Intermediate Topic 587 of 1102 Acids, Bases & Electrochemistry
Prevention of Corrosion
Painting, galvanizing, alloying and cathodic protection prevent corrosion.
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In-depth explanation of Prevention of Corrosion
Corrosion can be prevented by isolating the metal from oxygen and water with barriers such as paint, plastic coatings or oil. Alloying, as in stainless steel with at least about 11 percent chromium, forms a passive oxide film that resists further attack. Sacrificial protection uses a more reactive metal connected to the iron, and impressed-current cathodic protection holds the metal at a potential where it does not oxidize. The choice of method depends on cost, environment and required service life. These approaches are used on bridges, ships and pipelines.
Going deeper: Prevention of Corrosion
Key ideas: Methods: barrier coatings (paint, oil, plating), sacrificial anodes (Zn, Mg), galvanizing, cathodic protection by impressed current, alloying (stainless steel with over 10.5 percent Cr), and inhibitors. Keep potential of the structure below that of the corrosion couple by connecting it to the negative terminal of a DC source or to a more active metal.
Common mistakes and connections: Mistake: believing tin plating protects as well as zinc after scratching; tin is less active than iron, so a scratch speeds corrosion of iron. Zinc continues to protect because it is the preferred anode. Buried pipelines use both coatings and cathodic protection. Link to electrochemical series.
Visualization of Prevention of Corrosion
Stainless steel contains at least 11 percent chromium, which forms a thin passive Cr2O3 film that stops oxygen reaching the iron beneath. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Stainless steel contains at least about 11 percent chromium, which forms a protective oxide layer on its surface.
Frequently asked questions about Prevention of Corrosion
What is Prevention of Corrosion?
Painting, galvanizing, alloying and cathodic protection prevent corrosion.
Is Prevention of Corrosion a beginner, intermediate or advanced topic?
Prevention of Corrosion is a intermediate topic in Acids, Bases & Electrochemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Prevention of Corrosion?
Study these earlier topics in Acids, Bases & Electrochemistry first: Solid-State Batteries, Corrosion, Rusting of Iron.
What comes after Prevention of Corrosion?
The next topics in Acids, Bases & Electrochemistry are Sacrificial Anode and Galvanization.
Can I practise Prevention of Corrosion with quizzes?
Yes. The interactive lesson includes a self-check question on Prevention of Corrosion, and the Acids, Bases & Electrochemistry quiz draws on every topic in this area.
Where Prevention of Corrosion fits in Acids, Bases & Electrochemistry
Prevention of Corrosion is topic 77 of 105 in Acids, Bases & Electrochemistry.