Optimization method for self‐healing improver in fiber‐reinforced ceramics using SiC healing agent

Abstract An optimization method for lowering the effective self‐healing temperature of fiber‐reinforced self‐healing ceramics (shFRC) was investigated using B 4 C as a self‐healing improver. B 4 C was selected based on its ability to oxidize at lower temperatures than SiC, a typical self‐healing agent. B 4 C/SiC powder mixtures were studied for their high‐temperature oxidation behavior, revealing reaction initiation around 600°C during constant heating rate. At 1000°C, B 4 C oxidation accelerated SiC oxidation by 15 times. Several shFRCs with B 4 C/ SiC interlayer were fabricated to investigate self‐healing behavior. Results showed strength recovery after heat treatment at 650°C for 1 h with ≥6 vol% B 4 C, and at 600°C for 1 h with ≥12 vol% B 4 C. However, treatments above 700°C led to no strength recovery due to component degradation from oxide formation. The study concludes that optimizing self‐healing improvers requires consideration of their stability prior to reaction, heat generation relative to the amount added, and characteristics of the produced oxide. In the case of B 4 C, 12 vol% with maximized self‐healing performance at 600°C is optimal. This research demonstrates the potential of B 4 C in lowering the effective self‐healing temperature of shFRCs, while emphasizing the importance of balancing improver content and treatment temperature to maintain the composite's integrity.