Six mainstream surface treatment processes for MIM components

Surface treatment is a process of artificially forming a surface layer on the surface of a matrix material that has different mechanical, physical, and chemical properties from the matrix. The purpose of surface treatment is to meet the corrosion resistance, wear resistance, decorative or other special functional requirements of the product. MIM parts generally require various surface treatments to achieve better corrosion resistance, wear resistance, and conductivity, as well as high-quality surfaces.

1. Metal Polishing

Polishing treatment refers to the process of using mechanical, chemical, or electrochemical effects to reduce the surface roughness of the workpiece, in order to obtain a bright and flat surface

2. Electroplating treatment  

Electroplating is the process of using electrolysis to attach a metal film to the surface of metal or other materials. Electroplating can prevent metal oxidation (such as rust), improve wear resistance, conductivity, reflectivity, corrosion resistance (such as copper sulfate), and enhance aesthetics. MIM components are placed on the cathode, and metal ions receive electrons attached to the surface of the MIM component. Generally, copper, zinc, and other coatings are more common.

3.  PVD treatment

PVD refers to the process of using physical processes to transfer substances, transferring atoms or molecules from the source to the surface of the substrate. Its function is to spray certain particles with special properties (high strength, wear resistance, heat dissipation, corrosion resistance, etc.) onto the lower performance matrix, making the matrix have better performance. The workpiece is placed in a sealed space filled with inert gas, and metal ions are splashed onto the surface of the workpiece under high pressure, forming a metal film. The basic methods of PVD include vacuum evaporation, sputtering, and ion plating.

4.  Blackening treatment or Bluing: 

Blackening is a common method of chemical surface treatment, which involves producing an oxide film on the metal surface to isolate air and achieve rust prevention. When the appearance requirements are not high, blackening treatment can be used, and the main components of blackening solution are sodium hydroxide and sodium nitrite.

5.Phosphating treatment

Phosphating is a process of chemical and electrochemical reactions to form a phosphate film. The main purpose of phosphating is to:

1) Provide protection for the base metal, to a certain extent, to prevent corrosion of the metal;

2) Used for priming before painting to improve the adhesion and corrosion resistance of the paint film layer.

6. Spray coating

Spray coating is a coating method in which a spray gun or disc atomizer is used to disperse uniform and fine droplets of mist onto the surface of the coated object using pressure or centrifugal force.

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