Green fruits, especially bananas, often contain much starch, but the ripening process changes the starch to sugars. In general, starch is a white, amorphous powder having a specific gravity from 0.499 to 0.513. It is insoluble in cold water but can be converted to soluble starch by treating with a dilute acid. When cooked in water, starch produces an adhesive paste. Starch is easily distinguished from dextrins as it gives a blue color with iodine while dextrins give violet and red. The starch molecule is often described as a chain of glucose units, with the adhesive waxy starches as those with coiled chains. But starch is a complex member of the great group of natural plant compounds consisting of starches, sugars, and cellulose, and originally named carbohydrates because the molecular formula could be written as C n (H 2 O) x ; but not all now-known carbohydrates can be classified in this form, and many now-known acids and aldehydes can be indicated by this formula. Starch can be fractionated into two polymers of high molecular weight. Amylose is a straight-chain fraction having high adhesive properties for coatings and sizings, and amylopectin is a branched-chain fraction best known as a suspending agent for food- stuffs. Amylose is chemically identical with cellulose, but the chain units of the molecule have an alpha linkage and are coiled, while the cellulose molecule is rigid. It has a molecular weight of 150,000, while amylopectin has a molecular weight above 1 million. The 1–4 alpha linkage of amylopectin with random branches at the 6-carbon position makes the material easily dispersible in cold water but resistant to gelling. Amylopectin is thus best suited for thickening, but because it can be combined and cross-linked with synthetic resins and is highly resistant to deterioration, it is used with resins for water-resistant coatings for paper and textiles. Tapioca is the starch from the root of the large tuber Manihot utilissima, now grown in most tropical countries. It is called cassava in southern Asia, manioc in Brazil, mandioca in Paraguay, and yuca in Cuba. This perennial vegetatively propagated shrub was cul- tivated as far back as 2,500 years ago, and there is some indirect evi- dence that it has been grown for 4,000 years in the Americas. Its fresh roots contain 30 to 40% dry matter and have a starch content of approximately 85% of the dry matter. It is used in enormous quanti- ties for food in some countries, and in some areas much is used for the production of alcohol. In the United States it is valued for adhesives and coatings, and only a small proportion in globules and flakes, known as pearl tapioca, is used in foodstuffs. Gaplek, used for cat- tle feed in Asia, is not the starch, but is dried and sliced cassava root. Tapioca starch may be sold under trade names. Kreamgel, used as a thickener for canned soups, sauces, and pastries, is refined tapioca that gives clear solutions without imparting odor or flavor. 910 STARCH 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 Potato starch, produced from the common white potato, Solanum tuberosum, has been the most important starch in Europe, but in the United States it is usually more expensive than cornstarch. It forms heavier hot pastes than tapioca. It is also free of flavor and is used as a thickener in foods. It does not crystallize easily. Arogum, of Morningstar-Paisley, Inc., is potato starch used to give tough, resilient coatings on paper and textiles, and Arojel P is pregelatinized potato starch used as a beater additive to improve the strength and scuff resistance of kraft paper. Sweet-potato starch is from the tuber Opomoea batata. An average of 10 lb (4.5 kg) of starch is produced per bushel. The root has poor shipping qualities, and the starch is expen- sive, but it has excellent colloidal qualities and gelatinizes completely at 165°F (74°C). It is used in some foodstuffs. It has a pleasant, sweet- ish flavor, and in Latin countries great quantities are marketed in the form of a stiff gel as a dessert sweet known as dulce de batata. Arrowroot starch is from the tubers of the Maranta arundinacea of the West Indies. It is easily digested and is used in cookies and other food products, especially baby foods. Florida arrowroot is from Zamia floridana. East