Rust

a- water/ lots of rust 

b- salt, water and air/ not much rust at all

c- water no oxygen 

Rust Faster

Salt

Water

Oxygen

Rust Slower

Zinc

No Oxygen

Painted

rusting of iron requires water and oxygen. when either of these is removed no rusting will occurs. the rusting process is sped up when salt is also present. the easiest way to slow the rusting process is to ensure the iron does not come into contact with either oxygen or water

an iron nail will corrode if it comes into contact with the environment corrosion also occurs quicker if salt or water are present. corrosion of iron can be prevented by creating a barrier between the iron and the oxygen. this can be accomplished by coating the iron in plastic, grease or paint. Iron can also be coated in more reactive metals such as zinc, iron or steel nails coated in zinc are called galvanised.