Ablation behavior and mechanism of SiO2f/SiO2, SiO2f/BN and Si3N4f/BN radar wave transparent composites

The ablation behavior and mechanism of SiO2f/SiO2, SiO2f/BN and Si3N4f/BN wave-transparent composites have been comparatively investigated by an oxyacetylene torch test. Viscous SiO2 formed during ablation improves the ablation resistance, while BN undergoes complex ablative oxidizing and absorbs heat via oxidants vaporization. The refractory BN matrix also acts as an tough frame that decreases the scouring of oxygen-resistant SiO2 glass. The reinforcing silicon nitride fiber in the Si3N4f/BN composite suffers from active oxidation under ablation conditions, which degrades its anti-oxidation resistance. The heterogeneous reactions during ablation are analyzed and the ablation mechanisms of the different composites are proposed.