Teflon Defender Swivel housings???
Something we are quite often asked about are teflon swivel housings. This term is a bit of a misnomer as the coating referred to is actually the result of a process called Nitrotec which gives the part its grey anthracite / black finish.
Just to give you a bit of a low down on the process, Nitrotec is a surface treatment technology which acts as an alternative to Zinc and Hard Chrome Plating and replaces the less environmentally friendly Chromium plating.
- Increased wear resistance
- Improved fatigue performance
- Excellent corrosion resistance
- Indentation resistance
- Weight saving
The finish is not a coating (unlike Teflon) it is a heat treatment process in a controlled nitrocarburising atmosphere, and takes several hours, at a specific temperature to produce the desired properties. It is then followed by a post oxidising treatment. This finish gives a dramatic improvement in frictional characteristics, corrosion resistance properties, and fatigue performance superior to those obtained when using hard chromium plating techniques.
A key property of the Nitrotec surface layer is that it has columnar micro-porosity which is capable of retaining lubricant - and so not only is the component hard, but it can hold a lubrication layer. These properties of hardness and intrinsic lubrication together lead to the resistance to wear of the part.
When dry you may see a dark grey slightly patchy mottled looking finish, this is normal, if you wipe the surface with an oily rag you will see how the surface turns a darker black and slowly changes as it absorbs oil into the surface.
Some replacement swivel balls on the market manufactured from distant lands use an incorrect finish of Black Oxide or Chemical Black. This might look nice and shiny but provides little corrosion resistance, no lubricating retention properties, and no additional load bearing fatigue properties.
We are not sure who the idiot was who first described the finish treatment as Teflon, but it has stuck, which is a bit ironic given Teflons properties. You will find lots of webshops describing the finish as Teflon, its not. So,please when you are buying swivel housings, make sure they really do have a Nitrotec finish - you really don't want a teflon finish- that's great for non-stick saucepans but not so great for swivels!
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