Certified Reference Material for Handheld XRF Coating Thickness Applications

You are called into your boss’ office because a new situation with a vendor or client requires coating thickness measurements of extremely large parts.  No problem, you think, we have a bench-top XRF analyzer for coating thickness verification.  You soon realize that the problem you are faced with is that even the large chamber bench-top analyzers on the market max out at sample sizes of about 13x23x19 (h-w-d)…smaller than the part you need to measure and you can’t destroy samples to perform the test.

Samples too large for a desktop analyzer are one situation when organizations will look to Handheld XRF analyzers for their coating thickness measurement requirements because a handheld system doesn’t have a maximum sample size limitation.  Other common situations to turn to Handheld XRF for coating thickness quality control are when you need to measure on the floor for higher throughput efficiencies, want to be able to travel to different facilities (yours or your vendors) to verify thickness, or have a primary use of positive material identification (alloy analysis) for incoming goods.

One of the few handheld x-ray fluorescence systems on the market that can perform thickness measurements is Oxford Instruments X-Met8000 analyzer.  An Oxford Instruments’ Application Specialist can prepare a customized empirical calibration for certain coating applications with the proper software package (Calibration SW) and appropriate certified reference materials (CRM’s).

The last part of that equation, certified reference materials, is a critical aspect of setting up a reliable calibration curve for coating thickness.  Even if your organization already has a bench-top XRF analyzer with reference standards, you will need to invest in new sets for use with the handheld system.

The reason is that a handheld unit will have a larger collimator than a desktop model (typically 3mm, when desktops can be under 0.1mm).  So, the measurement area that you will find on reference standards for desktop analyzers can be the size of a pin head (plated XRF standards) or paper hole punch (foil XRF standards) while the area required for handheld standards will be about the size of a dime.

Certified Reference Materials: Desktop plated, foil, Handheld plated

The larger size of the handheld reference material requires a different certification process.  While reference standards for desktop analyzers are measured in that very small area, the handheld standard needs to be measured at multiple points within the dime-size area and then averaged out.  The in-house standards laboratory of Eastern Applied Research is Accredited to ISO/IEC 17025 and will be able to provide certified reference standards for both desktop and handheld XRF analyzers.

Handheld XRF analyzers excel at single layer measurements within certain parameters (ie Ag/Cu, Zn/Fe) and can sometimes be used in alloy coating measurements (ie the increasingly popular ZnNi/Fe)

So, when your boss requires you to measure the coating of samples too large for your desktop XRF, look no further than Handheld XRF – and keep in mind that Eastern Applied offers rentals of Oxford Instruments XMet8000 systems for when you are faced with this situation and limited budget.


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