The blue-black powder called lithium cobaltite, LiCoO 2 , is used in ceramic frits to conserve cobalt, since the lithium adds fluxing and adherent properties. The pigment known as smalt, and as royal blue and Saxon blue, is a deep-blue powder made by fusing cobalt oxide with silica and potas- sium carbonate. It contains 65 to 71% silica, 16 to 21 potash, 6 to 7 cobalt oxide, and a little alumina. It is used for coloring glass and for COBALT OXIDE 247 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 vitreous enameled signs, but does not give good covering power as a paint pigment. Thenaud’s blue is made by heating together cobalt oxide and aluminum oxide. Rinmann’s green is made by heating together cobalt oxide and zinc oxide. COCAINE. An alkaloid derived from the leaves of the coca shrub. It is used as a local anesthetic and as a narcotic. It is habit-forming. In small and moderate doses it is stimulating and increases physical energy. Depression usually follows. Continued heavy use of cocaine has debilitating effects on the nervous system and can lead to insan- ity. Cocaine crystallizes from alcohol and is readily soluble in ordinary solvents except water. In the manufacture of cocaine, the alkaloids of coca leaves are hydrolyzed to ecgonine. COCHINEAL. A dyestuff of animal origin, which before the advent of coal-tar dyes was one of the most important coloring materials. Cochineal is the female of the Coccus cacti, an insect that feeds on various species of cactus, Nopalea coccinellifera, of Mexico. The insects have no wings, and at the egg-laying season they are brushed off the plants, killed by boiling, and dried; or they are bagged in linen and dried in an oven, preserving a peculiar white down covering the insect. They are dark reddish brown. Cochineal contains 10 to 20% pure coloring matter, carminic acid, mostly in the eggs, from which the carmine red, C 11 H 12 O 7 , is obtained by boiling with mineral acid. Carmine red produces brilliant lake colors of various hues with differ- ent metals. Commercial cochineal may be adulterated with starch, kaolin, red lead, or chrome lead. The brilliant red pigment known as carmine lake is made by precipitating a mixture of cochineal and alum, and a fiery scarlet is obtained by treating with stannous and stannic chlorides. Salmonella-free cochineal in water solution is now used in foods to give a reddish-purple color. A species of cochineal insect that feeds on the leaves of the tamarisk tree, Tamarix mani- fera, produces manna, a viscous, white, sweet substance composed mostly of sugars. It forms in small balls and falls usually in May to July. When dry, it is hard and stable and is a good food. It is native to the Near East. COCOA BEANS. The seed beans from the large fruit pods of the cacao tree, Theobroma cacao, native to Mexico, and T. leiocarpum, native to Brazil. The tree was cultivated in Mexico from ancient times, and the beans were used by the Aztecs to produce a beverage called choclatl which contained the whole substance of the fermented and roasted bean flavored with vanilla. Cocoa beans are now produced in many countries, and the United States imports them from about 40 countries. Ghana, 248 COCAINE 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 Nigeria, and Brazil are noted producers. The flavor and aroma vary with soil and climate, and differences in curing methods also produce differences in the beans, so that types and grades are best known by the shipping ports and districts in which they grow. Mico coca is wild cocoa of Central America. The beans are smaller and are noted for fine flavor. Cocoa beans are shipped dried but not roasted. They are roasted just before use to develop the flavor, to increase the fat content, and to decrease the tannin content. The hard shells are removed, and the roasted seeds are ground and pressed to produce bitter chocolate, generally known as chocolate liquor. Sweet chocolate is made by adding sugar and flavoring, usually vanilla. Cocoa, for beverage pur- poses, is made by removing about 60% of the fatty oil from chocolate by hydraulic pressing and powdering the residue, to which is usually added ground cocoa shells. The removed fatty oil is cocoa butter, used for bakery products, cosmetics, and pharmaceuticals. A hundred pounds of cocoa beans yields 48 lb (21.8 kg) of chocolate powder, 32 lb (14.5 kg) of cocoa butter, and 20 lb (9.1 kg) of waste. Also an artificial cocoa butter is made by fractionating palm kernel oil. Pakena, a substi- tute cocoa butter, contains 53% lauric acid, 21.5 myristic, 12 palmitic, 8 oleic, 3.5 stearic, and 2 capric acids. Besides fat, chocolate contains much starch and protein and has high food value, but is not as stimulat- ing as the cocoa since the alkaloid is largely contained in the waste and shells. These contain 1 to 1.5% theobromine and are used for the syn- thetic production of caffeine. The chocolate is used in the manufacture of confectionery, chocolate bars, bakery products, and flavoring syrups. Microfine cocoa, used for bakery products, is ground to 325 mesh and contains from 9 to 16% cocoa butter. Postonal is a German substitute for cocoa butter for pharmaceuticals. It is a polymerized ethylene oxide containing chemically combined castor oil. Cocoa powder, used in the United States for beverages and for adding chocolate flavor to foodstuffs, as distinct from the sweet choco- late used in Latin countries for beverages, was originally made from the shells, but is now made from the residue cake after extraction of the chocolate liquor and the pressing out of the cocoa butter. It is widely used as a flavor for cakes and confectioneries. Sugar makes the powder easily soluble in water; instant cocoa is cocoa powder processed with about 70% sugar and sometimes with nonfat milk pow- der. The fat content of commercial cocoa powders ranges from 6 to 22% with a color range from light brown to reddish black. Breakfast cocoa is the high-fat grade. Cocoa powder is usually acidic with the pH as low as 3.3, but Dutch cocoa, for nonacid foods, is stabilized cocoa with the pH raised to as high as 9.0 by treatment with solu- tions of sodium or potassium carbonate. COCOA BEANS 249 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 [...]