Gasnitriding | In a cracked ammonia atmosphere, nitrogen diffuses into the components at 500 - 530°C. With long treatment periods of 10 - 160 hours, nitration hardness depths (NHD) of 0.1 - 0.9 mm are achieved, depending on the used material. Process results are for example improvements of component strength and gliding properties, increased wear resistance, temperature resistance and fatigue strength under reversed bending stresses.
Partial treatment can also be carried out.

Gas and plasma nitrocarburization | This process is carried out at 570 - 580°C in a gas mixture of mediums releasing nitrogen-carbon. The result from this process is an increased wear or corrosion protection. It presents an alternative to salt bath nitrocarburization with slow batch cooling.

Gas and plasma nitrocarburization Ox | During cooling off in oxidizing atmospheres, corrosion resistance can be improved further. The oxidation treatment following nitrocarburization is possible after all treatment versions. For all nitrocarburization processes, the following is valid: Treatment is carried out for creating the desired white layer (WL), the precipitation layer is normally of secondary importance.

Plasma-nitriding takes place in a vacuum chamber under ionized gas atmosphere. Ammonia, nitrogen, methane and hydrogen are available as treatment gases. In order to create wear-oriented layers, mixed gases are also used. The gas composition, pressure, temperature and treatment time determine the quality. Usually, only finished components are plasma nitrided.

The salt bath nitrocarburization is carried out at 570 - 580°C in molten salt. Treatment time is usually 60 - 120 minutes, cooling off occurs in a water bath or warm salt bath, depending on the material. This treatment is usually offered for improving wear and corrosion protection, however, for high loads, salt bath nitrocarburization is less suited. Partial salt bath nitrocarburization is not possible.

For several years, we have applied salt bath nitrocarburization according to the TENIFER® principle for components made of steel, cast iron and sintered iron, to increase wear resistance, fatigue strength and – particularly in connection with the oxidizing cooling off – the corrosion resistance. In many cases, the TENIFER process is an alternative to other surface layer hardening processes.

TENIFER® Q, QP or QPQ process respectively (Quench - Polish Quench)
As is usual for treating components in salt baths, first of all the components are pre-heated in the air to approx. 350 °C. Nitrocarburization is carried out in the so-called TF 1 bath at 480-630°C, whereby 580 °C is usually selected as the standard temperature. The molten salt mainly consists of alkali cyanate as well as alkali carbonate, and is operated in a crucible of special material with aerator. The active ingredient in the TF 1 bath is alkali cyanate. During the nitrocarburization process, alkali carbonate is created through reaction of the alkali cyanate with the component surface. Through targeted addition of the nonpoisonous regenerator REG 1, the nitrate-active component is recreated directly in the molten salt, and the activity if the TF 1 bath is kept within strict limits.

Tenifer®: registered trademark of Houghton Durferrit GmbH