Energydispersive x-ray microanalysis in the analytical electron microscope

A review is made on the quantitative microanalysis of thin samples in the analytical electron microscope (AEM) with the energy dispersive spectrometer (EDS). This review is concerned with a basic approach to the quantification and some applications to Ni base alloys. Covered first are the simplicity of the ratio method for the microanalysis of thin samples and the importance of the experimental determination of /c-factors needed in the ratio method. The way to estimate the effects of X-ray absorption and fluorescence is described by having examples from two typical Ni base alloys. For the correction of absorption, two methods are raised; one is the extrapolation method and the other is the differential X-ray absorption (DXA) method, both of which do not require the thickness measurement. Application to a unidirectionally solidified Ni-AI-Mo eutectic alloy is demonstrated, where the calculation of the minimum mass fraction (MMF) is included. Finally, a simple technique is shown to identify the particles of which sizes are smaller than the electron probe size.