Al2O3对MgO陶瓷微观结构和性能的影响

Effect of Al_2O_3 on Microstructure and Performance of MgO Ceramic

采用X射线衍射仪、扫描电镜(SEM)、电子能谱(EDS)、电子万能试验机和Archimedes排水法研究了不同Al_2O_3添加量对MgO结构和性能的影响。结果表明:Al_2O_3的添加改善了MgO陶瓷的烧结性能;Al_2O_3与MgO反应生成起结合作用的MgAl_2O_4分布在MgO陶瓷晶粒的周围,使颗粒间结合紧密并填充孔隙,从而降低气孔率,提升致密度;当Al_2O_3添加量为20%时,在1500℃烧结2h的样品综合性能最好,此时样品的线收缩率为20.93%,体积密度为2.422 g·cm^(-3),气孔率为12.41%,抗弯强度为45.6 MPa;Al_2O_3加入提高了MgO陶瓷的抗热震性,Al_2O_3添加量为10%时,MgO陶瓷的抗热震性最好。

The microstructure and performance of MgO ceramics with different Al2O3 contents were investigated by X-ray diffractometer （XRD）, scanning electron microscope （SEM）, EDS analysis, electronic universal testing machine and Archimedes drainage method. The results show that addition of Al2O3 improved sinterability of MgO ceramics, During the sintering process, Al2O3 reacted with MgO to form MgAl2O4ceramic phase around the MgO particles, which can make the particles combined closely and fill the pores, so as to reduce the porosity and enhance the density. The sample sintered at 1500 ℃ for 2 h had linear shrinkage ratio of 20.93%, volume density of 1.4995 g. cm-3, porosity of 12.41% and the bending strength of 45.6 MPa, when the adding amount of Al2O3 was 20%. With the addition of Al2O3, the thermal shock resistance of MgO ceramics is improved, when the adding amount of Al2O3 was 10%, the thermal shock resistance of MgO ceramics is the best.