Nitriding of Aircraft Parts

Nitriding is a heat treatment process that diffuses nitrogen into the surface of a metal to improve its hardness, wear resistance, and fatigue strength without significantly altering its core properties. It is commonly used in aircraft landing gear, engine components, and structural parts that require superior surface durability.

Unlike traditional hardening methods, nitriding occurs at relatively low temperatures (500–600°C), reducing the risk of distortion in precision aerospace components.

How Nitriding Works

1. Surface Preparation – The part is cleaned to remove contaminants.
2. Nitriding Process – Nitrogen atoms are introduced into the metal’s surface through one of the following methods: Gas Nitriding – Exposes the part to ammonia gas (NH₃) at high temperatures. Plasma (Ion) Nitriding – Uses an electric field in a vacuum to ionize nitrogen gas, allowing controlled diffusion. Salt Bath Nitriding – The part is immersed in a molten nitrogen-rich salt bath.
3. Formation of a Hard Nitride Layer – Nitrogen reacts with elements like iron, chromium, and titanium, forming hard nitride compounds that enhance surface properties.
4. Cooling & Finishing – The part is cooled and may undergo additional polishing or grinding for precise tolerances.

Benefits of Nitriding for Aircraft Parts

✅ Increased Surface Hardness (up to 1100 HV) – Improves wear resistance for moving parts. ✅ Improved Fatigue Strength – Reduces crack initiation under high stress. ✅ Corrosion Resistance – Forms a protective nitride layer that prevents oxidation. ✅ Minimal Dimensional Changes – Unlike carburizing or quenching, nitriding does not significantly distort parts. ✅ No Need for Post-Hardening – Since it occurs at low temperatures, parts retain their original mechanical properties. ✅ Suitable for High-Temperature Applications – Common in jet engine and exhaust system components.

Aerospace Applications of Nitriding

✔ Landing Gear Components – Enhances wear resistance in shock-absorbing structures. ✔ Aircraft Engine Shafts & Gears – Prevents wear and fatigue failure. ✔ Turbine Blades & Compressor Disks – Improves high-temperature durability. ✔ Hydraulic Actuators & Cylinders – Reduces friction and increases lifespan. ✔ Fasteners & Bearings – Protects against wear and galling in high-load applications.

Comparison: Nitriding vs. Other Surface Hardening Methods