01

Vacuuming the oven chamber

Beforehand, the parts are carefully washed in dedicated machines. Ion nitriding is carried out in a vacuum furnace in an air-free environment to avoid contamination by external elements such as oxygen. This preliminary step ensures that the environment remains neutral and conducive to top-quality nitriding.

02

Gas injection

Injection of the active gas mixture, under reduced pressure, is carefully controlled to maintain optimum mass flow. These gases, often a mixture of nitrogen or hydrogen, are used to facilitate the formation of atomic nitrogen on the metal surface.

03

Plasma creation

By creating a plasma ionizing the furnace atmosphere, nitrogen ions are generated, helping to pickle and heat parts. Modern furnaces, often equipped with additional heating by resistors or active grids, optimize this process to reach the required temperatures without overheating the material.

The nitrided layer comprises :

- on the surface, a combination layer, often referred to as the white layer, from 5 to 25 µm in thickness, in which the nitrogen is combined in the form of iron nitride (γ, ε or γ +ε), conferring very high hardness. This layer promotes sliding, thus increasing resistance to wear and seizure.

- an underlying diffusion layer, generally between 0.1 and 0.5 mm deep, which ensures good fatigue resistance and also enhances wear resistance. The composition and thickness of this layer depend on the steel grade and the specific treatment parameters used.

04

Cooling

At the end of the diffusion cycle, cooling is achieved by forced circulation of neutral gas, such as nitrogen, to ensure uniform, controlled cooling. All treatment parameters, including temperature, time, mass flow rates and plasma characteristics, are rigorously managed by an advanced computer system.