PASSIVATION

Passivation, to render chemically passive, is the last step in the finishing process of precision stainless machined parts. It maximizes the ability of stainless steel parts to resist corrosion. Passivation removes surface contamination from particles of free irons that may have adhered to the part during the machining process. If these iron contaminants aren’t removed, they may cause discoloration, rusting, or pitting.

Passivation also forms a protective, non-reactive oxide layer that makes the material rust resistant. The formation of the oxide layer on stainless steel is a natural process; however, the passivation of stainless steel speeds up this natural process and helps the oxide layer to develop faster and thicker than if left to occur naturally.

Once the parts have been cleaned with detergent, they are immersed in a citric acid bath. After the passivation process is complete, the parts are thoroughly rinsed and dried. Then they are tested with a copper sulfate test to ensure that free iron particles were removed and that the part is corrosion resistant.

Swiss Precision Machining uses a state-of-the-art passivation line that takes the finished parts through the entire process in a way that meets the rigorous specifications and requirements of medical device manufacturers. Our in house passivation line is for 300 Series Stainless Steel parts. Our exceptional passivation services ensure that the stainless steel machined parts we produce can withstand corrosion throughout their life cycles.