| abstract |
An aqueous hydraulic fluid composition comprising of one or more lubricants such as a monovalent metal salt, ammonium, or amine salt of a dicarboxylic acid, such as a C21 dicarboxylic acid is described in which the aqueous hydraulic fluid composition demonstrates increased thermal stability when exposed to elevated temperatures for a prolonged period of time while being able to tolerate the presence of 10% v/v synthetic seawater. The aqueous hydraulic fluid composition contains less than about 20% by weight (preferably none or substantially none) of an oil selected from the group consisting of mineral oils, synthetic hydrocarbon oils, and mixtures thereof. The hydraulic fluid hereof preferably comprises a cyclical or ring base tertiary amine with no hydroxyl functionality such as 1,4-dimethyl piperazine. |