METAL FINISHING If the metal parts you order or manufacture require a metal finishing operation , MPI can meet your needs. Our metal finishing meets all your certification needs. Below are the current plating and surface treatment processes in use: Gold Plating Nickel Plating Electroless Nickel Copper Plating Electroless Copper Passivation Tin Plating Solder Plating Bright Dip Electro Polishing Electro Etching Chemical Deburring Silver Plating Black Oxide