Deformation-induced reactions of ZnO and TiO2

Reactions of ZnO and TiO 2 (anatase and rutile) in different mole ratios induced by high-energy ball milling were studied by X-ray diffraction. It was found that three main reactions could involve during high-energy ball milling: (1) (4 - X)ZnO + (2 + Y) TiO 2 (anatase or rutile) → Zn 4-X Ti 2+Y O 8 ; (2) ZnO + TiO 2 (rutile) → ZnTiO 3 , and (3) TiO 2 (anatase) → TiO 2 (II) → TiO 2 (rutile). Cubic Zn 4-X Ti 2+Y O 8 nanocrystals with an average crystal size of about 15 nm can be prepared by high-energy ball milling, which could be an attractive process to fabricate material in industrial scale. No decomposition of ZnTiO 3 into Zn 2 TiO 4 and rutile was detected during milling. Anatase shows higher reaction activity than rutile and favours the formation of Zn 4-X Ti 2+Y O 8 while rutile favours the formation of ZnTiO 3 . During the anatase-to-rutile transformation a transient metastable phase, TiO 2 (II) which is a high-pressure phase of TiO 2 , is detected.