Densification behavior of mullite-Al2TiO5 composites by reaction sintering of natural andalusite and TiO2

Abstract In this work, mullite-Al 2 TiO 5 composites were fabricated by natural andalusite with TiO 2 as an additive. The densification characteristic, phase composition and mullitization process of andalusite with TiO 2 addition was investigated by the Archimedes’ principle, dilatometry, X-ray diffraction and scanning electron microscopy (SEM-EDS) techniques. The results showed that the incorporation of TiO 2 not only enhanced the thermal stability of in-situ Al 2 TiO 5 in the silica liquid yielded from the mullitization of andalusite, but also accelerated andalusite decomposition and retarded mullite formation, which facilitated the sintering and densification of mullite-Al 2 TiO 5 composites.