The process of laser formation of microholes in semiconductor substrates using an EM-4452-1 laser processing unit with a pulse repetition rate of a picosecond laser from 10 to 300 kHz at a radiation energy of up to 10 ?J was investigated. The combination of high-speed movements of the laser beam by the galvanoscanner system and precise positioning of the processed material increases the efficiency of laser microprocessing and expands the functionality of the equipment.

A possibility of obtaining thin continuous plasma-electrolyte protective oxide coatings on VT1-0 titanium in a nickel sulfate alkaline electrolyte without the addition of silicates in the sparking mode was studied. The elemental composition and the microstructure of coatings manufactured via plasma electrolytic oxidation (PEO) both on the substrate and after the destruction of the coating in 25% sulfuric acid were studied. As a result of the research, a possibility of forming thin (1 µm – 7 µm) continuous PEO coatings, with a treatment duration of 3–10 min, respectively, was established. The introduction of additives (for example, nickel sulfate) into the electrolyte is effective when the duration of PEO is more than 10 min. It was supposed that nickel was incorporated into the coating mainly due to the action of plasma microarcs. The limited corrosion resistance of the resulting coatings in aggressive media was noted. An analysis of the elemental composition of the dry residue of the coating after destruction in a 25% sulfuric acid solution gives grounds to assume the electrochemical nature of the corrosion destruction of such coatings.

The paper presents the results of a statistical study of the parameters of the microgeometry of the surface of the vertical walls of the construction objects during additive shaping via electron beam melting. An assessment was made of the influence of the construction conditions and the hatching mode parameters on the surface roughness. The influence of the hatching mode parameters on the roughness of the side surface, when constructing samples with vertical walls, was established. It is shown that the value of the average size of the height of the irregularities Rz increases with the intensification of the energy regime of hatching. A physical model is proposed that describes the influence of the hatching mode on the roughness of vertical walls, based on the hypothesis of a possibility of penetration of the melt micro-flow during hatching onto the outer surface of the contour. It is shown that the distribution of the surface roughness values of the vertical walls has a non-Gaussian character, the curves are, as a rule, right asymmetric (the mode is located to the left of the size grouping center), which indicates the influence of non-random factors, the number or values of which systematically change over time.

The paper presents the theory of surface electronic states induced by a high-voltage field and considers applications of the theory of surface electrons to electrohydrodynamic flows. Theoretical considerations were carried out within the framework of a one-electron quantum mechanical model. It is shown that surface electrons initiate the injection of negative charges from the cathode into a liquid dielectric containing an electron-withdrawing impurity, for example, molecular iodine. Comparison of the theoretic and experimental data is satisfactory.

The article presents the findings on the effect of the substrate pre-impregnation in the cerium (III) nitrate and glycerin aqueous solutions on the corrosion-protective properties of the coatings generated on the magnesium alloy MA8 surface by microarc oxidation. The coatings were formed in the A-K mode from a silicate-alkaline base electrolyte solution containing compounds with fluoride ions. The corrosion resistance of the magnesium alloy ensured by oxide-ceramic coatings and without them was evaluated by the electrochemical corrosion parameters: corrosion potential, corrosion current density, and polarization resistance. The study has shown that the coatings formed on the surface of the magnesium alloy MA8 provide effective anticorrosive properties of the substrate of MA8 in the solutions containing chloride ions. It was established that the preliminary impregnation of a substrate made of magnesium alloy MA8 in aqueous solutions of cerium (III) nitrate and glycerin affects the mechanism of the resulting corrosion damage.

It is shown that the response of the functional property of the precipitate to the action of dimensional factors of the electrolysis conditions equally determines the dimensional property of the electrolyte. It was established that the most universal methods for estimating size effects can be formed on the basis of the correlation of dimensionless values of a number of given and magnitude-directed values of the size factor with a number of corresponding values of the sediment functional parameter. With the help of such methods, it is possible to quantify the relative coincidence or mismatch of changes in a given series of values of a size parameter with the obtained values of a series of sediment parameters, or by the proportion of coincidence of changes in a number of values of a size parameter with changes in a number of values of a sediment parameter. It is also shown that the study of the dimensional properties of electrolytes and deposits, depending on the type of dimensional factors and their scales, can expand the possibilities of the electrolytes used, increase the controllability of the formation of the functional parameter of the deposit, obtain new information about the process of the deposition of nanostructured deposits, and reveal the factors that were not previously in the focus of attention. A method of determination and a cell for the quantitative evaluation of the dimensional properties of the precipitate and the electrolyte from internal and external dimensional factors are presented.

It is shown that during the electrodeposition of Co-W coatings from a citrate electrolyte two types of size effects of the process rate (dependence of the electrodeposition rate on the surface dimensions) can be observed: a microeffect due to the influence of microelectrode sizes on the diffusion current density and a macroscopic size effect associated with the structure of the cobalt complex.

The features of deformation of microdrops of magnetic emulsions in an alternating electric field are experimentally investigated. It is shown that the nature of deformation can vary depending on the frequency of an electric field. In the case of low frequencies of an electric field, the droplets flatten along its direction, at higher frequencies they take an elongated shape. It was established that the frequency value corresponding to the transition of the microdroplet shape from the flattened to the elongated state depends on the electrical conductivity of the droplet, the value of the electric field strength, and temperature. A possibility of compensating for the deformation of the droplet caused by the action of an electric field using an additionally applied magnetic field was shown. The analysis of the obtained results was carried out taking into account the movement of liquid phases caused by the accumulation of a free charge at the interphase boundaries of droplets and electrodes that create a field.

This paper deals with an effect of a uniform magnetic field on heat transfer during the bubble boiling of a magnetic fluid on a horizontal surface with a point heater. Boiling curves are obtained for magnetic fluids with a volume concentration of a solid phase 12%, 8%, and 5.5% in magnetic fields of various strengths. It was found that the curves are non-monotonic. The magnetic field strength corresponding to the maximum heat flux was determined. The effect of the magnetic field on the heat flux increases when the concentration of the solid phase increases. In addition, an equation that satisfactorily described the experimentally observed effect of the magnetic field on the heat flow at bubble boiling mode using an approximate theory for boiling fluids heat transfer was derived. Also the forces acting on a vapor bubble in a nonuniformly heated magnetic fluid were analyzed.