Synthesis of ZrO2-Nitride Composite Powder and Effect of Its Addition on Properties of Low Carbon Al2O3-C Refractories

摘要

Using zircon and activated carbon as raw materials,ZrO2-nitride composite powder was synthesized by carbothermal reduction and nitridation (CRN) in nitrogen atmosphere.The effect of ZrO2-nitride composite powder addition on thermal shock resistance (TSR) and oxidation resistance of the Al2O3-C refractories was compared by residual CMOR ratio after 1100°C-air quenching and the thickness of oxidation layer respectively.Phase compositions and microstructure of the Al2O3-C refractories were investigated by X-ray diffraction (XRD) and scanning electronic microscope (SEM) fitted with an energy-dispersive spectroscopy (EDS) analyzer.XRD results of ZrO2-nitride composite powder showed that the relative content of ZrO2 and nitride reach about 30％ and 70％,respectively.The mainly phases of the nitride are:Zr7O8N4(30％),Si2N2O (20-30％),besides of them,some of ZrN(5％) and β-Si3N4(3％) were also obtained.TSR and oxidation resistance of Al2O3-C refractories can be improved obviously by the addition of the synthesized ZrO2-nitride composite powder.