HOT-PRESSING OF THE AlN-Al2O3 SYSTEM.

Aluminum nitride was studied as a candidate material for composite materials. Its refractory as well as thermal properties were examined. The powder mixtures in the AlN-Al//2O//3 system were hot-pressed under 200 kg/cm**2 at 1600 to 2100 degree C for one hour. The effect of Al//2O//3 addition on the densification rate was remarkable especially in the AlN rich composition range. Several crystalline phases were observed in the hot-pressed specimens. Oxynitride of spinel type was formed at 1700 degree C in the entire range of the system. The oxynitride reacted on AlN at the temperature higher than 1900 degree C and the pseudo-polytypes of AlN were formed.