According to an aspect of the present invention, an aqueous composition contains at least one selected from a group consisting of a carboxylic acid compound represented by the following formula (1), a carboxylic anhydride represented by the following formula (2), and a trimellitic anhydride; a basic compound; and water. In the formula (1), “R” represents an alkanediyl group having 2 to 4 carbons, a vinylene group, or a benzene ring, and “a” represents 2 or 3. In the formula (2), “R” represents an alkanediyl group having 2 to 4 carbons, a vinylene group, or a benzene ring.

According to an aspect of the present invention, an aqueous composition contains at least one selected from a group consisting of a carboxylic acid compound represented by the following formula (1), a carboxylic anhydride represented by the following formula (2), and a trimellitic anhydride; a basic compound; and water. In the formula (1), “R” represents an alkanediyl group having 2 to 4 carbons, a vinylene group, or a benzene ring, and “a” represents 2 or 3. In the formula (2), “R” represents an alkanediyl group having 2 to 4 carbons, a vinylene group, or a benzene ring.

Problems addressed by the present invention are to provide a lubricant composition that is capable of being used as an alternative to chemical conversion treatment by means of phosphate, to provide a lubricant composition having practical stable lubricative performance without the need for additional unwanted operations, and to provide a method for using this to form a lubrication coating, and a metal workpiece at which a lubrication coating is formed on a surface thereof. Provided as a means for solving such problems is a lubricant composition for causing formation of a hemimorphite-containing lubrication coating that contains a silicate compound (e.g., colloidal silica) and water-soluble zinc in solution.

Problems addressed by the present invention are to provide a lubricant composition that is capable of being used as an alternative to chemical conversion treatment by means of phosphate, to provide a lubricant composition having practical stable lubricative performance without the need for additional unwanted operations, and to provide a method for using this to form a lubrication coating, and a metal workpiece at which a lubrication coating is formed on a surface thereof. Provided as a means for solving such problems is a lubricant composition for causing formation of a hemimorphite-containing lubrication coating that contains a silicate compound (e.g., colloidal silica) and water-soluble zinc in solution.

Brine-tolerant lubricants are provided. The brine-tolerant lubricants may comprise an oil component, a surfactant component, and, optionally, an additive component. In one aspect, the oil component comprises a fatty acid alkyl ester. In one aspect, the surfactant component comprises at least one of an alkoxylated fatty acid and an alkoxylated fatty alcohol. Also provided are methods for increasing the lubricity of a drilling fluid by contacting the drilling fluid with the brine-tolerant lubricants.

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, 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 composition of a lubricant including a GTL hydrocarbon, fatty acid amine, and styrene block polymer.

The present invention provides a water/glycol-based hydraulic fluid that includes a total fatty acid and dimer acid of more than 0.4 and no more than 1.2 mass % as a fatty acid lubricant, and also a phosphate ester at between 0.01 and 0.07 mass %. The phosphate ester has the following structure (1) here R1 and R2 each represent a hydrogen atom or a hydrogen group with a carbon number between 1 and 30, and may either be mutually identical or mutually different; R.sub.3 represents a hydrocarbon group with a carbon number between 1 and 20; R.sub.4 represents a hydrogen atom or a hydrocarbon group with a carbon number between 1 and 30; and X.sub.1, X.sub.2, X.sub.3, and X.sub.4 each indicate an oxygen atom or a sulfur atom, where these may either be mutually identical or mutually different.

##STR00001##

The present invention provides a water-glycol hydraulic fluid composition comprising an alkanolamine compound according to the general formula (1), wherein the water-glycol hydraulic fluid composition comprises 20-60% by mass water, 20-60% by mass glycol, 0.6-1.2% by mass fatty acid lubricant, and 0.01-0.06% by mass alkaline hydroxide compound selected from potassium hydroxide and/or sodium hydroxide, and has an alkali reserve of 10-25, wherein R.sub.1 and R.sub.2 are hydrocarbon groups having from 1 to 8 carbon atoms, and R.sub.3 is a hydrocarbon group having 2 or more carbon atoms.

##STR00001##