Indian arrowroot is from the plant Curcuma angustifolia, which belongs to the ginger family. Arrowroot from St. Vincent, used in instant-pudding mixes and icings, is mar- keted as a precooked powder of about 200 mesh. It swells in cold water and does not add flavor. The starches do not crystallize as sugar does, and they may be added to some confections to minimize crystallization. They are also used as binders in candies and in tablet sugar, but any considerable quantity in such products is considered as an adulterant. Metabolism of starch in the human system requires conversion to sugars, and the taking in of excessive quantities of uncooked starch is undesirable. Modified starches are starches with the molecule altered by chemi- cal treatment to give characteristics suitable for particular industrial requirements. The modified starches and especially prepared starches are usually sold under trade names. Superlose is amylose from corn- starch, and Auperlose is amylose from potato starch. Ramalin is amylopectin. Amylon, of National Starch & Chemicals Corp., is corn- starch containing 57% amylose, and Kosul is cornstarch high in amy- lopectin. Textaid, of the same company, is a modified starch which reacts with water to form a grainy structure. It is used in commin- uted meat products to give a firm texture. The ColFlo thickening agents, stable and soluble in frozen foods, are modified, waxy corn- starches, high in amylopectin. Pregelatinized starches are pre-heat-treated starches that require no cooking for use in dry food mixes or adhesives. Snow Flake starch is a cornstarch of this type. Wheat starch is a fine, white starch made by separating out the gluten of wheat flour by wash flotation. It is used in prepared mixes STARCH 911 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 for foam-type cakes and pie crusts to improve texture, add volume, and reduce the amount of shortening needed. It replaces up to 30% of the wheat-flour content of the mix. Starbake starch, of Hercules, is wheat starch. Paygel, of General Mills, is also wheat starch, but alant starch, or inulin, (C 6 H 10 O 5 ) 6 и H 2 O, is not a starch in the ordi- nary sense, but is an insoluble sugar which occurs as the reserve polysaccharide in many plants. It is obtained from the roots of the artichoke, Helianthus tuberosis, native to America but now grown widely in Europe. Unlike starch, the molecule has fructose units held in glucoside linkage, and hydrolysis converts it to fructose. Starch acetate, or acetylated starch, is used for textile sizing, in adhesives, and for greaseproofing paper. The insertion of acetate radi- cals reduces the tendency of the molecular chains to cling together. The acetylated starches are gums which gelatinize at lower tempera- tures than starch, and produce stable, nonlumping pastes which give strong, flexible films. Miralloid and Mira-Film, of A. E. Staley Mfg. Co., are acetylated cornstarches. Morgum is a hydroxyethyl ether- ized starch which gives high film strength in coatings. The Kofilms of General Mills are acetylated cornstarches which give greaseproof, craze-resistant coatings on paper and textiles. Laundry starches are usually ordinary starches, but silicone resin emulsions may be added to starches to permit higher ironing tempera- tures, improve slipperiness, and improve the hand of the starched fabric. The so-called permanent starches, for household use, that are not removed by washing, are not starch, but are emulsions of polyvinyl acetate. Oxidized starch, a resistant starch for coatings, is made by the chloro-oxidation of a starch solution. Sumstar 190 is a diallyl starch made by acid oxidation of cornstarch. Small amounts of the powder added to kraft, tissue, or toweling pulp increase the wet and dry strengths and the folding endurance of the papers. An ammoniated starch called Q- Tac starch is cornstarch reacted with quaternary ammonium groups. A less than 1% solution improves paper strength. Sulfonated starches are used as dirt-suspending agents with detergents for cleaning textiles. Nu-Film is a starch of this type. Clear Flo starch is a modified starch containing a carboxyl group and a sulfonic acid group in the molecule. It has high hydrating capacity and gelatinizes sharply at low temperatures. It is used in adhesives and water paints. Cato starch is a carboxymethyl starch used in paper sizing to add strength. Dry Flo starch is modified to contain a hydrophobic radical, such as CH 2 , which makes the mate- rial insoluble in water but soluble in oils. It is used in paints. Many enzymes hydrolyze starch to maltose, but some enzymes con- vert the starch to the hard, tough glucosides known as mannans, such as the mannose of the ivory nut. Phospho mannan, produced by the fermentation of starch, is such a material used in adhesives. 