The authoritative public forum
  for Metal Finishing since 1989
-----

Steel Corrosion Treatment

2000

Hi there, My name is Rob and I work for a snowmobile manufacturing company. We have been trying to determine the best corrosion resistant treatment for steel flanges that are to be shrink-fitted onto a belt drive sprocket to keep the belt from sliding off.

The coating has to be cheap, common and corrosion resistant. Galvanized (zinc) is not suitable since it will wear off quickly and is not good for the heat-shrinking and removal.

My boss has suggested "Black Oxide", but I have never heard of it. Can anybody send me in the right direction?

Rob Pilgrim
- Quebec City, Canada

---

Black Oxide is more commonly known as "Gun Bluing." It's pretty, that's about all. See my post- I'm looking for the same thing you are. If you have any luck, let me know.

PC

Patrick Clark
- Anchorage AK USA
2000

---

Most gears, sprockets, and couplings you would get from a power transmission house would be black oxided. If you've seen such black sprockets, that's what you were looking at. As Patrick observes, black oxide is not very corrosion resistant.

This is just an idea, not a carefully considered opinion, but you might look into salt bath nitriding. Kolene has placed some info about that process on this site.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2000

From your brief description of the problem, I would recommend you try high phosphorous electroless nickel. It is not as "cheap" as zinc, but is close in price in some areas and if it solves a major problem, isn't it worth a little more?

Dan Weaver
- Toccoa, Georgia
2000