Disclosed is a lubricating oil composition comprising an oil of lubricating viscosity and an oil soluble synergistic mixture of antioxidants, said mixture comprising: a) a hindered amine antioxidant according to formula (I) ##STR00001## wherein each R.sup.1 is independently selected from a substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; R.sup.2 is selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.3 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.4 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; n is an integer from 1 to 4; and m is an integer from 1 to 5; and b) a molybdenum succinimide complex.

An organophosphorus compound has a structure represented by the general formula (I): ##STR00001## The functional groups are defined in the description. The organophosphorus compound has prominent bearing capacity and excellent antiwear and antifriction performances, and can be used as an extreme pressure antiwear additive and used in lubricating oil and lubricating grease.

A composition of an oil-soluble ionic detergent that does not contribute metal ions to the composition, and which comprises a quaternary non-metallic pnictogen cation and an organic anion having at least one hydrocarbyl group of sufficient length to impart oil solubility to the detergent, the detergent having a total base number (TBN) to total acid number (TAN) ratio of at least 2:1 imparts ash-free basicity to a lubricant composition.

A method for improving wear control in an engine or other mechanical component lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that includes a lubricating oil base stock as a major component; and at least one phosphazene represented by the formula ##STR00001##
as a minor component. In the above formula, Q is nitrogen, sulfur or oxygen; a is a value from about 2 to about 6, c is a value from about 2 to about 6, e is a value from about 2 to about 6, g is a value from about 2 to about 6, i is a value from about 2 to about 6, and k is a value from about 2 to about 6; b is a value of 2a+q, d is a value of 2c+r, f is a value of 2e+s, h is a value of 2g+t, j is a value of 2i+u, and l is a value of 2k+v; q, r, s, t, u and v are independently a value of 0 or 2; with the proviso that not all of a, c, e, g, i and k are the same value. A lubricating oil having a composition that includes a lubricating oil base stock as a major component; and at least one phosphazene represented by the above formula as a minor component. The lubricating oil is useful in internal combustion engines.

A composition of an oil-soluble ionic detergent that does not contribute metal ions to the composition, and which comprises a quaternary non-metallic pnictogen cation and an organic anion having at least one hydrocarbyl group of sufficient length to impart oil solubility to the detergent, the detergent having a total base number (TBN) to total acid number (TAN) ratio of at least 2:1 imparts ash-free basicity to a lubricant composition.

Disclosed is a lubricating oil composition comprising an oil of lubricating viscosity and an oil soluble synergistic mixture of antioxidants, said mixture comprising: a) a hindered amine antioxidant according to formula (I)

##STR00001## wherein each R.sup.1 is independently selected from a substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; R.sup.2 is selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.3 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; each R.sup.4 is independently selected from the group consisting of a hydrogen atom or a, substituted or unsubstituted, branched or linear, C.sub.1-C.sub.20 hydrocarbyl group; n is an integer from 1 to 4; and m is an integer from 1 to 5; and b) a molybdenum succinimide complex.

An organophosphorus compound has a structure represented by the general formula (I):

##STR00001##

The functional groups are defined in the description. The organophosphorus compound has prominent bearing capacity and excellent antiwear and antifriction performances, and can be used as an extreme pressure antiwear additive and used in lubricating oil and lubricating grease.

A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A represented by Chemical formula 1 and a component B represented by Chemical formula 2: ##STR00001##
wherein X in Chemical formula 1 represents OH ##STR00002##
wherein X in Chemical formula 2 represents OCH.sub.2CH(OH)CH.sub.2OH,
and the lubricant compound further contains a component C made of a specific compound having a phosphezene ring in the structure thereof.

A composition of an oil-soluble ionic detergent that does not contribute metal ions to the composition, and which comprises a quaternary non-metallic pnictogen cation and an organic anion having at least one hydrocarbyl group of sufficient length to impart oil solubility to the detergent, the detergent having a total base number (TBN) to total acid number (TAN) ratio of at least 2:1 imparts ash-free basicity to a lubricant composition.

An organophosphorus compound has a structure represented by the general formula (I): ##STR00001##
The functional groups are defined in the description. The organophosphorus compound has prominent bearing capacity and excellent antiwear and antifriction performances, and can be used as an extreme pressure antiwear additive and used in lubricating oil and lubricating grease.