912 STARCH 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 Granular starch, used in enzyme conversion processing, is in dense, granular particles produced by flash drying. Easy-Enz starch is such a starch. Cationic starch is a starch with the molecules of sta- ble negative polarity to give higher adhesion on the cellulose fibers of paper or textiles. Molding starch, for adding to sugar candies to give sharp molding characteristics, is starch containing an edible oil. The phosphate starch of American Maize Products Co. is an orthophosphate ester of cornstarch, marketed in sodium salt form as a light-tan, dry powder. It has high thickening power and makes a clearer paste than cornstarch. It has superior water-binding proper- ties at low temperatures. Frozen foods made with it do not curdle or separate when thawed, and canned foods thickened with the starch can be stored for long periods without clouding. It is also used as a briquetting binder for charcoal. Starch sponge is an edible starch in the form of a coarse-textured, porous, crispy, spongelike material, used for confections by impregnat- ing with chocolate or sweets. In crushed form it is added to candy or cookies. It is produced by freezing, thawing, and pressing starch paste. The freezing insolubilizes the starch so that no soluble starch goes off when the water is pressed out. Lycasin and Polysorb are hydro- genated starch hydrolysates produced by Roquette Corp. for food and feed applications. Nitrostarch, or starch nitrate, C 12 H 12 O 10 (NO 2 ) 3 , is a fine, white powder made by treating starch with mixed acid. It is highly explosive and is used for blasting, as a military explosive, and in signal lights. Grenite is nitrostarch mixed with an oil binder for use in grenades. Trojan explosive is a mixture of 40% nitrostarch with ammonium and sodium nitrates and some inert material to reduce the sensitiveness. Sepol starch coagulants, of Grace Dearborn, are used to break emulsions in waste treatment of lubricating oils, sol- uble oils, and synthetic coolants, including oils containing dissolved solids and water. STATUARY BRONZE. Copper alloys used for casting statues, plaques, and ornamental objects that require fine detail and a smooth, red- dish surface. Most of the famous large bronze statues of Europe con- tain from 87 to 90% copper, with varying amounts of tin, zinc, and lead. Early Greek statues contained from 9 to 11% tin with as much as 5% lead added apparently to give greater fluidity for crisp details. A general average bronze will contain 90% copper, 6 tin, 3 zinc, and 1 lead. Statuary bronze for cast plaques used in building construction contains 86% copper, 2 tin, 2 lead, 8 zinc, and 2 nickel. The nickel improves fluidity and hardens and strengthens the alloy, and the lead promotes an oxidized finish on exposure. The statuary bronze used for hardware has 83.5% copper, 4 lead, 2 tin, and 10 zinc.Ω STATUARY BRONZE 913 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 STEARIC ACID. A hard, white, waxlike solid of composition CH 3 (CH 2 ) 16 COOH, obtained from animal and vegetable fats and oils by splitting and distilling. The hard cattle fats are high in stearic acid, but other fats and oils contain varying amounts. It is also called octodecanoic acid, and it can be made by hydrogenation of oleic acid. Stearic acid has a specific gravity of 0.922 to 0.935 and a melt- ing point of about 130°F (54°C), and it is soluble in alcohol but insolu- ble in water. It is marketed in cakes, powder, and flakes. Emory 3101-D is isostearic acid which has the solubility and physical properties of oleic acid while retaining the heat and oxidation stabil- ity of stearic acid. Pearl stearic acid is the material in free-flowing bead powder. The acid is used for making