How Electropolishing Improves Corrosion Resistance of Metal Alloys (draft)

Electropolishing is widely specified to enhance corrosion resistance on a wide variety of metal alloys. Although most commonly used on stainless steels, electropolishing offers corrosion resistance on other alloys as well. Due to the versatility and superior effectiveness, electropolishing is fast becoming a replacement process for passivation.

Electropolishing vs. Passivation Comparison

Multiple stainless materials were compared for corrosion resistance using independent lab testing per the ASTM B-117 salt spray test. Electropolished parts don’t show signs of rusting after 888 hours of testing.

electropolishing comparison salt spray test

Corrosion resistance and electropolishing

Limitations of Passivation

Passivation is a chemical process that has been used for years to help restore contaminated stainless steel to original corrosion specifications. Passivation is routinely specified by engineers because of the many sources of contamination. The intent of passivation is to remove free iron or other foreign matter from the surface of the metal and to create 
a chromium rich surface that is resistant to corrosion. However, passivation is generally not effective in removing embedded free iron and contaminants and will not remove heat tint or oxide scale on stainless steel.

Engineers looking to pass stringent salt spray and humidity tests have turned to electropolishing for a more aggressive replacement for passivation. The electropolishing process dissolves the outer skin of metal, removing deeply embedded contamination. Heavily contaminated surfaces such as machined parts, welded or brazed assemblies or other components that typically respond poorly to passivation alone, are good candidates for electropolishing. Unlike passivation, all stainless alloys including the 400 series and precipitating grades can be processed without distortion, flash attack or hydrogen embrittlement.

Just as electropolishing is used to enhance corrosion resistance on stainless steel, it offers corrosion resistance on other alloys as well. Many companies use the process to delay or retard the corrosion properties of copper, brass, aluminum, and carbon steels. On these and other alloys, the removal of surface skin and impurities enhances the corrosion resistant properties of the component.

The parts pictured on the right are made from type 303 stainless steel. After a series of machining operations, the parts needed to be decontaminated to remove embedded steel and other impurities.

Under 40X magnification using the scanning electron microscope, you can see the passivated part is actually rougher, due to the chemical attack of the 303 stainless steel by normal passivation. In contrast, the electropolished part is smooth and clean. By carefully monitoring the amount and rate of metal removal, electropolishing dissolves the surface skin and its impurities, including impinged steel flecks and other contaminants.

Contact us to learn more about electropolishing and corrosion resistance

Medical Device Manufacturing

Medical Device Manufacturing

From implantable devices to surgical instruments, electropolishing is a single-process treatment that results in biocompatible, safe and ultra clean parts.

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Aerospace

Aerospace

We offer aerospace vendors and original equipment manufacturers our signature metal finishing services to increase fatigue-resistance for their metal parts, rendering them capable of withstanding the stress and corrosion that comes with long-term use.

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Pharmaceutical

Pharmaceutical

Our strict adherence to industry standards ensures that pharmaceutical components are electropolished in accordance with ASTM B912 and ASME BPE specifications. These products are clean and smooth, corrosion resistant and contaminant free.

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Automotive

Automotive

Corrosion resistance and microfinish improvement are essential for critical automotive parts, making electropolishing an increasingly beneficial option for automakers.

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Consumer Appliance

Consumer Appliance

Our metal finishing services help increase corrosion resistance for these parts, and by removing the outermost layer of metal withelectropolishing the durability and longevity of these appliance components is increased.

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Food & Beverage

Food & Beverage

Electropolishing materials for this industry eliminates the buildup of bacterial biofilms, as well as keeping the equipment free of contaminants like Salmonella. Electropolishing delivers the level of sanitation required by a number of regulatory agencies.

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Hydraulics & Pneumatics

Hydraulics & Pneumatics

From robotics to mobile equipment, the uses of electropolishing in the hydraulics and pneumatics industry are many. By helping prevent premature part failure, electropolishing reduces downtime and increases the life cycle of these components.

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Electronics

Electronics

Improving conductivity and performance is just one benefit electropolishing offers for electronics parts. The surface finish is improved by as much as 50%, removing imperfections from the material without material removal.

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Electropolishing Blog

Electropolishing Process with the Highest Standards of Quality Control

For every successful project at Able Electropolishing, there is a meticulous, high-quality process at work behind the scenes. Our clients rely on us for precise and consistent results, customized to the demanding needs of industries like medical device manufacturing, food and beverage production – and industries like yours.

Electropolishing for More Durable and Corrosion Resistant Metal Fasteners

Electropolishing provides an ultrasmooth, ultraclean surface, and improves corrosion resistance for metal fasteners.

Learn Which Metal Finishing Process Is Right for Your Critical Metal Parts

Read Able Electropolishing’s guide on passivation, pickling, and electropolishing to learn about the benefits and drawbacks of each for your metal parts. 

Take Able's Electropolishing 101 Quiz to Test Your Metal Finishing Knowledge

Put your electropolishing knowledge to the test with our new Electropolishing 101 quiz!

Across industries, electropolishing is the go-to metal finishing method for parts with no room for error. From aerospace to medical manufacturing, engineers rely on electropolishing to eliminate surface defects and create a hygienic, passive and ultra-smooth finish with improved fit, function and durability.