| 摘要 |
PURPOSE:To obtain the title sintered body which is dense and excellent in light transmission properties and thermal conductivity by calcining the molded body of AlN powder incorporating a sintering auxiliary in the order of pressurization, decompression and furthermore a superhigh-pressure state in the specified conditions respectively to removed impurities. CONSTITUTION:AlN, a powdery sintering auxiliary consisting of the same composition as a sintering auxiliary (e.g. CaCO3) and substance for preventing volatilization of AlN are preferably arranged in a closed vessel containing the molded body of AlN powder incorporating the sintering auxiliary in such a state that these compds. are not brought into contact with an article to be calcined which is the above-mentioned molded body. Gaseous N2 is enclosed in the vessel and the temp. is raised and the pressure in the vessel is regulated by thermal expansion due to rise in temp. These compds. are calcined at 1,700-2,100 deg.C under pressurization of 1-10atm and then cooled at once and thereafter AlN or Al is arranged in the vessel in such a state that it is not brought into contact with the article to be calcined. Gaseous N2 is enclosed and the pressure is regulated similarly to the above-mentioned stage and these compds. are calcined at 1,700-2,000 deg.C under the pressure of 0.1-0.9atm. Furthermore while AlN or Al is arranged in the vessel in such a state that it is not brought into contact with the article to be calcined, gaseous N2 is enclosed and the pressure is regulated similarly to the above stage and these compds. are calcined at 1,800-2,000 deg.C under the pressure of 50-1,000atm. |
