The present disclosure relates to a lubricant composition comprising a first phosphorus compound, a second phosphorus compound, and a third phosphorus compound, wherein the first phosphorus compound is present in the lubricant composition in an amount to provide between about 120 and 350 ppm phosphorus. The lubricant composition may provide robust anti-wear and reduced pitting.

A lubricating oil composition which may contain a zinc dialkyl dithiophosphate, and whose color deterioration over time is alleviated. Such a lubricating oil composition may contain: a base oil (A); a zinc dialkyl dithiophosphate (B); and a sodium-based detergent (C). In such a lubricating oil composition, a content of zinc atoms may be 100 ppm by mass to 2,000 ppm by mass based on a total amount of the lubricating oil composition, and a content of sodium atoms may be 5 ppm by mass to 1,000 ppm by mass based on the total amount of the lubricating oil composition.

The present invention relates to a lubricant composition, in particular for a gas or steam turbine, comprising: —at least one base oil; —at least one phenylnaphthylamine (PAN) compound, preferably alkylphenyl-α-naphthylamine (APAN) compound; —at least one diphenylamine (DPA) compound, preferably dialkyl-diphenylamine compound; and —at least one phosphite ester compound, preferably triaryl phosphite ester compound; in which the ratio by weight between said diphenylamine compound(s) and said phosphite ester compound(s) is strictly greater than 1.0.

A lubricating oil composition including a base oil (X) having a tertiary carbon atom at a content of 8.0 at % or more based on the total carbon of hydrocarbons and an antioxidant (Y) having an amine-based antioxidant (A), a phenol-based antioxidant (B), and a phosphor-based antioxidant (C). The amine-based antioxidant (A) includes a diphenylamine compound (A1) represented by the following general formula (a1):

##STR00001##

where R.sup.a1 and R.sup.a2, na1 and na2 are defined in the disclosure.

Systems and methods for automatic maintenance of lube oil quality include a storage tank for storing fresh lube oil, a lube oil reservoir containing a volume of operational lube oil, and an oil disposal tank. A first controllable flow system transports lube oil from the reservoir to the oil disposal tank, and a second controllable flow system transports fresh lube oil from the storage tank to the reservoir. Provided are a level transmitter to measure a level of lube oil within the reservoir and an antioxidant sensor to measure a concentration of antioxidant level inside the lube oil reservoir. A control system activates and deactivates the first controllable flow system based upon the concentration of antioxidant measured by the antioxidant sensor, and activates and deactivates the second controllable flow system based upon the level of lube oil measured by the level transmitter.

A lubricating oil composition may have excellent long-term anti-foaming performance and detergency while blending a silicone-based anti-foaming agent. Such a lubricating oil composition may contain a base oil (A) and a silicone-based anti-foaming agent (B). A silicon atom content may be 50 ppb by mass to 4,000 ppb by mass, based on a total amount of the lubricating oil composition.

The invention relates to phosphorous-containing compounds useful as antiwear additive components, lubricant additive compositions and lubricant compositions each comprising such compounds, methods for making and using the same, including methods of lubricating machines and machine parts and methods of extending the useful life of elastomeric seal components of such machines.

A hydraulic lubricating oil composition is provided which contains a synergistic mixture of three phosphorous antiwear components in order to provide good thermal stability and good demulsibility to the lubricating oil composition.

A lubricating composition comprising at least 90% by weight of a base oil, and an antioxidant composition comprising the components, set forth as weight % of the lubricating composition: (1) solid alkylated-phenyl-alpha-naphthylamine at 0.01-0.3%, (2) an alkylated diphenylamine derivative of triazole, tolutriazole or benzotriazole, at 0.01-0.3%, and (3) methylenebis(di-n-butyldithiocarbamate), at 0.01-0.4%.

A base stock having at least 90 wt. % saturates, an amount and distribution of aromatics, as determined by ultra violet (UV) spectroscopy, including an absorptivity between 280 and 320 nm of less than 0.015 l/gm-cm, a viscosity index (VI) from 80 to 120, and having a cycloparaffin performance ratio greater than 1.05 and a kinematic viscosity at 100° C. between 4 and 6 cSt. A base stock having at least 90 wt. % saturates, an amount and distribution of aromatics, as determined by UV spectroscopy, including an absorptivity between 280 and 320 nm of less than 0.020 l/gm-cm, a viscosity index (VI) from 80 to 120, and having a cycloparaffin performance ratio greater than 1.05 and a kinematic viscosity at 100° C. between 10 and 14 cSt. A lubricating oil having the base stock as a major component, and one or more additives as a minor component. Methods for improving oxidation performance and low temperature performance of formulated lubricant compositions through the compositionally advantaged base stock.