Hardened Steel vs. Electroless Nickel Coated or Anodized Titanium and Galvanic Corrosion

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Hello,

We have a titanium machine part which used to be electroless nickel plated, but due to the application process being environmentally nightmarish, we've gone to anodize. The part has a bearing housing which is contacted by the outer race of a tapered roller bearing, made of hardened steel. The bearing does not see the typical daily cycling through, such as wheels turning constantly, but think of it more or less as being used to "dial in" a setting on occasion. Hmmm, I hope I'm clear on this description...

We knew that the electroless nickel plating showed no signs of galling or galvanic type of corrosion while it was still being used. However, we've allowed the vendors to switch to anodize in the meantime; but we're not sure if anodize will "pass the test of time".

What are the major differences between nickel and anodize? (besides cost...)

Does anyone have any suggestions? I think I read in another post where someone was powder-coating over anodized aluminum. Does this provide a durable hard shell over the anodoze? Cost? Benefits? Can the thickness of anodize be controlled? ie. is thicker necessarily more protective or harder?

Thanks for any input.

Edward J. Yuhas, Jr.
Mechanical Engineer - Picatinny Arsenal, NJ