氧化铝-钛酸铝-莫来石复相陶瓷抗热震性研究

Research on thermal shock resistance of alumina-aluminium titanate-mullite ceramics

为了提高氧化铝陶瓷的抗热震性,将具有低膨胀系数的钛酸铝和莫来石加入到Al2O3中,通过无压烧结工艺,制备出了氧化铝-钛酸铝-莫来石复相抗热震陶瓷.结果表明,钛酸铝加入量w（Al2O3.TiO2）=10%-20%、烧结温度为1470-1550℃时,陶瓷可获得较高密度.陶瓷样品能够承受1500℃温差（空冷）的热震破坏.采用SEM对陶瓷进行组织结构分析,发现在基体内部形成长柱状固溶体,并呈无规分布状态.这样的显微组织有利于缓解热应力和提高强度,对提高陶瓷的抗热震性具有重要作用.同时,在基体内部存在大量的微孔和微裂纹,使材料表现出更低的热膨胀.

In order to improve the thermal shock resistance of alumina ceramics, both aluminium titanate with low thermal expansion and mullite powder were added into Al2O3 powder, and the alumina-aluminium titanate-mullite ceramics with good thermal shock resistance was fabricated by means of pressureless sintering technology. The experimental results show that the density of the ceramics is the highest when the adding mount of aluminium titanate is w （aluminium titanate） = 10% -20% and the sintering temperature is 1 470- 1 550 ℃. The fabricated ceramics can resist thermal shock with the temperature difference of 1 500 - （cooling in air）, The SEM observations on the microstructure of ceramics reveal that the strip-like solid solution has formed in the matrix, and distributes without any orderliness. Such microstructure is effective to abate thermal stress and improve the strength of ceramics, and plays an important role in enhancing the thermal shock resistance of the ceramics. In addition, there exist a lot of small pores and micro-cracks in the matrix so that the ceramics can exhibit smaller thermal expansion.