Fabrication and properties of highly transparent Li0.07Al2.76O3.64N0.36 ceramics by aqueous gelcasting and two-step preparation

Highly transparent Li0.07Al2.76O3.64N0.36 discs (phi 22 x 2.0 mm) and blocks (45 x 40 x 12 mm) were successfully prepared by aqueous gelcasting and two-step preparation. After introducing a small amount of lithium, the lower N1s binding energy and higher intensity of Al-N bonds on the surface of Li0.07Al2.76O3.64N0.36 powder cause Al-N breakage to be effectively avoided, which inhibits the hydrolysis of powder. Using MAM and MABM as monomers and gelling agents, a stable aqueous suspension with solid loading up to 55 vol% and low viscosity of 83 mPa s was prepared, and the rheological properties and gelating behaviour of the slurries were evaluated. Due to its composition and novel crystalline structure, the Li0.07Al2.76O3.64N0.36 component presented significantly different performances from gamma-AlON. The Vickers hardness reached 15.44 +/- 0.34 GPa at a load of 9.8 N, and the in-line transmittance reached similar to 84.7% at 3.7 mu m.