**3. Surface treatments: enhancing the overall corrosion and mechanical properties**

The overall corrosion and mechanical properties of stainless steels can be enhanced by subjecting them to different types of surface treatments including anodization, electrodeposition, dip-coating, micro-arc oxidation (MAO), and surface mechanical treatments. Anodization is a surface modification technique involving the passage of constant current and voltage through the cathode and anode resulting in the deposition of the natural oxide layers on the material surface [24] with an improved thickness and properties thereby turning the metal surface into an excellent finish which is anodic oxide in nature, corrosion-resistant, durable, and wear/abrasion-resistant.

As a form of surface treatments (anticorrosion processing methods), electrodeposition is a conventional phenomenon, and the combination of reduction and oxidation reactions whereby dissolved metals and alloys cations are cathodically reduced by the passage of electric current in electrolytes leading to the formation of a thin layer coating on electrodes [25]. By this, thin layers of functional materials including alloys and metals can be electrolytically deposited on the surface of Mg alloys (acting as the cathode in the electrolytic cell) to improve the corrosion properties and the overall mechanical behaviour.

The dip-coating process can be highlighted in five ways depending on the immersion time and speed as well as the withdrawal speed, (a) dipping the substrate into the desired solution, (b) removal of the dipped substrate from the solution, (c) deposition of the film on the substrate after removal, (d) removal of excess liquid from the material surface, and (e) dispersal of the solvent from the liquid film. Meanwhile, micro-arc oxidation is the electrochemical oxidation process through which hard, dense, and protective ceramic oxide coatings are formed on metal surfaces for corrosion protection under the influence of various processing conditions and parameters [26–28].
