Corrosion barrier performance of Amorphous/Nano crystalline ZrO 2 coatings produced on S.S. by electro-deposition Zirconia (ZrO 2 ) coatings were prepared by heat treating the electrodeposited zirconium hydroxide produced by pulse current on 316L stainless steel. The results showed that a coating with amorphous structure is obtained after heat treating at 200 o C, which reveals no corrosion barrier performance. X-ray diffraction patterns obtained, indicated thatheat treating at 400 o C resulted in ZrO 2 coating with nanocrystalline/amorphous structure, which reveals a strong corrosion barrier performance.As the temperature was raised to 600 o C, an entirely nanocrystalline tetragonal structure was found for the ZrO 2 coating. Crestalline size of the coatings determined by Sherier equation were 9 and 25 nanometer for zirconia coating heat treated at 400 and 600 ?C, respectively.TEM investigation of ZrO 2 coating obtained at 600 ?C shows that by increasing the heat treatment temperature, a complete nanocrystalline phase of ZrO 2 with an average size of about 30 nm is achieved. Scanning electron microscopy investigation showed that the heat treatment of the coatingshada significant effect on the morphology of coatings.No cracks were found during the heat treatment of deposits at 200 ?C. The coatings showed no corrosion barrier performance because of incomplete dehydration of zirconium hydroxide at this temperature. The coating heat treated at 600 ?C revealed muddy shape cracks, with inferior corrosion barrier performance.Furthermore,EIS data obtained from ZrO 2 coatings revealed that a very high value of pore resistance and Warburg impedance, which indicating the diffusion-controlled nature of corrosion reactions, were observed for 400 ?C heat treated ZrO 2 coatings.The improved mechanical properties, including higher nanohardness and higher elastic modulus were observed for 400 and 600 ?Cheat treated zirconia coating. Nanoindentation results of ZrO 2 coatings produced by heat treating at 600 o C showed an increase in mechanical properties such as the hardness and elastic modulus. This can be attributed to the crystallization of ZrO 2 and development of tetragonal phase in the coatings. Key Word Zirconia; nanostructure; electrodeposition; stainless steel; corrosion resistance
