Electropolishing

Electropolishing employs the use of electrical current and chemicals in a highly controlled bath designed to remove burrs, contaminants, and metallic debris while producing a high luster finish. This process (sometimes called reverse plating) preserves the detail on highly detailed surfaces, removes surface contaminants, passivates, and creates a purified oxide layer that resists corrosion. This process can be performed on either stainless steel or aluminum

With 300 & 400 series stainless steel, corrosion begins on or near the surface. This is not due to the alloying process but rather all added fabricating and handling practices in a part's production. Surface contaminants, including grease, dirt, iron, and other metallic particles inherent to the metal fabrication process are introduced to the surface. Additional mechanical cutting, handling and polishing will leave ferrous particles and abrasives embedded in the surface. The presence of surface contaminates like carbon steel creates potential sites for future corrosion.  The same is true for aluminum substrates.

During the electropolishing process of either aluminum or stainless steel, parts are immersed in an electrolytic chemical bath which reaches both interior and exterior surfaces. An electrical current is then applied to the bath at a controlled rate. The electropolishing process removes burrs, weld marks, scale from heat treating, and smoothes the microscopic surface peaks to a high-luster surface finish. This process is ideal for finishing decorative parts and in the case of stainless steel for parts subject to very corrosive environments.

Electropolishing is used in a variety of industries. Examples include: Aerospace, Biotechnology, Electronics, Food Service Equipment , Marine Hardware, Medical/Surgical Instruments, Water Treatment Equipment.

Electropolishing will meet and exceed all traditional passivation requirements for corrosion resistance. The electropolishing process removes all free iron and other metallic ions from the surface of the work piece, which has the obvious effect of eliminating free iron corrosion up front. Unlike Nitric passivation (which PowderTech also offers), a mild electropolishing cycle removes a small amount of surface material including additional free iron beneath the surface of a part.  

Features of the Electropolishing Process

• Creates a very smooth and uniform finish  
• Removes burrs and weld marks and foreign metal ions on the surface  
• The best form of  passivation  
• Aesthetic appeal: bright, reflective appearance  
• Bonded oxide layer resists corrosion for many years  
• Need for additional finishing operations is generally not needed