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A study of compaction characteristics and properties after sintering of ceramic powders

陶瓷粉末烧结后的压实特性及性能研究

基本信息

批准号：
61550056
负责人：
SHIMA Susumu
金额：
$ 1.15万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

The main objective of this study is to carry out three-dimensinal compaction of ceramic powders to investigate their characteristics and thereby to develop constitutive equations or compaction criteria for general stress state. If this could be done, the properties after sintering could be investigated in terms of the compaction criteria.The three-dimensional compaction was carried out using a ceramic powder (Si3N4), either with or without sintering additives and the characteristics in compaction were discussed. In a low stress range the ceramic powders are said to behave in particular manner, i.e. tapping of the powder particles, fracture of the agglomerates and rearranging of the particles are likely to occur. The following results were obtained.(1) The powder with sintering additives can be compacted in a lower stress level compared to that without additives.(2) The compaction criterion apperars to be given by part of ellipsoid in the principal stress space.(3) The values of the parameters which are included in the criterion are quite dependent on the characteristics of the powders. The relationship between the parameters and the characteristics should be further investigated.By employing the characteristics and the constitutive equations for the powders, the rigid-plastic finite element analysis of isostatic compaction (CIP) was carried out. The shape of the compacts and distribution of the density in the compacts depended on the characteristics of the powder and also on the strength of the capsule. The compacts after sintering will thus provide different properties depending on the characteristics. This is a very important point in compactin of ceramic powders.

本研究的主要目的是对陶瓷粉末进行三维压制，研究其特性，从而建立一般应力状态下的本构方程或压制准则。采用陶瓷粉末（Si_3N_4）进行了三维压制，讨论了有无烧结添加剂对压制过程的影响。在低应力范围内，据说陶瓷粉末以特定方式表现，即可能发生粉末颗粒的轻敲、团聚体的破裂和颗粒的重新排列。获得了以下结果。(1)与没有添加剂的粉末相比，具有烧结添加剂的粉末可以在较低的应力水平下被压实。(2)压实准则在主应力空间中表现为椭球的一部分。(3)标准中所包含的参数值与粉末的特性密切相关。利用粉末的本构方程和特征参数，对等静压成形过程进行了刚塑性有限元分析。压块的形状和压块中密度的分布取决于粉末的特性以及胶囊的强度。因此，烧结后的压块将根据特性提供不同的性能。这是陶瓷粉末压制过程中非常重要的一点。