Splat formation of plasma sprayed functionally graded YSZ/NiCrCoAlY thermal barrier coatings

Splat morphologies of YSZ/NiCrCoAlY TBCs by plasma spray were characterized using SEM. Based on some assumptions, plasma jet temperature field was established by numerical simulation and the effects of spray parameters are individually studied to optimize the spray process parameters. Furthermore, the interaction wetting ability was taken into account in order to investigate the interaction effect between ZrO₂ and NiCrCoAlY droplets. It shows that T enhances markedly with increasing in I and decreasing in F_Ar; while in despite of the insignificant effect of F_He on T, the temperature of powder in plasma jet enhances with increasing in F_He. As a result of higher thermal conductivity of powder in He plasma gas. NiCrCoAlY droplet impacting solidified NiCrCoAlY splat wets well and spreads fluently while that impacts solidified YSZ splat spreads restrictedly for the poor wetting on the YSZ splat surface.