Morphology of Very Thin Layers Made by Electrochemical Vapour Deposition at Low Temperatures

Thin zirconia/yttria (ZY) layers on porous a-alumina substrates, prepared by the (Electro)Chemical Vapour Deposition (CVD/EVD) technique at 700-800°C, have been investigated. After about 40 minutes of deposition time the layers are gas tight; the thickness is estimated to be < 1 μm.

Preliminary results indicate that ZY, deposited at 700-800°C, forms polycrystalline layers with a crystallite size of about 20 nm; the crystallite size is slightly increasing with increasing deposition time. The ZY layers grown at 700-800°C for several hours have crystallites equal in size compared to layers grown at 1000°C for several hours; the fraction of monoclinic ZY is larger at low temperatures under current process conditions.