Excessive consumption of palladium in POP activator
We are a Job Shop to Plating on Plastic. We have higher consumption of palladium in our Futuron activator. We believe that it can be due to contamination with Sodium-Meta-Bisulfite Our reducer contains 30 gr/liter Sodium-Meta-Bisulfite.
Then we have three counter-flow rinse that let us a dilution of 30000:1
The following step is a Pre-Dip with 30% of hydrochloric acid. Our Drag-out is 0.002 ml/sq. dm. But we don't know which is the maximum Meta-Bisulfite that can support our activator.
Can somebody help us?Norberto G. Martin
The palladium in the activator is present as a colloid. palladium as the ground state metal and stannous tin (keeps the palladium in solution)chloride. The Bisulfite is probable not effecting the palladium directly, but is chemically going after the tin. Is there a little sludge at the bottom of the activator? Using a little stannous chloride in the pre-dip might protect the activator. Do try this off-line first. Don't experiment with production. Three counter-flow rinses is a good thing, but is there any agitation of the rinse water (air) or parts? Might be all you need.
Note: If you're using Electroless Copper you might want to change from 30% hydrochloric acid pre-dip to a lower Normality sodium chloride type of pre-dip (health reasons).
Regards,Fred Mueller, CEF
- Royersford, Pennsylvania
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