Spectral analysis of the behavior and properties of solid surface layers. Nanotribospectroscopy

The paper demonstrates the feasibility of spectral analysis of acoustic vibrations and friction resistance force for studying the behavior, structure and properties of surface layers and coatings. Numerical simulation was performed on the nanoscopic scale with the use of the movable cellular automaton method. A method of analysis of elastic waves based on time dependences of velocity components, pressure and stress intensity at a certain point of the counterbody surface was proposed. The main peaks due to eigenfrequencies of the system, geometric and adhesion parameters of the model and the roughness of the interacting surfaces were identified in the obtained spectra. It is shown that the pressure spectra in the model are qualitatively similar to acoustic spectra in actual experiment. The feasibility of tribospectroscopic analysis based on calculation of the friction force for diagnostics of nanoscopic heterogeneities and discontinuities in a surface layer of thickness up to 100 nm is given theoretical grounds. The results of studies demonstrate the possibility of estimating the parameters of nanoscopic discontinuities such as the characteristic spatial period and linear dimensions. The applications of the proposed method as a promising nondestructive technique for studies of the behavior and diagnostics of the structure and damages in coatings and surface layers of nanoscopic thickness are discussed.