soaps, candles, paint driers, lubricating greases, and buffing compositions, and for compounding in rubbers, cosmetics, and coatings. Successive pressings remove liquid oils, thus raising the melting point and giving a whiter, harder product of lower iodine value. Oleo oil is a yellow oil obtained by cold-pressing the first-run cattle tallow. Tallow oil is the oil following the first two grades of oleo oil. Industrene 4518 is the single-pressed grade, available as a molten liquid or in flakes, from Humko Chemical Div. of Witco Corp. Industrene 5016 is the double-pressed variety. Oleostearin, used for treating leather, is the stearin remaining after extraction of the oils. Stearin is the glyceride of stearic acid. Acetostearins are the monoglycerides acetylated with acetic anhydride. They are closely related to fats, but are nongreasy and are plastic even at low temper- atures. The highly acetylated stearins melt below body temperature and are edible. Acetostearins are used as plasticizers for waxes and synthetic resins to improve low-temperature characteristics. Stearite is a trade name for synthetic stearic acid made by the hydrogena- tion of unsaturated animal and fish oils. It is used in rubber com- pounding, as it is more uniform than ordinary stearic acid. Hystrene, of Humko Chemical, is purified and hardened stearic acid in grades of 70, 80, and 97% stearic acid, with the remainder palmitic acid, used for candles, cosmetics, and stearates. However, Hystrene 5016 is a triple-pressed oil. Intarvin is a synthetic edible fat made from stearic acid by converting it to margaric acid, or daturic acid, C 16 H 33 COOH, and then esterifying with glycerin. It is used as a fat for diabetics as it does not undergo the beta oxidation to lose two car- bon atoms at a time and produce acetoacetic acid in the system as do the even-carbon food acids. Wilmar 272 is refined stearic acid in flake form for use in candles and coatings. Hydrofol is a double- and triple-pressed rubber grade that is also used in coatings and candles. It is produced by Sherex Chemical Co. Flexchem B is sodium stearate, NaC 18 H 35 O 2 , in the 914 STEARIC ACID 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 form of a water-soluble, white powder which is insoluble in oils. It is used as a bodying agent in cosmetic creams. Myvacet is an ace- tostearin used as an edible plastic coating for poultry, cheese, and frozen fish and meats to prevent loss of the natural color and flavor. It is a white, waxy solid with melting points from 99 to 109°F (37 to 43°C), but it also comes as an oil with congealing point of 45°F (7°C) for use as a release agent on bakery equipment. Alfol is a high-purity, syn- thetic, linear primary alcohol from Vista Chemical Co. A similar stearyl alcohol, Adol, is from Sherex Chemical and is used as a chemical inter- mediate. Cachalot is a food-grade product of M. Michel and Co. Stearin pitch is a brown-to-black by-product residue obtained in the splitting and distillation of fats and oils in the manufacture of soaps, candles, and fatty acids. While the word stearin implies that it contains only stearic acid, it usually comes from a variety of oils and has mixed acids, and it may take the name of the oil, such as linseed pitch or palm pitch. It is used in varnishes and cold-molding compositions. STEEL. Iron alloyed with small amounts of carbon, 2.5% maximum, but usually much less. The two broad categories are carbon steels and alloy steels, but they are further classified in terms of composi- tion, deoxidation method, mill-finishing practice, product form, and/or principal characteristics. Carbon is the principal influencing element in carbon steels, although manganese, phosphorus, and sulfur are also present in small amounts, and these steels are further classified as low-carbon steels (up to 0.30% carbon), medium-carbon steels (0.30 to 0.60), and high-carbon steels (more than 0.60). The greater the amount of carbon, the greater the strength and hardness, and the less the ductility. Alloy steels are further classified as low-alloy steels, alloy steels, and high-alloy steels, those having as much as 5% alloy content being the most widely used. The most common desig- nation systems for carbon and alloy steels are those of the American Iron and Steel Institute and