Synthesis and Stability of cubic silicon nitride
Experiments using a planar metal disc flyer driven by explosives and a cylindrical chamber was designed to synthesize cubic silicon nitride with the mixtures of α-Si3N4 and copper powders as starting materials. The ratio of transformation from α-Si3N4 to γ-Si3N4 approached to 80％ percent at 45 GPa pressures and 4000K temperatures. The purity of γ-Si3N4 reached 100％ after the synthesized samples were treated with hydrofluoric acid at 440K for 9-10h. High pressure sintering was carried out with a DS6×800A link-type cubic anvil apparatus at a pressure of 5.7GPa and calculated temperature of 1370-1670K over the course of 15 minutes. The result showed that γ-Si3N4 was completely transformed into β-Si3N4 at 5.7GPa, 1420-1670k and was partly transformed into β-Si3N4 at 5.7 GPa, 1370k. Micro-analysis indicated that the typical microstructure of sintered Si3N4 was elongated β-Si3N4 rod crystals in disordered orientation, the highest relative density of the sintered samples was 99.06％ and Vickers hardness of them was 21.15GPa.
cubic silicon nitride shock-wave synthesis sintering phase transformation
YAO Huai XU Qiaoyu TANG Jingyou
School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471 School of Electromechnical Engineering, Henan University of Science and Technology, luoyang 471003,C School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyan
国际会议
青岛
英文
1467-1470
2009-10-09（万方平台首次上网日期，不代表论文的发表时间）