Study on water corrosion behavior of ZrSiO4 materials

ZrSiO4 bulk was prepared by pressureless sintering process and ZrSiO4 coating was deposited on the SiCf/SiC substrate using air plasma method. The microstructures of ZrSiO4 bulk and ZrSiO4 coating are both dense. A preliminary study of a water vapor corrosion test for ZrSiO4 bulk and ZrSiO4 coating was performed under the conditions of 1.013x10(5) Pa, 90%H2O/10%O-2, 1300 degrees C, and low gas velocity. Results show that some pores appear on the surface of the ZrSiO4 bulk. The main crystal phase is ZrO2 and the weight loss of ZrSiO4 bulk is only 0.236 mg/cm(2) after corrosion. The ZrSiO4 coating peels off from the substrate after 109 h. The number and intensity of diffraction peaks of ZrO2 in the coating increase, and the major crystal phase of the coating is still ZrSiO4. A porous microstructure accompanied with cracks is observed on the surface of ZrSiO4 coating after corrosion.