Effect of ZrO_2-nitrides Composite Powder Addition on Oxidation Resistance of Al_2O_3-C Refractories

Oxidation of carbon is the main problem of Al2O3-C refractories.ZrO2-nitrides composite powder was synthesized through carbothermal reduction and nitridation (CRN) of zircon.The effect of ZrO2-nitrides composite powder addition on oxidation resistance of the Al2O3-C refractories was investigated by measuring the thickness of oxidation layer.Phase compositions of the Al2O3-C refractories before and after oxidation were investigated by X-ray diffraction (XRD).Results show that the oxidation resistance of the Al2O3-C refractories can be obviously improved by adding the synthesized ZrO2-nitrides composite powder.The formation of mullite and zircon in the oxidation layer results in the densification of oxidation layer,which prevents oxygen diffusion and improves the oxidation resistance of the Al2O3-C refractories.