How Electropolishing Improves Plating Results to Leave Plated Parts More Durable and Corrosion Resistant

Electropolishing is well known for the smooth and defect free surface finish it creates as the last step in the process of finishing metal parts, but its benefits are just as impressive when it is used to improve the surface of parts that will undergo the additional step of plating.

Many different metal parts undergo plating with a coating of copper, nickel, brass, zinc or other metal to add strength, conductivity, corrosion resistance, friction reduction, and to improve appearance. But regardless of the plating being used, the quality of the finish prior to applying it is key to achieving the best results. When the underlying metal is smooth and free of defects, plating results are significantly improved.

The Benefits of Electropolishing for Plated Parts

Electropolishing, sometimes described as “reverse electroplating,” is an electro-chemical process that combines an electrolytic solution and an electrical current to remove a precise and consistent layer of surface material, stripping away surface imperfections and eliminating defects that include burrs and microcracks.

The process leaves parts with an improved surface finish and improved resistance to corrosion, significant advantages for parts that will undergo plating. Parts that undergo electropolishing are left with a slight radius on the edges that serves to prevent plating material from building up.

Electropolishing is effective for a wide range of alloys, including stainless steel, carbon steel, copper, nickel, aluminum, brass, Nitinol and titanium, among others.

The Challenges of Plating Metal Parts with Inconsistent Surface Roughness

Without electropolishing, surface defects and roughness on metal parts can make it challenging to ensure a smooth coating of plating material and can also leave the coating susceptible to chipping or cracking.

Microfinish Improvement and More

Unlike some mechanical finishing methods that create inconsistent areas of surface roughness, electropolishing’s ultrasmooth surface finish enables a smooth application of the plating. Prior to plating, electropolishing offers numerous benefits:

• Deburring
• Microfinish improvement of up to 50%
• Ultraclean and shiny surface appearance
• Enhanced corrosion resistance
• Enhanced durability

Pre-Plating Electropolishing for Agricultural, Automotive and Energy Parts

Applications for electropolishing prior to plating include parts that are plated for both added corrosion resistance as well as aesthetic appeal, including parts for agricultural and food processing equipment, automotive and medical parts, battery components and household products.

Other applications include electropolishing to improve the surface finish which leads to less electrical resistance and enhanced chemical stability of plated parts.

A 2010 issue of the International Journal of Hydrogen Energy describes research into the benefits of electropolishing for pre-plated stainless steel fuel cell parts. Compared to the same parts that were coated after mechanical polishing only, the electropolished parts showed “remarkably smooth and uniform surface morphologies … compared to the surfaces of the plates that were coated after mechanical polishing only,” the abstract reported.