How Electropolishing Improves Corrosion Resistance

Corrosion resistance and electropolishing
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.

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.

Electropolishing: Passivation + Corrosion Resistance

All electropolished parts are also passivated as part of the process while also being more resistant to corrosion on stainless steel and other alloys, including 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.

Whitepaper: Advantages of Electropolishing for Deburring Metal Parts

Electropolishing, with its ability to remove a microscopically precise layer of surface material with consistent results, is the finishing process of choice for such parts, for many reasons. Learn why electropolishing is more effective than other methods for removing burrs.

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Whitepaper: Electropolishing for Significantly Improved Corrosion Resistance

Learn why enhanced corrosion resistance is one of the most common reasons engineers across a variety of industries rely on electropolishing to finish their critical metal parts, especially for parts made of stainless steel. Three included case studies show the difference electropolishing makes.

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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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