ZrB₂-SiC(Al) ceramics with high resistance to oxidation at 1500°C

In this paper, we study the oxidation behaviour of a ZrB₂/Al-doped SiC composite at 1500°C. The composite was prepared by hot-pressing the mixture of ZrB₂ and polymer-derived SiC(Al). The oxidation behaviour was studied by measuring the weight change as a function of oxidation time and by observing the structure of the oxide layer. It is shown that the ZrB₂-SiC(Al) exhibits different oxidation behaviour and improved oxidation resistance as compared to the conventional ZrB₂-SiC without Al-doping. The improvement in oxidation resistance is attributed to that Al-doping could increase the bond strength of the Si-O and suppress the active oxidation of SiC.