Nickel-Boron Coating
Nickel-Boron Coating of Aircraft Parts
Nickel-boron (Ni-B) coating is an advanced electroless plating process used in the aerospace industry to provide high hardness, superior wear resistance, and excellent corrosion protection for critical aircraft components. This coating is an alternative to traditional hard chrome plating and electroless nickel-phosphorus (Ni-P) coatings, offering better performance in specific applications.
How Nickel-Boron Coating Works
- Surface Preparation – The aircraft component is cleaned and activated to ensure proper adhesion.
- Electroless Deposition – A chemical bath containing nickel salts and boron-reducing agents (e.g., sodium borohydride or dimethylamine borane) deposits a uniform nickel-boron layer on the part.
- Heat Treatment (Optional) – Some applications require post-plating heat treatment to enhance hardness and wear resistance.
Benefits of Nickel-Boron Coating for Aerospace Components
✅ Extreme Hardness (700-1100 Vickers HV) – Harder than standard electroless nickel and chrome plating, improving wear resistance. ✅ Superior Corrosion Resistance – Protects against oxidation, moisture, and harsh chemicals. ✅ Excellent Lubricity & Low Friction – Reduces wear in moving parts, making it ideal for sliding or rotating components. ✅ Uniform Coating Thickness – Deposits evenly on complex shapes without edge buildup, unlike electroplating. ✅ Alternative to Hard Chrome Plating – Does not contain toxic hexavalent chromium, making it more environmentally friendly. ✅ Solderable & Conductive – Unlike Nickel-Phosphorus (Ni-P) coatings, Ni-B coatings offer better electrical conductivity and solderability.
Aerospace Applications of Nickel-Boron Coating
✔ Landing Gear Components – Enhances wear resistance and corrosion protection. ✔ Hydraulic Actuators & Cylinders – Reduces friction and prevents galling. ✔ Fuel System Components – Protects against corrosion from aviation fuels. ✔ Jet Engine Components – Used for high-temperature parts that require wear resistance. ✔ Aircraft Fasteners & Bearings – Improves durability and reduces maintenance cycles. ✔ Electronic & Electrical Contacts – Provides excellent solderability for aerospace electronics.
Comparison: Nickel-Boron vs. Other Aerospace Coatings
Challenges & Considerations
✖ Higher Cost than Ni-P Coatings – Ni-B coatings are more expensive due to the use of boron-based chemistries. ✖ Brittleness at High Thicknesses – Excessively thick Ni-B layers may become brittle. ✖ Requires Precise Process Control – The deposition process must be carefully monitored to achieve uniformity and performance.
Industry Standards & Compliance
- AMS 2403 – Aerospace specification for electroless nickel coatings.
- MIL-C-26074 – Military standard for electroless nickel coatings.
- ASTM B733 – Standard specification for electroless nickel coatings on various substrates.
| Coating Type | Hardness (HV) | Corrosion Resistance | Wear Resistance | Lubricity | Key Benefit |
|---|---|---|---|---|---|
| Nickel-Boron (Ni-B) | 700-1100 | High | Excellent | Low Friction | Harder than Ni-P, no toxic Cr |
| Electroless Nickel-Phosphorus (Ni-P) | 500-950 | Very High | Good | Moderate | Best for corrosion resistance |
| Hard Chrome Plating | 800-1000 | Moderate | High | Low | Aerospace standard but contains toxic Cr |
| HVOF Tungsten Carbide | 1000-1400 | High | Superior | Moderate | Best for extreme wear applications |
| PVD Coatings (TiN, DLC) | 1500+ | Moderate | Very High | Very Low | Ultra-thin, high-wear resistance |
Parts that require Nickel-Boron Coating
| Part Number | Name | Alt Part Number | ATA Chapter | Cage Code | NSN | Rotable | Repair Stations | Suppliers |
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