Electrochemical reaction degrading metals.
Corrosion is the electrochemical degradation of metals: anodic oxidation M→Mᶻ⁺+ze⁻ and cathodic reduction (O₂+2H₂O+4e⁻→4OH⁻). Needs anode, cathode, electrolyte and a conductive path. Rate measured as mm/year or mpy; Pourbaix and polarisation diagrams describe behaviour.
Steel rusts in moist air as iron oxidises to hydrated iron oxide.
Corrosion destroys metals by electrochemical reaction, so understanding it lets you prevent failures in pipes, structures and vehicles.
Electrochemical reaction degrading metals.
Corrosion destroys metals by electrochemical reaction, so understanding it lets you prevent failures in pipes, structures and vehicles.
An electrochemical process where a metal loses electrons to an environment, forming oxides or dissolved ions.
Moisture, dissolved salts, acidity, temperature and the presence of more noble metals all increase the rate.
Typical applications include explaining why an iron pipe rusts in wet soil, predicting the corrosion of a steel bolt in a marine environment and choosing a material for a tank that holds acid.
Study "Powder metallurgy" first (topic 28 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
Galvanic series. Passivity. Rust formation.
Steel rusts in moist air as iron oxidises to hydrated iron oxide.
The next topic is "Galvanic and pitting corrosion", which builds directly on this one.
It is classed as Beginner in Materials & Chemical (topic 29 of 100). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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