ore of copper occurring in the oxidized parts of copper veins of Arizona and New Mexico. It is a hydrous copper silicate of composition CuSiO 3 и 2H 2 O. It occurs in compact masses with a specific gravity of 2 to 2.4 and a hardness of 2 to 4. The color is green to bluish. It was used as a green pigment by the ancient Greeks. Large reserves of this ore occur in Gambia and other copper regions of Africa, and it is treated by high-temperature methods to obtain the copper. Atacamite is an ore found in Bolivia, Arizona, and Australia. It is a copper chloride with copper hydroxide, CuCl 2 и 3Cu(OH) 2 , generally found in confused crystalline aggregates, fibrous or granular. The hardness is 3 to 3.5, specific gravity 3.75, and the color may be vari- ous shades of green. The unique copper ores of Japan, called kuromono, are complex sulfide-sulfate replacement minerals. Much native copper metal occurs in the Lake Superior region, par- ticularly in Michigan, but it occurs irregularly and not in continuous veins. The Ontonagon boulder of native copper in the National Museum, weighing 3 tons (2.7 metric tons), came from Michigan. A mass of native copper found in 1847 was 10 ft (3 m) long and weighed 6 tons (5.4 metric tons). The largest ever found weighed 18 tons (16.3 metric tons). COPPER OXIDE. There are several oxides of copper, but usually the term refers to red copper oxide, or cuprous oxide, Cu 2 O, a reddish crystalline powder formed by the oxidation of copper at high tempera- tures. It also occurs naturally in cuprite ore. The specific gravity is 6.0, and the melting point 2255°F (1235°C). It is insoluble in water but solu- ble in acids and alkalies. It is used in coloring glass and ceramics red, in electroplating, and in alternating-current rectifiers. Rextox, of Westinghouse Electric Corp., is copper upon which a layer of copper oxide has been formed. Electric current will flow easily from the oxide to the copper, but only with difficulty from the copper to the oxide. It may be used for transforming alternating current to pulsating direct current. Black copper oxide, or cupric oxide, CuO, is a brownish-black amor- phous powder of specific gravity 6.4 and melting point 1949°F (1065°C). It is used for coloring ceramics green or blue. In its natural ore form, it is called tenorite. Together with the red oxide, it is used as a copper paint for ships’ bottoms. Copper hydroxide, formed by the action of an alkali on the oxides, is a poisonous blue powder of composition Cu(OH) 2 and specific gravity 3.37. It is used as a pigment. COPPER STEEL. Steel containing up to 0.25% copper and very low in carbon, employed for construction work where mild resistance to cor- rosion is needed and where the cost of the more resistant chromium steels is not warranted. It is employed in sheet form for culverts, ducts, pipes, and such manufacturing purposes as washing-machine 280 COPPER OXIDE 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 boilers. The copper-bearing grade specified for culverts by the ASTM contains not less than 0.20% copper and not more than 0.10 carbon, manganese, phosphorus, sulfur, and silicon as impurities. The alloy steels containing considerable copper for special purposes are not classified as copper steels. The copper neutralizes the corroding influ- ence of the sulfur in the steel and aids in the formation of a fine- grained oxide that retards further corrosion. Copper is not added to unalloyed high-carbon steels because it causes brittleness and hot- shortness. Since the carbon content of copper steel is usually very low, the material is more a copper iron. Unless balancing elements, especially nickel, are present, more than 0.2% copper in steel may cause rolling defects. Molybdenum in small quantities may also be added to give additional corrosion resistance, and the percentage of carbon may be raised to 0.40% when about 0.05% molybdenum is added. Toncan iron has this composition and has a tensile strength of 40,000 to 48,000 lb/in 2 (276 to 331 MPa), elongation of 32 to 40%, and density of 0.283 lb/in 3 (7,833 kg/m 3 ). COPPER SULFATE. Also called bluestone, blue copperas, and blue vitriol. An azure-blue, crystalline, lumpy material of composition CuSO 4 и 5H 2 O and specific gravity 2.286. It is soluble in water