Processing of YSZ thin films on dense and porous substrates

Yttria-stabilized zirconia (YSZ) thin films with a Zr/Y molar ratio of 0.84:0.16 were synthesized on both dense Si substrates and porous Ni–YSZ anodes using the spin coating technique. Two polymeric precursors were used to process the YSZ films on the Si substrates. The first one utilized a commercial precursor, with butanol added as the diluting solvent. By controlling the content of butanol in the solution, dense and crack-free YSZ films with thickness of 500 nm were obtained after 8 coating runs with a final anneal of 700 °C for 4 h. X-ray diffraction was used to monitor the crystallization process in the films during annealing, which indicated that the YSZ films started to crystallize at 300–400 °C and became fully crystalline with a cubic structure at temperature ≥ 600 °C. In the second case, a new YSZ polymeric precursor was prepared and used for coating. It was found that the viscosity of the precursor solution is critical in controlling the film quality. Relatively thick, dense YSZ films were also synthesized on porous Ni–YSZ anode substrates using a combined colloidal–polymer method.