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Injection Molding of Alumina-Chromia-Yttria Composites

F. Sommer, F. Kern, R. Gadow

University of Stuttgart, Institute for Manufacturing Technologies of Ceramic Components and Composites, D-70569 Stuttgart, Allmandring 7b, Germany

received September 21, 2011, received in revised form October 19, 2011, accepted October 26, 2011

Vol. 2, No. 4, Pages 211-216   DOI: 10.4416/JCST2011-00035

Abstract

A submicron alumina powder was co-doped with chromia and yttria in order to obtain a homogeneous microstructure with grain boundaries strengthened by yttrium aluminium garnet (YAG) precipitates and a solid solution of chromia in alumina leading to high hardness and enhanced fracture toughness. The ceramic injection molding (CIM) process was applied as one of the most high-performance technologies for complex components and near-net-shape series production capability. To ensure the production of samples without defects, the injection parameters were optimized. CIM specimens were pressurelessly sintered in a hydrogen atmosphere in order to avoid chromium tri­oxide evaporation and improve sinterability. Materials with a bending strength of 570 MPa and a fracture toughness of 3.52 MPa√m (Evans) were obtained.

Keywords

Alumina, yttria, YAG, composite, injection molding

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