Investigation of the high temperature corrosion behavior of AISI 304 steel coated with Ni-Co-CeO2-ZrO2 composite

Among the applications of austenitic stainless steels, it can be mentioned the application in solid oxide fuel cells and boiler tubes. It is necessary to protect these steels at high temperatures. One of the best effective methods to increase the life of these steels at high temperature is to apply surface coatings. In this research, Ni-Co-CeO2-ZrO2 composite coating was fabricated by electroplating method on the surface of AISI 304 austenitic stainless steel. In order to investigate the high temperature corrosion resistance, isothermal oxidation tests at 800°C for 300 hours and cyclic oxidation at 800°C for 50 cycles were performed on uncoated and coated samples. Scanning electron microscope (SEM) was used to observe the morphology and X-ray diffraction (XRD) was used to determine the formed phases. The results showed that the formed coating at the current density of 15 mA/cm2, pH of 3, and a concentration of 25 g.l-1 of ZrO2 particles and a concentration of 10 g.l-1 of CeO2 particles was without holes and cracks. In isothermal and cyclic oxidation tests, the coated samples showed a lower weight gain than the uncoated samples due to the formation of NiFe2O4 and CoFe2O4 spinels. These spinels prevented the outward diffusion of chromium cations from and improved the oxidation resistance of the 304 steel substrate.