Current density in copper strike prior to nickel plate on aluminum.
We have an aluminum prep line leading up to a sulfamate nickel plate. Just before nickel plate we utilize a copper strike bath. I noticed that it is common protocol to begin the copper strike at a relatively high current density for a short time then switch to a lower current density for a longer time. What is the reason for the switch from higher to lower current density ? Thanks ... Greg FuquaGreg Fuqua
- Jacksonville, Florida
Sounds like the reverse procedure to me, but you would have to tell us the current density at the start and when you drop the current. You may be too high or too low at some point.
Is this copper strike over some zincate coating? -tom
Falls Township, Pennsylvania
This is a common practice to strike at a higher current density for a short time when plating complex shapes. The copper covers the low current density areas faster before the zincate dissolves and blistering occurs. Once there is total coverage you can turn the amperage down to normal ranges.
Anoplex - Dallas, Texas USA
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