Surface Engineering and Applied Electrochemistry最新文献

The article uses an analytical solution to the Schrödinger equation for an electron in each layer and the boundary conditions between layers to simulate the behavior of electrons in multilayer quantum nanostructures and also creates a Visual Basic program for the process under consideration. The program has the ability to change the effective mass of an electron in each layer, the height and width of the potential barrier in it, to calculate the coefficients of transmission and the return of electrons through barriers and the probability of being in them, and also to send the calculation results to MS Excel. Using the program, the dependence of the transmission and reflection coefficients of electrons on barriers and the probability of staying in them on the thickness and the width of the barriers and the electric field was studied.

The influence of electrolyte composition on morphology, chemical composition, and reflection coefficient of oxide layers on titanium obtained by high-voltage electrochemical oxidation is considered. It is shown that, depending on the processing mode and used electrolyte, the oxide layers of various morphologies are formed on the titanium surface with a specular reflection coefficient in the visible spectral range of 0.03–2.5%.

Laser hardening of cast irons was analyzed. A model was developed to describe the formation of longitudinal temperature stresses during laser treatment. The longitudinal deformations and stresses were calculated at various speeds of the laser beam. The modeling of the stress formation process showed that the maximum stress value and the depth of its location depend on the speed of the laser beam.

The study of the distribution of the magnetic field over the surface of the magnetic system in the cylindrical magnetron is performed. It is shown that the use of a shunt made of magnetic steel of grade SUS 420 J2 allows increasing the uniformity of the resulting magnetic field, which directly affects the uniformity of the sputtered coatings. Furthermore, the thickness of the shunt does not affect its leveling ability and the magnitude of the magnetic induction over the magnetic poles decreases with an increase in its thickness. The results of physical and mathematical modeling are confirmed experimentally.

The influence of the electrolyte composition and the deposition mode on the composition and microstructure of Fe–Ni–C–Cr electrochemical coatings has been studied. It is shown that an increase in the concentration of chromium chloride in the electrolyte and the current density in the considered range of values leads to an increase in the chromium content in the coatings and their microhardness. In the range of current densities of 60–160 mA/cm², Fe–Ni–C–Cr coatings with a dendritic surface microrelief are formed. The coating structure contains carbon in the form of films and ultrafine particles as well as dispersed particles, including those with a high chromium content. The content of these phases in the coating structure increases with increasing current density. The mechanism of electrocrystallization of coatings is considered.

Nanostructured nitride TiAlSiN and carbonitride TiAlSiCN coatings were formed by reactive magnetron sputtering on various types of substrates. Elemental composition was studied by energy dispersive X-ray spectroscopy (EDX) as well as structure by X-ray diffraction and micromechanical properties by nanoindentation. It was found that the formed coatings have a single-phase structure, which is a disordered solid solution with a face-centered cubic lattice. It was detected that a decrease in the degree of reactivity α from α = 0.605 to α = 0.421 leads to an increase in the deposition rate of nitride TiAlSiN and carbonitride TiAlSiСN coatings on silicon substrates by 200–300%. The hardness of the formed coatings varies in the range H = 28.74–48.99 GPa and Young’s modulus is E = 324.97–506.12 GPa. TiAlSiN and TiAlSiCN coatings demonstrate high indices of impact strength H/E * = 0.07–0.12 and resistance to plastic deformation H³/E *² = 0.13–0.72. The micromechanical properties of the formed nanostructured nitride and carbonitride coatings TiAlSiN and TiAlSiCN are promising for use in space technologies.

The ways of increasing the durability of boring cutting tools with micrometric adjustment of the blades are considered, stress models in the threaded adjustment mechanism during mechanical tension creation and coating are proposed and analyzed, and the results of experimental studies of the surface of the threaded connection are presented.

Digitalization of the induction heating systems development in the metallurgical industry goes from numerical simulation of electromagnetic fields to the construction and use of digital twins. The request for development of digital twins for such production processes as metallurgical technologies using induction heating is determined by relevance and acceptable costs. The main stages in the development of digital simulation, computational experiments, and digital twins of induction heating systems are considered. The main features in the development of digital twins have been identified. Efficient methods for computation electromagnetic fields in induction heating devices and principles for constructing multiphysical models, including the most important electrothermal models, have been developed. A complex of specialized programs for modelling not only induction heating devices, but also technologies using induction heating has been developed. A close connection between optimal design and control of induction heaters is shown. Examples of digital twins of various complexes using induction heating are considered.

A method for calculating the scattering capacity using a sectional anode for the electrolytic-plasma polishing variant, both with and without taking into account the edge effects, has been developed and tested. An increase in the scattering capacity of the electrolyte is shown to depend on both an increase in the hydrodynamic parameters of the sulfate electrolyte and a decrease in the processing voltage, in the electrolyte temperature, and in the concentration of ammonium sulfate in the electrolyte. The maximum scattering capacity (taking into account the edge effects) was found to be 95% at a processing voltage of 250 V, an electrolyte temperature of 60°С, and an ammonium sulfate concentration of 3%.

The deviation from the straightness of the steel cord is affected by the level and distribution of residual stresses. One of the effective ways to reduce residual stresses in the steel cord is the use of alternating metal cord bending. A scheme of alternating metal cord bending on a deforming roller is presented. The influence of the diameter of the deforming roller on the deviation from straightness of the complex design of the metal cord was assessed using the criterion of a comprehensive assessment. The results of the experiment obtained in the manufacture of steel cord using deforming rollers are presented. The diameters of the deforming rollers are determined, which make it possible to reduce the deviation from the straightness of the metal cord of a complex design.