WAN Jun, WANG Zhoufu, WANG Xitang, LIU Hao, MA Yan
(The State Key Lab of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China)
Abstract：Al2O3-LaAl11O18 composites were prepared by the activated alumina as raw material, respectively, La2O3, LaAlO3 and presynthesized LaAl11O18 for different source of lanthanum. The effects of different sources of lanthanum, content and sintering temperatures on the properties of Al2O3-LaAl11O18 composites were investigated. The phase composition and microstructure of the samples were characterized by XRD and SEM. The results showed that the addition of La2O3, LaAlO3 and pre-synthesized LaAl11O18in the activated alumina could form LaAl11O18 phase. The lanthanum hexa-aluminate grains are distributed along the grain boundary of corundum grains, which is not conducive to the sintering of corundum ceramics. The density of samples with LaAlO3 as source of lanthanum is higher than others. With the increase of LaAlO3 content, the degree of densification decreases .When the calcination temperature is 1650 ℃, the densification degree of the sample is higher, and the grain size of corundum and lanthanum hexaaluminate is relatively small.
Key words: corundum; lanthanum hexa-aluminate; composites; microstructure