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Aluminum Titanate Formation by Solid‐State Reaction of Fine Al 2 O 3 and TiO 2 Powders

1987; Wiley; Volume: 70; Issue: 1 Linguagem: Inglês

10.1111/j.1151-2916.1987.tb04849.x

1551-2916

B. Freudenberg, Alain Mocellin,

Microwave Dielectric Ceramics Synthesis

The formation of Al 2 TiO 5 has been studied in equimolar Al 2 O 3 ‐TiO 2 powder mixtures of ∼1μm particle sizes and moderate purity (∼99.8 wt%) at temperatures around 1300°C, where the free energy of formation is very small. Micro‐structural development and reaction kinetics indicate that different mechanisms operate depending on the advancement of the reaction. The rapid initial reaction stage is interpreted as the nucleation‐growth of Al 2 TiO 5 cells in a virtually non‐reacting matrix. The final reaction stage corresponds to the slow diffusion‐controlled elimination of Al 2 O 3 and TiO 2 dispersoids trapped during the growth of the initial Al 2 TiO 5 cells.