Pressure and Temperature Effects on Viscosity of Synthetic Lubricants

Abstract

Viscosity of several synthetic lubricants is measured in a diamond-anvil high=pressure cell by the falling sphere method at elevated temperature. Viscosity-pressure coefficients of bicyclohexylcyclohexylmethane, dimethylsilicone and a mixture of them, which are important in elastohydrodynamic lubrication and traction coefficient, are obtained. In order to discuss the property of the mixture, the Wright method is applied and shows agreement with the present data. Viscosity-temperature characteristics under high pressure are also discussed using Walther's equation, and this equation proves to be effective even under high pressure. Factors relating the viscosity=temperature property of the mixture are close to those of dimethylsilicone.