We are surrounded by stainless steel parts—bolts, screws, medical devices, airplane components, and more. The first step in manufacturing these parts is to fabricate them according to the appropriate design guidelines, but that’s not the end of the process. If you were to turn out the parts for use at that point, they would corrode and ultimately fail to perform as needed.
(Pixabay / Brett_Hondow)
To ensure the integrity and functionality of stainless steel parts, fabrication must be followed by a process called passivation. When the components come out of fabrication, they carry traces of oil, grease, and other debris. They are also covered with an oxide film that develops when they are exposed to oxygen. When a stainless steel part is not completely free of contaminants, it becomes more susceptible to scratching and corrosion. Over time, it can become weak, damaged, and corroded.
Passivation involves two stages.
- Acid cleaning. In the first stage, the components are bathed in a strong mineral acid that removes contaminants including iron or iron compounds without affecting the surface of the component.
- Oxidizer conversion. An oxidizer is then used to transform the chromium metal on the surface of the steel components into a chromium-oxide protectant.
In essence, passivation removes any impurities and then adds a protective layer so that the steel parts are impervious to oxidation or other effects from outside chemicals. When components are properly passivated, they will be able to withstand high humidity, salt water, water immersion, and more.
For materials for passivation and other metal plating supplies, contact Gold Plating Services.