... 220mm6. Coating:Ni, Zn, NiCuNi, gold, copper, epoxy, chemical, parylene, Everlube, passivation ,tin ... can help to control well in quality, tolerance, process cost and delivery.9.Surface Treatment Method: a)Metallic Zinc, Nickel, Nickel+Nickel, Copper ... +Nickel, Nickel+Copper ...