Insights into Common Hardware Surface Treatment Processes
Drawing on 18 years of practical experience, Jiantong has mapped common processes to typical customer requirements:
1. Electroplating (Zinc, Nickel, Chrome plating, etc.)
Principle: Electrolysis is used to deposit a metal coating onto the substrate surface.
Characteristics:
Zinc plating: Cost-effective; commonly used for fasteners and sheet metal structural parts; requires passivation to enhance salt spray resistance.
Nickel/Chrome plating: Glossy finish and good wear resistance; often used for decorative parts and visible components.
Points to Note:
Porosity and uneven coating thickness can lead to localized rusting; allow for sufficient tolerances during design.
2. Electrophoresis (Cathodic/Anodic)
Characteristics: Uniform coating with strong adhesion; capable of fully covering complex shapes.
Applications: Automotive parts, structural components for home appliances, outdoor hardware.
Advantages: Superior corrosion resistance and a finer finish compared to standard spray painting.
3. Electrostatic Powder Coating
Characteristics: Solvent-free; thick coating; resistant to wear and impact; wide range of color options.
Applications: Equipment chassis and cabinets, industrial equipment housings, large sheet metal parts.
Note: Pre-treatment (degreasing, derusting, phosphating/passivation) is essential; otherwise, the coating is prone to delamination or blistering.
4. Anodizing (Primarily for aluminum parts)
Characteristics: Creates a dense aluminum oxide layer that enhances hardness, wear resistance, corrosion resistance, and electrical insulation.
Added Value: Can be dyed (black, gold, silver, etc.) and offers a high-quality aesthetic finish.
Commonly Used For: Aluminum housings, precision instrument panels, consumer electronics accessories.
5. Dacromet / Geomet (High-corrosion-resistance coatings)
Characteristics: High-temperature resistance; salt spray resistance ranging from hundreds to over a thousand hours; no risk of hydrogen embrittlement.
Applications: Automotive components, parts for highly corrosive outdoor environments, bridge fasteners, etc. Disadvantages: Relatively high cost; somewhat dull or dark appearance; unsuitable for applications requiring high aesthetic appeal.
6. Passivation and Phosphating (typically used as pre-treatments or supplementary protective measures)
Phosphating: Forms a crystalline phosphate layer on iron or steel surfaces to enhance coating adhesion and provide a degree of rust resistance.
Passivation: Commonly applied to stainless steel, aluminum, and zinc alloys to improve the stability of their native oxide films.
