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Bubble chrome structure

2006

After sandblasting Cu-surface (before blasting mirror polished: Rz below 0.2µ) after blasting Rz is between 1.1-1,3µ.
My aim is that roughness will not change by Chrome plating (approx. 30 µ), but that structure will change from sharp till rounded bubble structure
I succeeded on small scale: roll diameter 210 mm, but I failed until now on bigger scale: 900 mm Who can tell me what is cause, and how to investigate differences

as chrome process, I use HEEF-25, current density of 30-50 A/dm2, plating time of 90 min
Frans Brock
client of industrial plating shop - Oosterhout, Holland

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You are experiencing geometrical leveling that comes with thickness. You may need dull satin copper deposit instead of a bright one that will give you a rougher surface before chrome plating.
regards,
Rudolf Kempf
- Haan, Germany
2006