Electrochemical and adhesion properties of hydrothermally deposited nano-ZrO2 coatings on oxide layers of stainless steel

ZrO2 coatings on pre-oxidized stainless steel (304L) surfaces have been developed by hydrothermal process and the coating adhesion and corrosion resistance properties of the coated specimens have been studied. The role of pre-oxidized SS surfaces composed of different oxides like spinels and α-Fe2O3 with different morphologies has been studied. The thicknesses of the ZrO2 coatings are in the range of 50 nm to 350 nm depending upon the compositions of the pre-oxidized layers. The coating is thick and compact when developed on α-Fe2O3 with high surface roughness and shows the best corrosion resistance properties. ZrO2 coatings developed on large size spinel oxides are thin and porous. The nano-mechanical properties and the local adhesion force have been studied by atomic force acoustic microscopy and force-distance spectroscopy. The adhesion force of ZrO2 coating on α-Fe2O3 is around 100 nN while for the coatings developed on other pre-oxidized surfaces are around 50 nN.