and insoluble in alcohol. When heated, it loses its water of crystallization and melts at 302°F (150°C). In its natural form, called chalcanthite, it is a rare mineral found in arid regions and deposited from the water in copper mines. It is produced as a by-product in copper refineries, or by the action of sulfuric acid on copper or copper oxide. A major market for copper sulfate is agriculture, where it is used in fungicides, micronutrients for fertilizers and animal feeds, and seed treatment. In chemical processes, it is used as an algicide in water treatment, for separating sulfide ores, in electroplating, in froth flota- tion, in leather tanning and hide preservation, and as a raw material for other salts and dyes. It is a component of chromated copper arsenate, a mixture of potassium dichromate, copper sulfate, and arsenic pentoxide, a major wood preservative that is being phased out of commercial use due to its carcinogenic properties. CORAL. A shiny, hard, calcareous material valued for jewelry, buck- les, beads, and novelties. It is a growth composed of the skeletons of Corallium nobile and other species of aquatic protozoa. The struc- tures are built up by these creatures into forms like leafless trees or shrubs, fans, mushrooms, or cups. White coral is common and is not used commercially. The most valuable is red coral, a twiglike species that grows about 12 in (30 cm) high with thin stems. Pink coral and black coral are also valued. Red and pink corals come from the CORAL 281 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 Indian Ocean and off the coast of northeastern Africa. Black coral is from southeastern Asia. The red and black varieties are very hard and take a beautiful polish. The pink is softer, with a more delicate appearance, and is used for beads. The rate of growth of coral is very slow. The gleaming white sand of tropical beaches called coral sand is usually not coral, but consists of the disintegrated limy skeletons of the seaweed Halimeda opuntia. CORDAGE. A general term for the flexible string or line of twisted fibers used for wrapping, baling, power transmission, and hauling. Cordage fibers are any materials used for making ropes, cables, twine, and cord. In general, cordage fibers are hard compared with those used for weaving into fabrics, but cotton and some other soft fibers are used for cord. Twine is cordage less than 0.1875 in (0.48 cm) in diameter and is composed of two or more rovings twisted together. Rope is cordage made by twisting several yarns into strands and then twisting the strands into a line. A cable is a strong rope, usually referring to the large sizes of special construction. Cord is an indefi- nite term for twine but is, more specifically, the soft cotton twines used for wrapping. The term string is applied to the weak cotton cords used for wrapping light packages. Seaming twines are made of flax fibers. Seine twine is a three-strand cotton twine with 2 to 56 plies per strand. Most of the binder twine is made from sisal, but Indian twine is made from jute. Ramie fiber is used for marine twines. Binder twine has 15 turns per foot (49 turns per meter) and 500 ft/lb (336 m/kg). Baler twine, for heavier work, has 12 turns per foot (39 turns per meter) and 125 ft/lb (84 m/kg). Before the advent of synthetics, about half of American strong cordage was from Manila hemp and about 30% from sisal. Manila hemp is very resistant to sea- water. Sisal is used for the cheaper grades of rope, but it absorbs water easily. True hemp is considered a superior fiber for strong ropes. Untarred hemp rope is used for elevator cables, and tarred hemp is employed for ship cables. Marine rope, used by the Navy, was formerly true hemp, then Manila hemp, and is now often syn- thetic fiber. Most industrial rope has at least three strands, each strand having at least two yarns, and may be hard lay, medium lay, or soft lay. Twisting may be S twist or Z twist, conforming approximately to the shape of these letters. Cable twist has the twists alternating in each successive operation. Hawser twist, to give greater strength and resilience, has the plies twisted SSZ. Cordage fibers are also obtained from a wide variety of plants. Generally, after the fibers are retted, the softer and finer fibers