Electrodeposition of NiO/YSZ from hydroalcoholic solutions containing Chitosan

NiO-YSZ films - of thicknesses in the range ca. 1-15 μm - have been fabricated by multi-step galvanostatic deposition from acidic hydroalcoholic solutions of NiCl2, ZrOCl2 and YCl3, containing Chitosan. The crystallographic structure of the electrodeposits has been studied by XRD, their chemical composition has been evaluated by EDX analysis, their morphology has been observed by SEM and optical microscopy and their adhesion has been quantified by the scratch-test method. Deposition-rate measurements have pinpointed some kinetic factors, relevant to process optimisation and bath management. As-plated samples exhibit an X-ray amorphous structure, that can be converted to crystalline fcc-NiO/cubic-fluorite YSZ by heat treatment. The YSZ composition is Y/Zr ca. 0.2 (molar ratio) and does not depend appreciably on processing conditions; the NiO content can be tuned in the range Ni/(Zr + Y) ca. 0.2-2 (molar ratio) by adjusting the electrodeposition parameters.