White PaperMedical
Passivation, Pickling or Electropolishing: Which Metal Finishing Process Is Right for Your Parts?
SPONSORED BY: ![]()
Not all metal finishing processes are created equal. In this free guide, we break down the key differences between passivation, pickling, and electropolishing — so you can make the right choice for your parts. Learn why electropolishing is often the superior method, how each process works, and what to consider when selecting a finishing technique for your application.
Don't have an account?
Overview
This technical guide explores three key metal finishing processes: passivation, pickling, and electropolishing, highlighting their unique benefits and applications for improving the surface quality and corrosion resistance of metal parts.
Passivation is primarily a cleaning process that enhances corrosion resistance by removing free iron and other contaminants from the surface of stainless steel and titanium parts. It creates a chromium-rich passive layer, improving durability without removing surface material. Passivation is effective for various stainless steel alloys but may not be suitable for metals with lower chromium and nickel levels due to the risk of flash attack, which can damage the base material.
Pickling is another cleaning method that removes oxide scale and surface contaminants, particularly from welded or brazed components. However, it does not improve corrosion resistance or remove surface material. Pickling is often used in conjunction with other processes to prepare parts for further treatment.
Electropolishing stands out as a more advanced technique that combines a chemical bath with an electric current to remove a controlled layer of surface material. This process effectively strips away contaminants and microscopic imperfections, improving the roughness average (Ra) by up to 50%. Electropolishing not only enhances the aesthetic quality of parts but also significantly increases corrosion resistance—up to 30 times more than passivation alone—by removing embedded contaminants that can lead to sub-surface corrosion. It is particularly effective for a wide range of metal alloys, including stainless steel, aluminum, titanium, and Nitinol.
The guide emphasizes that electropolishing offers precise and customizable material removal specifications, making it ideal for improving both the fit and function of treated parts. Overall, the document serves as a valuable resource for manufacturers and engineers seeking to choose the most suitable metal finishing process for their specific applications.