Electropolishing vs. Passivation

Electropolishing vs. Passivation

Electropolishing vs. Passivation Technical Guide


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Which Is Better for your Parts?

While passivation is useful for removing free iron and contaminants from stainless steel, electropolishing offers a wider range of benefits:

  • Electropolishing is 30x more effective than passivation for preventing corrosion and pathogen contamination, and improving cleanability for food and medical parts
  • Ony electropolishing can remove burrs, cracks and other surface defects with microscopic precision and Ra improvement of up to 50%
  • Electropolishing can be used on far more metal alloys than passivation even when there are low levels of chromium and nickel – this includes aluminum, Nitinol and titanium

Download our Electropolishing vs. Passivation technical guide to learn more about how electropolishing compares to passivation.

Metal parts are also passivated as a result of the electropolishing process

Side-by-Side Comparison

Point of Comparison

  • Removes Surface Contaminants
  • Typically Includes Precleaning/Degreasing
  • Effective for Sizing
  • Microscopic Precision
  • Consistent, Uniform Results
  • Improves Fatigue Life
  • Improves Corrosion Resistance
  • Deburrs Metal Surface
  • Removes Microcracks
  • Removes Heat Tint
  • Removes Oxide Scale
  • Improves Microfinish
  • Cleans Welds Effectively
  • Passivates Part

Electropolishing

Passivation

Pickling

Point of Comparison
Removes Surface Contaminants
Electropolishing
Passivation
Pickling
Point of Comparison
Typically Includes Precleaning/Degreasing
Electropolishing
Passivation
Pickling
Point of Comparison
Effective for Sizing
Electropolishing
Passivation
Pickling
Point of Comparison
Microscopic Precision
Electropolishing
Passivation
Pickling
Point of Comparison
Consistent, Uniform Results
Electropolishing
Passivation
Pickling
Point of Comparison
Improves Fatigue Life
Electropolishing
Passivation
Pickling
Point of Comparison
Improves Corrosion Resistance
Electropolishing
Passivation
Pickling
Point of Comparison
Deburrs Metal Surface
Electropolishing
Passivation
Pickling
Point of Comparison
Removes Microcracks
Electropolishing
Passivation
Pickling
Point of Comparison
Removes Heat Tint
Electropolishing
Passivation
Pickling
Point of Comparison
Removes Oxide Scale
Electropolishing
Passivation
Pickling
Point of Comparison
Improves Microfinish
Electropolishing
Passivation
Pickling
Point of Comparison
Cleans Welds Effectively
Electropolishing
Passivation
Pickling
Point of Comparison
Passivates Part
Electropolishing
Passivation
Pickling

Corrosion Protection

Below are results from an independent lab’s testing of eight stainless steel allows after 24 and 888 hours of ASTM B-117 salt spray testing – no rust formed on any electropolished alloy compared but did form on each passivated alloy:

After 24 hours

304 Electropolished
304 Passivated
410 Electropolished
410 Raw
420 Electropolished
420 Raw
Trinament Electropolished
Trinament raw

After 888 hours

304 Electropolished
304 Passivated
410 Electropolished
410 Raw
420 Electropolished
420 Raw
Trinamet electropolished
Trinamet raw

More Stainless Steel Corrosion Examples

A set of parts was submitted to ASTM B-117 salt spray testing at an independent testing facility. The test parts included a wire weldment fabricated from 304 stainless steel. The testing was performed for 144 hours on each part in the raw, passivated and electropolished state.

304 Stainless Steel Wire Weldment

Fig. 5a - Wire Weldment Raw

Raw

Fig. 5b - Wire Weldment Passivated

Passivated

Fig. 5c - Wire Weldment Electropolished

Electropolished

After 72 hours of exposure to the salt spray, the raw and passivated wire weldments developed red corrosion in the resistance welded areas. The electropolished part showed no visible corrosion after 144 hours of testing. Electropolishing is effective in treating the carbide precipitation condition that occurs in the heat-affected zone during welding. It also improves the chrome to iron ratio on the surface which greatly improves the corrosion resistance.

The Able Electropolishing Advantage

The Able Electropolishing Advantage

Learn how electropolishing promotes corrosion resistance, fatigue life improvement & pathogen resistance in our new video

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Electropolishing Before & After

Read our case studies to learn more about the electropolishing services we have provided across a wide range of industries

Read Our Case Studies

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

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

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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.

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