the SAE, which follow a four- or five-digit numbering system based on the key element or elements, with the last two digits indicating carbon content in hundredths of a percent. Plain carbon steels (with 1% maximum manganese) are desig- nated 10XX; resulfurized carbon steels, 11XX; resulfurized and rephosphorized carbon steels, 12XX; and plain carbon steels with 1 to 1.65% manganese, 15XX. Alloy steels include manganese steels (13XX), nickel steels (23XX and 25XX), nickel-chromium steels (31XX to 34XX), molybdenum steels (40XX and 44XX), chromium-molybde- num steels (41XX), nickel-chromium-molybdenum steels (43XX, 47XX, and 81XX to 98XX), nickel-molybdenum steels (46XX and 48XX), chromium steels (50XX to 52XX), chromium-vanadium steels STEEL 915 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 (61XX), tungsten-chromium steels (72XX), and silicon-manganese steels (92XX). The letter B following the first two digits designates boron steels, and the letter L leaded steels. The suffix H is used to indicate steels produced to specific hardenability requirements. High-strength, low-alloy steels are commonly identified by a 9XX designation of the SAE, where the last two digits indicate minimum tensile yield strength in 1,000 lb/in 2 (6.9 MPa). In contrast to rimmed steels, which are not deoxidized, killed steels are deoxidized by the addition of deoxidizing elements, such as aluminum or silicon, in the ladle prior to ingot casting. Thus we have such terms as aluminum-killed steel. Deoxidation markedly improves the uniformity of the chemical composition and resulting mechanical properties of mill products. Semikilled steels are only partially deoxidized, thus intermediate in uniformity to rimmed and killed steels. Capped steels have a low-carbon steel rim characteris- tic of rimmed-steel ingot and central uniformity more characteristic of killed-steel ingot, and are well suited for cold-forming operations. Steels are also classified as air-melted, vacuum-melted, or vacuum- degassed. Air-melted steels are produced by conventional melting methods, such as open hearth, basic oxygen, and electric furnace. Vacuum-melted steels are produced by induction vacuum melting and consumable electrode vacuum melting. Vacuum-degassed steels are air-melted steels that are vacuum processed before solidifi- cation. Vacuum processing reduces gas content, nonmetallic inclu- sions, and center porosity and segregation. Such steels are more costly, but have better ductility and impact and fatigue strengths. Steel-mill products are reduced from ingot into such forms as blooms, billets, and slabs, which are then reduced to finished or semifinished shape by hot-working operations. If the final product is produced by hot working, the steel is known as hot-rolled steel. If the final product is shaped cold, the steel is known as cold-finished steel or, more specifi- cally, cold-rolled steel, or cold-drawn steel. Hot-rolled mill products are usually limited to low- and medium-nonheat-treated carbon steels. They are the most economical steels, have good formability and weld- ability, and are widely used. Cold-finished steels, compared with hot-rolled products, have greater strength and hardness, better surface finish, and less ductility. Wrought steels are also classified in terms of mill-product form, such as bar steels, sheet steels, and plate steels. Bar steel used to reinforce concrete is called rebar, a low-grade steel made from melted steel scrap and often coated with epoxy for corro- sion protection. Fermar is a higher-quality more corrosion- and fatigue-resistant steel developed at the University of California, Berkeley. Containing less carbon, thus less carbides, it is less suscepti- ble to electrolytic corrosion on water contact. Cast steels refer to those used for castings, and PM (powder metal) steels refer to powder compositions used for PM parts. Steels 916 STEEL 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 are also known by their key characteristic from the standpoint of application, such as electrical steels, corrosion-resistant stain- less steels, low-temperature steels, high-temperature steels, boiler steels, pressure-vessel steels, etc. STEEL POWDER. Powder used mainly for the production of steel PM parts made by consolidating the powder under pressure