Investigation of the Dependence of Friction Coefficients of Antifriction Materials Based on Silver on Ambient Pressure in Vacuum

This article presents a method for determining the friction coefficients of an antifriction coating based on silver with the addition of molybdenum disulfide or graphite in a vacuum. The method of determining the coefficients of friction is implemented on a vacuum tribometer. The dependences of the friction coefficients in the contacting pair are obtained — steel SHX-15 and an antifriction coating based on silver with the addition of molybdenum disulfide, and in another case graphite, depending on the ambient pressure. The value of the average coefficient of friction in a pair of a ball made of SHX-15 steel and a ring with an antifriction coating containing 94 % silver and 6 % molybdenum disulfide at an atmospheric pressure of 1000 mbar is 0.114 with a standard deviation of 0.012, and at a pressure of 0.03 mbar 0.168 with a standard deviation of 0.01.

For an antifriction material based on silver with the addition of 6 % graphite, the coefficient of friction varies from 0.144 to 0.26 when the pressure changes from 1000up to 0.03 mbar. Analytical dependences of the coefficient of friction for both antifriction materials on the height of lift in the atmosphere have been obtained, which will make it possible to develop a methodology for calculating spherical articulated bearings for high-altitude aircraft.

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