Nitrocarburizing
Nitrocarburizing is a thermochemical process for enriching the surface layer of a workpiece with nitrogen and carbon . This creates a nitrided layer consisting of a connecting layer and a diffusion layer. In contrast to this, only nitrogen is stored in nitriding .
The process can be carried out in different media:
- in gas (gas nitrocarburizing)
- in the salt bath (salt bath nitrocarburizing)
- in plasma (plasma nitrocarburizing)
Gas nitrocarburizing
The gas nitrocarburizing is carried out at temperatures between 500 ° C. and 630 ° C. in a gas mixture which can give off nitrogen (e.g. ammonia ) and carbon (e.g. carbon dioxide ). The aim is to improve the wear resistance and corrosion resistance of low to medium-alloy steels. Higher-alloy steels with a chromium content of over 13% are generally unsuitable because of the formation of a passivation layer . Cooling down in oxidizing atmospheres usually increases the corrosion resistance .
Salt bath nitrocarburizing
In salt bath nitrocarburizing, components made of low-, medium- and high-alloy steels and cast iron are treated in a molten salt at temperatures of 550 ° C to 630 ° C. The advantages of the process are the short treatment time, the high level of wear resistance and corrosion resistance. Oxidative aftertreatment shows the same positive effect as gas nitrocarburizing. Alkali cyanates and alkali carbonates serve as salt bath components ; the consumed salts can be topped up during the reaction.
Plasma nitrocarburizing
With plasma nitrocarburizing, high-alloy steels can also be hardened in the surface layer. The components are treated with ionized gas at temperatures from 350 ° C to 600 ° C. As a rule, no mechanical post-treatment of the parts is required.
See also
swell
- ^ Nitriding, nitrocarburizing
- ↑ Overview of a special salt bath nitrocarburizing process ( Memento of the original of September 30, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.62 MB)
