plating, anodizing, & finishing Q&As since 1989
Electroless nickel plating over babbitt alloy
I need do this electrodeposition. But I don't know if this alloy is autocatalytic with respect to nickel.L. Medeiros
Babbitt is an antique bearing surface, but it still has applications where it is the one of choice. If you EN over the top of it you are going to kill almost all of the reason for using it. Bad choice from my distant perspective.
Activating it is going to be more of a problem because of the alloy ingredients are significantly different.
The EN start is less of a problem as you can impose a negative charge on the parts for a few seconds, which should be enough to start the electroless deposition. (you will need a temporary anode, like SS). Alternative would be a short nickel strike.
Babbitt metal can be anything between 90% Pb and 90% Sn, with Sb and Cu. None of these metals are catalytic to regular acid or neutral EN plating solutions and will also poison them.
However, there is an ammoniacal, nickel sulfamate and pyrophosphate based solution, that operates at pH 10 and 185F that will plate directly on babbitt metal, at least as a tie coat before regular EN.
Ron Duncan [deceased]
- LaVergne, Tennessee
It is our sad duty to note Ron's passing on Dec. 15, 2006. A brief obituary opens Episode 13 of our Podcast.
You need a Nickel Strike layer prior to the EN.
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