Highly enhanced aging resistance of rapidly solidified zirconia toughened alumina bioceramics with refined eutectic microstructure

摘要

A novel zirconia toughened alumina bioceramic (ZTA) with a unique microstructure was prepared by rapid solidification with laser floating melting zone technique. The magnitude of microstructure dimension of the solidified samples is refined at the level of the submicron scale (150 nm similar to 630 nm). The aging behavior of assolidified ZTA bioceramic is investigated. The monoclinic ZrO2 phase content of the solidified samples after 145 h of aging decreases from 30 % to 5.3 % when the solidification rate increases from 8 mu m/s to 100 mu m/s, lower than that of the sintered sample with the same composition. The growth rate (alpha(d)) and the nucleation rate (N-r) of monoclinic phase of the solidified samples are lower than the sintered sample and the former is the dominant factor determining the aging behavior. Therefore, the solidified ZTA bioceramics exhibit excellent aging resistance that may cast light on extending the clinical application of all-ceramic dental prosthesis.