Nitriding Systems

 

Plasma heat treatment, especially pulse plasma nitriding and pulse plasma nitrocarburizing is used for surface treatment of work pieces for protection against wear. For the treatment by plasma, the parts have to be placed in a vacuum vessel and are electrically insulated from the case. At a pressure of 50 - 500 Pa, a pulsed electrical D.C. voltage of several hundred volts is used between work piece and vessel, whereby the workload is switched cathodically. The ionizing of the remaining gas in the vessel results in a glow discharge. The electrical, positive ions are moving towards the work piece and impact with high kinetic energy. During this process at the surface the following happens:

• sputtering, cleaning and activation of the surface
• heating of the work piece by absorption of kinetic energy of ions
• reactions of highly active ions with elements in basic work material
• diffusion of elements -which are to be found in gas- into the work piece

Depending on the material and the results required, the treating temperature and time are chosen in advance.


Advantages of the process by using plasma are the following:

• no environmental and safety problems, as neither dangerous nitriding materials are used nor produced
• minimal requirement of gas, as, by ionizing the gas used may be exploited effectively
• the structure of the nitride layer may be controlled
• surface parts which may not be treated, can be protected by covering
• steels containing chrome may be nitrided without previous depassivation
• if required the temperature of work pieces may be kept very low; thus it is possible to treat cold work steel.
  

You can get more information about our nitriding systems at the websites of our subsidiary PlaTeG GmbH:

 

www.plateg.de