Sometimes wild Pokemon are holding it, such as: Bronzor, Bronzong (that is where I found a metal coat for myself), and I think maybe beldum?
I hope I've helped!
.:Funkeheap15>.<:.
you go to your bag select steel coat go down to give and it will have it.
in the pokecave you have to find the rare pearl
in Pokemon pearl scyther evolves when you give it a metal coat and then it evolves about level 25
Metal Coat
Onix evolves into Steelix when it is holding a Metal Coat and traded to someone else.
When held by a Pokémon, the Metal Coat boots the power of Steel-type moves.
You gotta dig it up (underground.)
Heatran is a Fire / Steel type
ice and rock
The evolution of onix is steelix which you can get by trading it with a steel coat
different types of Pokemon like you can't get a dialga in pearl it is STEEL\dragon type and palkia is WATER\dragon type so maybe steel Pokemon may appear!
Trade Onix with the steel coat item to evolve it.