Pseudo low-temperature sintering effect and microstructure evolution of SiBCO ceramics

Incorporation of B atoms into SiOC ceramic can suppress the carbothermal reaction and improve the thermal stability. Polymer derived ceramics from single source preceramic polymer is a good solution but the B/Si ratio could not be efficiently adjusted. In this article, a simple, low cost, but efficient method to synthesize SiBCO preceramic polymers was introduced. The B/Si ratio could be adjusted from 1:10 to 5:10, and transformed into SiB 0.05 C 0.66 O 1.22 , SiB 0.07 C 0.62 O 1.28 , and SiB 0.27 C 0.54 O 1.32 upon sintering. The boron content could be readily tuned and the “pseudo low-temperature sintering” effect was systematically investigated. The boron content of sintered SiBCO ceramics could reach 4.9 wt%. The addition of boron suppresses the crystallization of β-SiC and improved thermal stability, indicating possible applications under harsh environments.