Towards Reliable Quantification of Steel Alloys at Low Voltage

Whether it be inclusions, precipitates or segregation at grain boundaries, the development of new steel alloys and processes hinges on the chemical quantification of submicrometer features. The combined requirements for high spatial resolution and accurate measurements of several elements make field emission electron microprobes suitable instruments for studying steel alloys. For quantitative analyses, the spatial resolution is determined by the x-ray emission volume the dimensions of which depend on the sample composition, the beam energy and the overvoltage ratio. For most elements, lowering the beam energy directly translates into the necessity of using lower energy x-ray lines. However, the improvement of the spatial resolution comes with additional challenges, mainly a lower intensity (worst statistics), a larger influence of contamination and oxidation, and inaccuracies of the quantification.