Mechanically induced reaction between alkaline earth metal oxides and TiO₂

This paper outlines the formation of alkaline earth metal titanates, of the general formula MTiO₃, directly from the metal oxides and rutile by mechanical activation in a laboratory ball mill at room temperature. X-ray diffraction analysis showed that the reaction was essentially complete within 100 h for all metals except magnesium. The titanates formed all had a Scherrer crystallite size of 11-12 nm and a lattice strain of 0.5-0.6%, neither of which were affected by extended milling. Annealing studies confirmed that the titanate was formed during milling and showed that grain growth could be achieved at temperatures below that generally used for their formation. Mixed cation titanates could also be formed by milling, but tended to be barium rich until annealed.