Mechanical plating is an effective means of applying zinc, tin, or other ductile metals or mixtures of ductile metals to metal substrates – usually steel. In the mechanical plating process, impact energy is transferred from a rotating open-ended oblique barrel through glass beads, resulting in the cold-welding of fine metal dust particles to the substrate. The resulting deposit is slightly porous, matte in finish, and provides corrosion protection to the articles so plated without introducing hydrogen embrittlement into the part. It is therefore used widely to provide corrosion protection to high – strength fasteners, particularly those above about Rockwell C 40.
