Gas Nitriding / Ferritic Nitro-Carburizing (FNC)

Ferritic Nitro-Carburizing (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 nitro-carburizing 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.