Two-step sintering of titania nanoceramics assisted by anatase-to-rutile phase transformation

A remarkable suppression of grain growth was achieved by taking advantage of the anatase-to-rutile phase transformation during the final stage of a two-step sintering process. The minimum grain size obtainable via two-step sintering of a sample with full-rutile (98%) phase at the end of the first sintering step was around ∼250 nm, whereas the anatase-to-rutile transformation at the end of the second step facilitated a reduction in grain size to around 100 nm.