Microstructure and Properties of MoSi2-RSiC Composites Prepared by PIP and MoSi2-Si-Al Alloy Melting Infiltration Composite Process

Abstract

The combination of phenolic resin (PF) impregnation-pyrolysis (PIP) and MoSi2-Si-Al alloy activated melting infiltration (AAMI) combination process were used to prepare MoSi2-RSiC composites, in which the RSiC works as a matrix. Influence of infiltrated temperatures on the composition, microstructure, mechanical and electrical properties of the composites were studied by XRD, SEM, mechanical test et. al.. The results showed that an almost fully dense MoSi2-RSiC composite with 3-D interpenetrated network structure was obtained, the compositions of it were mainly SiC, MoSi2 , Mo (Si,Al)2, and small amount of residual Si. With the increase of infiltrated temperatures, the flexural strength of the composites increased first and then decreased, it reached 171.40MPa when infiltrated at 1800°C, which was 107.63% higher than that of RSiC matrix. The fracture properties of the composites exhibited a typical brittle rupture. The composites possessed a volume resistivity of 2.90×10-3 Ω·cm when infiltrated temperature equaled to 1900°C, which was nearly four order of magnitude lower than that of RSiC.