Oxidised Brass Metal Wall
It is a brass plate, but highly oxidised. It has rust, pores and tiny bumps everywhere. This metallic texture is a good candidate for worn metal walls.
 
Rusty and Oxidized Steel Plate
It is a thick metal plate of steel which is highly oxidized, so it has a lot of erosion and darken holes and dents. This texture is marvellous for sci-fi walls and machinery parts of factories.