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Ask the Experts Metals

How can I identify the stain or discoloration on my part after a heat treating process?

Jiyun Xu
Senior Research Chemist

Analytical techniques can help characterize a stain.

If the stain is mainly inorganic (chip, scale or rust), an elemental analysis by X-ray fluorescence (XRF) or scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) will most likely be sufficient. However, if the stain is rather thin (a few monolayers) and surface sensitivity is an issue, X-ray photoelectron spectroscopy (XPS) can help determine the type of stain through elemental and chemical analysis.

If the stain is organic in nature, such as oil, grease and surfactants, infrared (IR) spectroscopy would be the tool of choice.

Air Products can help characterize your stains, whether by comparing the stain’s IR spectrum with Air Products’ library featuring over 17,000 compounds or by using our other analytical tools. Give us a call at 800-654-4567.
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