02-19-2017, 02:55 AM
Hi Joe, this is something I looked deeply into a while back and really nerded out about. This being the technical forum, I'll lay out what I learned, for what it's worth.
First, there are some good overviews (and opinions) I liked from coating engineer Bill Riehl here and here.
Electroless nickel (EN) is great for adding corrosion resistance to steel, as well as reducing friction. High phosphorous EN is better at corrosion resistance, but softer and wears more than low P. Add in some boron and you start to get NiB/NiB-X, and it's harder and much lower wearing, though not as slick. Check out this chart. The Taber wear is a lowest for the low-mid B column, which is roughly the NiB. Adding in PTFE (Teflon) particles reduces the friction even further from normal EN, but it still doesn't wear as well as NiB. The Taber wear I've seen from PTFE/NP3 is about 20, which isn't great. There are tons of articles on this, like Liew, et. al (2013). Evaluation on tribological design coatings of Al2O3, Ni–P–PTFE and MoS2 on aluminium alloy 7075 under oil lubrication. Materials and Design, 48©, 77–84. http://doi.org/10.1016/j.matdes.2012.08.010.
The best of all is probably to embed particles of not only PTFE, but also tungsten, but as far as I know those aren't commercially available (though I believe Bill's company Black Fire Engineering is working on the latter?). Here is an overview of the wear benefits of tungsten additives.
Roguard, Armor Tuff, Cera Hide, and I assume Cerakote's Micro Slick are polymeric/epoxy coatings with embedded lubricants like PTFE or MoS2. My impression is these are great for superficial and relatively low-wear applications, not so much for internal or high force applications.
The cool thing about EN overall is that you can spend a ~$150 for a kit and gear, and coat a bunch of parts for yourself.
First, there are some good overviews (and opinions) I liked from coating engineer Bill Riehl here and here.
Electroless nickel (EN) is great for adding corrosion resistance to steel, as well as reducing friction. High phosphorous EN is better at corrosion resistance, but softer and wears more than low P. Add in some boron and you start to get NiB/NiB-X, and it's harder and much lower wearing, though not as slick. Check out this chart. The Taber wear is a lowest for the low-mid B column, which is roughly the NiB. Adding in PTFE (Teflon) particles reduces the friction even further from normal EN, but it still doesn't wear as well as NiB. The Taber wear I've seen from PTFE/NP3 is about 20, which isn't great. There are tons of articles on this, like Liew, et. al (2013). Evaluation on tribological design coatings of Al2O3, Ni–P–PTFE and MoS2 on aluminium alloy 7075 under oil lubrication. Materials and Design, 48©, 77–84. http://doi.org/10.1016/j.matdes.2012.08.010.
The best of all is probably to embed particles of not only PTFE, but also tungsten, but as far as I know those aren't commercially available (though I believe Bill's company Black Fire Engineering is working on the latter?). Here is an overview of the wear benefits of tungsten additives.
Roguard, Armor Tuff, Cera Hide, and I assume Cerakote's Micro Slick are polymeric/epoxy coatings with embedded lubricants like PTFE or MoS2. My impression is these are great for superficial and relatively low-wear applications, not so much for internal or high force applications.
The cool thing about EN overall is that you can spend a ~$150 for a kit and gear, and coat a bunch of parts for yourself.