Characterization of nano-sized alpha-Al2O3 compacts prepared via modified theta-Al2O3@PEG technology

Modified (core) theta-Al2O3@ (shell) polyethylene glycol (PEG) technology was used to prepare alpha-Al2O3 green compacts composed of <100-nm alpha-Al2O3 crystallites using theta-Al2O3 as the starting material. The preparation process has two steps. In the first step, theta-Al2O3 compacts in which alumina crystallites were apart individually after the removal of PEG were made. In the second step, the theta-Al2O3 was transformed into alpha-Al2O3.The compact showed phase purity of >85% alpha-Al2O3 with crystallites sizes ranging from 50 to 100 nm and the compact density was >60% of the theoretical value.