The surface treatment and coating of die-casting products are to improve the appearance quality of the product, protect the surface of the product, increase the additional functions of the product and prolong the service life of the product. The common surface treatment and coating methods of die casting products are as follows:
Sand blasting treatment is to spray sand particles at high speed, and remove impurities such as scale, residual sand cores and pores on the surface of the casting through impact and friction, so that the surface of the casting can meet the smoothness requirements. This method is suitable for situations that do not require a high surface finish of the product, such as body castings.
Polishing treatment is to mechanically polish and chemically dissolve the surface of the casting to achieve a certain degree of smoothness and brightness. This method is suitable for occasions that require high surface finish, such as jewelry, toys, etc.
The electroplating treatment is to put the casting into the electroplating tank containing metal ions, and the metal ions are reduced to metal elements by the action of electric current, and a metal protective layer is formed on the surface of the casting. Common electroplating methods include chrome plating, nickel plating, galvanizing, etc., which can improve the corrosion resistance and decoration of products.
Anti-oxidation treatment: Anti-oxidation treatment is to protect the surface from oxidation by coating the surface of the casting with a layer of non-oxidizable material to form an oxide layer. Common anti-oxidation methods include coating method, chemical treatment method, etc., which can improve the oxidation resistance of the product. Spray coating: Spray coating is to spray paint on the surface of castings to form a protective layer to protect and beautify. Coatings can be selected according to needs, such as epoxy resin coatings, polyurethane coatings, etc., which can improve the wear resistance, corrosion resistance and decorative properties of the product. Paint treatment: Baking paint treatment is to put the product in an oven for baking, so that the coating is cured to form a film, and the weather resistance and wear resistance of the product are improved. This method is suitable for occasions that require high product appearance and high protection performance. Carburizing treatment: Carburizing treatment is to immerse the casting in the medium containing carbon element, and make the surface of the casting rich in carbon element through the diffusion of carbon atoms under high temperature conditions, forming a layer of high carbide protective layer to improve the hardness and wear resistance of the product . Oxidation treatment: Oxidation treatment is to immerse the surface of the casting in a medium containing an oxidant, and make it oxidize under high temperature conditions to form an oxide film to increase the surface hardness and corrosion resistance of the product.
Electrophoretic coating is a method of encapsulating charged paint particles on the surface of castings under the action of an electric field. The paint particles will automatically deposit on the surface of the casting under the action of the electric field force, and form a uniform and dense coating. Electrophoretic coating has the advantages of high efficiency, energy saving and environmental protection, and is suitable for castings of various shapes.
Thermal spraying is the use of thermal energy to melt or heat metals, ceramics, plastics and other materials into powders, wires and other forms, and spray them on the surface of castings by spraying, blowing and other methods. Thermal spraying has excellent wear resistance, temperature resistance and corrosion resistance, and is widely used in pneumatic nozzles, anti-corrosion coatings and other fields.
Cold spray: Cold spraying is a method of applying material in powder form to the surface of a casting at room temperature. Cold spraying does not require a high-temperature heat source and can effectively reduce the heat-affected zone. It is suitable for situations with high requirements on the surface of castings, such as aerospace. Gas phase surface modification: Gas phase surface modification is to use methods such as gas discharge to form a coating with special functions on the surface of the casting. This method can increase the adhesion, wear resistance, corrosion resistance and other properties of the casting surface, and is suitable for products requiring high additional functions and special purposes. Dust treatment: Dust-proof treatment is to form a layer of dust-proof coating on the surface of castings to block the entry of dust particles and keep the surface of the product clean and beautiful. This method is suitable for occasions that require high cleanliness on the surface of the product, such as electronic products, precision instruments, etc.. Phosphate conversion coating: Phosphate conversion coating is to immerse the casting in the phosphate conversion solution, and form a conversion coating on the surface of the casting through chemical reaction. This coating can improve the anti-corrosion performance and lubricating performance of the product, and is suitable for use in some special environments. Fireproof coating: Fireproof coating is to spray the coating with fireproof performance on the surface of the casting to form a layer of fireproof isolation layer, which is used to improve the fireproof performance of the product. This kind of coating usually has high temperature resistance, anti-flammability and flame retardancy, and is suitable for some occasions with high fire safety requirements, such as construction, transportation and so on.The above are the common surface treatment and coating methods of die casting products, which play different roles in different application fields and product requirements. Choosing the right surface treatment and coating method can improve the quality and performance of the product and meet the needs of the market and customers.