Preparation of zirconium boride based composite ceramic powder and ablative resistance of spraying coating

Ultra-high temperature ZrB2/MoSi2 ceramic coating can effectively improve the high temperature ablation resistance of C/C ceramic matrix composites. The composite powder was prepared by spray drying agglomeration granulation method, and then the composite powder was densified by plasma densification process. The influence of plasma densification process parameters on the properties of the treated powder was studied. After plasma densification, the bulk density and fluidity of the powder were significantly improved. The loose pack density and fluidity of ZrB2/MoSi2 powder were 3.26 g/cm3 and 21.5s /50g, respectively. Compared with agglomerated powder, the loose pack density and fluidity were increased by 108.97 % and 59.01 %, respectively. After densification, the oxygen content of the powder was reduced to 0.05 wt.%. The ZrB2/MoSi2 composite powder was almost not oxidized during the plasma densification process. The ablation test of the plasma spraying coating shows that the coating structure is intact and no spalling occurs after ablation, which indicates that the prepared ZrB2/MoSi2 coating has good high-temperature ablation resistance.