Affiliation:
1. Guangdong University of Technology, School of Electro-mechanical Engineering, Guangzhou, China
Abstract
In this paper, the influence of the starting powder characteristics for five
commercial Si3N4 powders on sintering behavior, microstructure and mechanical
properties of hot-pressed Si3N4 ceramics with and without the addition of
La2O3-Yb2O3-MgO sintering additives was investigated. For the system without
sintering additives, the high amount of the impurities in the starting
powders could facilitate the densification process and promote ?-Si3N4 grain
growth. However, large whisker-like particles (? phase) present in the
initial powders inhibited the sintering process, which led to a lower density
of Si3N4 ceramics. On the other hand, when the sintering additives were
introduced in the beginning stage of the powder processing step, the effects
of impurities content and particle morphology in the initial powders on the
densification and microstructure were not apparent. There was tendency that
finer powder size resulted in finer microstructure. However, a high ?-phase
ratio in the initial powders could accelerate the abnormal grain growth and
thus lead to better mechanical properties.
Publisher
National Library of Serbia
Subject
Materials Chemistry,Metals and Alloys,Condensed Matter Physics,Ceramics and Composites
Cited by
13 articles.
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