材料期刊网

A silicide coating was prepared on Ti3SiC2-based ceramic by pack cementation to improve the oxidation resistance of Ti3SiC2, which is a technologically important material for high temperature applications. The microstructure, phase composition and oxidation resistance of the coated sample were investigated. The results demonstrated that the silicide coating was mainly composed of TiSi2 and SiC. A single layer of a mixture of SiO2 and TiO2 was formed on the surface of the coated sample during isothermal oxidation at 1100 degreesC and 1200 degreesC for 20h. Compared to Ti3SiC2, the parabolic rate constant of silicide coated Ti3SiC2 decreased by 2similar to3 orders of magnitude. Furthermore, the coated sample showed much better cyclic oxidation resistance than Ti3SiC2 during the cyclic oxidation at 1100 degreesC for 400 times. However, during the preparation of the coating, a number of fine cracks formed in the outer layer of the coating. When these cracks penetrated the whole coating during the cyclic oxidation, the oxidation rate was accelerated, which degraded the oxidation resistance.