Amphoteric metals

Definition

Amphoteric metals such as aluminum and zinc can be destabilized at high pH, unlike metals attacked mainly by low pH.

Their protective behavior depends on pH staying in a stable window, so high pH can dissolve them. This makes pH control a two-sided concern, since both low and high extremes threaten different metals. It is a reason to track pH as a critical monitoring parameter.

Related concepts

pH effects on corrosion · Critical monitoring parameters

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Part of The Blueprint of Water · 🧱 materials