are separated for use in weaving into fabrics and the harder and coarser fibers are marketed as cordage fibers. New Zealand hemp, or New 282 CORDAGE 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 Zealand flax, is a strong cordage fiber obtained from the leaves of the swamp lily Phormium tenax, grown in New Zealand and Argentina. The fibers are white, soft, and lustrous. One variety of the plant reaches a height of 16 ft (4.9 m) and the other variety 6 ft (1.8 m). Olona fiber, grown in Hawaii and used locally for fishnets, is from the nettle plant Touchardia latifolia. The bast fibers of the bark of the slender branches are soft and flexible, are very water-resistant, and have a tensile strength 3 times that of Manila hemp. Gravatá is a Brazilian name for the very long and resistant fibers from the leaves of the pineapple plant Ananas sagenaria. The leaves of this species are up to 7 ft (2.1 m) in length. The fiber known as widuri of Indonesia is bast fiber from the tree Calotropis gigantea which yields the madar kapok. It has great strength and is resistant to seawater. It is used for ropes and fishnets. Agel fiber is from the stems and leaves of the gebang palm of the Celebes where the various grades are used for sailcloth, rope, and fishnets; the coarser fibers are woven into Bangkok hats. The fibers from the leafstalks are fine and white. Caraguatá is a strong, highly resistant fiber from the plant Bromelia balansea of Paraguay. It is employed by the Indians for making ham- mocks, and is now used for cordage and burlap fabrics. Synthetic fibers are also used for cordage. Nylon rope is about twice as strong as Manila rope, is lighter, and because of its property of stretching rapidly but recovering slowly, it makes a desirable rope for lifting and towing, giving a smooth, shock-absorbing pull. Nylon ropes are used for pulling airplane gliders and for tugboat lines. Mylar rope, is made by slitting Mylar film and stretching and spin- ning the strands. A three-strand rope of 1-in (2.5-cm) diameter has a breaking strength of 18,000 lb/in 2 (124 MPa), compared to 9,000 lb/in 2 (62 MPa) for Manila rope of the same size. Moisture absorption is less than 0.3%. Elongation at 50% of breaking strength is about 4.75%. Saran rope, for chemical-plant use, is formed of three strands of vinylidene chloride monofilament. The breaking strength is 70% that of Manila rope, and it is flexible and chemical-resistant, but it is not recommended for temperatures above 170°F (77°C). M-cord is a strong wrapping twine made with a core of Manila fiber wrapped with a tough, smooth paper. Nylon and some other plastics have a tendency to fray in cordage and may be coated with polyvinyl butyral to give abrasion resistance. Chemclad is rayon cordage coated with poly- vinyl chloride. Nylon rope is steel-wire rope with an extruded coating of nylon in various colors, used for automotive brake cables, aircraft control cables, and luggage handles. Glass rope, woven from continu- ous filaments of glass fiber, is used for chemical and electrical applica- tions where resistance to chemicals or electrical insulation is needed. It is strong, but is expensive and has low flexing strength. It comes in CORDAGE 283 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 diameters from 0.25 to 0.75 in (0.64 to 1.90 cm). Fiberglas cordage, of Owens-Corning Fiberglas Corp., is marketed in diameters from 0.0156 to 0.125 in (0.04 to 0.32 cm) and made of continuous filament or staple glass fibers. The 0.125-in (0.32-cm) untreated continuous-filament cord has a breaking strength of 258 lb (116.5 kg). Newbroc is chemical-resistant and heat-resistant thread and cord made with continuous-filament glass fiber impregnated with Teflon plastic, in diameters from 0.0046 to 0.076 in (0.12 to 0.19 cm). It remains flexible at subzero temperatures and is used for lacings and for sewing canvas. The 0.020-in (0.05-cm) fiber has a tensile strength of 70 lb (31.6 kg). Cordage made with high-mod- ulus polyethylene fiber has high tensile strength and elasticity and is used for tugboat hawsers. CORE OILS. Liquid binders used for sand cores in foundry work. The binder should add strength to the core, should bake to a dry bond, should not produce much gas, and should burn out after the metal