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Distinguish clearly between a) Galvanizing & Tinning b) Cathodic and anodic coating
written 6.3 years ago by
vibhavarikulkarni
• 480
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modified 2.2 years ago
by
yashbeer
★ 11k
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written 6.2 years ago by
vibhavarikulkarni
• 480
|
modified 6.1 years ago
by
awari.swati831
• 100
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| Sr.No. | Galvanizing | Tinning |
|---|---|---|
| 1 | Processof covering iron or steel,with a thin coat of ZINC to,prevent it from rusting. | Process of coating steel with a,thin coat of TIN to prevent it,from corrosion |
| 2 | Zinc protects iron sacrificially.,Since it is more electro-positive,than iron and does not permit iron to pass into the solution. | Tin protects the base metal iron,from corrosion due to its noble,nature and higher corrosion,resistance. |
| 3 | In galvanized articles, zinc continues to protect the underlying iron by galvanic cell action, even if the coating of zinc,is broken at any place | Tin protects underlying iron till the coat is intact. Any break in coating causes rapid corrosion of,iron. |
| 4 | Galvanized containers cannot be used for storing acidic foodstuffs as zinc reacts with food acid forming poisonous compounds | Tin coated containers and utensils can be used for storing any food stuff as tin is non-toxic and protects metal from corrosion |
| 5 | Ideal temperature is around 450 degree C | Ideal temperature is around 250 degree C |
| 6 | Ammonium chloride is used as flux | Zinc chloride is used as flux |
| Sr.No. | Anodic Coating | Cathodic Coating |
|---|---|---|
| 1 | It protects base metal,sacrificially | It protects base metal due to high corrosion resist. & noble behavior. |
| 2 | Coating metal is at lower,potential than base metal | Coating metal is at higher potential than base metal. |
| 3 | Corrosion of base metal does not increase even on breaking as it heals its film | Corrosion of base metal increases,if there is a break in coating |
| 4 | e.g. galvanizing i.e. Zn coating on iron/steel. | Tin coated containers and utensils can be used for storing any food stuff as tin is non-toxic and protects metal from corrosion |
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