Churilov I. Peculiarities of thermal influence on morphological changes and the mechanism of liquid phase formation in condensed one-component films (Pb, Sn, In, Bi) and in binary layered films (Bi/Sn, Pb/Sn, Pb/In)

The purpose of the dissertation is to solve the scientific problem, which is to determine the peculiarities of the formation of the liquid phase, as well as to clarify the peculiarities of morphological changes that occur with the participation of the liquid phase in single-layer polycrystalline films of metals (Sn, Bi, Pb, In) and layered binary films (Bi/Sn, Pb/Sn, Pb/In). The kinetics of through-pore growth and de-wetting of samples that are solid in the initial state are investigated. The activation energy of surface self-diffusion for Pb, Sn, and In films was determined. The concentration dependence of the activation energy of diffusion processes for layered Bi/Sn samples was obtained. It was found that the melting of polycrystalline samples occurs in a certain temperature range. It is explained as a manifestation of the inner size effect due to the influence of the energy of grain boundaries (for single component films) and the energy of interphase boundaries of components in binary layered structures. The energy of the grain boundaries in Sn and Pb films has been determined. The energy of interphase boundaries of the components for Bi/Sn and Sn/Pb films is estimated. It has been shown, when studying the melting of islands formed during film dispersion, that the particle size distribution is rather narrow and unimodal. The most probable particle radius and the half-width of the distribution histograms depend linearly on the mass thickness of the condensate. It has been found that the excess energy that causes de-wetting of the films that are solid in the initial state practically does not change for thick films, and decreases sharply when the mass thickness of the film decreases below a certain critical value. At the same time, the morphological structure of the films changes. The concentration dependence of the most probable particle radius and half-width of the histograms for the binary Pb/In system was obtained. It was found that for films containing from 20 to 80 wt. % Pb, these values do not depend on the film composition, but significantly decrease when changing to pure components. The peculiarities of the morphology of the films obtained by vapor-liquid condensation are investigated. It was found that they are typical for high values of the coefficient of coverage of the substrate by the film and bimodal distribution of particles by size.