Reactions in Vapor-Phase Electrolytic Deposition for Preparing Yttria-Stabilized Zirconia Thin Films

The process of vapor-phase electrolytic deposition (VED) for the formation of yttria-stabilized zirconia (YSZ) films has been studied. This technology, which is similar to the electrochemical vapor deposition (EVD) process, is based on electrolytic deposition, using a glow-discharge plasma as the conductive medium. Radio-frequency (rf) glow-discharge plasma is generated in the vapor phase of a metal chloride (ZrCl4 or YCl3), A porous electrode layer, which is deposited on the stabilized zirconia layer, is connected to a de power source. The grounded electrode, which is located in the plasma, is used as a counter electrode to complete the de circuit. X-ray photoemission spectroscopy and electron probe microanalysis measurements identify the deposited layer to be YSZ that contains 8 mol% of Y2O3. This layer is free from pores and cracks, within the scale of scanning electron microscopy observation. The conductivities of the YSZ films that are prepared at different current densities via the VED process are almost equal, and the conductivity values of these thin films are very similar to that of the sintered YSZ pellet. The dependence of the current efficiency on the de current density is investigated. The current efficiency decreases as the current density increases.