Plasma/Ion Nitriding

what is plasma nitriding?

Plasma technology is primarily for stainless steel and other low alloy steels which are not suitable for a “standard” heat treatment process. The process uses a Plasma discharge of Hydrogen and Nitrogen gases both to heat the steel surfaces and to supply nitrogen ions for nitriding. Plasma nitriding is an established and successful process particularly important for precision machined parts. It is a heat treatment process that is used to improve wear-resistance, surface hardness and material fatigue.

the process

The process takes place in a gas mixture of nitrogen and hydrogen. If necessary, a carbon-donating gas can also be used. The necessary temperature is relatively low. In addition, voltage is created between the wall of the furnace and its chamber. This leads directly to the creation of an ionized atmosphere in the furnace chamber, the so-called plasma. There, the ions hit the surface of the component and generate nitrogen-rich nitrides. As soon as these disintegrate, the surface of the material is enriched with atomic nitrogen. Depending on the composition of the gas mixture, different surfaces and degrees of hardness can be created.

fields of application

Plasma nitriding is suitable for all ferrous materials as well as for sintered steels, cast iron and high-alloy tool steels. This method is used especially when components are to contain nitrided and hardened areas as well as soft areas. Please note: If the process is carried out at particularly low temperatures, the corrosion protection does not change. Titanium and Nickel alloys are also Plasma Nitrided. The hard layer formed when Nitriding these materials tends to be relatively thin (<20 microns) but very hard and wear resistant.

This low temperature, low distortion process is used widely throughout the automotive, aerospace and general engineering sectors and a wide variety of applications. Commercially most common components are engine camshafts, engine crankshafts, and gears.

Components or parts are usually nitrided to make wear resistance. The advantages of Plasma/ Ion Nitriding include:

The white compound layer can be minimized down to appropriate levels for the customer requirements.
It is often used for finished parts – as no further machining is typically needed.
The diffused layer will be only on the exposed parts (line of sight) of the component – (usually by mechanical masking).
The opportunity to eliminate copper plate masking through use of simple mechanical masks.
Mechanical masking is the best option for large batch components.
Wear resistance is created by a diffused hard layer.
The ability of to avoid dimensional change and deliver a uniform case on complex geometries.
Improved fatigue properties: the process induces compressive stress, which will improve fatigue strength.
No reduction in the core hardness of the base metal or alloy of the component.
Completed on near finished components –e. requiring very minor (or zero) lapping, polishing or grinding.
The potential for reducing scrap through precisely repeatable cycles.
The opportunity to eliminate environmental pollution because there is no use of toxic salt or toxic gases.