is poured, so that the sand core will collapse. Linseed oil is considered one of the best binders, but it is usually expensive and may be mixed with cheaper vegetable oils or mineral oil. In some cases fish oil or rosin is also used. Molasses, dextrin, or sulfite liquor may be included in prepared core oils. The specifications of the American Foundrymen’s Society call for 50% raw linseed oil, 25 H grade rosin, and 25 water-white kerosene, with no fish oil. A good core oil should have a specific gravity of 0.9368 maximum, flash point 165 to 200°F (73 to 93°C), Saybolt viscosity 155 minimum, and iodine number 154, and should be of light color. However, any drying oil or semidrying oil can be used to replace all or part of the linseed oil. Perilla and corn oils are used, and core oils of linseed and soybean oil mixtures have good strength. The liquor from sulfite pulp mills contains lignin and is used as a core binder. Glutrin is a core oil with sulfite liquor. Truline is a resinous binder in a powder form marketed by Hercules Inc. Uformite 580, of Rohm & Haas Co., is a core binder especially for aluminum sand cores. It is a modified urea-formaldehyde resin which bakes in the core at 325 to 375°F (162 to 190°C), and it will break down in the core at temperatures above 450°F (232°C). Cycor 191, of American Cyanamid Co., is a urea-formaldehyde resin in water solution for sand cores for short-cycle baking in an electronic oven. Dexocor and Kordex are dextrin binders. CORK. The thick, spongy bark of a species of oak tree, Quercus suber, grown in Spain, Portugal, Italy, Algeria, Morocco, Tunisia, and to a limited extent the United States. It is used for bottle stoppers, insulation, vibration pads, and floats for rafts and nets. The scrap cuttings are used for packing for the transportation of fruits and the 284 CORE OILS 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 manufacture of linoleum and pressed products. When marketed as granulated cork, this material usually comes in sizes of 0.5 in (1.27 cm) and No. 8 mesh. Cork is also used natural or in the form of pressed composition for gaskets, oil retainers, roll coverings, polishing wheels, and many other articles. The material has a cellular struc- ture with more than 50% of the volume in air cells. The cell structure is peculiar, and each cell is in contact with 14 neighboring cells, and because of lack of capillarity it does not absorb moisture. When dried, cork is light, porous, easily compressed, and very elastic. It is one of the lightest of solid substances, the specific gravity being 0.15 to 0.20. It also has low thermal conductivity. Charring begins at 250°F (121°C), but it ignites only with difficulty in contact with flame. The cork tree grows to a height of about 30 ft (9 m). After it has attained the age of about 25 years, it can be barked in the summer, and this barking is repeated every 8 or 10 years. The quality of the bark improves with the age of the tree, and with proper barking, a tree will live for 150 years or more. The thickness of the bark varies from 0.5 to 2 in (1.27 to 5.08 cm). Cork bark is shipped in bales of 170 lb (77.1 kg), and cork wastes in bales of 148 lb (67.1 kg). Brazilian cork is the bark of the tree Angico rayado, called pao santo bark, and also the trees Piptadenia incuriale and P. colomu- rina. The bark has a cellular structure and, when ground, has the appearance of a low grade of true cork, but is softer. It is suitable for insulation. A substitute for cork for insulation packings and acousti- cal panels is Palmetex. It is the compressed pith from the internal fibers of the sawtooth palm Cerano repens, of the eastern Gulf states. It has lower conductivity than cork, but without a binder it is more friable. Corkboard is construction board made by compressing gran- ulated cork and subjecting it to heat so that the particles cement themselves together. It is employed for insulating walls and ceilings against heat and cold and as a sound insulator. Cork tile is cork- board in smaller, regularly shaped blocks for the same purposes. The natural gum in the cork is sufficient to bind the particles, but other binders may be used. CORN. One of the most important food grains of the world for both human and animal consumption, but also used