Electropolishing & Passivation

Electropolishing and passivation are two related processes commonly used in the surface treatment of metals, especially stainless steel, to improve their corrosion resistance and enhance their aesthetic appearance.


The pharmaceutical industry requires a smooth surface to reduce surface tension and create a passive layer to reduce corrosion. The process of electropolishing employs electrical current and chemicals to effectively remove surface material and imperfections from metal objects.

Electropolishing improves the corrosion and erosion resistance of the base metal while removing the peaks of the surface and smoothing the depressions. This results in a finish with a high-luster. Think of it as essentially the reverse of electroplating. In the plating process the metal ions are deposited from the solution onto the work piece. In the electropolishing process, the metal work piece is dissolved, adding metal ions to the solution.

More importantly, the deformed amorphous outer layer of the metal is removed, leaving a chromium-rich, passive surface free of imbedded contaminants and work-induced residual stresses.
One of the most notable advantages of electropolishing is the improved appearance of the surfaces. Visually the surface is brighter, smoother and more reflective. Functionally, the benefits are superior deburring, corrosion resistance, micro-finish improvement and reduced product adhesion.


-Creates a clean, uniform finish

-Removes burrs and weld marks
-Improves aesthetic appeal giving a bright, reflective appearance

-Improves cleaning and sterilization

-Reduces the microscopic crevices where bacteria can propagate

-Enhances chromium content and corrosion resistance-Provides the most superior form of passivation for stainless steel


Passivation improves the corrosion resistance properties of stainless steel by dissolving iron that has been imbedded in the surface during forming or machining. If allowed to remain, the iron can corrode and give the appearance of rust spots on the stainless steel.
Casella Process Solutions also offers Citric Acid Passivation.

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Casella has developed an extensive product offering through partnerships with industry leading sanitary process manufacturers. With extensive experience in the industry, count on us to meet your needs while improving your facility’s operation and efficiency.