| abstract |
Lubricating oil and functional fluid compositions having better stability at elevated temperatures and containing at least one composition containing phosphorus and at least one composition soluble in oil and containing nitrogen. More particularly, the lubricant and functional fluid compositions described herein comprise (A) a large amount of an oil of viscosity indicated for lubrication, and a lower amount of (B-1) at least one soluble amine salt at least one substituted phosphoric acid composition characterized by formula (I), wherein R1 represents hydrogen or a hydrocarbyl group, R2 is a hydrocarbyl group, and the two groups X represent either O or S, and (C) at less a soluble nitrogen-containing composition prepared by the reaction of a hydrocarbon-substituted succinic acid-producing compound with at least about half an equivalent, per equivalent of the acid-producing compound, of an amine containing at least one hydrogen attached to a nitrogen atom. Preferably, the amine salts of the phosphoric acids used in the lubricating compositions described here are derived from primary amines, and the soluble compositions containing nitrogen (C) also contain boron. The lubricant compositions described above are particularly useful in applications relating to gears requiring high thermal stability at temperatures around 160 ° C, with intermittent operation at temperatures up to about 200 ° C. |