A lubricating grease composition includes a base oil, a thickener, and a solid lubricant, wherein the base oil is a synthetic hydrocarbon oil with a kinematic viscosity of 600 to 2000 mm.sup.2/s at 40 C., the thickener is a barium complex soap, and the solid lubricant is an inorganic fine particle with Mohs hardness of 3 to 6 and an average particle size of 10 to 40 m.

The present disclosure is related to provide a lubricating grease composition having a high static friction coefficient while maintaining excellent low-temperature torque characteristics, high-temperature shear stability, and high-temperature oil separation characteristics. A lubricating grease composition of the present disclosure contains a base oil, a thickener, and a solid lubricant, wherein the solid lubricant is calcium carbonate, the amount of the calcium carbonate blended is 1 to 60% by weight based on the total weight of the lubricating grease composition, the calcium carbonate has an average particle diameter of 0.1 to 30 m, the base oil has a kinematic viscosity of 18 to 300 mm.sup.2/s at 40 C., and the lubricating grease composition has a worked penetration of 240 to 320.

An object of the invention is to provide a grease composition that does not deteriorate resin, particularly, acetal resin, in contact therewith even under a high temperature condition. The object can be attained by a grease composition for resin, including (A) a lubricating base oil, (B) a thickener, and (C) at least one selected from the group consisting of an organic molybdenum compound and a sulfur-based extreme pressure agent, wherein when the grease composition includes the sulfur-based extreme pressure agent, a content of the sulfur-based extreme pressure agent is from 0.05 mass % to 2.5 mass % based on a total amount of the composition, and the grease composition is substantially free of zinc dialkyldithiophosphate.

A tribological system, comprising a main body and a sandwich lubrication, in which the sandwich lubrication includes a binder-free solid lubricant layer comprising a solid lubricant, and a lubricant layer comprising a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and wherein the mass ratio of solid lubricant to lubricant is at most 0.05:1.

A tribological system, including a main body and a sandwich lubrication, wherein the sandwich lubrication includes a binder-free solid lubricant layer including a solid lubricant, and a lubricant layer including a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and the mass ratio of solid lubricant to lubricant is at most 0.05:1. The solid lubricant includes polytetrafluoroethylene (PTFE), metal sulfide, graphite, graphene, boron nitride (hexagonal), calcium phosphate, silicate, layered silicate, or mixtures thereof.

A lubricating grease composition includes a base oil, a thickener, and a solid lubricant, wherein the base oil is a synthetic hydrocarbon oil with a kinematic viscosity of 600 to 2000 mm.sup.2/s at 40 C., the thickener is a barium complex soap, and the solid lubricant is an inorganic fine particle with Mohs hardness of 3 to 6 and an average particle size of 10 to 40 m.

A lubricating grease composition includes a base oil, a thickener, and a solid lubricant, wherein the base oil is a synthetic hydrocarbon oil with a kinematic viscosity of 600 to 2000 mm.sup.2/s at 40 C., the thickener is a barium complex soap, and the solid lubricant is an inorganic fine particle with Mohs hardness of 3 to 6 and an average particle size of 10 to 40 m.

The present disclosure is related to provide a lubricating grease composition having a high static friction coefficient while maintaining excellent low-temperature torque characteristics, high-temperature shear stability, and high-temperature oil separation characteristics.

A lubricating grease composition of the present disclosure contains a base oil, a thickener, and a solid lubricant, wherein the solid lubricant is calcium carbonate, the amount of the calcium carbonate blended is 1 to 60% by weight based on the total weight of the lubricating grease composition, the calcium carbonate has an average particle diameter of 0.1 to 30 m, the base oil has a kinematic viscosity of 18 to 300 mm.sup.2/s at 40 C., and the lubricating grease composition has a worked penetration of 240 to 320.

Provided herein is a grease composition capable of reducing an amount of wear in sliding parts of various members of automobiles, electrical devices, and the like. The grease composition includes a lubricant base oil, a thickener, an amide compound, and at least one of an -hydroxycarboxylic acid metal salt, and an -hydroxycarboxylic acid metal salt. The hydroxycarboxylic acid metal salts are contained in a total content of 0.1 to 2 mass % with respect to the total amount of the grease composition.

A grease composition comprising: (i) a mineral base oil containing one or more of fatty ammonium carboxylate salts of formula (I),

##STR00001## wherein R.sup.1 is selected from C.sub.12 to C.sub.20 saturated or unsaturated, branched or straight-chain hydrocarbyl groups; X is selected from NH, .sup.+NH.sub.2 and N(R.sup.4)NH.sub.3.sup.+; R.sup.2 and R.sup.4 are independently selected from C.sub.2 to C.sub.8 saturated or unsaturated, branched or straight chain hydrocarbyl groups, and may be the same or different; R.sup.3 is selected from C.sub.12 to C.sub.26 saturated or unsaturated, branched or straight-chain hydrocarbyl groups; and n is 1 or 2; and (ii) a simple lithium soap thickener, wherein said lubricating grease composition is prepared by a process comprising the steps of combining the mineral base oil with the one or more fatty ammonium carboxylate salts of formula (I) and then thickening said base oil fatty ammonium carboxylate salt mixture with the simple lithium soap thickener.