TY - THES

T1 - Quantitative analysis of ferroalloys, refractories and steel samples using Laser Induced Breakdown Spectroscopy (LIBS)

AU - Feiner, Maria

N1 - embargoed until 23-09-2029

PY - 2024

Y1 - 2024

N2 - The aim of this master thesis was the method development and the implementation of a data evaluation scheme for the quantitative analysis of in the steel industry relevant materials ferroalloys (FeMn and FeTi), refractory materials (Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3) and steel (Ti-stabilised interstitial free, short Ti-IF steel) by using Laser Induced Breakdown Spectroscopy, short LIBS. LIBS is to be evaluated as an alternative to the conventionally used analytical methods X-ray fluorescence analysis, spark optical emission spectroscopy and scanning electron microscopy. The focus is on quantitative analysis and the development of mapping images to visualise the element distribution over the sample surface. All LIBS measurements were performed with the nanosecond 193 nm ArF excimer laser ablation system (imageGEO193, Elemental Scientific Lasers, Bozeman, MT, USA) and the LIBS detector system, a multi-channel spectrometer (ESLumen, Elemental Scientific Lasers, Bozeman, MT, USA) in the laboratories of the Chair of General and Analytical Chemistry at the Montanuniversität Leoben. Data analysis was performed using the time-resolved spectroscopy software Iolite (version 4.9.1, Elemental Scientific Lasers, Bozeman, MT, USA) and Excel 365 (Microsoft Corporation, Redmond, WA, USA). The method validation is based on the use of the certified reference materials (CRM) FeMn CRM 502-2 and 583-1, FeTi CRM 510-1 and 584-1, and refractory material CRM 776-1. The powdered materials also served as a calibration standard for the quantitative analysis. For this purpose, the substances were mixed with vanillic acid as a binding agent and pressed into pellets. The homogeneity of the resulting calibration standards was characterised by preparing a mapping and calculating the standard deviations, SDs, for the selected ablation lines within the pellets. The reference values and SDs of the FeMn calibration sample are 14.62 wt.% ± 5.49 wt.% C, 12.38 wt.% ± 5.17 wt.% Fe, 66.03 wt.% ± 6.58 wt.% Mn, 0.126 wt.% ± 0.19 wt.% P and 0.85 wt.% ± 5.85 wt.% Si. That of the FeTi calibration sample are 6.47 wt.% ± 2.23 wt.% Al, 5.75 wt.% ± 3.41 wt.% C, 47.37 wt.% ± 7.82 wt.% Fe, 33.45 wt.% ± 8.73 wt.% Ti, 0.029 wt.% ± 0.01 wt.% P and 1.62 wt.% ± 0.39 wt.% Si. Those of the refractory pellet are 29.28 wt.% ± 1.13 wt.% Al2O3, 62.76 wt.% ± 2.33 wt.% SiO2, 0.476 wt.% ± 0.09 wt.% MgO and 1.62 wt.% ± 0.20 wt.% TiO2. The Chair of Ferrous Metallurgy at the Montanuniversität Leoben provided two different FeMn types, FeTi75, four different representatives Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3 of the refractory material group as well as Ti-IF steel for LIBS analysis. In the quantitative analysis of the FeMn ferroalloys, recoveries of 87 % - 247 % for C, 98 % - 124 % for Fe, 92 % - 104 % for Mn, 93 % - 124 % for P and 103 % - 416 % for Si were achieved. The quantitative analysis of the FeTi substances resulted in recoveries of 110 % for Al, 174 % for C, 92 % for Fe, 104 % for Ti, 103 % for P and 84 % for Si. The LIBS measurement of the refractory materials allowed for a clear classification of the substances into the groups Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3 based on the measured chemical composition. A spot size of at least 100 µm × 100 µm was required to analyse the Ti-IF steel sample.

AB - The aim of this master thesis was the method development and the implementation of a data evaluation scheme for the quantitative analysis of in the steel industry relevant materials ferroalloys (FeMn and FeTi), refractory materials (Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3) and steel (Ti-stabilised interstitial free, short Ti-IF steel) by using Laser Induced Breakdown Spectroscopy, short LIBS. LIBS is to be evaluated as an alternative to the conventionally used analytical methods X-ray fluorescence analysis, spark optical emission spectroscopy and scanning electron microscopy. The focus is on quantitative analysis and the development of mapping images to visualise the element distribution over the sample surface. All LIBS measurements were performed with the nanosecond 193 nm ArF excimer laser ablation system (imageGEO193, Elemental Scientific Lasers, Bozeman, MT, USA) and the LIBS detector system, a multi-channel spectrometer (ESLumen, Elemental Scientific Lasers, Bozeman, MT, USA) in the laboratories of the Chair of General and Analytical Chemistry at the Montanuniversität Leoben. Data analysis was performed using the time-resolved spectroscopy software Iolite (version 4.9.1, Elemental Scientific Lasers, Bozeman, MT, USA) and Excel 365 (Microsoft Corporation, Redmond, WA, USA). The method validation is based on the use of the certified reference materials (CRM) FeMn CRM 502-2 and 583-1, FeTi CRM 510-1 and 584-1, and refractory material CRM 776-1. The powdered materials also served as a calibration standard for the quantitative analysis. For this purpose, the substances were mixed with vanillic acid as a binding agent and pressed into pellets. The homogeneity of the resulting calibration standards was characterised by preparing a mapping and calculating the standard deviations, SDs, for the selected ablation lines within the pellets. The reference values and SDs of the FeMn calibration sample are 14.62 wt.% ± 5.49 wt.% C, 12.38 wt.% ± 5.17 wt.% Fe, 66.03 wt.% ± 6.58 wt.% Mn, 0.126 wt.% ± 0.19 wt.% P and 0.85 wt.% ± 5.85 wt.% Si. That of the FeTi calibration sample are 6.47 wt.% ± 2.23 wt.% Al, 5.75 wt.% ± 3.41 wt.% C, 47.37 wt.% ± 7.82 wt.% Fe, 33.45 wt.% ± 8.73 wt.% Ti, 0.029 wt.% ± 0.01 wt.% P and 1.62 wt.% ± 0.39 wt.% Si. Those of the refractory pellet are 29.28 wt.% ± 1.13 wt.% Al2O3, 62.76 wt.% ± 2.33 wt.% SiO2, 0.476 wt.% ± 0.09 wt.% MgO and 1.62 wt.% ± 0.20 wt.% TiO2. The Chair of Ferrous Metallurgy at the Montanuniversität Leoben provided two different FeMn types, FeTi75, four different representatives Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3 of the refractory material group as well as Ti-IF steel for LIBS analysis. In the quantitative analysis of the FeMn ferroalloys, recoveries of 87 % - 247 % for C, 98 % - 124 % for Fe, 92 % - 104 % for Mn, 93 % - 124 % for P and 103 % - 416 % for Si were achieved. The quantitative analysis of the FeTi substances resulted in recoveries of 110 % for Al, 174 % for C, 92 % for Fe, 104 % for Ti, 103 % for P and 84 % for Si. The LIBS measurement of the refractory materials allowed for a clear classification of the substances into the groups Al2O3, SiO2, Al2O3·TiO2, and MgO·Al2O3 based on the measured chemical composition. A spot size of at least 100 µm × 100 µm was required to analyse the Ti-IF steel sample.

KW - Element distribution

KW - Mapping

KW - Laser ablation

KW - LIBS

KW - Ti-IF steel

KW - Elementverteilung

KW - Mapping

KW - Laser Ablation

KW - LIBS

KW - Ti-IF Stahl

M3 - Master's Thesis

ER -