Erosion mechanism of ternary-phase SiC/ZrB2-MoSi2-SiC ultra-high temperature multilayer coating under supersonic flame at 90° angle with speed of 1400 m/s (Mach 4)

A ternary-phase SiC/ZrB2-MoSi2-SiC multilayer coating was prepared on graphite by two-step reactive melt infiltration (RMI) method. The formation mechanism of the coating was studied by HSC chemistry software 6.0. The erosion resistance of the coating was investigated by supersonic flame erosion test at 90° angle, temperature of 2173 K and speed of 1400 m/s (Mach 4) for 120 s. Erosion test results revealed that the SiC/ZrB2-MoSi2-SiC multilayer coating had very good erosion resistance. Weight change percentage, mass erosion rate and linear erosion rate of the coating were −0.18 %, −0.027 × 10−3g cm−2 s−1 and 0.33 μm s−1, respectively. Microstructural characterization demonstrated that interesting structures such as rod-like, flake-like, spherical, worm-like and fibrous structures were formed during erosion test. The erosion mechanism of ZrB2-MoSi2-SiC coatings is controlled both chemically and mechanically. The reduction of chemical degradation can be attributed to the presence of MoSi2 particles and the reduction of mechanical degradation can be related to the presence of ZrB2 particles.