Nickel-Plated Aluminum Alloy Diecast Components

Nickel Plating Methods On Aluminum Diecastings

Nickel plating on the surface of aluminum die-castings involves depositing a nickel layer on the surface of aluminum materials through chemical or electrochemical methods to enhance corrosion resistance, wear resistance and adhesion. The following are common process schemes:

Electroless nickel plating

Sodium hypophosphite is used as the reducing agent to form a nickel-phosphorus alloy coating on the aluminum surface through autocatalytic reaction. This process does not require electricity and is suitable for complex structural components (such as deep holes and blind slots). The coating is uniform and has strong corrosion resistance, but it needs to undergo zinc immersion or sandblasting pretreatment first. ‌

Pretreatment by zinc immersion method

The oxide layer on the aluminum surface is replaced by two zinc immersion reactions, forming a porous zinc film to enhance the adhesion of the coating. The process includes degreasing, pickling, two rounds of zinc immersion and zinc removal. It is cost-effective and suitable for conventional plating types, but the thickness of the zinc coating (1-2μm) must be strictly controlled. ‌

Direct electroplating process

Special conductive polymers are adopted to replace the traditional zinc immersion step, and direct electroplating is achieved through steps such as nano-etching and molybdate activation. This technology is environmentally friendly and has a 20% increase in the yield rate, making it suitable for scenarios that require RoHS certification. ‌

Suggestions for process selection

small batch/complex structure ‌ : electroless nickel plating or zinc immersion is preferred

For large quantities/high corrosion resistance requirements ‌ : direct electroplating is recommended

Environmental protection requirements ‌ : In coastal areas, electroless nickel plating can be selected; in inland areas, direct electroplating is recommended.