Chemical nickel plating
Chemical nickel is a chemical coating. It is usually deposited on metallic materials as a wear or corrosion protection. Chemical nickel layers are created in the process.
Chemical nickel plating
Chemical nickel is deposited as a chemical deposit without an external electrical power source. The component is immersed in an aqueous process solution with a defined content of nickel ions. In the course of the process, these ions are reduced to nickel metal. A nickel-phosphorus alloy layer forms on the surface of the workpiece, effectively protecting it against wear and corrosion.
Excellent gliding behaviour
The performance spectrum of the chemical nickel coating ranges from chemical resistance, dimensional stability and excellent sliding behaviour to electrical conductivity and exceptional hardness. In this way, the coating ensures optimum finishing even for geometrically complex workpieces with edges and recesses, accessible cavities or bores. Blind holes with Ø < 10 mm and depressions exceeding several times the diameter may have different layer thicknesses due to insufficient renewal with the chemical nickel solution.
The wear resistance depends on the phosphorus content of the coating. The thickness of the coating also influences the durability of the finish: Coating thicknesses of 2 to 10 μm withstand mild corrosion conditions, thicknesses of 5 to 10 μm withstand mild wear. Moderate stress requires layer thicknesses of 10 to 25 μm, heavy stress requires thicknesses of 25 to 50 μm, very heavy stress requires layer thicknesses of more than 50 μm. Post-treatment by tempering increases the hardness and thus improves the wear resistance.
The corrosion protection of the coating is mainly based on a high phosphorus content and the deposition of a pore-free layer. It is always also dependent on the base material and its processing, such as polishing, grinding, turning, milling. The pre-machining of the material in turn influences the adhesive strength of the coating.
Chemical nickel-plated workpieces are characterised by good thermal conductivity: 0.0105 to 0.0135 Cal/cm/sec/°c. The thermal conductivity (λ with the unit W/(m-K))
The layer distribution is very good, the layer thickness is very uniform even on complex shaped components. Also recesses, bores, threads and other poorly accessible places can be provided with sufficient nickel coating using this process. The dimensional accuracy of the layers is also very good.
The appearance of the coating depends on the pre-processing of the base material on which the coating is deposited: Blasted surfaces remain matt, polished surfaces remain glossy. The appearance of the layer cannot be visually adjusted by additives in the electrolyte as is the case with electroplated coatings (e.g.: brighteners). Colour: Metallic bright, slightly yellowish.
All steel, nickel and nickel alloys are suitable for this process. For cast iron, brass, copper, aluminium or aluminium alloys, chemical nickel plating is also possible in principle, but requires special pre-treatment / activation.prinzipiell auch möglich, bedarf aber einer speziellen Vorbehandlung / Aktivierung.
Medium to high phosphorus electroless nickel plating process
High phosphorus electroless nickel plating process
Hard to medium phosphorus electroless nickel plating process
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