Oxidation behavior of silicide coating on Ti 3 SiC 2 -based ceramic

. A silicide coating was prepared on Ti 3 SiC 2 -based ceramic by pack cementation to improve the oxidation resistance of Ti 3 SiC 2 , 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 TiSi 2 and SiC. A single layer of a mixture of SiO 2 and TiO 2 was formed on the surface of the coated sample during isothermal oxidation at 1100 °C and 1200 °C for 20h. Compared to Ti 3 SiC 2 , the parabolic rate constant of silicide coated Ti 3 SiC 2 decreased by 2~3 orders of magnitude. Furthermore, the coated sample showed much better cyclic oxidation resistance than Ti 3 SiC 2 during the cyclic oxidation at 1100 °C 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.