industrially for the production of starch, glucose, alcohols, alcoholic beverages, and corn oil. Corn was unknown to Europe before the discovery of America, where it was one of the chief foods of the Indians from Canada to Patagonia. In Europe and in foreign trade, it is known by its original name maize, and the Incan name choclo still persists in South America for the grains on the cob. In Great Britain, corn means all hard grains including wheat, and the U.S. term corn is an abbreviation CORN 285 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 of the name Indian corn. In South Africa, it is called mealies. Corn is the seed grain of the tall leafy plant Zea mays, of which there are innumerable varieties of subspecies. It grows in temperate climates and in the high elevations of the tropics where there is a warm grow- ing season without cold nights; but high commercial yields are limited to areas where there is a combination of well-drained friable soil, plenty of moisture, few cloudy days, and no night temperatures below 66°F (19°C) during the growing season of 4 months. Corn is an unnat- ural plant, with seeds not adapted for natural dispersal; it does not revert to a wild species. It is a product of long selection. No wild plants have ever been found, but it is believed to have been a culti- vated selection from the grass teosinte of Mexico. About half the world production of corn is in the United States and Argentina, but large amounts are also grown in southern Europe and northern India. Confectionery flakes, used as an additive and conditioner in candy, cookies, and pastries, is a bland, yellowish, flaky powder made from degerminated yellow corn. It contains 8% protein and is pregela- tinized to require no cooking. The pregelatinized corn flour of General Foods Corp., used to improve texture, binding qualities, and flavor of bakery products, is a cream-colored powder which hydrates in cold water and needs no cooking. It contains 82% starch, 9 protein, 1 corn oil, and 8 moisture, and it is a food ingredient rather than an additive, although it may replace 10% of the wheat flour. In the corn belt of the United States, 40% of the corn grown is used for hog feed, while in the dairy belt the hogs are fed on skim milk, buttermilk, and whey, and most of the corn is fed to poultry or shipped commercially. Corn grains grow in rows on a cob enclosed by leafy bracts. They are high in starch and other food elements, and they form a valuable stock feed especially for hogs and poultry. Nearly 90% of the commer- cial corn in the United States is for animal feed. But corn is one of the cheapest and easiest sources of starch, and much of the Argentine corn is used for starch and glucose. Sweet corn is a type of soft corn, Z. saccharata, cultivated for direct eating and for canning. There are about 70 varieties grown widely on farms, but not cultivated for industrial applications. Popcorn, Z. everta, has very hard, small, elongated oval grains which, when heated, explode into a white, fluffy, edible mass without further cooking. It was used by the Indians as a food for journeys and is now grown for food and confections. The corns cultivated for stock feeding and for starch and glucose are varieties of flint corn, Z. indurata, and dent corn, Z. indentata. Flint corn has long, cylin- drical ears with hard, smooth grains of various colors. Dent corn has larger and longer ears which are tapering, with white or yellow grains. About 300 varieties of dent corn are grown in the corn belt of the United States, while the Argentine corn is largely flint varieties 286 CORN 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 which yield high starch. Much of the corn grown in the United States is hybrid corn. This is not a species, but consists of special seed stocks produced by crossing inbred strains. It is resistant to disease and gives high yields. Bt-corn is a genetically engineered corn made by Monsanto Co. The waxy corn grown in Iowa produces a starch comparable with the root starches. In the wet milling of corn for the production of cornstarch, the germ portion of the grain is separated as a by-product and used for the extraction of corn oil, or maize oil. The germ contains 50% oil which is a bright-yellow liquid of specific gravity 