High (10−3 s−1) densification rates at

Abstract

We measured the real-time densification rates in the current activated pressure assisted densification (CAPAD) of nanocrystalline MgO. The rates of samples densified from powders with grain sizes ~40 nm are similar to those measured previously for other nanocrystalline materials while those from 29 nm powder are higher. Exposing the powders to a humid environment increases the densification rates and allows densification at lower temperatures. The densification rate curves of samples with absorbed water display two peaks implying two controlling mechanisms, while the dry samples display one. We attribute lower temperature densification to Mg(OH)2-MgO conversion and the higher to diffusion-controlled densification.