Synthesis and properties of in situ Al2TiO5/Al2O3 composite

A novel route to simple processing of an in situ aluminum titanate-alumina composite is described. This process offers a simple means of tailoring the composition and microstructure of ceramic material. The process involves and equimolar mixture of Al2O3-TiO2 mixed with a varying equal proportion of FeTiO3 + Fe2O3 (1-10 wt.%, 50/50 mixture). It is known that the kinetic transformation of the aluminum titanate is slow, leaving unreacted Al2O3 and TiO2 after the AbTiO(5) transformation, besides the iron pseudobrookite: Fe2TiO5 grows at the expense of hematite-ilmenite solid solution at 1100 degreesC which is isostructural with Al2TiO5 and forms a complete solid solution, the obtained structure over 5% addition was Al2TiO5 with dispersed unreacted Al2O3. The XRD patterns did not show the presence of FeTiO3, TiO2 or Fe2O3 signals that makes to believe that they enter completely in solid solution with the aluminum titanate. The variation in composition allows an increase in the aluminum titanate Vickers hardness: 10 GPa partly due to the additive strengthening and to the alumina reinforcement. (C) 2003 Elsevier Science B.V. All rights reserved.