Stainless Steel Passivation: What It Is & How It’s Done.
What is Stainless Steel Passivation?
Stainless steel passivation is a process by which corrosion-causing contaminants are removed from the surface of stainless steel and other metals. This process helps to restore, improve or even increase the corrosion resistance of the metal. Passivation involves treating the metal surface with an acidic or a citric based solution which removes built-up oxides and impurities, restores chromium oxide on the metal and helps to protect it against corrosion.
Benefits of Passivation
Passivation is a process that has multiple benefits for stainless steel; here is how passivation can help prolong the longevity of metal:
- It helps to prevent rust and corrosion– passivation removes iron particles and impurities which helps to protect the metal against rust, pitting and other forms of corrosion.
- It increases durability– passivating stainless steel helps to reduce surface friction which leads to less wear down and improved durability.
- It restores original luster– after passivation the metal’s luster, color and texture are restored. This is important when it comes to applications in products such as medical instruments, food service equipment and lab equipment.
How is Stainless Steel Passivation Done?
Passivation is usually done in conjunction with other metal finishing processes like pickling and electro-polishing. It involves treating the metal surface with a solution of citric or nitric acid which removes rust and other contaminants from the surface of the metal. The acid helps to restore the chromium oxide layer which helps to protect the metal from corrosion. After passivation the metal should be wiped down and dried with a lint-free cloth before its ready for use.
Depending on the grade and type of stainless steel, the temperatures and concentration of the solution used will vary as they must be closely monitored in order to generate the best results. Professional passivation services are available to ensure that this process is carried out correctly.
Stainless steel passivation is a process which helps to protect the metal from corrosion and wear. This process is a relatively inexpensive alternative to other treatments and can prolong the life of a metal. Passivation should only be carried out by a professional as it can be a hazardous process if done incorrectly. Stainless steel passivation is an important process that increases the corrosion resistance of stainless steel and is used in many industries across the world. Passivation is the removal of any impurities that exist on the surface of the stainless steel, usually a chromium oxide layer, allowing the material to be more resistant to the elements. Although stainless steel is inherently corrosion-resistant, the process of passivation further increases this resistance.
Passivation is achieved by exposing the stainless steel to an acidic solution, usually a citric acid-based cleaner. This exposure removes any particles left behind from the finishing process that can reduce the stainless steel’s corrosion resistance, such as oil or grease. The active ingredients in the citric acid dissolve the free iron particles from the surface, creating a protective chromium oxide layer.
The process of passivating stainless steel is relatively simple and can typically be done onsite. It is beneficial to do the process in a clean environment, however, as any particles left on the surface of the stainless steel can cause corrosion.
Once the stainless steel has been exposed to the acid, the stainless steel is then thoroughly rinsed with clean water. This removes any remaining acidic residue, as well as any particles that were brought to the surface during the passivation process.
Finally, the stainless steel is dried using a lint-free cloth or air gun to ensure a coat of oil is not left on the surface. Not leaving any oil residue is key to the durability of the stainless steel and its ability to resist corrosion.
In conclusion, stainless steel passivation is an essential process that further increases the corrosion resistance of the material while ensuring a quality finish. Passivation is often done in a simple manner and can typically be completed onsite. Cleaning the surface before and after the passivation process is key to its effectiveness, as any oil residue will reduce the corrosion resistance of the stainless steel.