0.920 to 0.925, iodine value 123. It contains 56% linoleic, 7 palmitic, 3 stearic, and the balance mainly oleic acid. About 1.75 lb (0.80 kg) of oil per bushel of corn is obtained by crushing the germ, and another 1.4% is obtained by solvent extraction. About 1% of oil remains in the corn oil meal marketed as feed. Corn oil is used as an edible oil as a substitute for olive oil and in margarine, and also in soaps, belt dressings, corn oils, and for vulcanizing into factice. Corn syrups and glucose are produced directly from the starchy corns. Zein is a protein extracted from corn. It is dissolved in alcohol to form a lacquerlike solution which will dry to a hard, tough film. It is used as a substitute for shellac and is more water-resistant than shellac. Zein G210 is a water solution of prolamine protein extracted from corn gluten, used to produce hard, tough, grease-resistant coatings and for formulating polishes and inks. Corn tassels are used for live- stock and poultry feed. They are a rich source of vitamins. About 270 lb (122 kg) of dry tassels is produced per acre. Cornstalks contain up to 11% sugars, usually about 8% sucrose, and 2 other sugars, but lit- tle sugar is produced commercially from this source, the stalks being used as cattle feed. Corncobs are used to produce cob meal for feeds and are processed to produce lignin, xylose, furfural, and dextrose. Korn-Kob is granular corn cob used as an abrasive material for fin- ishing metal parts in tumbling barrels. It is tougher than maple and will not absorb water as wood granules do. Kafir corn is a variety of sorghum grass not related to true corn. The plant is a tall annual with a stalk similar to corn but with smaller leaves and long, cylindrical, beardless heads containing small, round seed grains. It is widely grown in tropical Africa, and a number of subvarieties are grown on a limited scale in Kansas, Texas, and Oklahoma. The grain is similar in composition to corn, but has a peculiar characteristic flavor. It is used as flour in bread mixtures and in biscuit and waffle flour. CORROSION-RESISTANT CAST ALLOYS. In general, these are the cast counterparts to 3XX and 4XX wrought stainless steels and, thus, are also referred to as cast stainless steels. Designations of the Alloy Casting Institute of the Steel Founders Society of America and the CORROSION-RESISTANT CAST ALLOYS 287 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 wrought designations to which they roughly correspond (compositions are not identical) include CA-15 (410), CA-40 (420), CB-30 (431), CC-50 (446), CE-30 (312), CF-3 (304L), CF-3M (316L), CF-8 (304), CF-8C (347), CF-8M (316), CF-12M (316), CF-16F (303), CF-20 (302), CG-8M (317), CH-20 (309), and CK-20 (310). There are also other alloys that do not correspond to wrought grades. The cast alloys corresponding to 3XX wrought grades have chromium contents in the range of 17 to 30% and nickel contents in the range of 8 to 22%. Silicon content is usually 2.00% maximum (1.50 for CE-8M), manganese 1.50 maxi- mum, and carbon 0.08 to 0.30 maximum, depending on the alloy. Other common alloying elements include copper and molybdenum. Those corresponding to 4XX grades may contain as much chromium but much less nickel: 1 to 5.5%, depending on alloy. Manganese and silicon contents are also generally less, and carbon may be 0.15 to 0.50%, depending on the alloy. All the alloys are iron-chromium-nickel alloys, and the most widely used are CF-8 and CF-8M, which limit carbon content to 0.08%. CN-7M and CN-7MS contain more nickel than chromium and, thus, are referred to as iron-nickel-chromium alloys. The alloys are noted primarily for their outstanding corrosion resis- tance in aqueous solutions and hot, gaseous, and oxidizing environ- ments. Oxidation resistance stems largely from the chromium. Nickel improves toughness and corrosion resistance in neutral chloride solu- tions and weak oxidizing acids. Molybdenum enhances resistance to pitting in chloride solutions. Copper increases strength and permits precipitation hardening to still greater strength. After a 900°F (482°C) age, for example, the room-temperature tensile properties of CB-7Cu are 187,000 lb/in 2 (1,290 MPa) ultimate strength, 160,000 lb/in 2 (1,100 MPa) yield strength, 10% elongation, and 