Fabrication of YSZ thin films in an aqueous solution by electro-chemical deposition

In our present study, YSZ thin films were fabricated on glass substrates in an aqueous complex solution by electro-chemical deposition. Zirconia is very important for their many characters, and we aim to make their thin films for large area and homogeneous thickness by using environment friendly materials and low cost method. Composition and concentration of the precursor aqueous solution is 94mol%ZrO₂-6mol%YO_1.5and 0.073 mol/dm ³ (YSZ solution). ZrO(NO₃)₂-2H₂O and Y(NO₃)₃-6H₂O were used Zr and Y sources. Ammonia solution in appropriate quantities (0-0.5 vol%) was added to adjust the acidity and to occur a radical exchange reaction between ZrO(NO ₃)₂ and NH₄OH to produce an intermediate form of ZrO(OH)₂. After the mixture was stirred for l h in an ice bath, a homogeneous colorless and transparent solution was obtained. YSZ thin Him was deposited on the glass substrate which was placed on the carbon electrode by applying the voltage 2.0-4.5V for 300s. As-deposited films were flat and transparent but amorphous and so heat-treated at temperature 573-773K for 1 h afterwards. From XRD patterns of the films, the peaks of YSZ were observed at samples annealed at 673, 773 K. After this heat treatment, transparent, pure, relatively hard thin films which thicknesses were about 0.05 to 0.3μm, were get on glass surface. Composition of the films were almost same with that of aqueous solution. It was confirmed that the crystallization of the films were depended on the applied voltage and the amount of added NH₃aq..