Better performance for you materials


Discover the benefits that will quickly pay off for your company.

Nitriding is a thermo-chemical treatment for the enrichment of the edge zone of a work-piece with nitrogen – or, in nitrocarburizing, with carbon. We use various treatments to achieve the required improvement to your tools, for example by improving the wear behavior, the strength under static and dynamic loading and the corrosion behavior. An improvement of performance characteristics is achieved by forming a nitrided layer that normally consists of the compound layer and diffusion layer sub-layers.

Shared advantage
in expertise...

…thanks to decades of experience and successful cooperation with renowned steel manufacturers.


In plasma nitriding, the nitrogen is introduced into a vacuum chamber, ionized using an electric field (glow discharge), accelerated in the direction of the tool surface, and absorbed.


Areas of application

Automotive industry | Medical technology | Aerospace industry
Textile industry | Mechanical engineering | Tool making


Material groups

All steel qualities

Plasma nitriding heat treatments

  • Plasma nitriding
  • Plasma nitrocarburizing
  • Improx® oxidizing (oxidizing in plasma)
  • Combination of plasma nitriding or nitrocarburizing with oxidizing



  • A specific coating structure is possible (e.g. nitriding without the compound layer)
  • An environmentally friendly process
  • Partial nitriding is possible
  • Increase in resistance to abrasive wear
  • Less tendency to stick
  • No adherence and better demolding
  • Improved corrosion resistance in unalloyed and low-alloy steels


In the gas nitriding process, ammonia is introduced into a chamber. Under the influence of heat, the ammonia decomposes on the tool surface, which acts as a catalyst. The atomic nitrogen diffuses into the surface.


Areas of application

Automotive industry | Medical technology | Aerospace industry Textile industry | Mechanical engineering | Tool making


Material groups

Low-alloy and alloyed steels up to a maximum Cr content of 5%.

Gas nitriding
heat treatments

  • Gas nitriding
  • Gas nitrocarburizing
  • Oxidizing
  • Combination of gas nitriding or nitrocarburizing with oxidizing



  • Drill holes can be nitrided
  • Nitriding possible on all sides
  • Treatment of bulk materials is possible



An evolution in high-chromium steels

Through the evochrome process, H-O-T is now able to nitride rust and acid-resistant steels with a high content of chromium and alloy in gas. The nitriding depth is considerably higher than with plasma nitriding, but with comparable process times, and even drill holes and recesses are nitrided. Corrosion resistance – which is greatly reduced by plasma nitriding – is largely retained with the new evochrome process.

Areas of application

Mechanical engineering | Mold making
Medical technology | Electrical engineering

Material groups

Rust and acid-resistant steels
e.g. 1.4542, 1.4462, 1.4305, 1.4301, …


  • Excellent corrosion resistance
  • Extreme nitriding depth
  • Drill holes and recesses are nitrided

Notes on production

  • Blasting is required after the process (charge payable)
  • Sharp edges must be mechanically rounded or must be covered
  • A production process-related increase in dimensions of approx. 20–30µm must be factored in


Salt bath nitrocarburizing involves immersing the tools to be treated in molten salt, which releases nitrogen and carbon onto the component surface at a temperature of approx. 580°C, resulting in increased hardness.

Areas of application

Machinery and apparatus engineering | Vehicle manufacturing | Precision engineering
Automotive industry


Material groups

All steel qualities


Salt bath nitrocarburizing heat treatments

  • Salt bath nitrocarburizing
  • Post-oxidation



  • Very short treatment time
  • Treatment of high-alloyed/high-chrome steels is possible without any problems
  • Partial treatment is possible
  • Improved corrosion resistance
  • Better slide characteristics

Talk to us. 
We’ll be happy to advise you.

T: +49 (0)911 36014-1042

Nitriding brochure (german) 

Flyer evochrome (german)

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