Effect Of Andalusite Kyanite And Sillimanite On Properties Of Mullite-corundum Materials

In this paper, andalusite, kyanite and sillimanite were added to mullite-corundum materials and the effect of andalusite, kaynite and sillimanite on properties of mullite-corundum materials was studied. This can offer theory instruction for fabricating low creep mullite-corundum materials.At first, the effect of particle size and additions of andalusite on mullite-corundum materials were studied. The paper studied the decomposition of andalusite by XRD and SEM. The effect of particle size and additions of andalusite on sintering, mechanical properties and thermal expansion properties of samples was also discussed. The results showed that when the particle size of andalusite exceeded 0.5mm the decomposition of andalusite become slower at the temperature higher than 1500℃. Thus when mullite-corundum materials are used at higher temperature, the andalusite can continue to decompose and improve high temperature properties of products.Secondly, the effect of particle size and additions of kyanite on properties of mullite-corundum was studied. The decomposition of kyanite was studied by XRD and SEM. The results showed that when the particle size of kyanite added to mullite-corundum materials exceeded 0.088mm microcracks would formed in the samples because of the expansion produced by the decomposition of kyanite. The particle size of kyanite added to mullite-corundum would be less than 0.088mm, the optimum addition are 10-15wt%.At last, this paper studied the effect of particle size and additions of sillimanite on properties of mullite-corundum materials. The decomposition of sillimanite was studied by XRD and SEM. The results showed that the decomposition temperature of sillimanite was very high. When sillimanite was added to mullite-corundum, the sintering temperature of sample was higher than 1600℃.