**3. Conclusion**

Low Electron Energy Loss Spectroscopy can be used as effective non-destructive method at investigation of physical-chemical properties materials in the nano-size near surface region.

Ionization energy losses allows to investigation layer-by-layer concentration profile for the singe crystal alloys with monolayer resolution, element distribution on the depth for the polycrystalline alloys and study of kinetics of surface processes at thermo-induced treatment or after ion irradiation of the surface.

Plasmon excitations are very sensitive to structural and chemical state of surface and bulk and it can be used for study of electronic states of free electrons in the near surface region and influence of different kinetic processes on changing of electronic structure of materials.

Analysis of intensity line of surface and bulk plasmons depending on primary electron energy E0 allows to define a surface-bulk interface when electron beam probes just near surface region with different physical-chemical properties as compared to the bulk material. These results have good correlation with data of surface composition on depth which obtained by IS and AES.
