ISO/TC 202/SC 2 - Electron probe microanalysis

This document specifies procedures for quantitative analysis of Mn dendritic segregation in steel billets, blooms, slabs using electron probe microanalysis (EPMA). This document is mainly applicable to continuously cast products with Mn content more than 0,01 % by mass. It can also be used for steel ingots and steel products, such as cast iron and cast steel. The minimum size of analysable dendrites is totally dependent on the resolution of microscope of EPMA and beam size of filament used for quantitative analysis.

This document provides guidelines for performing routine diagnostics and quality assurance procedures on electron probe microanalysers (EPMA). It is intended to be used periodically by an instrument's operator to confirm that the instrument is performing optimally, and to aid in troubleshooting if it is not. It covers the properties of reference materials required and the analysis procedures necessary to independently test and fully evaluate the functionality of the main components of an EPMA system. The analytical procedure described herein is distinct from single-element diagnostic procedures, which can be performed more rapidly. Such procedures are valid for the diffractor position and conditions under which the test is performed, whereas the procedure described herein is intended to qualify an instrument's capabilities for exploratory analysis of unknowns, trace analysis and non-routine work (such as peak interferences). This document is applicable to EPMA and other wavelength dispersive spectrometer (WDS) systems in which elemental identification and quantification are performed by analysis of the energy and intensity of the characteristic X-ray lines observed in wavelength-dispersed X-ray spectra. It is not directly applicable to elemental analysis using energy dispersive spectrometry (EDS).

ISO 22489:2016 specifies requirements for the quantification of elements in a micrometre-sized volume of a specimen identified through analysis of the X-rays generated by an electron beam using a wavelength dispersive spectrometer (WDS) fitted either to an electron probe microanalyser or to a scanning electron microscope (SEM). ISO 22489:2016 also describes the following: - the principle of the quantitative analysis; - the general coverage of this technique in terms of elements, mass fractions and reference specimens; - the general requirements for the instrument; - the fundamental procedures involved such as specimen preparation, selection of experimental conditions, the measurements, the analysis of these and the report. ISO 22489:2016 is intended for the quantitative analysis of a flat and homogeneous bulk specimen using a normal incidence beam. It does not specify detailed requirements for either the instruments or the data reduction software. Operators should obtain information such as installation conditions, detailed procedures for operation and specification of the instrument from the makers of any products used.

ISO 14594:2014 gives the general guidelines for the determination of experimental parameters relating to the primary beam, the wavelength spectrometer, and the sample that need to be taken into account when carrying out electron probe microanalysis. It also defines procedures for the determination of beam current, current density, dead time, wavelength resolution, background, analysis area, analysis depth, and analysis volume. It is intended for the analysis of a well-polished sample using normal beam incidence, and the parameters obtained can only be indicative for other experimental conditions. It is not designed to be used for energy dispersive X-ray spectroscopy.

ISO 14595:2014 gives recommendations for single-phase certified reference materials (CRMs) used in electron probe microanalysis (EPMA). It also provides guidance on the use of CRMs for the microanalysis of flat, polished specimens. It does not cover organic or biological materials.

ISO 17470:2014 gives guidance for the identification of elements and the investigation of the presence of specific elements within a specific volume (on a μm3 scale) contained in a specimen, by analysing X-ray spectra obtained using wavelength dispersive X-ray spectrometers on an electron probe microanalyser or on a scanning electron microscope.

ISO 16592:2012 gives guidance on a method for the determination of the carbon content in steels containing other alloying elements (less than 1 % to 2 % by mass) using the calibration curve method. It specifies the sample preparation, X-ray detection, establishment of the calibration curve and the procedure for the determination of the uncertainty of the measured carbon content. It is applicable to steels containing a mass fraction of carbon of less than 1,0 %. The method is not applicable to steels with higher carbon contents, which could significantly affect the accuracy of the analysis results. ISO 16592 applies to analyses performed using normal beam incidence and wavelength-dispersive X-ray spectrometry; it is not designed to be used for energy-dispersive X-ray spectrometry.

This International Standard provides procedures for electron microprobe elemental-mapping analysis using wavelength-dispersive spectrometry. The choice between mapping with the electron beam moving digitally across the specimen (electron beam mapping) and mapping with stage movement only (large-area mapping) is assessed. It describes five types of data processing: the raw X‑ray intensity data method, the k‑value method, the calibration method, the correlation method and the matrix correction method.

ISO 22489:2006 specifies requirements for the quantification of elements in a micrometre-sized volume of a specimen identified through analysis of the X-rays generated by an electron beam using wavelength-dispersive spectrometers fitted either to an electron probe microanalyser or to a scanning electron microscope. It describes the principle of the quantitative analysis, the general coverage of this technique in terms of elements, mass fractions and reference specimens, the general requirements for the instrument, and the fundamental procedures involved, such as specimen preparation, selection of experimental conditions, the measurements, the analysis of these and the report. It is intended for the quantitative analysis of a flat and homogeneous bulk specimen using a normal incidence beam. It does not specify detailed requirements for either the instruments or the data reduction software. Operators should obtain information such as installation conditions, detailed procedures for operation and specification of the instrument from the makers of any products used.

ISO 16592:2006 gives guidance on a method for the determination of the carbon content in steels containing other alloying elements (less than 1 % to 2 % by mass) using the calibration curve method. It specifies the sample preparation, X-ray detection, establishment of the calibration curve and the procedure for the determination of the uncertainty of the measured carbon content. It is applicable to steels containing a mass fraction of copper of less than 1,0 %. The method is not applicable to steels with higher carbon contents, which could significantly affect the accuracy of the analysis results. ISO 16592:2006 applies to analyses performed using normal beam incidence and wavelength-dispersive X-ray spectrometry; it is not designed to be used for energy-dispersive X-ray spectrometry.

ISO 17470:2004 gives guidance for the identification of elements and the investigation of the presence of specific elements, within a specific volume, contained in a specimen, by analysing X-ray spectra obtained using wavelength dispersive X-ray spectrometers on an electron probe microanalyser or on a scanning electron microscope.

ISO 14594:2003 gives the general guidelines for the determination of experimental parameters relating to the primary beam, the wavelength spectrometer and the sample that need to be taken into account when carrying out electron probe microanalysis. It also defines procedures for the determination of beam current, current density, dead time, wavelength resolution, background, analysis area, analysis depth and analysis volume. ISO 14594:2003 is intended for the analysis of a well-polished sample using normal beam incidence, and the parameters obtained may only be indicative for other experimental conditions.

ISO 14595:2003 has been developed to facilitate international exchange and compatibility of analysis data in electron probe microanalysis (EPMA). It gives guidance on evaluating and selecting reference materials (RMs), on evaluating the extent of heterogeneity and stability of RMs and it gives recommendations for the determination of the chemical composition of RMs for production as EPMA certified reference materials. ISO 14595:2003 gives recommendations for single-phase certified reference materials (CRMs) used in electron probe microanalysis (EPMA). It also provides guidance on the use of CRMs for the microanalysis of flat, polished specimens. It does not cover organic or biological materials.