High-Temperature Lubrication

The first question is what is a high temperature for chains A temperature of more than 150°F may be considered a high temperature for many chains. This is a practical limit for standard steel and plastic chains using common petroleum lubricants. Special lubricants are nsnally needed when temperatures are more than 150°F, and special chains may be needed when temperatures are more than 350°F. 

Most plastic chains should not be used when the temperature is more than 150°F (wet) to 180T (dry). Special heat-resistant plastics can be used in temperatures up to 250°F, but only for a limited 

FIGURE 13-17 Flat-top chain comer track lubrication. 

High-Temperature Lubricants Petroleum-Based Lubricants 

Some pelroleum-based oils and greases can work at temperatures up to about 250T. However, many petroleum oils should be used only at 180T or less. Petroleum-based lubricants rapidly break down at higher temperatures. They lose their lubricity and form carbon deposits that can prevent fresh lubricant from reaching the critical joint areas. 

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HEXAFLUOROBENZENE The development of commercial routes to hexafluoroben2ene [392-56-3] included an intensive study of its derivatives. Particularly noteworthy was the development of high temperature lubricants, heat-transfer fluids, and radiation-resistant polymers (248). 

Barium improves the performance of lead ahoy grids of acid batteries (see Batteries) (34). In the form of thin films, barium has been found to be a good high temperature lubricant on the rotors of anodes operating at 3500 rpm ia vacuum x-ray tubes (35). 

Phenylben oate [93-99-2] CgH COOCgH, mp, 70—71°C bp, 314°C at 101.3 kPa. This has been suggested as an antioxidant (qv) for certaiu high temperature lubricants (41). Phenyl benzoate exists as a nonisolated iatermediate iu the production of phenol from benzoic acid. 

Bismuth trisulfide has been used as a high temperature lubricant and has been of interest for its photo- and thermoelectric properties. 

Graphite fluoride continues to be of interest as a high temperature lubricant (6). Careful temperature control at 627 3° C results in the synthesis of poly(carbon monofluoride) [25136-85-0] (6). The compound remains stable in air to ca 600°C and is a superior lubricant under extreme conditions of high temperatures, heavy loads, and oxidising conditions (see Lubrication and lubricants). It can be used as an anode for high energy batteries (qv). 

High temperature lubrication, as in some metal-forming processes, requites dry graphite. Although the coefficient of friction of graphite is higher than that of petroleum lubricants, it is often added as a safety measure should the carrier lubricant fail (17) (see Lubrication and lubricants). 

Molybdenum is also used as a catalyst in petroleum refining, as a pigment for paints and printer s ink, and as a high-temperature lubricant (molybdenum disulphide-MoS ) for use by spacecraft and high-performance automobiles. 

Barium hydroxide is used to produce barium soaps which are additives for high temperature lubricants. Other chemical applications include refining of vegetable oils vulcanization of synthetic rubber in drilling fluids in corrosion inhibitors as an ingredient in sealing compositions in plastics stabilizers for softening water and to prepare other alkalies. 

Lead sulfide occurs in nature as the mineral galena. Most lead comes from this ore. Additionally, lead sulfide has several industrial applications. It is used in infrared detectors transistors photoconductive cells high temperature lubricants and for glazing earthenware. It also is used as a catalyst in petroleum refining for removal of mercaptans from petroleum distillates. 

Jin, C.-M., Ye, C., Phillips, B.S., Zabinski, J.S., Liu, X., Liu, W., and Shreeve, J.M., Polyethylene glycol functionalized dicationic ionic liquids with alkyl or poly-fluoroalkyl substituents as high temperature lubricants,. Mater. Chem., 16, 1529-1535, 2006. 

One curious observation is that high activities for direct sulfur extraction from thiophene derivatives are only exhibited by metal sulfides that form stacked lamellar crystallites, similar to graphite structures (1-3). MoS2 is classic in this regard and has found applications as a high-temperature lubricant with properties very similar to those of graphite. The other widely used metal sulfide in HDS is WS2, which also forms lamellar crystal struc-... 

A certain metal sulfide, MS2, is used extensively as a high-temperature lubricant. If MS2 is 40.06% sulfur by mass, what is the identity of the metal M ... 

PG-1 covers the development of a category for manual transmissions used in trucks and buses. The key performance needs are thermal stability, seal compatibility, copper corrosion, anti-wear, high temperature lubricant stability and foaming. PG-1 is known as GL-7 ... 

These subsystems contain phases of technological interest MoS2 is used as a high-temperature lubricant, other suitable refractory sulfides with layered structures might be substituted. However, it has been experimentally proven that some M S2 compounds will not react with some nonferrous alloys up to 850 °C, even under high pressure. 

O Ferrocene is the common name given to a unique compound that consists of one iron atom sandwiched between two rings containing hydrogen and carbon. This orange, crystalline solid is added to fuel oil to improve combustion efficiency and eliminate smoke. As well, it is used as an industrial catalyst and a high-temperature lubricant. 

Adhvaryu, A., and Urban, S. Z. 2002. Epoxidized Soybean Oil as a Potential Source of High-Temperature Lubricants. Ind. Crops Prod., 15, 247-254. 

Stronger van der Waals forces hold the sheets in line with each other so that boron nitride is not as good a lubricant as graphite. However, research is being conducted on the use of boron nitride as a high-temperature lubricant because of its chemical stability. 

Polyfluororoalkoxy-cyclophosphazenes display high thermal and hydrolytic stability and do not rearrange to oxophosphazanes on heating. They are promising high temperature lubricants. 

Preparation and Structure. Many minerals exist as sulfides, and these have been outlined in Section 2.1.1. The alkali and alkali earth metals form simple ionic sulfides that are water soluble. Many sulfides, polysulfides, and their complexes are known and there have been a number of reviews illustrating their structures, catalytic uses, and biological significance. Excellent reviews illustrate the complexity of this area for the chemistry of Cr, Mo, and W sulfides. Many of the sulfides exist in different phases depending upon the conditions used in their synthesis and they may be interconverted by anneaUng, etc. M0S2 is used as a high-temperature lubricant. 

Jin, Y.S. and Zhou, C.H., The Effectiveness of High Temperature Lubrication by In Situ Formation of Graphite/MoSj Films, Wear, 205, 77, (1997). 

Common applications of PCAs include high temperature lubricants, plasticizers, flame retardants, and additives in adhesives, paints, rubber, and sealants [4-6]. Table 1 shows the consumption patterns of PCAs in the United States, Canada, and Western Europe. 

In Sweden it has been estimated that as much as 55 %, i. e., 227 tons/year, of the C10-C13 PCAs used as high-temperature lubricants in industry may be directly discharged as waste into the air and water [3]. A much lower estimate, on a per capita basis, of -161 tons was made for the United States in 1991 [2,21]. 

Cerium Fluoride can be used as an additive to lubricant formulations to improve extreme-pressure[19]. In addition, this fluoride has been proposed as a high temperature lubricant. 

Hartley claims that the effects of ion implantation on wear reduction are due to physical rather than chemical mechanisms . This is probably true for the systems considered in this model. But there are certainly cases where chemical effects are important too, especially in tribological systems, including lubrication. For fluid lubricants it is well known that certain chemical elements improve the adhesion of the lubricating films. These elements may be introduced by ion implantation. This is also possible for high-temperature lubrication where the lubricant is incorporated in the material. Here chemical methods for the production of surface films (oxides, fluorides, sulfides) are common. Ion implantation is an alternative method of incorporating the effective element into the surface region of the material. 

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