Zinc-Nickel Coating
Zinc-Nickel (Zn-Ni) Coating of Aircraft Parts
Zinc-Nickel (Zn-Ni) coating is a high-performance electroplated alloy coating used in the aerospace industry for corrosion resistance, wear protection, and durability. It is an advanced alternative to traditional cadmium (Cd) plating, which is being phased out due to environmental and health concerns. Zn-Ni coatings typically contain 10-15% nickel, offering superior corrosion protection compared to pure zinc coatings.
How Zinc-Nickel Coating Works
- Surface Preparation The aircraft part is cleaned, degreased, and sometimes pretreated with an activation process. Grit blasting or pickling may be used to enhance adhesion.
- Electroplating Process The part is submerged in an electrolyte bath containing zinc and nickel ions. An electric current is applied, causing the Zn-Ni alloy to deposit onto the substrate.
- Post-Treatment (Optional) A chromate or passivation layer is applied to further enhance corrosion resistance and adhesion. Sealers, topcoats, or primers may be used for additional protection.
Benefits of Zinc-Nickel Coating for Aircraft Components
✅ Superior Corrosion Resistance – 10× better than pure zinc and a leading cadmium replacement. ✅ High-Temperature Performance – Withstands up to 400°C (752°F) without significant degradation. ✅ Excellent Adhesion to Base Metals – Ensures long-lasting protection on aluminum, steel, and titanium alloys. ✅ Great Wear & Abrasion Resistance – Ideal for landing gear, fasteners, and high-friction parts. ✅ Environmentally Friendly (Cadmium-Free Alternative) – Meets REACH and RoHS compliance. ✅ Compatible with Paint & Sealants – Works well with topcoats for additional protection. ✅ Good Electrical Conductivity – Suitable for EMI/RFI shielding applications.
Aerospace Applications of Zinc-Nickel Coating
✔ Landing Gear Components (Shock Struts, Axles, Actuators) – Protects against corrosion and wear. ✔ Fasteners, Bolts, and Screws – Provides long-term durability in harsh environments. ✔ Aircraft Structural Parts & Frames – Improves corrosion protection for steel and aluminum parts. ✔ Hydraulic & Pneumatic Systems – Ensures corrosion and wear resistance in fluid-exposed parts. ✔ Engine & Exhaust Components – Withstands high temperatures without oxidizing.
Comparison: Zinc-Nickel vs. Other Aircraft Coatings
Challenges & Considerations
✖ Requires Precise Control of Electrolyte Bath Composition – Zn-Ni ratios must be carefully controlled for optimal performance. ✖ Slightly More Expensive Than Zinc Coating – Higher cost but offers significantly better durability. ✖ Post-Treatment May Be Necessary – Chromate conversion coatings, sealers, or paints enhance corrosion resistance. ✖ Not as Hard as Hard Chrome – May not be ideal for extreme high-wear applications without additional treatments.
Industry Standards & Compliance
- AMS 2417 – Aerospace standard for Zn-Ni plating.
- MIL-PRF-32648 – Military specification for Zn-Ni coatings as a cadmium replacement.
- ISO 19598 – International standard for Zn-Ni coatings.
- REACH & RoHS Compliant – Meets environmental regulations for cadmium-free coatings.
- FAA & EASA Approved for Aviation Use.
| Coating Type | Corrosion Resistance | Wear Resistance | Environmental Impact | Heat Resistance | Application |
|---|---|---|---|---|---|
| Zinc-Nickel (Zn-Ni) Coating | ✅ Very High | ✅ High | ✅ Eco-Friendly | ✅ Up to 400°C | ✅ Landing gear, fasteners |
| Cadmium Plating (Cd) | ✅ Very High | ✅ High | ❌ Toxic, Restricted | ✅ High | ❌ Being phased out |
| Zinc Coating | ❌ Moderate | ❌ Low | ✅ Eco-Friendly | ❌ Low | ❌ Weaker alternative |
| Hard Chrome Plating | ✅ High | ✅ Very High | ❌ Hazardous Waste | ✅ High | ❌ Being replaced by HVOF |
| HVOF Thermal Spray | ✅ Very High | ✅ Very High | ✅ Eco-Friendly | ✅ Very High | ✅ Structural, high-wear areas |
Parts that require Zinc-Nickel Coating
| Part Number | Name | Alt Part Number | ATA Chapter | Cage Code | NSN | Rotable | Repair Stations | Suppliers |
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