THERMAL ANISOTROPY OF TIALITE (AL2TIO5) BY POWDER XRD

Tialite was synthesized from stoichiometric mixtures of commercial cor undum and rutile (8-10 mu m) or nanophase coprecipitated alumina and t itania precursor powders. Uniaxially compressed tablets of these precu rsors were calcinated at a temperature in the 1,200-1,500 degrees C ra nge, and cooled to room temperature. One of the nanometric precursors showed appearance of tialite already at 1,300 degrees C, while the com mercial powders began to react only at 1,400 degrees C. DE all cases t he synthesis was complete at 1,500 degrees C. The X-ray diffractograms of the products showed that tialite derived from commercial precursor s assumed a preferred orientation, which was probably induced by the c ompression of the tablet. Na anisotropy was noted after adding a small amount of silica to the commercial powder, however, this led to mulli te formation. Nanophase precursors yielded crystallites with random or ientation.