Способ снижения пределов обнаружения неметаллических включений в металлических сплавах при их определении методом атомно-эмиссионной спектрометрии с искровым возбуждением

Abstract

The determination of non-metallic inclusions and their size distribution in steels and alloys is regulated to be performed by the time-consuming optical or scanning electron microscopy methods. However, the development of pulse discrimination analysis – optical emission spectroscopy ( PDA-OES ) has made the on-line determination of inclusions possible. This technique is implemented with the industrial spectrometers registering the spectral lines’ intensities by photomultipliers ( PMT s). Using the linear solid-state radiation detectors instead of PMTs provides more information about spectra which opens up new possibilities to reduce the inclusions’ limits of detection and determine their chemical composition. This paper is devoted to the search for the new single-spark spectra-processing algorithms to use with the linear solid-state detectors based spectrometers. To reduce the inclusions’ detection limits, it is proposed to use the background near the spectral line as an internal standard. Filtering spectral line intensity peaks containing spectra was implemented to determine the background shape. Using the background as an internal standard allowed us to reduce the spectral line intensities’ standard deviation in the pulsogram (time dependence of spectral line intensity) by 10-50 %. To lower the errors, it was suggested to determine the dissolved content of an element by complementary integral spectrum. These decisions led to lower limits of detection for non-metallic inclusions and lower errors in element soluble/insoluble concentration determination. Keywords: PDA-OES, solid-state linear optical detectors, non-metallic inclusions, analysis of steels and alloys DOI: http://dx.doi.org/10.15826/analitika.2016.20.4.005 D.N. Bock 1, 2 , V.A. Labusov 1, 2, 3 1 Institute of Automation and Electrometry, SB RAS, 1 Academician Koptug ave, Novosibirsk, 630090, Russian Federation 2 VMK-Optoelektronika, 1 Academician Koptug ave, Novosibirsk, 630090, Russian Federation 3 Novosibirsk State Technical University, 20 K. Marksa ave, Novosibirsk, 630073, Russian Federation