Plasma nitriding
Because it does not involve the use of toxic gases, plasma nitriding is one of the most environmentally friendly methods of surface hardening.
It produces only a fraction of the exhaust gases generated by other hardening processes. Furthermore, the thermochemical process is suitable not only for all iron-based materials, but also for sintered steels with high porosity, cast iron, and high-alloy steels.
During the plasma nitriding of stainless steels, the first step in the process involves breaking up the component’s oxide layer must be broken down . This process is called sputtering. Next, in the nitrogen-hydrogen gas mixture—which serves as the nitriding medium—a high voltage is applied between the charge and the furnace wall. This electrically conductive gas is calledplasma. Positively charged ions then strike the workpieces, leading to the formation of nitrogen-rich nitrides, which enrich the component surface with nitrogen as they decompose. Since there are virtually no dimensional changes, the component is ready for immediate use.
Due to the high energy density of the plasma, the process can be carried out even at low operating temperatures of less than 500°C, making it suitable for materials that are sensitive to warping.
While the achievable surface hardness depends primarily on the steel grade, the thicknesses of the resulting layers are also influenced by the treatment temperature, the treatment duration, and the nitrogen content in the process gas. Plasma nitridingis primarily used for components that are intended to have both nitrided and non-nitrided areas, since areas covered by metal can be protected from hardening.
Consequently, contact surfaces and bearing surfaces are not nitrided. For parts that are to be hardened on all sides, holes must be provided for hanging the parts during the process.Acrucial factor is that bulk material cannot be treated in the plasma. The components must therefore be loaded individually, with spacing maintained between them.
KEY FIGURES FOR PLASMA TREATMENT
Temperature:
up to 565°C
Oven size:
1,000 x 1,500 mm
Processing time:
24 hours or more
Nitriding hardening depth:
up to 0.8 mm
Max. load capacity*:
1,500 kg
*per batch for standard sizes and treatments
Advantages of Plasma Nitriding
No delay
Nitriding is the only hardening process that does not cause any process-related distortion of the component.
Hardening of specific areas
Specific areas of the component can be hardened by covering the other surfaces with a protective paste.
Outstanding component properties
Nitriding produces components with improved corrosion resistance and high wear and fatigue strength, capable of withstanding the most severe loads.
No post-processing
Since no distortion occurs during the hardening process, components can generally be nitrided after they have been manufactured.
ADVANCED NITRIDING TECHNOLOGY
Plasma nitriding is undisputedly the most advanced nitriding technology. Compared to gas nitriding, the process parameters can be controlled even more precisely. This allows the component surface to be modified very precisely to achieve the desired properties.
By varying the gas mixture, it is possible to different nitriding layer structures and hardness profiles can be achieved. Oxide-free nitriding is possible at high nitriding hardening depths. The component surfaces are clean and exhibit lower surface roughness than those produced by other nitriding processes.
We look forward to hearing from you!
Please use our contact form or contact our sales team directly.
Silvio Stranek
Sales, Technical Consulting / Quotes (Upper Austria, Tyrol, Salzburg, Vorarlberg, Bavaria, South Tyrol)
Email. s.stranek@htr.at
Phone: +43 (0) 664 / 88 92 78 10
Thomas Stadlober
Sales, Technical Consulting / Quotes (Styria, Vienna, Lower Austria, Carinthia, Slovenia)
Email. t.stadlober@htr.at
Phone: +43 (0) 664 / 88 64 15 06
OTHER NITRIDING PROCESSES
gas nitriding
In gas nitriding, nitrogen is released from ammonia; at temperatures between 500°C and 600°C, this nitrogen penetrates the surface of the component, where it forms a wear-resistant nitride layer.
Salt bath nitriding
In salt bath nitriding, the parts to be treated are immersed in a nitriding bath to increase their surface hardness and are then oxidized in a quenching bath.
Back to overview
OUR INDUSTRIES
Automotive industry
Aerospace
Medical technology
Tool and Machine Manufacturing
Your Questions, Answered
We have compiled a list of frequently asked questions to help you better understand our services.
What is plasma nitriding?
Plasma nitriding is a modern thermochemical hardening process in which nitrogen is introduced into the surface layer of a component in an ionized gas atmosphere (plasma). This results in a clean, nitrogen-enriched surface with high resistance to abrasion and wear—without any process-induced distortion.
What makes plasma nitriding so special?
Plasma nitriding is considered the most advanced form of nitriding. The precise control of process parameters enables exactly defined hardness profiles and coating structures. There is no change in dimensions, and the surface remains clean and smooth. In addition, the process is particularly environmentally friendly, as it does not use toxic gases and produces only very low emissions.
What are the advantages of this procedure?
Plasma nitriding combines numerous technical and environmental benefits:
– No warping: Ideal for dimensionally stable or delicate components
– No post-processing: Finished parts can be nitrided directly
– Environmentally friendly: No use of toxic gases, low emissions
– Precise curing of specific areas: Can be precisely controlled using a metallic or paste-like coating
– Clean, smooth surfaces: No residue or buildup
– Low-distortion heat treatment: Can be performed even at temperatures below 500 °C
For which materials is plasma nitriding suitable?
This method is very versatile. It is suitable for:
– All iron-based materials
– High-alloy steels
– Sintered steels with high porosity
– Cast iron
– Stainless steels (after sputtering treatment)
The surface must be clean, metallically pure, and free of grease, oil, or oxidation.
How does the process work?
The nitriding process takes place in several stages:
-
Sputtering: First, the oxide layer on the workpiece surface is removed.
-
Plasma generation: High voltage creates an ionized gas (plasma) in the nitrogen-hydrogen mixture.
-
Diffusion: Positively charged ions strike the surface and enrich it with nitrogen.
-
Layering: Nitrogen-rich nitrides form, resulting in a hard, wear-resistant surface layer.
Due to the high energy of the plasma, a moderate processing temperature of less than 500°C is sufficient—ideal for materials prone to warping.
Where is plasma nitriding most commonly used?
This method is used in particular in situations where:
– When the highest precision is required
– Specific areas are to be selectively hardened or left untreated
– Components cannot tolerate any change in dimensions
– High resistance to corrosion and wear is required
Typical applications include tools, machine parts, drive system components, and precision parts subjected to high stress.