X-ray Fluorescence Spectroscopy

XRF analysis is a non-destructive analytical technique that does not require sample removal. A reading is taken from the surface of the sample/sample site. The sample material is irradiated with electrons resulting in the emission of x-rays characteristic to the elements present. The energy emissions are translated into spectral peaks of varying intensity, resulting in a spectrum profile, which identifies the different inorganic elements present in the sample (ie lead, iron, copper, zinc etc.).

As XRF analysis takes a broad reading from the surface, the results present an overall reading from the area sampled, and considers all layers of the sample site (if multiple layers present/in-tact). The analysis is not quantitative. The X-ray intensity (size of spectrum peaks) is directly proportional to the concentration of the elements in the sample. While the results give a good indication of the elements present, in order to characterise individual paint layers or further confirm XRF results, elemental analysis using SEM-EDS would need to be undertaken.

The results are interpreted and presented in a report, with the XRF spectra included (example below):

XRF Spectra, with zinc and barium predominate in the sample, traces of calcium, iron, cobalt, lead and strontium
XRF Spectra, with zinc and barium predominate in the sample, traces of calcium, iron, cobalt, lead and strontium