High temperature oxidation behavior and mechanism of SiC-TaB2 composites

In order to improve the oxidation resistance of SiC in its ceramic matrix composites (CMCs), monolithic SiC ceramics doped with various proportions of TaB2 were prepared, isothermal and non-isothermal oxidation was investigated in detail as well. It was found that even a small proportion addition of TaB2 can effectively alleviate the intense oxidation of SiC between 1200 ºC to 1600 ºC, i.e., an oxidation degree of SiC can be reduced by 37% in the case with 10 wt% TaB2 under non-isothermal oxidation from room temperature to 1600 ºC. The oxidation resistance mechanism was also studied via analyzing the composition and microstructure of the formed oxide layer, it was found that the transformation of Ta2O5 in the multiphase oxide layer from grainy to flaky shape at about 1500 ºC plays the most important role in the excellent high temperature oxidation resistance of composites.