How can an alloy be ID'd from XRF?

• A. Compare relative proportion of each element present to known alloy compositions
• B. Compare absolute concentrations to reference alloys
• C. Measure the color of the alloy
• D. Calculate the sample's density from the spectrum

Answer: (A)

Alloy identification with XRF rests on the elemental fingerprint—the relative amounts of elements present. The XRF scan gives you how much of each element is in the sample (usually in weight percent). By comparing these relative proportions to the known compositions of reference alloys, you can find which alloy matches the measured fingerprint. This pattern-based approach works because alloys are defined by specific ratios of elements, not just the presence of a few elements together. Absolute concentrations can vary with calibration, sample geometry, and matrix effects, making them less reliable for ID. Colors or density from the spectrum aren’t dependable indicators of alloy type and can be affected by coatings, finishing, or measurement artifacts.