Concentration depth distribution of grain boundary segregation measured by wavelength dispersive X-ray spectroscopy.

A method using wavelength dispersive X-ray spectroscopy (WDS) is applied to the measurement of grain boundary segregation of Sn in silicon steel. The quantification of monolayer concentration of Sn is acquired, which demonstrates an obvious segregation of Sn at grain boundaries. In consideration of the fact that segregated impurities (Sn or other species) distribute in multilayer and not just monolayer segregation can be characterized by WDS, the Gaussian distribution is applied to formulate the multilayer concentration depth distribution according to the measured total concentration. A correction factor is then put forward to improve the quantification. Based on the measured segregation of Sn and the derived formula of multilayer concentration depth distribution, the grain boundary concentrations of Sn are calculated for different thicknesses of segregated layer. From the experimental measurement, theoretical analyses and calculated results, an effective approach for the research of grain boundary segregation is provided.