Thin films of yttria-stabilized zirconia (YSZ) were formed onto nickel oxide substrates by an electrochemical vapor deposition process using the substrates as oxygen sources, and ZrCl4 and YCl3 as metal sources. After deposition at 1000 degrees C for 1-6 h, dense films of cubic YSZ were formed. The film thickness increased linearly with deposition time, and the linear growth rate constant was 1.1 x 10(-4) mu m s(-1). The deposition kinetics were discussed, and it was concluded that the rate-determining step of this process is not the electrochemical transportation of the oxide ions and electrons through the growing film, but the mass transport of oxygen gas, which is dissociated from the NiO substrate, through the substrate pores to the NiO/YSZ interface.