Influence of process parameters on microstructure and corrosion properties of hopeite coating on stainless steel

• The Fe2+ ions were introduced by the curing process to initiate the coating formation.
• The influences of temperature and pH value on hopeite coating formation were discussed.
• The uniform and fine hopeite coating was fabricated on stainless steel at 75 °C with bath pH of 2.75.

The effects of process parameters on hopeite coating formation and corrosion resistance on stainless steel surface are researched. Higher temperature and pH value favor the formation of hopeite coating. The coatings formed at different temperatures and pH values have similar phase and crystal shape. The electrochemical analysis reveals that the corrosion resistance of the coatings can be improved by temperature and pH value. Furthermore, the optimum process parameters for the formation of hopeite coating is observed at 75 °C with bath pH 2.75, at this condition the interfacial shear strength between the coating and substrate is 13.05 ± 2.2 MPa.