Determination of Elemental Impurities in Iron-nickel-based Superalloys by Glow Discharge Mass Spectrometry

A method for the determination of impurities in iron-nickel-based superalloys by high-resolution glow discharge mass spectrometry is described. The optimum discharge conditions were investigated to obtain stable discharge and good sensitivity. The interference was separated in high resolution mode of the instrument. The calibration relative sensitivity factors (RSF) for 12 elements were obtained with the matrix-matched certified reference material. IARM Ni909-18. The reference material was analyzed by using the calibration RSFs. The relative error of the measured value was within 16.4% compared with the certified value, and the relative standard deviation (RSD) was less than 7.0%. The 12 elements in the iron-nickel-based superalloy were determined using the calibration RSFs (quantitative analysis) and the standard RSFs (semi-quantitative analysis) in the instrument, including C, N, O and S. The results of the verification methods, such as inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), high frequency combustion infrared absorption and inert gas pulse infrared thermal conductivity, were closer to quantitative analysis results. The elements without certified values in the reference material were determined by using the standard RSFs. There was no significant difference between the results of GDMS and the verification by ICP-MS. The validation revealed that the proposed analytical approach achieves reliable results for the rapid determination of several impurities, such as metals as well as non-metals, even the gas elements C, N, O and S.