Industrial Hard Chrome Plating, Electropolishing or Passivation?
Your desired end result will be the determining factor in choosing which process to select, Hard Chrome Plating or Electropolishing or Passivation.
Industrial Hard Chrome Plating brings a wide variety of characteristics and beneficial properties. This electrolytic process utilizes a chromic acid-based electrolyte bath that is activated via DC current to build chromium metal on the surface of the immersed part. The resultant Hard Chrome Plating, also known as “engineering” or “functional” chromium, is one of the most durable, wear-resistant surface finishes for the machinery industry and is applicable to interior as well as exterior surfaces.
Hard Chrome is harder than most industrial abrasives. It provides superb substrate adhesion, can be applied to a wide variety of substrates, and offers high abrasion resistance. It offers high metal-to-metal sliding wear resistance, produces a low co-efficient of friction, is stable and non-corrodible, and can provide a variety of finishes from a mirror type finish to a rough matte type finish.
If the appearance and esthetics of the piece are important then Electropolishing is the definitive choice. If simple oxidation prevention is your desire, then Passivation would best serve your needs.
Electropolishing produces a “clean, bright, cosmetically attractive” finish by electrochemically removing a microscopic amount of material. The end result is a unidirectional pattern that is stress-free, microscopically smooth and often highly reflective. Improved surface finishes reduce opportunities for bacterial growth due to the removal of hydrogen leaving a chromium-rich, passive surface free of embedded contaminants and work-induced stresses. Electropolishing typically is used for final processing rather than a technique to improve badly roughened finishes.
Passivation while serving to remove free iron remaining on the surfaces of stainless steel parts thereby making them passive to oxidation, does not provide the surface improvement qualities that Electropolishing provides.