Morphology and microstructure of ZrB2–SiC ceramics after ablation at 3000 oC by oxy-acetylene torch

Application of ZrB2–SiC ceramic at temperatures above 2500 °C requires evaluation of the ablation behavior of the material. The ZrB2–SiC ceramics with SiC contents of 15% and 30% in volume were fabricated by SPS under a temperature of 1580 °C. The ceramics were then ablated by an oxy-acetylene flame with a temperature of 3000 °C. It was found that ZrB2–SiC consists of three distinct ablation layers (ZrO2, SiO2-rich, and SiC-depleted) after ablation. The ablation mechanism revealed that ZrB2–SiC forms a SiO2-rich layer, which slows down the diffusion of oxygen but accelerates the active oxidation of SiC.