Passivation vs. Electropolishing

It is widely known how important it is to keep surfaces free of corrosion and contaminants when manufacturing products for human consumption, such as food, beverages, pharmaceuticals, purified water, and water for injection.

All metallic surfaces have a layer that contains contaminants, microscopic cracks, free Iron, and Iron Oxides. It is essential to remove these and replace them with Chromium Oxides, to achieve the formation of a “Passivated film.”

In addition to using high-quality stainless steel equipment and accessories, the food and pharmaceutical industries rely on a process known as "Passivation," which is a "chemical bath" applied to the metal surface. This process is especially recommended for new systems to ensure the cleanliness of the process system or "loop."

Before carrying out the Passivation process, the equipment to be Passivated must first be cleaned, including tanks, pipes, valves, heat exchangers, pumps, fittings, auxiliary equipment and hoses that are part of the loop.

Next, the system is put into operation, circulating the solution or electrolyte throughout the entire process line to be Passivated.

Finally, the line is thoroughly rinsed to ensure no chemical residues remain, and the success of the Passivation is confirmed with a Ferroxyl test.

In the past, highly toxic chemicals were used for Passivation, which, in addition to being dangerous to handle, posed an ecological problem for disposal. Nowadays, less harmful and corrosive chemicals, such as citric or acetic acids, are used.

Although the results may be favorable, the duration of the Passivation service depends on how and with what it was performed, as it is determined by the quality of the materials and the properties of the substances used.

A more robust process that surpasses the purpose of Passivation is Electropolishing, which combines the effects of acids with an electrical current to remove a thicker layer than through Passivation.

Besides the chemical bath, the electrical current generates an electrolytic removal that "repairs" cracks, deformations in the structure, and the shape of the surface grain, resulting in a flatter and smoother surface—an effect that is not achieved with Passivation.

  The Electropolishing process is carried out on tanks, tubing, fittings, and equipment before installation. This helps to ensure that the surface of the steel is prepared for a more effective and efficient subsequent cleaning, surpassing the roughness parameters required by industry standards.

This is in addition to other benefits such as: reduced corrosion, less product adherence and friction, a shiny finish that is aesthetically more appealing, and a longer material lifespan compared to a standard finish.

Don’t risk having a bad experience and extraordinary costs on your project. Put it to the test and ensure the surface quality of the products for your critical installations by requesting OGMAN’s electropolished finish. We are pioneers of the process in Mexico and guarantee all our services and products 100%.