and then sin- tering, and, to a limited extent, for steel-mill products, principally tool-steel bar products. For PM parts, the powder may be admixed for the desired composition or prealloyed; that is, each powder particle is of the desired composition. For mill products, prealloyed powder is used primarily. Steel powder is widely used to make small to moder- ate-size PM parts, having compositions closely matching those of wrought steels. Among the more common are carbon steels, copper steels, nickel steels, nickel-molybdenum steels, and stainless steels. Ancorsteel 41 AB, of Hoeganaes Corp., is a premixed, highly com- pressible, low-alloy steel powder containing 0.5% carbon, 0.9 man- ganese, 0.85 molybdenum, and 0.75 chromium. Formed parts are intended for surface hardening by carburizing, nitriding, carbonitrid- ing, or nitrocarburizing. Stainless Steel Plus, of the Specialty Metals Division of Ametek, are powders of 303L, 304L, or 316L stainless steels blended with 10% powder of 15 nickel, 8 tin and copper. They are said to provide greater corrosion resistance than conventional stainless steel powders. Powders for injection-molding PM parts are often of iron-nickel or stainless steel but of very fine particle size. STEEL WOOL. Long, fine fibers of steel used for abrading, chiefly for cleaning utensils and for polishing. It is made from low-carbon wire that has high tensile strength, usually having 0.10 to 0.20% carbon and 0.50 to 1 manganese. The wire is drawn over a track and shaved by a stationary knife bearing down on it, and it may be made in a con- tinuous piece as long as 100,000 ft (30,480 m). Steel wool usually has three edges but may have four or five, and strands of various types are mixed. There are nine standard grades of steel wool, the finest of which has no fibers greater than 0.005 in (0.0027 cm) thick, the most commonly used grade having fibers that vary between 0.002 and 0.004 in (0.006 and 0.010 cm). Steel wool comes in batts, or in flat ribbon form on spools usually 4 in (10 cm) wide. Stainless steel wool is also made, and copper wool is marketed for some cleaning operations. STILLINGIA OIL. A drying oil obtained from the kernels of the seeds of the tree Stillingia sebifera, cultivated in China and the southern United States. The seeds contain about 23% of a light-yellow oil resembling linseed oil but of somewhat inferior drying power. The oil has a specific gravity of 0.943 to 0.946 and iodine value of 160. It has the peculiar property of expanding with great force at the congealing STILLINGIA OIL 917 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 point. Stillingia oil is edible, but deteriorates rapidly, becoming bitter in taste and disagreeable in odor. Stillingia tallow, also known as Chinese vegetable tallow, is obtained by pressing from the coating, or mesocarp, of the seeds, yielding about 25 to 35% fat. Sometimes the whole seed is crushed, producing a softer fat than the true tallow. The tallow contains palmitic and oleic acids and is used in soaps and for mixing with other waxes. Some stillingia trees are grown in Texas. STRIPPABLE COATINGS. Coatings that are applied for temporary pro- tection and can be readily removed. They are composed of such resins as cellulosics, vinyl, acrylic, and polyethylene; they can be water-base, solvent-base, or hot-melt. The choice of base depends on the surface to be protected. Water-base grades are neutral to plastic and painted surfaces, whereas solvent-base types affect those surfaces. Clear vinyl strippable coatings, perhaps the most widely used, are usually applied by spraying in thicknesses of 0.03 to 0.04 in (0.08 to 0.10 cm). Acrylic strippable coatings impart a clear, high-gloss, high-strength, temporary film to metal parts. Polyethylene strip- pable coatings are relatively low-cost and can be used on almost all surfaces except glass. Cellulosic strippable coatings are designed for hot-dip application. Film thicknesses range widely and can go as high as 0.2 in (0.51 cm). The mineral oil often present in these coat- ings exudes and coats the metal surface to protect it from corrosion over long periods. STRONTIUM. A metallic element of the alkaline group. It occurs in the minerals strontianite, SrCO 3 , and celestite, SrSO 4 , and resem- bles barium in its