Mechanical and electrical properties of MoSi2-RSiC composites via a combination of phenolic resin infiltration-pyrolysis and MoSi2-Si-Ti alloy-activated melting infiltration composite processes

摘要

A three-dimensional interpenetrated network structure composite was designed and prepared via a combination of phenolic resin infiltration-pyrolysis and MoSi2-Si-Ti alloy-activated melting infiltration processes to effectively merge the desirable properties of MoSi2 and RSiC. Influence of infiltration temperature on the microstructure, mechanical and electrical properties of the composites was examined. Almost dense MoSi2-RSiC composites with the designed structure were obtained at 1900 degrees C. Formation of the gradient interface modified the interface combination and enhanced the mechanical and electrical properties of the composite. Flexural strength of the composites reached approximately 114.262 MPa (room temperature) and 128.392 MPa (1400 degrees C), respectively, indicating corresponding increases of 37.08 and 35.69% compared with the RSiC matrix. Volume resistivity decreased to 57.63 m Omega cm, nearly five orders of magnitude lower than that of RSiC. Influence of the interpenetrated network structure and interface combination on the electrical conductivity behaviour of the composites was discussed via a modified mixture rule.