Effect of milling on properties and consolidation of TiO2 by high-frequency induction heated sintering

Commercial TiO2 powders were high-energy ball milled for various durations and consolidated using highfrequency induction heated sintering (HFIHS). The effect of milling on the sintering behavior, crystallite size and mechanical properties of TiO2 powders were evaluated. A nanostructured dense TiO2 compact with a relative density of up to 98% was readily obtained within 1 min. The ball milling effectively refined the crystallite structure of TiO2 powders and facilitated the subsequent densification. The sinter-onset temperature was noticeably reduced by the prior milling for 10 h. Accordingly, the relative density of TiO2 compact increased as the milling time increases. Furthermore, the microhardness and fracture toughness of sintered TiO2 increased as the density increases. It is clearly demonstrated that a quick densification of nano-structured TiO2 bulk materials to near theoretical density could be obtained by the combination of HFIHS and the preparatory high-energy ball milling processes.