28.5 ϫ 10 6 lb/in 2 (196,500 MPa) elastic modulus. Hardness is Brinell 412 and impact strength (Charpy V-notch) 7 ft и lb (9.5 J). At 800°F (426°C), yield strength approaches 120,000 lb/in 2 (827 MPa). Higher aging temperatures, to 1150°F (621°C), decrease strength somewhat but markedly increase impact strength. The alloys are widely used for pumps, impellers, housings, and valve bodies in the power-transmission, marine, and petroleum industries; and for chemical, food, pulp and paper, beverage, brewing, and mining equipment. CORUNDUM. A very hard crystalline mineral used chiefly as an abra- sive, especially for grinding and polishing optical glass. It is alu- minum oxide, Al 2 O 3 , in the alpha, or hexagonal, crystal form, usually containing some lime and other impurities. It is found in India, Burma, Brazil, and in states of Georgia and the Carolinas, but most of the commercial production is in South Africa. The physical 288 CORUNDUM 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 properties are theoretically the same as for synthetic alpha alumina, but they are not uniform. The melting point and hardness are gener- ally lower because of impurities, and the crystal structure also varies. The hexagonal crystals are usually tapered or barrel-shaped, but may be flat with rhombohedral faces. The Hindu word corundum was originally applied to gemstones. The ruby and the sapphire are corundum crystals colored with oxides. Oriental topaz is yellow corundum containing ferric oxide. Oriental emerald is a rare green corundum, but it does not have the composi- tion of the emerald, and the use of the name is discouraged in the jewelry industry. The clear-colored crystals are sorted out as gem- stones, and the premium ore is the large-crystal material left after sorting. Some material is shipped in grain. The crude ore is washed, crushed, and graded. There are four grades of abrasive corundum shipped from South Africa: Grade A is over 92% Al 2 O 3 , Grade B is 90 to 92%, Grade C is 85 to 90%, and Grade D is under 82%. In the United States most of the natural corundum used for optical-glass grinding is in sizes from 60 to 275 mesh, while the grain sizes for coarse grinding and snagging wheels are 8 to 36 mesh. Corundum is now largely replaced by the more uniform, manufactured aluminum oxide, and even the name synthetic corundum, or the German name Sintercorund, is no longer used. COSMETICS. Substances applied to the outer surface of the body for enhancing appearance and/or for improving the condition of the skin. Most cosmetics also contain odorants and perfume oil. Face powders are composed of white pigments having high covering power, such as titanium oxide and zinc oxide; pigments, such as iron oxide and talc (hydrated magnesium silicate), to import slip; and adhesion-promoting ingredients, such as zinc or magnesium stearate. Rouges for the face, which contain many of the ingredients present in face powders, are produced in pressed powder or paste form. The coloring agents are usually water-insoluble, bright red lakes, and the binder is an oil, lanolin, or gum tragocanth. The ingredients of lipstick are principally a vehicle of castor oil and a mixture of waxes, such as beeswax, car- nauba wax, candililla wax, lanolin, butyl stearate, and spermaceti. A great variety of other substances are used for special effects. The color ingredients are usually lakes. Mascaras, used on eyelashes, are made of an oil-soluble soap base, such as triethanolamine stearate; waxes; and color pigments, such as carbon blacks, iron oxide, and ultramarine blue. Nail polishes, or nail lacquers, are made of a nitrocellulose, gum resins, and plasticizers dissolved in a mixture of solvents. For color and opacity, lakes and a substance like titanium oxide are also present. COSMETICS 289 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 from 1.1 25 to 1.3 75 in in length The common grades of cotton fiber in the United States vary in diameter from 0.0006 to 0.0009 in (0.0 152 to 0.0229 mm) Sea Island cotton fiber is as fine as 0.0002 in (0.0 05 mm), compared with 0.001 in (0.0 25 mm) for the coarse Indian cotton The cotton of India, China, and the Near East is from G herbaceum, and the fiber is short, 0.3 75 to 0. 75 in (0. 