Our proprietary heat treatment has a two-fold purpose. The heat treatment strengthens the steel by bonding the carbon, oxygen and nitrogen in the top layer of the metal. This is not a coating that can wear off. The steel itself is transformed. The heat treatment gives the steel its aesthetically pleasing black appearance and provides a surface with a high resistance to the corrosion and oxidation associated with the extreme thermal cycling experienced in aircraft braking systems. This makes it an excellent choice for agricultural aircraft that work in a harsh, chemical environment, as well as anyone who leaves their plane outside for most of its life.