Relationship of densification rate and relative density for submicronα-Al2O3green compacts during low heating rate sintering

The sintering of α-Al2O3 powder compacts with the mean particle size of 350 nm has been investigated at constant heating rates of 0˙5–5°C min–1. Curves of the instantaneous relative density differences and the temperature for different heating rates were constructed, the changing trend of which was consistent with that of densification rate v. temperature. The correlation between densification rate and the relative density was also constructed from the beginning to the end of the sintering process. Maximum densification rates occur at the same relative density of ∼73% and are independent of heating rates. For samples with the same initial relative density, the logarithm of temperature derivative of the densification rate v. the relative density fits within a single, relatively narrow band.