Plasma Nitriding, also known as ion nitriding, is the process in which a plasma field is generated in a partial-pressure atmosphere to diffuse nitrogen into the surface of a part. This creates a case-hardened, protective surface on the component that eliminates the need for any further finishing and provides a pore-free surface.
Alloys commonly treated through Plasma Nitriding
- Alloy Steels, e.g., 4140, 4340, 8620
- Nitriding Steels, e.g., N-135
- Tool Steels, e.g., A-2, H-13
- Cast Iron
TMT’s Equipment and Variations of Plasma Nitriding
The gas mixture of Hydrogen and Nitrogen can be controlled to produce a white layer or minimal amount. The white layer is a very hard, but brittle surface layer. Methane can be added as a third process gas to perform Ferritic Nitrocarburizing. Typical case depths are in the .001″-.020″ range.
Applications of Plasma Nitriding
- Plasma nitriding is used in applications when high-surface hardness is required. In general, case depths are lower than carbonitriding and carburizing due to the lower processing temperature.
- Plasma nitriding takes place at subcritical temperatures, meaning there is no phase transformation during the process. This results in extremely low distortion compared to processes, such as carburizing, carbonitriding, and through hardening.
- Plasma nitriding can improve the corrosion resistance of a part. The nitrogen atoms infused in the metal create a barrier that prevents corrosive elements from reaching the metal surface of the part.
- Plasma nitriding offers superior wear resistance due to the increased hardness from the nitrogen content. The infused nitrogen atoms create a hard, durable surface making this an excellent treatment for components that must undergo high levels of wear and tear during normal operation. Plasma nitriding can also increase a metal’s fatigue strength–its resistance to repeated stress.
What To Consider When Specifying
- Case Depth
- White Layer Composition (if required)
- Spec (if required)