Comparative study of spark-optical emission spectroscopy and x-ray fluorescence spectroscopy for quantitative analysis of ferrous and non-ferrous alloys

Electrical spark-optical emission spectroscopy (OES) has been used for over 50 years for the direct analysis of alloys in the steel industry. This method has undergone continual improvement over time, but conventional OES can barely reach the new specification limits required for some critical steel alloys. As part of a continuous improvement process, instrument manufacturers, academic and industrial researchers are now showing a particular interest for x-ray spectroscopy (XRF) as an alternate and/or complementary approach for the analysis of steel alloys, mainly precious metals. In this work, by using the same optical mounting (i.e. same spectrometer model with the same spectral lines), we have directly compared the analytical performances of these two sources. By comparing the calculated concentrations obtained with these two sources using the same samples and the same standards, we show that in general the two sources give comparable quantitative results for major, minor and trace elements. The precision obtained with XRF is improved by a factor of two when compared to traditional spark Optical Emission Spectrometer. The results obtained in this work establish OES as a potential method for the quantitative analysis of steel alloys in different industries.