Why surface treat metals?

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Whether it is ferrous metals, non-ferrous metals, or non-metallic materials such as concrete, wood, and plastics, when applying coatings, linings, spraying, or electroplating to their surfaces, it is necessary to treat the surface of the material in order to achieve a good adhesion between the material to be protected and the coating or lining layer, thereby ensuring better corrosion protection and decorative effects. The adhesion of the corrosion-resistant layer to the substrate is one of the many factors that lead to the failure of the corrosion-resistant layer. Experience shows that about 70% of coating failures are caused by poor or inadequate surface preparation of the substrate before applying the anti-corrosion coating. There are many methods for surface treatment at the grassroots level, which can be mainly divided into two categories: mechanical methods and chemical methods. Mechanical methods include dry sandblasting, wet sandblasting, shot blasting, and manual mechanical rust removal ； Chemical methods include chemical rust removal, electrochemical rust removal and degreasing, as well as surface phosphating and passivation. Before anti-corrosion treatment, the appropriate surface treatment method for various devices or workpieces should be selected based on their material composition and the manufacturing process. It is generally believed that the sandblasting method yields the best rust removal results, followed by the acid washing method, with manual rust removal giving the worst results.