多孔陶瓷材料的抗热震性能

Thermal shock resistance of porous ceramic materials

测定了氧化铝、碳化硅等多孔陶瓷的热膨胀性能,采用水冷法对两种多孔陶瓷进行了抗热震性能实验,测定了热震实验前后陶瓷的弹性模量以及抗折强度的变化情况。实验结果表明:氧化铝和碳化硅多孔陶瓷的平均热膨胀系数分别为7.03×10-6/K,1.14×10-6/K,表明碳化硅陶瓷具有更好的抗热震性能;陶瓷材料的强度随着热震温差的增加而降低。对碳化硅多孔陶瓷进行强度-热应力校核,碳化硅陶瓷的弹性模量随着热震温差的增加而降低,其热震临界温差范围为300～400℃。

Thermal expansion properties of porous alumina and silicon carbide ceramics were examined using a dilatometer.Thermal shock resistance property of the ceramics were studied by water-quenching method,and strength and elastic modulus of the ceramics before and after thermal shock experiments were examined.The average thermal expansion coefficient of porous alumina and silicon carbide ceramics were 8.49×10-6/K and 1.14×10-6/K,respectively.The results show that the thermal shock resistance of silicon carbide is better than that of alumina and the residual strength of the ceramic materials decreases with increasing of temperature difference.The residual strength and thermal stress of porous silicon carbide ceramic is checked and a critical temperature difference exists for thermal shock experiment of the ceramic,and its elastic modulus decreased with the increase of temperature difference.The critical temperature difference of the porous silicon carbide is 300-400 ℃.