SiC晶须对ZrO_2-莫来石陶瓷烧结性能及抗热震性能的影响

The Effect of SiC Whisker on the Sintering and Thermal Shock Resistance Property of ZrO_2-mullite Ceramic

为了提高ZrO_2-莫来石陶瓷的综合性能,以纳米莫来石和ZrO_2纤维为原料,SiC晶须为添加剂,利用机压成型和N2气氛保护下无压烧结工艺制备ZrO_2-莫来石陶瓷。通过检测试样的相对密度、线变化率和热震次数,利用XRD和SEM等手段对试样的性能、组成和显微结构进行分析和表征,重点研究SiC晶须对ZrO_2-莫来石陶瓷烧结性能和抗热震性能的影响。结果表明:SiC晶须的加入使得ZrO_2-莫来石陶瓷试样的相对密度降低,气孔率增大;SiC晶须与ZrO_2晶形转变的协同作用提高了ZrO_2-莫来石陶瓷的断裂韧性;SiC晶须的加入明显提高了ZrO_2-莫来石陶瓷的热震稳定性,且加入20vol.%SiC晶须试样的热震次数达到50次,抗热震性能达到最佳。

In order to improve the comprehensive property, the ZrO2-mullite ceramic was prepared by mechanical shaping method and pressureless sintering in nitrogen atmosphere, using nano-mullite and ZrO2 fiber as materials, and SiC as an additive. The effect of SiC whisker on the property, crystalline phase composition and microstructure of the specimens was investigated by analyzing the relative density, apparent porosity, XRD and SEM. Results indicated that the relative density of the ceramic specimens was decreased and the apparent porosity was increased with the doping of SiC whisker. The fracture toughness of ZrO2-mullite ceramic was increased with the introduction of SiC whisker and the phase translation of ZrO2. The optimal thermal shock resistance of ZrO2-mullite ceramic reached 50 times when 20vol.%SiC whisker was introduced to the ceramic.