Quantitative Test – Stainless Steel Passivation
There are 3 main types of analysis to perform a quantitative passivation test, to provide a numeric result related to the thickness of the passivation layer of stainless steel and the surface ratio between Chromium and Iron.
These techniques are generally expensive, as they require laboratory instruments that only Universities or specialized private laboratories feature. Moreover, the preparative of the samples is long and follows specific requirements.
These limitations have been overcome by the development of portable instruments for the passivation measuring, commonly called Stainless Steel Passivation Tester.
Back to the lab analysis used for the quantitative measurement of the passivation of stainless, two techniques are based on the bombardment of the sample by X-rays at high energy, while the third technique is based on an electrochemical method that returns the curves relating to ‘trend of current (therefore of the corrosive phenomena) on the basis of a potential imposed.
- AES: Auger Electron Spectroscopy
- XPS X-Ray Photoelectron Spectroscopy
- Cyclic Polarization
We’ll get into the specifics of the three techniques in next article (coming soon)