Porous stabilized zirconia coatings on zircon using volatility diagrams

A process for obtaining porous coatings of yttria stabilized zirconia on zircon substrates is described. The calcination in reducing atmospheres (oxygen partial pressures below 2 × 10−9 atm and at temperatures over 1300 °C) of test samples containing zircon and small amounts of yttria led to the formation of porous stabilized zirconia coatings (up to 240 μm thick) on the samples. The process led to the decomposition of the silica contained in the zircon, volatilized in the form of SiO(gas), originating pores in its place. The conditions required for the process were inferred from the volatility diagrams of the involved chemical species, which were likewise used to analyze the experimental results.