Galvanic Corrosion of Zinc (Sacrificial Anode)

概述

Zinc acts as a sacrificial anode when electrically connected to iron or steel, preferentially oxidizing to protect the less reactive metal. Zinc's standard reduction potential (-0.76 V) is more negative than iron's (-0.44 V), so zinc corrodes first. This is the principle of cathodic protection and galvanization.

参与者

日常示例

Galvanized steel roofing, fencing, and car bodies are coated with zinc that corrodes preferentially, protecting the steel underneath.

工业重要性

牺牲阳极保护法广泛用于保护船舶、海洋石油平台、地下管道和储罐中的钢铁设施。镀锌钢（热浸镀锌或电镀锌）利用同样原理保护钢铁，全球每年消耗约600万吨锌用于镀锌保护，显著延长金属设施寿命。