quantities in northeastern Brazil. There are two to five long kernelsin each nut, the kernel being only 9% of the heavy-shelled nut, andthese kernels contain 65% oil. A bunch of the fruits contains 200 to600 nuts. The oil contains as much as 45% lauric acid and is a directsubstitute for coconut oil for soaps, as an edible oil, and as a source oflauric, capric, and myristic acids. The melting point of the oil is 72 to79°F (22 to 26°C), specific gravity 0.868, iodine value 15, and saponifi-cation value 246 to 250. Tucum oil, usually classified with babassubut valued more in the bakery industry because of its higher meltingpoint, is from the kernels of the nut of the palm Astrocaryum tucumaof northeastern Brazil. The oil is similar but heavier with meltingpoint up to 95°F (35°C), and it consists of 49% lauric acid. InColombia it is called guere palm.

Another similar oil is murumuru oil, from the kernels of the nutof the palm A. murumuru, of Brazil. The name is a corruption of thetwo Carib words marú and morú, meaning bread to eat. The oil con-tains as much as 40% lauric acid, with 35% myristic acid, and somepalmitic, stearic, linoleic, and oleic acids. It is usually marketed asbabassu oil. The awarra palm, A. janari, of the Guianas, yields nutswith a similar oil. Cohune oil is a white fat from the kernels of thenut of the palm Attalea cohune of Mexico and Central America. It is asmall tree yielding as many as 2,000 nuts per year. The oil has theappearance and odor of coconut oil, and it contains 46% lauric acid, 15 myristic, 10 oleic, with stearic, capric, and linoleic acids. All theseoils yield a high proportion of glycerin. Cohune oil has a melting pointof 64 to 68°F (18 to 20°C), saponification value 252 to 256, iodinevalue 10 to 14, and specific gravity 0.868 to 0.971. The cohune nut ismuch smaller than the babassu but is plentiful and easier to crack.Curua oil is from the nut of the palm A. spectabilis of Brazil. It issimilar to cohune oil and is used for the same purposes in soaps andfoods. Mamarron oil is a cream-colored fat with the odor and charac-teristics of coconut oil, obtained from another species of Attalea palmof Colombia. Another oil high in lauric acid, and similar to babassuoil, is corozo oil, obtained from the kernels of the nuts of the palmCorozo oleifera of Venezuela and Central America. Macanilla oil is asimilar oil from the kernels of the nuts of the palm Guilielma gari-paes of the same region. Buri oil is from the nuts of the palmDiplothemium candescens of Brazil.

BABBITT METAL. The original name for tin-antimony-copper whitealloys used for machinery bearings, but the term now applies toalmost any white bearing alloy with either tin or lead base. The origi-nal babbitt, named after the inventor, was made by melting together4 parts by weight of copper, 12 tin, and 8 antimony, and then adding

88 BABBITT METAL

12 parts of tin after fusion. It consisted, therefore, of 88.9% tin, 7.4 anti-mony, and 3.7 copper. This alloy melts at 462°F (239°C). It has a Brinell hardness of 35 at 70°F (21°C) and 15 at 212°F (100°C). As ageneral-utility bearing metal, the original alloy has never beenimproved greatly, and makers frequently designate the tin-base alloysclose to this composition as genuine babbitt.

Commercial white bearing metals now known as babbitt are ofthree general classes: tin-base, with more than 50% tin hardenedwith antimony and copper, and used for heavy-duty service; interme-diate, with 20 to 50% tin, having lower compressive strength andmore sluggish as a bearing; and lead-base, made usually with antimo-nial lead with smaller amounts of tin together with other elements tohold the lead in solution. These lead-base babbitts are cheaper andserve to conserve tin in times of scarcity of that metal, but they aresuitable only for light service, although many ingenious combinationsof supplementary alloying elements have sometimes been used to givehard, strong bearings with little tin. The high-grade babbitts, how-ever, are usually close to the original babbitt in composition. SAEBabbitt 11, for connecting-rod bearings, has 86% tin, 5 to 6.5% cop-per, 6 to 7.5% antimony, and not over 0.50% lead. A babbitt of thiskind will have a compressive strength up to 20,000 lb/in2 (138 MPa)compared with only 15,000 lb/in2 (103 MPa) for high-lead alloys.

