BharatNotes
Sacrificial Anode
/ˌsækrɪˈfɪʃəl ˈænoʊd/A more electrochemically reactive metal (typically zinc, magnesium, or aluminium alloy) that is deliberately attached to a less reactive metal structure (iron, steel) to provide cathodic protection — the sacrificial anode corrodes preferentially, protecting the main structure from corrosion by acting as the anode in a galvanic couple.
Context & Background
Used extensively to protect underground pipelines, ship hulls, offshore oil platforms, water heaters, and bridges. Galvanising (coating iron with zinc) is a form of sacrificial protection — even when the zinc coating is scratched, zinc continues to corrode preferentially, protecting the underlying iron.
UPSC Exam Relevance
GS3 (Science & Technology). Prelims: definition; zinc/magnesium as sacrificial anodes; galvanising. Mains: corrosion prevention in infrastructure — economic importance; comparison of prevention methods.
