INDUSTRY & BUSINESS
Dry Film Good Lubricant Navy's d r y film lube keeps b e a r i n g running 2 4 0 hours at high t e m p e r a t u r e XTLDD SOMETHING new t o high tempera
ture lubricants. A versatile dry film lubricant for ball bearings has been developed by researchers at the aero nautical materials lab of the Naval Air Material Center in Philadelphia. T h e film is stable through a temperature range of - 3 0 0 ° F . to 750° F., lubri cates for as long as 240 hours. Another attraction: The film lubri cates bearings immersed, in liquid oxy gen, the material often used in propul sion systems and which can play havoc with other materials, mainly greases, causing explosions. The Navy film is composed of 5 5 ' '< molybdenum disulfide, 6f/c graphite, and 39'i- sodium silicate. The sodium silicate, used as a hinder, is a key to the success of t h e lubricant, Martin J. Devine of the materials lab told t h e 14th Annual Meeting of the Armed Forces Chemical Association, in Wash ington, D. C. In previous tests with film lubri cants, Mr. Devine and colleague E. R. Lamson used organic binders (phenolics, epoxies, a n d the like) instead of the silicate. But these didn't perform well, brought repeated failures in a short time. Navy scientists tried several binders, concluded that soluble sodium silicate looked most promising. Prior to putting the lubricating film —called 23A—through test paces, t h e bearing assembly must be taken apart and each part sprayed with t h e lubri cant. Curing, sometimes for as much as two days, forms a tough film on the components. (Mr. Devine feels that curing time can be c u t to about eight hours.) Reassembly follows. The first test calls for running the bearings at three different speeds *at 350° F . Results: At 1250 r.p.m., the bearings didn't fail until they ran for 240 hours. At 3500 r.p.m., time was 42 hours; at 10,000 r.p.m., 2 9 hours. Previous dry films the scientists worked with had relatively short life—three or four hours—at 10,000 r.p.m. and 350° F . At the other end of the temperature scale, —100° F . , 23A worked excep tionally well with regard to starting torque characteristics. It was compared
with a grease made especially to oper ate at —100° F. The starting torque value for the grease: 4764 gram-feet. But the dry film easily outshone it with a value of 472. In temperature stability tests, the Navy film was called on to outdo a commercial film that uses an organic binder and the best military grease de signed for high temperature use. At i yj\j
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in one hour, easily rubbed off. The base oil of the grease evaporated com pletely in four hours. With t h e 23A, there was no breakdown after 24 hours. In addition to these wear-and-tear tests, 23A had to go through a radia tion test. It was exposed to a gamma dosage of 5 X 10" roentgens. T h e film still gave good bearing operation. But grease, subjected to the same amount of radiation, turned into brittle solids. Mr. Devine says 23A is still in the re search stage af the materials lab, but he sees no reason why it couldn't be used commercially now.
Action Flares In Lithium Case When Lithium Corp. of America sud denly canceled its agreement late last month with Quebec Lithium Corp., the Canadian firm said it would hold LCA to its contract (C&EN, Aug. 3 1 , page 17). Last week, LCA's refusal to ac cept QLC's contractual shipments of spodumene did precipitate a $4,477,000 damage suit. Though Q L C had been expected to act in a Canadian court, it actually filed suit in federal court in Minneapolis, present home office of LCA. But LCA is now getting ready to move to New York; laboratory and product opera tions will be transferred to its Bessemer City ( N . C.) plant site. LCA won't comment on the situation now that the suit has been filed. Q L C officials term the contract with LCA— to deliver 17,000 lithium units per month of concentrate until M a r c h 1962 —a firm one with no escape clauses. About 90 Vr of QLC's production used to go to U. S. industry, and the major customer here was L C A . Q L C is now putting finishing touches on a chemical processing plant for making lithium salts, and hopes to increase sales of minerals to glassmakers in this country.
Plant Growth Factor Found USDA finds light sensitive pigment that controls d e velopment in plants OCIENTISTS at the U. S. Department
of Agriculture, Beltsville, Md., have found in plants a substance that con trols their development (C&EN, Sept. 14, page 29). T h e material is a blue pigment which exists in all plants in two forms—red light absorbing, and farred light absorbing. Color and inten sity of light hitting this pigment rule what developmental processes take place in plants, USDA says. Chemi cally, the pigment is a protein which acts like an enzyme. The finding is termed an "outstand ing basic- research achievement" by Dr. Byron T. Shaw, administrator of USDA's Agricultural Research Service. It means better control of plant devel opment for specific p u r p l e s such as better food, fiber, and industrial raw materials, Dr. Shaw says. Among USDA scientists involved in the discovery are Dr. Harry A. Borthwick, Dr. Sterling B. Hendricks, Dr. Harold \V. Siegleman, Dr. Warren But ler, and Carl Nor ris. • Red Light Is Key. The pigment is present in a reduced form when it is red light absorbing. In this form it absorbs light in the range of 5800 to 6300 A. While in t h e red light ab sorbing form, the material prevents flowering in some plants, promotes ger mination of some seeds, prevents elon gation of stems, and often promotes red coloring (anthocyanin) in the plant. On being struck by red light, the pigment is oxidized—exact mechanism is unknown—and becomes far-red light absorbing. In this state, when light in the range 7200 to 7800 A. strikes, all the plant reactions occurring under the reduced form are nullified or re versed. Thus, color of light controls which form of pigment is predominant in the plant a t a given moment, and thus which developmental process will oc cur. USDA scientists are now hard at work trying to purify the pigment fur ther. Once it is pure, chemical identifi cation should become less difficult. USDA hopes eventually to be able to modify the material, and thus its ef fects on plants, at will. SEPT.
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1959 C&EN
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