Microscopic distribution of minor elements in iron-based alloys analyzed by secondary ion mass spectrometry

This paper overviews analytical results of the microscopic distribution of minor elements in iron-based alloys, obtained by secondary ion mass spectrometry (SIMS). Since trace amounts of some elements play crucial roles in the properties of steels, it is very important to analyze their distribution in the microstructure of iron-based alloys. Time of flight SIMS (TOF-SIMS) and conventional dynamic SIMS are powerful methods for detecting minor elements in iron-based alloys and analyzing their distribution in the microstructure of these materials. In this paper, we report several examples of the microscopic distribution of minor elements in iron-based alloys, which provide significant information on complicated phenomena related to the alloy microstructure. The depth profiles obtained by dynamic SIMS showed how a specific trace element penetrates the alloy matrix, indicating that the diffusion of the element is strictly related to the microstructure. On the other hand, high-sensitivity and high-spatial-resolution TOF-SIMS was used to characterize the microscopic distribution of trace elements, such as boron and nitrogen, in iron-based alloys, which is also related to the alloy microstructure.