The process of crystal growth in a metastable multicomponent melt has a high speed of the solidification front, which captures atoms of some other components. As a result of such a growth, at the surface of the growing crystal the effect of “impurity capture” is observed, and the concentrations of components significantly deviate from the local equilibrium. Under such conditions, the conventional physico-chemical methods for description of processes at the interfacial surface become inapplicable. Therefore, a new variational approach was applied for an integrated description of diffusion and thermal processes at the phase interface. The growth rate of crystal nucleus in a metastable melt was obtained, using the methods of non-equilibrium thermodynamics. The developed approach allows estimation of the degree of metastable effects influence on a crystal growth rate.

One of the main problems common to all areas of technology is to increase the reliability and durability of machines, devices, and mechanisms. This problem can be solved by applying wear-resistant coatings and chromium-based alloys. The method of electrochemical chrome plating has a number of significant drawbacks: low current efficiency of chromium; the lowest dispersing capacity among galvanic processes; high energy intensity; the presence of high internal stress chrome plating; hydrogenation of chromium sediments and base alloy. Therefore, at present, a large number of works are being carried out aimed at intensifying the processes of chromium plating. This work is aimed at exploring the possibilities of optimizing the process of chrome plating by changing the composition of the electrolyte. Classification of currently used electrolytes of chromium plating was carried out according to the following parameters: electrolyte composition, process conditions, cathode output by current and quality of the coatings obtained. On the basis of experimental studies conducted by the authors, the possibility of intensifying the process of electrolytic chromium plating from aqueous solutions, due to a change in the composition of the electrolyte, is shown. The effect of a number of anions (SO2-4, SiF2-6,Cl-,F-, NH2SO-3, PO3-4, IO3-3, I2O4-7) on the quality of sediments and current efficiency is studied. The ways to improve the most popular universal electrolytes are proposed.