Why galvanised item always protected from rust?

  • Thread starter kingskj
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In summary, the zinc layer in galvanized articles protects the steel from rust, even after the layer is broken.
  • #1
kingskj
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In my science textbook it is written that even after the zinc layer in galvanised articles is broken, the items remain invincible to rust.

Why is it like that? How come it could not rust after losing the protective layer?
 
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  • #2
Have you looked up 'galvanization' from any source, like a book or the internet?
 
  • #3
Yeah
 
  • #4
http://en.wikipedia.org/wiki/Galvanization

Galvanizing protects in two ways:

-it forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate metal
-the zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
 
  • #5
kingskj said:
Yeah

what'd it say , wiseguy ?
 
  • #6
aroc91 said:
http://en.wikipedia.org/wiki/Galvanization

Galvanizing protects in two ways:

-it forms a coating of corrosion-resistant zinc which prevents corrosive substances from reaching the more delicate metal
-the zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.

I am with the OP on this one.
Galvanization works but how.

Protective, you mean like paint?
Sacrificial anode - what does that mean?

Most descriptions are of the type given by the Wiki, which with a lot of words, says little, leaving out the physics and chemical description, with the reader still not any wiser.

maybe a better approach is to ask and answer
So why zinc?
Why not copper?
 
  • #7
256bits said:
I am with the OP on this one.
Galvanization works but how.

Protective, you mean like paint?
Sacrificial anode - what does that mean?

Most descriptions are of the type given by the Wiki, which with a lot of words, says little, leaving out the physics and chemical description, with the reader still not any wiser.

maybe a better approach is to ask and answer
So why zinc?
Why not copper?

Research is like tracing a thread from a spider web: you start off wanting to know how galvanization works, and this leads to a discussion of galvanic action, then to anodes and cathodes, then to ...

You've got to start somewhere, but this doesn't mean necessarily that you can make only one stop along this path and gather all of the information to answer your question.
 

1. Why is galvanized steel protected from rust?

Galvanized steel is protected from rust because it has been coated with a layer of zinc, which acts as a barrier between the steel and the surrounding environment. This layer of zinc prevents oxygen and moisture from reaching the steel, which are two of the main causes of rust formation.

2. How does galvanization prevent rust?

Galvanization prevents rust by creating a physical barrier between the steel and the surrounding environment. The zinc coating on the galvanized steel acts as a sacrificial anode, meaning that it will corrode before the steel does. This sacrifices the zinc layer instead of the steel, effectively protecting the steel from rust.

3. Can galvanized items still rust?

While galvanized items are highly resistant to rust, they can still rust under certain conditions. If the zinc coating is damaged or worn away, the steel underneath can be exposed to oxygen and moisture, leading to rust formation. Additionally, if the galvanized item is constantly exposed to harsh environments, such as salt water or acidic substances, it may eventually rust.

4. How long does galvanized steel last before rusting?

The lifespan of galvanized steel before rusting depends on various factors such as the thickness of the zinc coating, the environment it is exposed to, and the quality of the galvanization process. On average, galvanized steel can last anywhere from 50-100 years before showing signs of rusting.

5. Is galvanization the only way to protect steel from rust?

No, galvanization is not the only way to protect steel from rust. Other methods include painting, powder coating, and using stainless steel. However, galvanization is one of the most effective and cost-efficient methods for preventing rust on steel, making it a popular choice for many applications.

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