GRAPHITE DISPERSED FERRITIC IRON ALLOY BEARING BY POWDER METALLURGY

摘要

In order to develop ferritic iron alloy bearing containing graphite of up to 10 mass % or so, pressing and sintering properties of Fe-Si-Sn-graphite mixed powders were investigated. To stabilize the ferrite phase of iron alloy, the silicon was added to the iron in the range of 3-6 mass %. The tin, a strong ferric former, plays an important role in sintering as a densification activator, but an excessive addition leads sintered compacts to be brittle. The minimum small addition of the tin combining with the silicon is of 0.5 mass %. Compacts sintered at 1420 K in H_2 show the structure of the ferrite matrix phase dispersing graphite particles and pores. With increasing sintering time, isolated pores in the matrix decrease rapidly and pores surrounding graphite particles come to shrink to the same size as particles. Good self-lubricating and tribological properties were confirmed.