What Is Passivation Of Metal?

Passivation is a chemical treatment used to enhance the corrosion resistance of stainless steel and remove surface contamination. In manufacturing and industrial applications, the natural protective oxide layer on steel can be broken down by dirt, dust and particles of iron from cutting tools. Learn the passivation process and understand why this method is ideal for protecting stainless steel from erosion. 

The passivation process

The deterioration of stainless steel is often caused by machining and fabrication. The metal finishing process of steel passivation uses nitric or citric acid to remove free iron contamination from the surface of the metal. The nitric and citric chemicals create a protective oxide layer that returns the stainless steel to a corrosion resistant state to maintain its durability. 

Here are the principles to protect stainless steel from erosion following the passivation of metal process:

  • Clean the steel surface to remove any foreign materials or oils.
  • Rinse it with deionized water.
  • Submerge the steel into either nitric or citric acid to allow the formation of the thin and transparent oxide layer that protects the steel. 
  • Rinse the metal again and dry it.
  • Test the passivized steel is to ensure its effectiveness. 
  • Once the process is complete, the oxide layer will form within 1-2 days to stop the underneath steel from rusting and extend the lifespan of the metal. 

Why is steel passivation useful?

The contaminations that can form on the surface of stainless steel are potential corrosion sites that can cause decomposition of the surface. The surface quality of stainless steel can typically be impacted from foreign materials or particles of iron from manufacturing and industrial environments. The passivation of stainless steel is a method of protecting it in applications that can contribute to corrosion. There is also the added benefit of sterilization during the passivation process. The acid that the steel is emerged into decontaminates its surface. 

Learn more about steel passivation services and metal finishing in Dorset with Dorsetware. Contact our expert team of electroplaters today for any enquiries, to discuss your project or to get a quote. Call us on 01202 677939 and we will be happy to assist.

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