GROWTH OF ISLAND FILMS FROM BINARY MELTS OR A VAPOR-PHASE AT THE OSTWALD RIPENING STAGE UNDER NONISOTHERMAL CONDITIONS

A theory on the growth of island films from binary melts or a vapor ph ase under non-isothermal conditions is developed. A system in which th e growth of island films takes place is thermally isolated, and both d iffusion and temperature fields exist in the system. Temperature field s are formed due to evolution of the latent heat of crystallization or the heat of sublimation. The diffusion and temperature fields and sel f-consistent with each other. A full set of equations describing this process is derived. By solution of this set of equations, the rules go verning the variation of the mean radius and the island density in tim e with different mechanisms for mass or heat transfer were found. It i s shown that islands grow due to two processes, diffusional or thermal . One of these processes, namely, the diffusional one, is related to a variation in the supersaturation, while the thermal process occurs du e to a change in the overcooling. It is also shown that the rate of is land growth is determined by the factor that relates coefficients of t he diffusion and thermal conductivity. Kinetic phase diagrams for bina ry systems are defined. A distribution relating the size of islands to their composition is obtained for the island films growing from binar y systems, which gives rise to a continuous range of solid solutions i n the solid state. The law of the variation of composition with time i s found. Open systems are discussed in the second part of the work. Th e possibility of controlling the processes of growth of islands by mea ns of sinks (sources) of heat or air is demonstrated. A model of growt h of island film assemblies from melts having the eutectic composition is constructed. The possibility of controlling the structure or compo sition of continuous films is demonstrated.