Fabrication of Internal Channels in Ceramics and Ceramic Composites

摘要

In engineering applications, ceramics possess important characteristics such as chemical inertness and high stiffness and hardness, which cannot be surpassed by most metals. However, difficulties in the processing of ceramic materials have limited the utilization of these excellent properties. In particular, it is difficult to fabricate ceramics with complex geometry, especially internal geometric features such as channels or cavities in the bulk of a ceramic component. This paper presents a unique and economical processing technique that utilizes a fugitive phase to produce cavities in the bulk of ceramics and ceramic composites. The fugitive phase elements in the shape of the desired channels are introduced into a die during powder compaction. Pre-sintering of the green body burns away the fugitive phase, leaving the cavities and channels. A final sintering step via either conventional or microwave heating produces a densifled ceramic component having bulk-penetrating channels or cavities. Ceramic/ceramic joining technology, developed by the authors and other researchers, together with the presented processing technique provide the potential for fabricating very complex parts joining subcomponents with other such subcomponents, which all have complex cavities.