Acid Neutralization Application
The medical device electropolishing wet bench has multiple polypropylene tanks to electropolish, rinse, nitric acid passivate / neutralize, and 2 final cascade overflow rinse tanks. This electropolishing wet bench has incoming parts already cleaned so electropolishing is the first stage. Other wet bench systems can have part cleaning and rinsing before the electropolishing stage.
See our page on How Electropolishing Works for a detailed explanation of electropolishing and the electrochemical process used to uniformly remove material from stainless steel and other material composition parts.
Electropolishing Wet Bench with Nitric Acid Passivation / Neutralization with Exhaust
Because the nitric acid is heated, it needs to be properly vented. The electropolishing wet bench is fully enclosed for this reason. Nitric acid serves not only as a passivation solution, but also to neutralize and fully “rinse” any electropolishing electrolyte from the part to ensure there is no residual phosphates or bromides remaining on the part which regular DI / RO rinse water can not remove easily.
Although the electropolishing process technically removes free irons from the surface to the level that some would say the part is passivated, it actually removes not only free irons but also chromium and therefore, needs to be acid passivated to remove free irons while leaving chromium and forming a truly passivated layer.
Medical device, surgical, orthopedic implant and medical instrument
Wet Bench for Electropolishing, Citric / Nitric Passivation, and Wet Chemical Processing