properties and combinations, but is slightly harder and less reactive and is not as white in color. It has a specific gravity of 2.54 and a melting point of about 1418°F (770°C), and it decom- poses in water. The metal is obtained by electrolysis of the fused chlo- ride, and small amounts are used for doping semiconductors. Its compounds have been used for deoxidizing nonferrous alloys, and were used in Germany for desulfurizing steel. But the chief uses have been in signal flares to give a red light, and in hard, heat-resistant greases. Strontium 90, produced atomically, is used in ship-deck signs as it emits no dangerous gamma rays. It gives a bright sign, and the color can be varied with the content of zinc, but it is short-lived. Strontium is very reactive and used only in compounds. Strontium nitrate is a yellowish-white, crystalline powder, Sr(NO 3 ) 2 , produced by roasting and leaching celestite and treating with nitric acid. The specific gravity is 2.96, the melting point is 1193°F (645°C), and it is soluble in water. It gives a bright, crimson flame and is used in railway signal lights and in military flares. It is 918 STRIPPABLE 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 also used as a source of oxygen. The strontium sulfate used as a brightening agent in paints is powdered celestite. The ore of Nova Scotia contains 75% strontium sulfate. Strontium sulfide, SrS, used in luminous paint, gives a blue-green glow, but it deteriorates rapidly unless sealed in. Strontium carbonate, SrCO 3 , is used in pyrotech- nics, ceramics, and ceramic permanent magnets for small motors. Strontium hydrate, Sr(OH) 2 и 8H 2 O, loses its water of crystalliza- tion at 212°F (100°C) and melts at 707°F (375°C). It is used in mak- ing lubricating greases and as a stabilizer in plastics. Strontium fluoride is produced in single crystals for use as a laser material. When doped with samarium, it gives an output wavelength around 25,600 nin (650 nm). STYRAX. A grayish-brown, viscous, sticky, aromatic balsam obtained from the small tree Liquidambar orientalis of Asia Minor. It is also called Levant styrax. It is used in cough medicines and for skin dis- eases, as a fixative for heavy perfumes, and for flavoring tobacco and soaps. American styrax is obtained by tapping the sweet gum, L. styraciflua, of Alabama, a tree producing 8 oz (0.2 kg) of gum per year. It is a brownish semisolid and has the same uses as Levant styrax. It is shipped from Central America under the name liquidambar, and in the southern United States is called sweet gum and storax. The gum is not present in large amounts in the wood, but its formation is induced by cuts. Benzoin is another balsam obtained from several species of Styrax trees. It is a highly aromatic solid with an odor like vanilla, and is used in medicine and in perfumes and incense. Sumatra benzoin is from the tree S. benzoin and comes in reddish-brown lumps or tears. In medicine it was originally called gum Benjamin. Siam benzoin, from southern Asia, is from the trees S. tonkinense and S. benzoides. It is in yellowish or brownish tears. The Sumatra benzoin contains cinnamic acid, while the Asiatic gum contains benzoic acid. Benzoic acid, or phenylformic acid, C 6 H 5 COOH, formerly produced from benzoin, is now made syntheti- cally from benzol and called carboxybenzene. It is a white, crys- talline solid melting at 252°F (122°C), soluble in water and in alcohol. It is used as a food preservative, as an antiseptic, for flavoring tobacco, as a weak acid mordant in printing textiles, and in the man- ufacture of dyestuffs, pharmaceuticals, and cosmetics. Because it is poisonous, not more than 0.1% is used in food preserving in the form of its salt, benzoate of soda, or sodium benzoate, C 6 H 5 COONa, which is a white, crystalline powder. A potassium salt is also available from Mallinckrodt, Inc. Sorbic acid, CH 3 CH:(CH) 2 :CHCOOH, a solid melting at 273°F (134°C), occurs in unripe apples, but is made syn- thetically. As a preservative and antimold agent it is more effective STYRAX 919 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 [...]