Structure evolution and high-temperature oxidation behavior of B-doped SiOC ceramic

Abstract

Boron (B)-doped SiOC (SiBOC) ceramics were prepared by sol-gel method with triethyl borate (B(OCH₂CH₃)₃ as modifier, and SiBOC ceramic bulks were prepared by spark plasma sintering (SPS). The structure evolutions of SiBOC ceramics with various B doping content and pyrolysis temperature were studied. Meanwhile, the oxidation behaviors of different SiBOC ceramic bulks at 1200 °C and 1500 °C were investigated. Results showed that B₂O₃ and borosilicate formed during oxidation can reduce the viscosity of SiO₂-based oxide layer and improve its self-healing ability. S0.05B-1600 ceramic showed the highest oxidation resistance, with the lowest oxidation rate of 6.82 × 10⁻⁵ mg²/(cm⁴·h) after oxidation 4 h at 1200 °C, for the dense and continuous oxide layer with high self-sealing ability and low oxygen diffusion coefficient.