SINTERED BODY OF ALUMINUM NITRIDE HAVING HIGHER THERMAL CONDUCTIVITY AND A PROCESS FOR PRODUCING THE SAME

摘要

Sintered body having higher thermal conductivity and consisting mainly of aluminum nitride, said sintered body being produced by sintering aluminum nitride powder to which 1.5 to 15 % by weight of gadolinium oxide is added. The sintered body have the relative density of more than 95 % and thermal conductivity at ambient temperature of more than 150 W/m.k. Grain boundary of the sintered body consist mainly of GdAlO3 + Gd2O3. The sintered body contains gadolinium of more than 0.01 % by weight but less than 1.0 % by weight calculated in terms of Gd2O3. The sintered body is produced by the steps comprising blending 85 to 99.0 % by weight of aluminum nitride powder whose oxygen contents is between 0.1 and 2.0 % by weight with 1.9 to 15 % by weight of gadolinium oxide powder, molding the powder mixture, then carrying out sintering at a temperature between 1800 and 2200 .degree.C in non-oxidizing atmosphere.