High energy ball milling of titania and titania–ceria powder mixtures

Titania alone and several titania–ceria blends of powders were milled by high energy ball milling for different periods of time. Phases, crystal size, particle size and morphology were evaluated. The research has demonstrated that milling reduces the mean crystallite size to less than 30 nm for any time whereas powder particles coalesce into coarse agglomerates. At the same time anatase titania transforms to rutile after 3 hour milling, but a thermal treatment at 700 °C for 1 h partially recovers the original crystal structure. The behaviour of ceria–titania blends is similar to that of titania alone, but the reversibility of the anatase–rutile transformation does not occur when the quantity of ceria is greater than a critical level which we have set between the composition with Ce/Ce + Ti ratios of 5 and 10 wt.%.