Shrinkage-free ZrSiO 4-ceramics: Characterisation and Applications

Abstract

Dense, shrinkage-free ZrSiO 4-ceramics can be produced by a reaction-bonding process using ZrSi 2, ZrO 2, and a polysiloxane as starting materials. Sinter shrinkage is compensated by the volume increase during oxidation of ZrSi 2. In addition, the use of a Si-containing so called low-loss-binder [polymethylsilsesquioxane (PMSS)] reduces shrinkage further. Near net-shape ceramic compacts can be produced by an embossing process. As the green bodies are extremely dense but not brittle, they can be mechanically machined. The reaction-bonding process has to be controlled in a way that first the pyrolysis of PMSS, followed by the oxidation of ZrSi 2, and finally the formation of ZrSiO 4 and the sintering to dense compacts take place. Due to the absence of shrinkage and the good mechanical properties obtained, these ceramics open up new applications in fields requiring high dimensional accuracy such as microsystem engineering or dentistry. ©