Chloride Attack

Definition

Chloride ions are small, mobile, and relentless film breakers that penetrate oxide films and form soluble metal-chloride complexes at the surface. These complexes carry metal away and prevent repassivation.

Rather than removing the whole film, chloride creates weak points and then exploits them, concentrating at the metal surface where complexes form. The result is deep, localized pitting rather than uniform thinning. Chloride also drives localized attack on stainless steel and migrates into pits to balance charge, producing an acidic salt-rich environment.

Related concepts

Film Saboteurs · Pitting Corrosion · Repassivation

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Part of The Blueprint of Water · 🧪 chemistry