A quaternary ammonium compound of formula (I): wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R.sup.5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R.sup.5 is hydrogen.

##STR00001##

A method of lubricating the contact between a first surface coated with a hydrogenous carbon film or coating of type a-C:H, ta-C:H, a-C:H:Me or a-C:H:X, as classified by VDI-Standard VDI 2840 and a second ferrous, preferably steel surface. The method comprises supplying to said contact a lubricating oil composition comprising a major amount of an oil of lubricating viscosity and (a) an oil-soluble or oil-dispersible molybdenum compound in an amount such as to provide between 150 and 1000 ppm by weight of molybdenum to the lubricating oil composition, and (b) between 0.1 and 5% by weight with respect to the weight of the lubricating oil composition of a polymeric organic friction modifier, the organic friction modifier being the reaction product of (i) a functionalised polyolefin, (ii) a polyether, (iii) a polyol and (iv) a monocarboxylic acid chain terminating group.

A lubricating composition which, when used with a device for clamping an article, such as a chuck, produces excellent lubricating properties whilst remaining strongly adhered to metal parts in a clamping mechanism of the device and showing enhanced chemical and physical resistance to fluids such as cutting fluids.

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N-α-naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N-α-naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

The invention provides a lubricating composition comprising a low viscosity base oil and a synergistic mixture of a functionalized ethylene-α-olefin copolymer, a poly(meth)acrylate polymer, and a metal-free anti-wear agent. The invention also provides a method of lubricating an internal combustion engine using such a lubricating composition.

This invention relates to the use of a boron-containing additive in a non-aqueous lubricant composition as an inhibit or of lead corrosion associated with ashless, organic ester, anti-wear additives and/or friction modifiers.

Disclosed are multifunctional compounds represented by structural formula (I):

##STR00001##

methods of producing compounds represented by structural formula (I) and their use in inhibiting corrosion in corrodible material.

Provided is a lubricating oil composition for use in turbomachinery, compressors, hydraulic equipments, or machine tools, which contains a mineral oil (A) and a synthetic oil (B) containing a polyalkylene glycol (B1) and a polyol ester (B2), in which the content of the mineral oil (A) is 5 to 95% by mass based on the total amount of the lubricating oil composition, and which is used in turbomachinery, compressors, hydraulic equipments, or machine tools. The lubricating oil composition is excellent in oxidation stability, has a strong effect of preventing sludge precipitation and has excellent water separability even in use for a long period of time in high-temperature environments.

This invention relates to the use of a metallic or non-metallic detergent which is a hydrocarbyl-substituted salicylic acid or a derivative thereof in a non-aqueous lubricant composition as an inhibitor of lead corrosion associated with ashless, organic ester, anti-wear additives and/or friction modifiers.

Provided is a lubricating oil composition for a transmission having excellent gear properties, clutch properties, cooling properties, and electric insulating properties. The lubricating oil composition for a transmission preparing by blending (A) a base oil, (B) a viscosity index improver having a mass average molecular weight of 10,000 to 50,000, and (C-1) a polyamide and/or (C-2) a polyol ester, the base oil (A) including (A-1) a synthetic oil having a kinematic viscosity at 100 C. of 1.0 to 10.0 mm.sup.2/s.