Mo_5Si_3-Si_3N_4複合材料の滑り摩耗と固体粒子***ージョン特性

概要

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Silicon nitride (Si_3N_4) matrix composites reinforced with 1.5-8.1 mass% Mo_5Si_3 particles were fabricated by sintering molybdenum solution-infiltrated porous Si_3N_4 at 1850℃ in nitrogen atmosphere, and the sliding wear and solid particle erosion behaviors of the Mo_5Si_3-Si_3N_4 composites were evaluated. During sliding wear, the formation of an adherent layer on wear scar of Mo_5Si_3-Si_3N_4 composite was inhibited, and the frictional resistance reduced compared with Si_3N_4 due to the self-lubricant effect of the Mo_5Si_3 particle. The friction coefficients of Mo_5Si_3-Si_3N_4 composites were in the range of 0.52-0.58, 〜6-16% lower than that of Si_3N_4. The specific wear rate of the Mo_5Si_3-Si_3N_4 composite decreased with decreasing content of Mo_5Si_3 particle, and was 0.61×0^<-8>mm^2/N for the 8.1mass% Mo_5Si_3-Si_3N_4 composite, lower than that of Si_3N_4 by 〜50%. As for solid particle erosion, when Mo_5Si_3 particles of 2 mass% or less were incorporated into Si_3N_4, remarkably better wear resistance than Si_3N_4 was shown. However, when a large fraction of Mo_5Si_3 particle was incorporated, the erosion rate was higher than that of the Si_3N_4, and increased with increasing content of Mo_5Si_3. This was due to the lower values of both fracture toughness and hardness of the composites.
2003-12-01