Formation of tough interlocking microstructures in silicon nitride ceramics by dynamic ripening
Formation of tough interlocking microstructures in silicon nitride ceramics by dynamic ripening
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DOI：
10.1038/417266a
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发表时间：
2002-05-16
期刊：
影响因子：
64.8
通讯作者：
Nygren, M
中科院分区：
文献类型：
--
作者：
Shen, ZJ;Zhao, Z;Nygren, M
基于Si 3 N4的陶瓷已得到全面研究，并广泛用于结构应用（1，2）。细长晶粒的互锁微观结构的发展对于确保该系列陶瓷具有良好的损伤容限至关重要（3，4）。到目前为止，这是通过将适当的粉末压块加热到1,700摄氏度以上的温度并延长时间来实现的。该过程包括控制晶种的大小和数量的必要步骤--非原位添加或原位形成--以确保选择性晶粒生长（5，6）。在这里，我们报告了非常快速（几分钟内）在原位形成的一个坚韧的联锁显微结构Si 3 N4基陶瓷。微观结构是通过动态熟化机制获得的，该机制是由快速加热速率引起的各向异性奥斯特瓦尔德熟化过程。所得到的微观结构是均匀的和可再现的晶粒尺寸分布和机械性能方面，并且很容易通过操纵的动力学定制。该工艺非常高效，为优化机械性能和经济高效地制造陶瓷开辟了新的可能性。
Ceramics based on Si3N4 have been comprehensively studied and are widely used in structural applications(1,2). The development of an interlocking microstructure of elongated grains is vital to ensure that this family of ceramics have good damage tolerance(3,4). Until now this has been accomplished by heating the appropriate powder compacts to temperatures above 1,700 degreesC for extended periods. This procedure involves a necessary step of controlling the size and population of seeds-added ex situ or formed in situ-to ensure selective grain growth(5,6). Here we report the very fast (within minutes) in situ formation of a tough interlocking microstructure in Si3N4-based ceramics. The microstructures are obtained by a dynamic ripening mechanism, an anisotropic Ostwald ripening process that results from the rapid heating rate. The resulting microstructures are uniform and reproducible in terms of grain size distribution and mechanical properties, and are easily tailored by manipulating the kinetics. This process is very efficient and opens up new possibilities to optimize mechanical properties and cost-effectively manufacture ceramics.