Study on nanocrystalline coating prepared by electro-spraying 316L metal wire and its corrosion performance

In this work, we study the corrosion performance of coatings prepared by electrical explosion spraying of metal wires. 316L metal wire with a diameter of 1.5 mm is used as spray material, and the coating is prepared on the 45^# steel substrate by electrical explosion spraying. The oil–water corrosion experiment of the coating is carried out in a constant temperature water bath of 60°C for 168 h. The scanning electron microscopy and energy-dispersive spectroscopy results of the experimental samples have shown that some metal oxides are found inside the coating, most of which are distributed at the grain boundaries with a size range of 30–50 nm. The corrosion rate of the coating is measured by weight loss method with a corrosion rate of 0.079 mm/annum. XRD results show that the corrosion generates CaCO₃, Fe₃O₄, and MgFe₂O₄. Coating corrosion is mainly caused by the formation of electrochemical corrosion between oxides and non-oxides in the coating, and pitting corrosion and intergranular corrosion in the presence of chloride ions.