Gas Nitriding / FNC


Ferritic Nitrocarburizing (FNC) is a thermochemical surface hardening process that involves diffusion of both nitrogen and carbon into the part.

This treatment is mainly used to improve wear and fatigue properties and to enhance corrosion resistance. Low-alloy steel parts are suitable for this process.

In FNC, ammonia and CO2 are used to obtain Nitrogen and CO, to produce a thin case consisting of a ceramic iron-nitrocarbide layer commonly called “white layer”, and an underlying diffusion zone where nitrogen and carbon are dissolved in the base metal. As a result, there are significant improvements of fatigue properties, adhesive wear resistance and anti-seize properties.

The primary objective of ferritic nitrocarburizing treatment is to improve the anti-scuffing characteristics of components. The compound layer exhibits significant improvement in adhesive wear resistance. With the introduction of nitrogen in the diffused zone fatigue properties are enhanced.

An added benefit of the process is minimal distortion due to short process cycle within the ferrite phase.

  • Our FNC furnaces provide the latest State of the Art in control systems and processing software.
  • The furnaces were designed to operate completely in an automatic mode.
  • Furnaces can modulate gas flow to have a close control to meet the white layer and diffusion zone specification according customer requirements.
  • In accomplishment with CQI 9.
  • All steps of the process are handled by a unique recipe according customer specifications.
  • Recipes are created by specific part number and in accordance with AMS 2759 or specific requirements from our customers.
  • The Process has typically been performed in close loop control system.
  • Trend charts are recorded for traceability.
  • With a controlled post-oxidation treatment after the FNC, the surface corrosion resistance can be enhanced.

Common applications include: brake rotors, spindles, cams, gears, dies, hydraulic piston rods, and powdered metal components.