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Silica content in electroless nickel

We have a problem in Electroless nickel plating on aluminium die cast shells, the consumption of Hypo is increasing from 14 to 20 than the regular additions(1:2).We would like to know what might be the reason .

SHIVANANDA MURTHY
- Bangalore, KARNATAKA AND INDIA
2005

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2005

The two most common reasons for excessive hypo usage are keeping the bath hot when it is not being used, and oxidizer contamination.

If the bath stays at above 65C while it is not used, hypo will continue to oxidize to orthophosphite producing only hydrogen. When plating is done, the bath should be cooled quickly for storage.

The presence of oxidizers in the bath will also consume hypo. The usual problem is nitric acid. I know of one shop whose reducers use doubled because the intake of the agitation air blower was next to the vent on their nitric acid storage tank.

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.