... yield strength of Inconel 600 at room temperature and nearly 3 times as much at 140 0°F (760°C) Its 1,000-h stress-rupture strength at 140 0°F is in the range of 20,000 to 30,000 lb/in2 (138 to 207 MPa) Still great tensile yield strength at room and elevated temperatures and a 25,000 lb/in2 (172 MPa) stress-rupture strength at 140 0°F are provided by Inconel 718 (19% chromium, 18.5 iron, 5.1 columbium, 3... (2 to 7) and other compositional changes They include CMSX-4 and -10, PWA 148 4, SC 180, and Rene N5 and N6 Compared with rhenium-free SRR 99, the 6 rhenium CMSX-10 (RR3000) increases 500-h creep strength by 46% and 20,000-cycle fatigue strength by 59% At 140 0°F (760°C), Cannon Muskegon’s CMSX-4 has a tensile yield strength of 140 ,000 lb/in2 (965 MPa), and it retains useful strength up to 2125°F (1163°C)... alloys are PWA 142 6, Rene 142 , and CM 186 LC, and have similar creep-rupture strength to the original “first generation” rhenium-free single-crystal alloys CM 186 LC, however, does not require solution heat treatment, thus reducing cost and avoiding recrystallization or incipient melting problems In early production, casting yields have approached 90% Cobalt-based superalloys are for the most part solid-solution... refrigerant, as a preservative, in bleaching, and for making other chemicals It liquefies at about 14 F (Ϫ10°C) As a refrigerant it has a condensing pressure of 51.7 lb (23.5 kg) at 86°F (30°C) The gas is toxic and has a pungent, suffocating odor, so that leaks are detected easily It is corrosive to organic materials but does not attack copper or brass The gas is soluble in water, forming sulfurous acid,... pleasant odor and taste obtained from the large seeds of the common sunflower plant, Helianthus annuus, of which there are many varieties The plant is native to Peru but is now grown in many parts of the world, particularly in California, Canada, Argentina, Chile, Uruguay, and Russia It requires boron in the soil The specific gravity of the oil is 0.925 Sunflower oil is used in varnish and soap manufacture... strength of about 100,000 lb/in2 (690 MPa) and a tensile modulus of 21.1 ϫ 106 lb/in2 (145 ,000 MPa) At 1200°F (649°C), tensile yield strength declines only slightly, to 88,000 lb/in2 (607 MPa), and its modulus is about the same or slightly greater It has a 1,000-h stress-rupture strength of about 21,000 lb/in 2 (145 MPa) at 1350°F (732°C) Other PH iron-based superalloys are Discoloy, Haynes 556 (whose... aircraft turbine parts RA333, from Rolled Alloys, contains 45 nickel; 25 chromium; 18 iron; 3 each of cobalt, molybdenum, and tungsten; 1 silicon; and 0.05 carbon The alloy features good resistance to oxidation and carburization to 2200°F (1200°C), has a tensile yield strength of 39,000 lb/in2 (269 MPa), 47% elongation, and a creep-rupture strength of 4,300 lb/in2 (30 MPa) for 10,000 h at 140 0°F (760°C)... (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 SUGAR PINE 925 Celanese Corp., it is 200 times sweeter than sugar and slightly more so than aspartame But since acesulfame-potassium suffers from a slight aftertaste, it is usually mixed with other sweeteners; the combination works... 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 934 SUPERALLOYS boron) Investment-cast, it provides a 1,000-h stress-rupture strength of 75,000 lb/in2 (517 MPa) at 140 0°F (760°C), 37,000 lb/in2 (255 MPa) at 1600°F (871°C), and 15,000 lb/in2 (103 MPa) at 1800°F (982°C) Other precipitation-strengthened... foods, such as for diabetics and infants, in oral hygiene, and pharmaceutical products Alitame, formed from the amino acids L-aspartic acid and D-alanine by Pfizer, Inc., is 2,000 times sweeter than sucrose, just as heat-stable, and has a shelf life up to 4 times that of aspartame Sucralose, being developed by McNeil Specialty Products Co., is 600 times sweeter than sugar, from which it is derived Natural . Terms of Use as given at the website. Materials, Their Properties and Uses Granular starch, used in enzyme conversion processing, is in dense, granular particles produced by flash drying. Easy-Enz. of steel PM parts made by consolidating the powder under pressure and then sin- tering, and, to a limited extent, for steel-mill products, principally tool-steel bar products. For PM parts, the. is, each powder particle is of the desired composition. For mill products, prealloyed powder is used primarily. Steel powder is widely used to make small to moder- ate-size PM parts, having compositions