ZrC-SiC-MoSi_(2)涂覆C/C-SiC-ZrC陶瓷基复合材料在氧乙炔焰下的烧蚀行为及机理

Ablation behavior and mechanisms of ZrC-SiC-MoSi2 coated C/C-SiC-ZrC ceramic matrix composites under oxyacetylene torch

为进一步提高C/C复合材料在不同烧蚀环境下的烧蚀性能,采用浆料刷涂法在C/C-SiC-ZrC陶瓷基复合材料上制备Zr含量分别为34%和60%(质量分数)的ZrC-SiC-MoSi_(2)涂层,并且利用氧乙炔焰研究涂层C/C-SiC-ZrC复合材料在3种不同氧气及乙炔流量下的烧蚀行为。结果表明:随着Zr含量的增加,涂层内部的ZrC和SiC颗粒尺寸明显减小,且颗粒分布更加均匀。Zr含量为60%的涂层线烧蚀率随氧气和乙炔流量的增加而增加,而Zr含量为34%的涂层线烧蚀率随氧气和乙炔流量的增加,先增加后降低。此外,详细讨论ZrC-SiC-MoSi_(2)涂层在不同条件下的烧蚀机理。随着氧气和乙炔流量的增加,主要的烧蚀机制由氧化变为氧化和蒸发的结合作用,最后变为氧化、蒸发及剥蚀的结合作用。

To further improve the anti-ablation property of C/C composites in different ablation environments,ZrC-SiC-MoSi_(2)coatings containing 34 wt.%and 60 wt.%Zr were prepared on C/C-SiC-ZrC ceramic matrix composites via slurry painting(SP)method.And the ablation behavior of the coated composites was investigated in oxyacetylene torch environment with three kinds of fluxes of oxygen and acetylene.The results show that with the increase of Zr content,the particle sizes of ZrC and SiC in the coatings are significantly reduced,with the particles distributing more homogeneously.The linear ablation rates of the coatings with 60 wt.%Zr increase with the increase of oxygen and acetylene fluxes,while for the coatings with 34 wt.%Zr,the linear ablation rates increase at the beginning and then decrease.The ablation mechanisms of the coatings under different conditions were discussed as well.With the increase of oxygen and acetylene fluxes,main ablation mechanisms change from oxidation to oxidation plus evaporation and then to the combination of oxidation,evaporation and denudation.