Microstructural Development During Gas‐Pressure Sintering of α‐Silicon Nitride
作者:
Mamoru Mitomo,
Satoshi Uenosono,
期刊:
Journal of the American Ceramic Society
(WILEY Available online 1992)
卷期:
Volume 75,
issue 1
页码: 103-107
ISSN:0002-7820
年代: 1992
DOI:10.1111/j.1151-2916.1992.tb05449.x
出版商: Blackwell Publishing Ltd
关键词: silicon nitride;sintering;grain growth;fracture toughness;phase transitions
数据来源: WILEY
摘要:
Gas‐pressure sintering of α‐Si3N4was carried out at 1850 ° to 2000°C in 980‐kPa N2. The diameters and aspect ratios of hexagonal grains in the sintered materials were measured on polished and etched surfaces. The materials have a bimodal distribution of grain diameters. The average aspect ratio in the materials from α‐Si3N4powder was similar to that in the materials from β‐Si3N4powder. The aspect ratio of large and elongated grains was larger than that of the average for all grains. The development of elongated grains was related to the formation of large nuclei during the α‐to‐β phase transformation. The fracture toughness of gaspressure‐sintered materials was not related to the α content in the starting powder or the aspect ratio of the grains, but to the diameter of the large grains. Crack bridging was the main toughening mechanism in gas‐pressu
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