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Copper plating on aluminum

I am using Zincate to plate on aluminum (Cu/Ni). The electroless copper (seed layer) coming this way just fine. But when I am trying to plate an electrolytic copper (phosphate bath)on the top - it is growing but shows very low adhesion and all blistered. May be somebody can help.

Irina Kulinets
- Melrose, Massachusetts
2002

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Irina,

From the very little info you give I see two possibilities
1- Your pyrophos copper is attacking the zinc underneath the E-less copper flash. Increase time and thickness of flash.
2- Your orthophosphate has reached a point where causes excesive internal stress, so plate blisters and cracks. There is no practical way to reduce the ortho but to discard part and add new formulation.

Guillermo Marrufo
Monterrey, NL, Mexico
2002