... represented by the C10XXX to C15XXX series of copper and copper alloy numbers of the Copper Development Association These include oxygen-free coppers, oxygen-free-with-silver coppers, and oxygen-bearing coppers (C10100 to C10 940 ); electrolytic-tough-pitch coppers and tough-pitch-with-silver coppers (C11100 to C11907); phosphorus-deoxidized coppers, fire-refined tough-pitch coppers, and fire-refined tough-pitch-with-silver... and poured into a mold without pressure They give finer detail than plasters, do not crack or chip, and are lightweight, and the cured material can be nailed and finished like wood Water content can be varied from 50 to 80% Flat steel products produced by cold-rolling hot-rolled products The hot-rolled product is cleaned of oxide scale by pickling and passed through a cold-reduction mill to reduce and... commercial-quality (CQ) steel, which is produced from rimmed, capped, or semikilled steel; drawing-quality (DQ), which is made from specially processed steel and is more ductile and uniform in forming characteristics; and drawing-quality special-killed (DQSK) steel, which is still more ductile and more uniform in forming characteristics Cold-rolled structural-quality (SQ) steel refers to cold-rolled steel... classified as high-lead bronze, but Johnson bronze No 44 , for bearings, contains 88% copper, 4 tin, 4 lead, and 4 zinc The hardware bronze used for casting hardware and automobile fittings to be highly polished and plated is likely to be a true copper-zinc brass or a leaded brass with only a small amount of lead Oreide bronze, a term still used in the hardware industry, was the metal employed for carriage... used, allows service temperatures up to about 300°F ( 149 °C) Bismaleimide (BMI), which has replaced epoxy to some extent in military aircraft applications, permits use to about 350°F (177°C) Cycom 525 0 -4 , 5260, and 527 0-1 are BMIs from Cytec Fiberite The 525 0 -4 and toughened 5260 have service temperatures to about 350°F (177°C), the 527 0-1 to as high as 45 0°F (232°C) Cycom 525 0 -4 RTM is for resin-transfer-molding... tough-pitch-with-silver coppers (C12000 to C13000); and certain coppers distinguished by very small amounts of specific ingredients such as cadmium copper (not to be confused with the high-copper alloys having a greater cadmium content), tellurium-bearing copper, sulfur-bearing copper, zirconium copper, and aluminum-oxide-bearing coppers (Cl4XXX to Cl5XXX) The highest-purity grade, oxygen-free-electronic... Thermally conductive Konduit compounds, from LNP Engineering Plastics, are polymers modified with ceramic or carbon fiber The Nylon 6–modified PTF 21 2-1 1 and and polyphenylene-sulfide-modified OTF 21 2-1 1 have a through-plane conductivity of 0.58 Btu/h ft °F (1.0 W/mK), the polypropylene-modified MT 21 0-1 4 has 0.69 Btu/h.ft.°F (1.2 W/mK) Specific gravities range from 1.85 to 2.23, tensile strengths from... be produced In “dry winding,” tows of pregreg are used In “wet winding,” the tows or bands are first drawn through a resin bath C-Bar, or composite rebar, is a PMC bar developed by Marshall Industries Composites for reinforcing concrete Intended to compete with epoxy-coated steel rebar, it consists of a pultruded rod core of fiber-reinforced urethane-modified vinyl ester with a helically ribbed exterior... ingredients are columbium alloys B-3 and D- 14, each with 5% zirconium, and columbium alloy D-36, (10 titanium and 5 zirconium) B-66, FS-85, C-129, Cb-752, and SCb-291 are moderate in strength and ductility Others in this group are columbium alloy AS-55 (10% tungsten, 1 zirconium, and 0.06 yttrium), columbium alloy D -4 3 (10 tungsten, 1 zirconium, and 0.1 carbon), columbium alloy PWC-11 (1 zirconium and 0.1 carbon),... of plastic materi- als, and they were introduced into the United States in 1908 The materials fall into two general categories: inorganic or refractory materials, and organic or nonrefractory materials Inorganic cold-molded plastics consist of asbestos fiber filler and either a silica-lime cement or portland cement binder Clay is sometimes added to improve plasticity The silica-lime materials are easier . creaseproofing and 242 COATED FABRICS Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 20 04 The McGraw-Hill Companies. All rights reserved. Any. Coverlight is a high-tear-resistant nylon fabric with specially formulated vinyl coating. The 22-oz (0.62-kg) grade for such heavy- duty, all-weather uses as truck-trailer covers and concrete-curing. close-packed hexagonal COBOLT AND COBALT ALLOYS 243 Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 20 04 The McGraw-Hill Companies. All rights