Copper hardens and toughens the alloy and raises the meltingpoint. Lead increases fluidity and raises antifriction qualities, but soft-ens the alloy and decreases its compressive strength. Antimony hard-ens the metal and forms hard crystals in the soft matrix, whichimprove the alloy as a bearing metal. Only 3.5% of antimony is nor-mally dissolved in tin. In the low-antimony alloys, copper-tin crystalsform the hard constituent; and in the high-antimony alloys, antimony-tin cubes are also present. Alloys containing up to 1% arsenic areharder at high temperatures and are fine-grained, but arsenic is usedchiefly for holding lead in suspension. Zinc increases hardness butdecreases frictional qualities, and with much zinc the bearings areinclined to stick. Even minute quantities of iron harden the alloys,and iron is not used except when zinc is present. Bismuth reducesshrinkage and refines the grain, but lowers the melting point andlowers the strength at elevated temperatures. Cadmium increases thestrength and fatigue resistance, but any considerable amount lowersthe frictional qualities, lowers the strength at higher temperatures,and causes corrosion. Nickel is used to increase strength but raisesthe melting point. The normal amount of copper in babbitts is 3 or4%, at which point the maximum fatigue-resisting properties areobtained with about 7% antimony. More than 4% copper tends toweaken the alloy and raises the melting point. When the copper is

BABBITT METAL 89

very high, tin-copper crystals are formed and the alloy is more abronze than a babbitt. All the SAE babbitts contain some arsenic,ranging from 0.10% in the high-tin SAE Babbitt 10 to about 1% inthe high-lead SAE Babbitt 15. The first of these contains 90% tin,4.5 antimony, 4.5 copper, and 0.35 lead, while babbitt 15 has 82%lead, 15 antimony, 1 tin, and 0.60 copper.

Because of increased speeds and pressures in bearings and the trendto lighter weights, heavy cast babbitt bearings are now little useddespite their low cost and ease of casting the alloys. The alloys areused mostly as antifriction metals in thin facings on steel backings,the facing being usually less than 0.010 in (0.03 cm) thick, in order toincrease their ability to sustain higher loads and dissipate heat.

Babbitts are marketed under many trade names, the compositionsgenerally following the SAE alloy standards but varying in auxiliaryconstituents, the possibilities for altering the physical qualities bycomposition rearrangement being infinite. Some of the trade namesthat have been used for babbitt-type alloys marketed in ingots areLeantin and Cosmos metal for high-lead alloys, stannum metalfor high-tin alloys, and Lubeco metal and Lotus metal formedium-composition alloys. Hoo Hoo metal and nickel babbittare high-tin alloys containing nickel, while Silver babbitt has notin but contains a small amount of silver to aid retention of the leadand to give hardness at elevated temperatures. Glyco is the name ofa group of lead-base alloys of Joseph T. Ryerson & Son, Inc. Satco, ofNL Industries, Inc., is a high-melting-point alloy for heavy service. Itmelts at 788°F (420°C). Tinite is a tin-base metal hardened withcopper. Ajax bull contains 76% lead, 7 tin, and 17 antimony, modi-fied with other elements.

BAGASSE. The residue left after grinding sugarcane and extractingthe juice, employed in making paper and fiber building boards. InEngland it is called megass. The fiber contains 45% cellulose, 32 pen-tosan, and 18 lignin. It is marketed as dry- and wet-separated, and asdry fiber. The dry-separated fibers bulk 4.5 lb/ft3 (72 kg/m3), with 62to 80% passing a 100-mesh screen. The dry fiber bulks 6 to 8 lb/ft3 (96to 128 kg/m3) and is about 14 mesh. The fibers mat together to form astrong, tough, light, absorptive board. The finer fibers in Cuba andJamaica are soaked in molasses and used as a cattle feed under thename of molascuit. Celotex is the trade name of the Celotex Corp.for wallboard, paneling, and acoustic tile made from bagasse fibers.Ferox-Celotex is the material treated with chemicals to make itresistant to fungi and termites. Celo-Rock is the trade name forCelotex-gypsum building boards. Acousti-Celotex is Celotex perfo-rated to increase its sound-absorbing efficiency. In India, the

90 BAGASSE