95 to 1.91 cm),... weighing 726 carats The Cullinan diamond, or Star of Africa, measured 4 by 2 .5 by 2 in (10 by 6 by 5 cm) and weighed 3,106 carats The annual world production of natural diamonds reaches as high as 28 million carats, or about 6 tons (5. 4 metric tons), of which 5 tons (4 .5 metric tons) are industrial diamonds An average of 250 tons (228 metric tons) of ore is processed to obtain 1 carat In Angola the... per 478-lb (217-kg) bale of cotton, and 100 lb ( 45 kg) of seed yields 15. 5 lb (7 kg) of oil When the seeds are crushed whole, the oil is dark in color and requires careful refining U.S practice is to hull the seeds before crushing The oil is colorless and nearly odorless and has a specific gravity of 0.9 15 to 0.921 Upland cottonseed contains about 25% oil, which has 40% linoleic, 30 oleic, and 20 palmitic... from 1. 25 to 2 .5 in (3.18 to 6. 35 cm), but it is cream-colored Egyptian cotton, grown in Egypt and the Sudan, came originally from Peruvian seed Peruvian cotton, G acuminatum, is long-staple, silky, has strength and firmness, but is brownish The tanguis cotton from Peru is valued for fine English fabrics Egyptian cotton, or maco cotton, is next in quality to Sea Island The long staple is from 1.1 25 to... trade names, such as J-metal and Star J-metal The hardest alloy, with a Rockwell C hardness to 68, contained about 45% cobalt, 32 chromium, 17 tungsten, 1 .5 iron, 1 .5 silicon, and up to 2.7 carbon The tensile strength is above 100,000 lb/in2 (689 MPa), and compressive strength is about 3 25, 000 lb/in2 (2,240 MPa) It is silvery white Delloy is of somewhat similar composition Other similar alloys were Speedaloy,... strong Cotton linters removed from the cottonseed after ginning are from 0.04 to 0.6 in (0.10 to 1 .5 cm) long The first cuts, or longer fibers, are used for upholstery and for mattresses, and amount to 20 to 75 lb (9 to 34 kg) per ton (907 kg) of seed The second-cut short fibers vary from 1 25 to 180 lb (57 to 82 kg) per ton (907 kg) of seed, and are called hull fiber The No 1 grade of long linters is... circuits in fighter-aircraft test equipment Because the diamond has 50 times the thermal conductivity of the oxide, its use simplified package design and improved performance For tungsten-carbide cutting inserts, thin-film diamond coatings applied by chemical vapor deposition permit machining speed of 1800 to 3000 surface ft/min (55 0 to 9 15 m/min) At Lockheed Missile & Space Co., diamond films are made... 140°C) Varnishes made with it are resistant to alkalies Nevindene, of the Neville Co., is a coumarone-indene resin of specific gravity 1.08 and melting point 50 to 320°F (10 to 160°C), used for compounding with rubber and synthetics Nevilloid C -55 is a coumarone-indene resin in water emulsion for coatings It forms cohesive translucent films of slightly tacky nature Blended with melamine resin, it forms... used for fabric-covered training planes, is a plain-woven cotton fabric of two-ply combed yarns mercerized in the yarn It is usually 4 oz/yd2 (0.14 kg/m2), but wide fabrics may be 4 .5 oz/yd2 (0. 15 kg/m2) The cotton is 1 .5 in minimum staple, and the threads per inch are 80 to 84 COTTONSEED OIL One of the most common vegetable oils, used pri- marily as a food oil in salad oils, margarine, cooking fats,... dispersing agents for latex, paper coatings, dyestuffs, and agricultural sprays Daxad 11 is a polymerized salt of alkyl naphthalene sulfonic acid Its action is to impart an electric charge to each particle, giving a repelling action to space the particles and to prevent agglomeration or settling It increases fluidity and permits a higher solids content in dispersions without increasing the viscosity To . website. Materials, Their Properties and Uses diameters from 0. 25 to 0. 75 in (0.64 to 1.90 cm). Fiberglas cordage, of Owens-Corning Fiberglas Corp., is marketed in diameters from 0.0 156 to 0.1 25 in. Society call for 50 % raw linseed oil, 25 H grade rosin, and 25 water-white kerosene, with no fish oil. A good core oil should have a specific gravity of 0.9368 maximum, flash point 1 65 to 200°F (73. to 93°C), Saybolt viscosity 155 minimum, and iodine number 154 , and should be of light color. However, any drying oil or semidrying oil can be used to replace all or part of the linseed oil. Perilla