A method of using lubricant compositions to reduce wear between two surfaces exposed to a load condition of at least 1 GPa is provided. The lubricant compositions comprise polysiloxane base oils having alkylaryl or a combination of alkyl and aryl functionality. The polysiloxane base oils may be defined according to the formula: wherein R, R′, and R″ are independently selected, such that R is an alkyl group having between 1-3 carbon atoms; R′ is an alkylaryl group comprising alkyl functionality with 3-12 carbon atoms and aryl functionality with 6 to 12 carbon atoms; R″ is an alkyl group having between 1-3 carbon atoms or an alkylaryl group comprising alkyl functionality with 3-12 carbon atoms and aryl functionality with 6 to 12 carbon atoms; and m and n are integers, such that 8<(m+n)<500.
