Yttria-stabilized zirconia (YSZ) thin films were prepared on NiO pellets by a vapour-phase reaction using ZrCl 4 and YCl 3 as metal sources and the NiO substrate as an oxygen source for the reaction. The film obtained was cubic YSZ, and its Y 2 O 3 content was approx. 8 mol%. The effect of the sintering temperature of NiO substrates was examined. A surface-oxidized nickel wire was then used as a substrate, and a cubic YSZ layer was coated over the wire. The substrate (nickel and nickel oxide) was dissolved in aqueous hydrochloric acid, and a hollow YSZ fibre of approx. 100 μm diameter was obtained.