Making Alumina Microcomponents From Al Powder

Abstract

Alumina microcomponents have distinguishing advantages over Si counterparts. However, the shrinkage of alumina, as high as 20%, makes it difficult to produce precision components that require a high tolerance. A new fabrication process is presented to greatly reduce the shrinkage. The process consists of forming an Al powdered component through sintering and transforming the Al powdered component into an alumina part. In this way, the shrinkage occurring in sintering the Al powder component will be compensated by the expansion occurred when Al transforms into alumina. The process involves producing micro-moulds, preparing metallic paste, filling the micro-moulds with the metallic paste, demoulding, sintering the green Al patterns and finally oxidising the sintered Al-based components to achieve alumina components. The process was proven successful. Characterization of the sintered alumina microcomponents has been undertaken, including SEM image analysis, density and scale measurements.