Abstract:Ni-20Cr powders mixed with tungsten, aluminum, titanium, and different contents of molybdenum disulfides were hot-pressed in graphite mould by powder metallurgy method. Their tribological properties from room temperature to 600 ℃ and mechanical properties at atmosphere were tested. The results show that the hardness and anti-bending strength of composites increase  by more than 20% when containing 6%(mass fraction) MoS₂. But when molybdenum disulfide content exceeds 6%, the hardness and anti-bending strength will decrease gradually. The addition of MoS₂ is favored to the reduction of friction coefficient of composite. The friction coefficient of composite decreases with the increase of molybdenum disulfide until the percentage of lubricant reaches 12%. In excess of this value, the friction coefficient value starts to ascend. The wear rates of composite with molybdenum disulfide are one order of magnitude lower than the alloy without lubricant. When the addition amount of MoS₂ is in the range of 6% and 12%, the wear rates keep at the resemble level.

Key words: Ni-20Cr; MoS₂; solid lubrication; self-lubricating composite; high-temperature; friction