Effects of Vacuum Heat Treatment of Nano Powder on Sintering of Transparent Nano-crystalline MgAl_2O_4 Ceramics

摘要

Nano-sized MgAl_2O_4 powders were treated at 500-1000 °C in a vacuum of 10~(-3)Pa for 2 h, and then sintered at 500-900 °C under 1-6 GPa. The powders with and without vacuum-heat-treatment were investigated by means of Transmission Electron Microscope (TEM) and Sedimentation Test. It was found that the vacuum-heat-treatment of nano powder could effectively get rid of the absorbed gas on the surface of nano-particles. Bulk nanostructured transparent ceramics without cracks were sintered easily with the treated nano-sized powder. The success rate of nano-sinteming of bulk transparent ceramics was greatly increased when a suitable vacuum-heat-treatment process was used for the starting nano-sized powder.