Electroplating – This process forms a thin metallic coating on the substrate. The electroplating process passes a positively-charged electrical current through a solution containing dissolved metal ions and a negatively charged electrical current through the metallic part to be plated. Common metals utilized for electroplating are cadmium, chromium, copper, gold, nickel, silver, tin, and zinc.
Chemical Treatment – This method involves processes that create thin films of sulfide and oxide by means of a chemical reaction. Typical uses are for metal coloring, corrosion protection, and priming of surfaces to be painted. Black oxide is a very common surface treatment for steel parts and “passivation” is used to remove free iron from the surface of stainless steel parts.
Anodic Oxidation – Anodization is a very common surface treatment that prevents corrosion on aluminum parts. If wear resistance is also desirable, engineers can specify a version of this method that forms a relatively thick, extremely hard, ceramic coating on the surface of the part.
Hot Dipping – This process requires the part to be dipped into dissolved tin, lead, zinc, aluminum, or solder to form a surface metallic film. Hot-dip galvanizing is the process of dipping steel into a vessel containing molten zinc. Used for corrosion resistance in extreme environments, guard rails on roads are commonly processed with this surface treatment.
Vacuum Plating – Vacuum vapor deposition, sputtering, ion plating, ion nitriding, and ion implantation are some of the more common metal surface finishing processes utilizing high vacuum as part of the plating process. Ionized metals, oxides, and nitrides are created in a controlled environment.
Painting – Surface treatment painting is commonly specified by engineers to enhance a part’s appearance and corrosion resistance. Spray painting, electrostatic painting, dipping, brushing, and powder coat painting methods are some of the most common techniques used to apply the paint to the surface of the component.
Thermal Spraying – This type of surface treatment involves melted or heated materials that are accelerated, then collided and bonded mechanically to the target surface. A wire or powder feedstock, usually metal or ceramic, is melted by injecting it into a flame, electrical arc, or plasma stream.
