Intermediate Topic 589 of 1102 Acids, Bases & Electrochemistry
Galvanization
Coating iron with zinc, which protects both by barrier and sacrificial action.
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In-depth explanation of Galvanization
Galvanization coats iron or steel with a layer of zinc, which protects the metal in two ways. First, the zinc forms a barrier that keeps oxygen and water away from the iron. Second, if the coating is scratched, the exposed iron is cathodically protected because zinc is more easily oxidized than iron and corrodes preferentially. This sacrificial action protects small exposed areas, which gives galvanized steel a long service life. Galvanizing is commonly applied by dipping the steel in molten zinc. It is used for roofing, fencing and structural steel.
Going deeper: Galvanization
Key ideas: Coating iron or steel with zinc, by hot dipping (about 450 C), electro-galvanizing or spraying. Zn forms a protective oxide and carbonate layer, and also acts as a sacrificial anode if scratched since Zn is oxidized before Fe (E standard Zn -0.76 V versus Fe -0.44 V). Lifetime depends on thickness, typically 50 to 100 micrometers.
Common mistakes and connections: Mistakes: assuming galvanization is only a barrier; it provides cathodic protection at breaks. Zinc is lost faster in acid rain or marine sites. Galvanized steel should not be welded without ventilation (zinc fume). Compared to tin plating, where the coating is cathodic to iron and fails badly when scratched.
Visualization of Galvanization
If a zinc coating is scratched, zinc still oxidizes in preference to the exposed iron, so galvanized steel is protected even where bare. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Galvanized buckets and roofing sheets resist rusting even when the zinc coating is scratched.
Frequently asked questions about Galvanization
What is Galvanization?
Coating iron with zinc, which protects both by barrier and sacrificial action.
Is Galvanization a beginner, intermediate or advanced topic?
Galvanization is a intermediate topic in Acids, Bases & Electrochemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Galvanization?
Study these earlier topics in Acids, Bases & Electrochemistry first: Rusting of Iron, Prevention of Corrosion, Sacrificial Anode.
What comes after Galvanization?
The next topics in Acids, Bases & Electrochemistry are Conductance and Conductivity and Molar Conductivity.
Can I practise Galvanization with quizzes?
Yes. The interactive lesson includes a self-check question on Galvanization, and the Acids, Bases & Electrochemistry quiz draws on every topic in this area.
Where Galvanization fits in Acids, Bases & Electrochemistry
Galvanization is topic 79 of 105 in Acids, Bases & Electrochemistry.