Cleaning copper oxidation from PCBs
Understanding oxidation
Copper oxidation ranges from light tarnish to thick cuprous oxide layers that inhibit solderability and increase electrical resistance. Oxidation often accelerates after exposure to moisture or elevated temperatures.
Effective cleaning solutions
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mild acid solutions or chelants can remove oxides without attacking base metal when properly controlled;
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mechanical micro-abrasion is sometimes used for severe cases;
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protect cleaned copper with inhibitor-containing rinses or flux designed for oxidized surfaces.
ZESTRON recommends controlled acidic dip processes or proprietary chelating cleaners with real-time monitoring when copper oxidation is present.