Ion(Plasma) or Gas Nitriding?

Following a recent discussion in The Monty on Ion Nitriding/Nitrion, Kevin Robinson, our resident expert on Nitriding (both Plasma and Gas) has these comments:

With regard to the recent postings on The Monty with respect to Ion(Plasma) Nitriding – I would like to add a few comments. Bill Jones has raised some valid views on the furnace technology itself and I think most of us would agree that Gas Nitriding furnace technology is a lot more forgiving in every aspect.

However, we must consider where it can be used and be cost effective and we must not lose sight of the fact that it is only Nitriding after all – a point that is often lost!

In the end it is the component designers and the requirement to get more properties from those components and associated treatments that direct the technology – Vacuum Carburizing being a case in point.
Across Europe Ion(Plasma) Nitriding is commonly used to treat high volume automotive parts in addition to more exotic applications in motorsport and aerospace.

The key process advantages of Ion(Plasma) nitriding that are exploited are:

The ability to use mechanical masking, this provides an extremely cost efficient method to achieve simple and accurate ’stop off’ on mass produced parts.
Surface treatment of sinter products, not easily reproduced in a gas atmosphere as the components tend to nitride inside out and may even break up.
Surface hardening of stainless steels, again this is a standard application for Ion(Plasma) Nitriding without the need to use etchants, blast media or other chemicals.
Low treatment gas consumptions and relatively clean emissions (usually only hydrogen and nitrogen), this has prompted the use of this technology ‘in-line’ in many captive heat treat shops.

It has been clear for some time now that the Ion(Plasma) technologies have been more successful in Europe and Japan than North America but as emissions regulations and cost of treatment gases increase then maybe Ion(Plasma) Nitriding may become less of a curiosity…….?