MoSi2–MoS2 composite antifriction material

Abstract

A new high-temperature antifriction composite material 90 % MoSi2 + 10 % MoS2 was developed with a static friction coefficient of less than 0.3. The material is functional at temperatures up 1500 °C under neutron irradiation in an inert gas environment. Modes of initial MoSi2 and MoS2 powder mixture preparation and hot pressing of the resulting charge in a vacuum induction unit in graphite molds were worked out at a temperature of 1600–1650 °C, specific hot pressing pressure of 25 MPa, and holding for 1 h at these values of temperature and pressure. Tribotechnical properties of the material depending on the compression force in the friction pair and on the counterbody material hardness were investigated. It was shown that the higher the compression force and the harder the counterbody material in the friction pair, the lower the coefficient of friction. The effect of temperature on the physical, mechanical and heat-transfer properties of the material was established. As the temperature increases from 20 to 1000 °C, the material compressive strength decreases from 1388 to 739 MPa. An increase in the temperature from 25 to 400 °C leads to an increase in the specific heat capacity from 427 to 596 J/(kg·K) and the coefficient of heat conductivity from 2.35 to 3.41 W/(m·K). Plain bearings made of this material successfully passed durability and reactor tests.