What are the preventions for corrosion?

Answer 1

That depends on the type of corrosion. There are paints that can help. You can galvanize metal for outside use. In industrial applications plating and powder coating are commonly used.

Electroless Nickel Plating is one of the most corrosion resistant surfaces available. Electroless Nickel plating is especially useful when corrosion protection, hardness, wear resistance, a smooth surface and uniform deposits are required.

Zinc electroplating is similar to galvanizing but thinner and more precise.

Powder coating is essentially a hard paint that prevents corrosion.

Essentially galvanizing is probably the best way to prevent corrosion on metals. Galvanizing is where the metal is dipped in liquid (molten) zinc and this prevents water and air getting onto the protected metal very well.