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determining phosphorus content in en plating using xrf spectroscopy continues Figure 7: Comparison of the destructive chemical analysis (ICP-OES) with previously determined XRF results. XRF measurements were performed standards-free according to the method described in[2]. Table 2: NiP/Al (hard disk): Excitation 50 kV with Al 0.5 mm filter and 10 kV non-filtered. Aperture Ø 3 mm, measuring time 20 s per excitation, 10 individual measurements at the same location (repeatability measurements). 46 The PCB Magazine • January 2014 4.3 Nickel-Phosphorus on a Printed Circuit Board Printed circuit boards are an important application for nickel/phosphorus coatings, on top of which, additional gold and/or palladium coatings are applied. The phosphorus content cannot be determined through these surface layers— the low energy P-K emission is absorbed. So, Au and Pd must be stripped prior to analysis or the uncoated nickel/phosphorus coating must be measured. The measuring application must be designed such that the copper undercoat does not influence the spectra evaluation. Coatings of a few tenths of a micron can then be measured. The measurement uncertainty is comparable to the example in Table 2. Table 3: Measurement of the phosphorus concentration; XDV-SDD, 10 kV non-filtered, aperture Ø 3 mm, measuring time 30 s, 10 individual measurements at the same location (repeatability measurements).