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M. Bonta, C. Gierl-Mayer, H. Danninger, A. Limbeck:
"Revealing the distribution of non-mteallic additions in steel samples using LA-ICP-MS";
Poster: 2014 Winter Conference on Plasma Spectrochemistry, Amelia Island, Florida, US; 06.01.2014 - 11.01.2014; in: "2014 Winter Conference Program and Abstracts", (2014), ISSN: 0161-6951; 140 S.

Especially in the field of powder metallurgy of steels non-metallic hardening substances (e.g. boron, phosphorus) are used to improve the sintering behavior as well as the mechanical and physical properties of the resulting materials. However, these constituents have a very limited solubility in the metallic phases and therefore higher concentrations may lead to embrittlement of the manufactured sinter steels due to segregation on the grain boundaries [1,2]. As a consequence exact knowledge of the processes during sintering of the materials is needed to optimize the amounts of non-metallic additions within the material. Furthermore information about the distribution of the mentioned additions can be of special interest to comprehend the mechanisms appearing during the sintering process of the material. In routine methods for investigations on the distribution of elements in sintered steels electron probe microanalysis (EPMA) is used [3]. Sensitivity of this technique is rather low and detection of technologically relevant elements (such as boron and phosphorus) is often hard to achieve or even impossible. The relatively weak sensitivity aggravates the analysis of elements appearing in low concentrations within the material structure. In this work laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is proposed as an alternative method to EPMA offering trace-analytical capabilities even for light elements such as boron.
In the presented study an imaging procedure to reveal the spatial distribution of diverse alloy constituents has been developed. The used method allows to differentiate different grain structures and to correlate elemental distributions with visual images of the etched sample surfaces. Iron alloy samples with different amounts of additions have been investigated to receive information about the distributions at changing concentrations of non-metallic additions. Especially boron-containing samples were investigated; the expected segregation of boron on the grain boundaries of the sinter materials could be confirmed.

LA-ICP-MS, signal quantification, steel samples