Methods of Metal Surface Oxidation Treatment

I. Electrophoresis

Electrophoresis, also known as electrodeposition coating or electrophoretic painting, was developed in the 1960s and first applied by Ford Motor Company for automotive primers. Due to its excellent anti-corrosion and anti-rust properties, it was quickly adopted in the military industry. In recent years, it has been extended to the surface treatment of daily hardware products.

Advantages:

• Lacks a metallic appearance and can be combined with sandblasting, polishing, or brushing.
• Processing occurs in a liquid environment, enabling surface treatment of complex structures.

II. Anodizing

Primarily used for aluminum, anodizing is an electrochemical process that forms an aluminum oxide layer on the surface of aluminum and its alloys. This oxide layer offers protective, decorative, insulating, and wear-resistant properties, among other special characteristics.

Advantages:

• Can achieve any color except pure white.
• Enables nickel-free sealing, meeting the nickel-free requirements of Europe, the United States, and other regions.

III. Micro-Arc Oxidation (MAO)

This process involves applying voltage to a workpiece using specialized MAO equipment, causing micro-arc discharges on the metal surface in an electrolyte solution. Under the influence of high temperature and electric fields, a ceramic coating forms on the metal surface, enhancing its properties. MAO is mainly applied to valve metals such as aluminum, magnesium, titanium, zirconium, niobium, and thallium.

Advantages:

• Simple pre-treatment; excellent corrosion and weather resistance; superior heat dissipation.
• Wide range of applicable materials: Al, Ti, Zn, Zr, Mg, Nb, and their alloys.

IV. Powder Coating

Powder coating involves using electrostatic spray equipment to apply powdered paint to a workpiece’s surface. Under electrostatic action, the powder evenly adheres to the surface, forming a powdery layer. This layer is then cured at high temperatures, resulting in a final coating with varied effects depending on the powder type.

Characteristics:

• Rich color options, including high-gloss and matte finishes.
• Strong ability to conceal surface defects.
• Cost-effective, suitable for architectural furniture, heat sinks, and enclosures.
• High material utilization and environmentally friendly.

V. Electroplating

Electroplating is a process that uses electrolysis to deposit a thin layer of metal onto a surface, providing corrosion resistance, improved wear resistance, conductivity, reflectivity, and aesthetic enhancement.

Characteristics:

However, it has poor environmental performance and poses risks of pollution.

High-gloss, premium metallic appearance.

Applicable to substrates like SUS, Al, Zn, Mg, etc.

Lower cost compared to PVD (Physical Vapor Deposition).