Ablation behavior of ZrB۲–SiC–Si composites with WC and MoSi۲ additives coated through SPS on graphite

The intention of this paper is to investigate the resistance to ablation of shielding composite coatings built with ultra-high temperature ceramic materials on graphite substrate. To apply the coating on the graphite, the spark plasma sintering route was employed. The applied monolayer coatings had the base compositions of ZrB۲–SiC–Si with the additives of WC and MoSi۲, both in the same contents of ۱.۲۵ and ۳.۷۵ vol%. The outcomes achieved from the ablation tests by oxyacetylene flame showed that applying the protective composite coatings notably enhances the resistance to ablation of the substrate made of graphite. The coating containing more of WC and MoSi۲ additives had better performance in terms of ablation resistance in ۳۰-۲۱۰ seconds. The formation of an oxide layer of (Zr,Si)O۲ at the beginning of the ablation process and creating a layer with a porous microstructure on the composite coating surface functioned as a barrier against the destruction and erosion of the inner parts during longer ablation times.The intention of this paper is to investigate the resistance to ablation of shielding composite coatings built with ultra-high temperature ceramic materials on graphite substrate. To apply the coating on the graphite, the spark plasma sintering route was employed. The applied monolayer coatings had the base compositions of ZrB۲–SiC–Si with the additives of WC and MoSi۲, both in the same contents of ۱.۲۵ and ۳.۷۵ vol%. The outcomes achieved from the ablation tests by oxyacetylene flame showed that applying the protective composite coatings notably enhances the resistance to ablation of the substrate made of graphite. The coating containing more of WC and MoSi۲ additives had better performance in terms of ablation resistance in ۳۰-۲۱۰ seconds. The formation of an oxide layer of (Zr,Si)O۲ at the beginning of the ablation process and creating a layer with a porous microstructure on the composite coating surface functioned as a barrier against the destruction and erosion of the inner parts during longer ablation times.