Electron beam microanalysis

K. F. J. Heinrich, Electron Beam Microanalysis, Van Nostrand, New York, 1981. 

Electron-beam microanalysis shows that the homogeneity range of the non-stoicheiometric phase Eui xB6 extends from x = 0 to x =0.10.337... 

The X-ray spectrum is used for the analytical determination of the element, preferably in X-ray fluorescence analysis and electron-beam microanalysis (L and M lines). These methods have gained much importance, primarily because there is no necessity for any prior chemical separations. Moreover, the matrix influences are much less compared to other methods. 

Similar to the dealloying behavior of other intermediate phases such as e-Ag—Cd [18], the selective dissolution of In from a y-Sn-In electrode with composition Sii8oIn20 was shown to result in a phase transformation with the Sn-rich terminal solid solution (f-Sn) as a product phase. Because of the close structural relationship of the parent and product phases this y-Sn-In — 8-Sn phase transformation is expected to produce negligible volume constraints [19]. Therefore, it should fulfill Wagner s criteria of diffusion driven phase transformations [20,21], that is, (1) a plane (stable) interface between the product and parent phase develops, (2) the interface advances into the parent phase with a parabolic rate law, and (3) the composition of both phases at this interface is given by the equilibrium phase diagram (see Fig. 3). These expectations have been confirmed both by metallography and by electron beam microanalysis [13]. 

Once again, it should be mentioned that the reaction products and the reactants together comprise a quasi-binary system which can be read from the phase diagram for the case where local thermodynamic equilibrium is maintained at the phase boundaries. If local equilibrium at all the phase boundaries is not established, then it is possible that certain product phases do not form, even though they are present in the equilibrium phase diagram. The probability that local equilibrium at the phase boundaries will, in fact, occur becomes better and better as the product layer grows. Reactions as discussed here are most easily studied experimentally today by means of the electron probe (electron beam microanalysis). 

Electron beam microanalysis of surface layers on galvanised hot-water steel tubes) (in German)... 

One vital method that can be applied to refractory sections is that of microanalysis in which small areas can be analyzed chemically after excitations with the incident electron beam. Microanalysis is normally used on polished sections while being examined by scanning electron microscopy. Analysis can be used to determine or confirm the composition of specific grains, particles, crystals, or bonds. By integrating the composition of grains or areas with spatial locations, reactions, diffusion profiles, and attack mechanisms can be evaluated particularly at interfaces. 

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