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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实，研究其特性，从而建立一般应力状态下的本构方程或压实准则。如果能做到这一点，烧结后的性能就可以根据压实标准进行研究。采用陶瓷粉（Si3N4）在添加和不添加烧结添加剂的情况下进行了三维压实，并讨论了压实特性。在低应力范围内，陶瓷粉末表现出特定的行为方式，即粉末颗粒的轻叩，团聚体的断裂和颗粒的重新排列可能发生。得到了以下结果：(1)与未添加烧结添加剂的粉末相比，添加烧结添加剂的粉末可以在较低的应力水平下被压实。(2)压实判据似乎由主应力空间中的部分椭球体给出。(3)标准中包含的参数值很大程度上取决于粉末的特性。参数与特性之间的关系有待进一步研究。利用粉末的特性和本构方程，对等静压实过程进行了刚塑性有限元分析。压实剂的形状和密度分布取决于粉末的特性和胶囊的强度。因此，烧结后的压块将根据不同的特性提供不同的性能。这是陶瓷粉末压实过程中非常重要的一点。