Ten types of metal surface treatment

Surface treatment involves creating a layer with one or more specialized properties on a material through physical or chemical methods. Surface treatment can enhance a product's appearance, texture, functionality, and other aspects.

1. Anodizing

Primarily anodizing aluminum, this process uses electrochemical principles to create a layer of Al2O3 (aluminum oxide) on the surface of aluminum and aluminum alloys. This oxide film possesses unique properties, including protective, decorative, insulating, and wear-resistant properties.

Process:

Single Color, Gradient Color: Polishing/Sandblasting/Brushing → Degreasing → Anodizing → Neutralizing → Dyeing → Sealing → Drying

Two-Color:

①Polishing/Sandblasting/Brushing → Degreasing → Masking → Anodizing 1 → Anodizing 2 → Sealing → Drying

②Polishing/Sandblasting/Brushing → Degreasing → Anodizing 1 → Laser Engraving → Anodizing 2 → Sealing → Drying

Technical Features:

1. Improved Strength

2. Achieve Any Color Except White

3. Achieve Nickel-Free Sealing, Meeting Nickel-Free Requirements in Europe, America, and Other Countries

Technical Difficulties and Key Improvements: The yield rate of anodizing affects the cost of the final product. Improving the yield rate depends on the appropriate oxidant dosage, temperature, and current density. This requires structural component manufacturers to continuously explore and seek breakthroughs during the production process.

Product Recommendation: E+G curved handle, made of anodized material, is environmentally friendly and durable.

2. Electrophoresis

Applied to stainless steel, aluminum alloys, etc., it can achieve a variety of colors while maintaining a metallic luster, while enhancing surface properties and providing excellent corrosion resistance.

Process Flow: Pretreatment → Electrophoresis → Drying

Advantages:

1. Rich colors;

2. No metallic texture, compatible with sandblasting, polishing, brushing, etc.;

3. Processing in a liquid environment allows for surface treatment of complex structures;

4. Mature process, suitable for mass production.

Disadvantages: Moderate defect concealment capability, requiring high pre-treatment for electrophoresis of die-cast parts.

3. Micro-arc oxidation

A process in which a high voltage is applied to an electrolyte solution (usually a weakly alkaline solution) to create a ceramic surface film. This process is the synergistic effect of physical discharge and electrochemical oxidation.

Process Flow: Pretreatment → Hot Water Wash → MAO → Drying

Advantages:

1. Ceramic texture, matte appearance, no high-gloss finish, delicate feel, and fingerprint resistance;

2. Wide range of substrates: Al, Ti, Zn, Zr, Mg, Nb, and their alloys;

3. Simple pre-treatment, excellent corrosion and weather resistance, and excellent heat dissipation. Disadvantages: Currently, colors are limited, with only black and gray being relatively mature, making vibrant colors difficult to achieve. Costs are primarily driven by high power consumption, making it one of the most expensive surface treatments.

4. PVD Vacuum Coating

Physical Vapor Deposition (PVD) is an industrial manufacturing process that primarily utilizes physical processes to deposit thin films.

Process Flow: PVD pre-cleaning → furnace vacuuming → target washing and ion cleaning → coating → coating completion, cooling, and removal from the furnace → post-processing (polishing, AFP)

Technical Features: PVD (Physical Vapor Deposition) can deposit a highly hard, wear-resistant, and metallic ceramic decorative coating on metal surfaces.

5. Electroplating

This technique uses electrolysis to deposit a metallic film on the metal surface, thereby preventing corrosion, improving wear resistance, conductivity, reflectivity, and aesthetics.

Process: Pretreatment → Cyanide-free Alkaline Copper → Cyanide-free White Copper Tin → Chrome Plating

Advantages:

1. High-gloss coating, high-quality metallic appearance;

2. Base materials include SUS, Al, Zn, Mg, etc.; Cost is lower than PVD.

Disadvantages: Poor environmental protection and a higher risk of environmental pollution.

6. Powder Coating

Powder coating is applied to the workpiece surface using a powder spraying machine (electrostatic sprayer). Under the action of static electricity, the powder is evenly adsorbed to the surface, forming a powder coating. The powder coating is then baked at high temperature for leveling and curing, resulting in a final coating with varying effects (different types of powder coatings).

Process: Part loading → Electrostatic dust removal → Spraying → Low-temperature leveling → Baking

Advantages:

1. Rich colors, with glossy and matte finishes available;

2. Low cost, suitable for architectural furniture, heat sink casings, etc.;

3. High utilization rate, 100% utilization, environmentally friendly;

4. Strong ability to conceal defects; 5. Ability to simulate wood grain effects.

Disadvantages: Currently rarely used in electronic products.

7. Metal Wire Brushing

A surface treatment method that creates lines on a workpiece's surface through abrasive grinding to create a decorative effect. Wire brushing can be categorized as straight, random, wavy, or swirl, depending on the finish.

Technical Features: Wire brushing imparts a non-mirror-like metallic luster to the metal surface while also removing minor surface imperfections.

Product Recommendation: LAMP handle with Zwei L finish, featuring superior grinding technology for a refined finish.

8. Sandblasting

A process that uses compressed air as a power source to create a high-speed jet of material that is applied to the surface of the workpiece. This process alters the surface's appearance or shape, achieving a desired degree of cleanliness and varying degrees of roughness.

Technical Features:

1. Achieves varying degrees of reflective or matte finish.

2. Removes minor burrs from the workpiece's surface, smoothing the surface and eliminating the harmful effects of burrs, enhancing the workpiece's quality. 3. Removes residual contaminants from pre-processing, improves the workpiece's finish, and reveals a uniform, natural metal color, resulting in a more aesthetically pleasing appearance.

Product Recommendation: E+G Classic Bridge Handle, Sandblasted Finish, High-End and Upscale.

9. Polishing

The surface modification of a workpiece is performed using flexible polishing tools and abrasive particles or other polishing media. Selecting the appropriate polishing wheel for each polishing process: rough polishing (basic polishing), intermediate polishing (finishing polishing), and fine polishing (glazing) can achieve optimal polishing results and improve polishing efficiency.

Technical Features: Improves the dimensional or geometric accuracy of the workpiece, achieving a smooth or mirror-like finish while also eliminating gloss.

Product Recommendation: E+G Long Handle, Polished Finish, Simple and Elegant.

10. Etching

Etching, commonly referred to as photochemical etching, involves removing the protective film in the area to be etched after exposure and development. During etching, the area is exposed to a chemical solution, which dissolves and corrodes, creating a concave, convex, or hollowed-out effect.

Process Flow:

Exposure Method: Engineers determine the material dimensions based on the design - Material preparation - Material cleaning - Drying → Lamination or coating → Drying → Exposure → Developing → Drying - Etching → Stripping → Finishing

Screen Printing Method: Cutting → Cleaning the sheet (stainless steel or other metal materials) → Screen printing → Etching → Stripping → Finishing

Advantages:

1. Allows for fine surface processing of metals;

2. Allows for special effects on metal surfaces;

Disadvantages: The corrosive liquids (acids, alkalis, etc.) used in etching are often environmentally hazardous.