PCB corrosion causes
Corrosion of PCB metals arises from chemical attack often facilitated by ionic contamination. Chlorides, sulfur-containing species, and acidic residues attack copper, tin, and silver finishes, leading to pitting, blackening, and loss of plating integrity.
Corrosion can be localized around through-holes, component leads, and exposed copper. It reduces mechanical strength, increases contact resistance, and accelerates subsequent failure modes. Preventive cleaning and selection of corrosion-resistant finishes help.
Role of ionic contamination in corrosion
Ions create localized electrolytes that support anodic and cathodic reactions. Halides are especially aggressive, penetrating passive oxide layers and initiating pitting. Acidic residues from flux accelerators lower pH and increase corrosion rates. Removing these ionic species prevents initiation of electrochemical attack.
Environmental factors influencing corrosion
Contributors include:
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high humidity and condensation events
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corrosive gases like sulfur dioxide and chlorine near industrial areas
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salt spray exposure for marine applications
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temperature cycling that concentrates residues by evaporation
ZESTRON conducts environmental assessments and formulates cleaning strategies and protective coatings to mitigate environmental corrosion drivers.