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以Y2O3-Al2O3-La2O3体系作烧结助剂,在5.4~5.7 GPa、1 620~1 770 K的高温高压条件下进行了α-Si3N4与γ-Si3N4粉体的烧结,研究了烧结体的相对密度、韦氏硬度和物相组成。结果表明:α-Si3N4、γ-Si3N4在烧结后完全转变为β-Si3N4;在相同烧结条件下,γ-Si3N4烧结体的相对密度、维氏硬度比α-Si3N4的高γ-Si3N4与α-Si3N4烧结体的最高相对密度与维氏硬度分别为99.20%,23.42 GPa和98.78%,21.87 GPa;烧结体由相互交错的长柱状β-Si3N4晶粒组成,显微结构均匀。
Sintering of α-Si3N4 and γ-Si3N4 powders under the conditions of high temperature and high pressure of 5.4 ~ 5.7 GPa and 1 620 ~ 1 770 K was carried out with Y2O3-Al2O3-La2O3 system as sintering aids. The relative density , Webster hardness and phase composition. The results showed that α-Si3N4 and γ-Si3N4 completely transformed into β-Si3N4 after sintering. Under the same sintering conditions, the relative density and Vickers hardness of γ-Si3N4 sintered body were higher than that of α-Si3N4 and α- The highest relative density and Vickers hardness of Si3N4 sintered body were 99.20%, 23.42 GPa and 98.78%, respectively, and 21.87 GPa. The sintered body consisted of long columnar β-Si3N4 grains interlaced with each other and the microstructure was uniform.