Ablation property of ZrB₂-SiC composite sharp leading edges with varying radiuses of curvature under oxy-acetylene torch

Ablation behavior of ZrB₂-SiC sharp leading edges with five different curvature radiuses was investigated using an oxy-acetylene torch. During the test, the curvature radiuses were 0.15 mm, 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm, respectively. Under the same ablation condition, the smaller was the radius, the severer ablation underwent. The sharp leading edge with a curvature radius of 0.15 mm had the highest surface temperature and maximum surface temperature rising rate, exceeded 2100 °C in less than 30 s. However, the surface of sharp leading edge with a curvature radius of 2.0 mm achieved only 1900 °C in more than 60 s. After 5 min ablation, the mass and linear ablation rates were measured. All the five sharp leading edges evolved to nearly a same radius after ablation. The microstructure of the oxidation layers was also investigated. A ZrO₂-SiO₂ layer generated from oxidation of ZrB₂-SiC acts as a thermal barrier and reduces the diffusion of oxygen.