Surface Engineering and Applied Electrochemistry最新文献

The corrosion of St3 steel in water containing sodium pyruvate was studied by gravimetric, electrochemical, and X-ray powder diffraction analyses. It was shown that the introduction of sodium pyruvate into the corrosion environment significantly reduces steel corrosion. Depending on the test time and inhibitor concentration, the corrosion rate decreased by a factor of 3.8–6.0 at a protection level of 73.9–83.3%.

Electron beam recording of raster images in a Ge₅As₃₇S₅₈/Se multilayer nanoperiodic structure (MNS) was carried out. The topography of the patterned Ge₅As₃₇S₅₈/Se MNS surface was studied using an atomic force microscope (AFM). According to the obtained results, the contribution of the lateral mass transport to the surface relief formation on the MNS was established. The formation of ridge-like lines on the MNS surface under the fast jumping of an electron beam between its targeted locations was revealed.

The mutual solubility of salts in the MeSO₄–MnSO₄–H₂O (Me = Ni, Co) systems at a solution temperature of 20, 40, and 60°C was studied by an isothermal method. It has been established that, depending on the temperature, the addition of manganese sulfate to a three-component solution leads to a decrease in the solubility of nickel and cobalt sulfates by 1.1–2.2 and 1.1–2.1 times, respectively.

This paper presents the approach to conducting experiments and determining their optimal number in experimental studies of hydrodynamic and energy characteristics during an electric explosion in a liquid. A comprehensive statistical analysis of the experimental data has been performed and a case study has been provided to illustrate the calculation of confidence intervals and the accuracy of pressure amplitude measurements during electric explosion. The application of this approach has enabled a significant reduction in the number of required experiments, while maintaining high levels of accuracy and reliability in the research outcomes.

The dependences of the main technological parameters on the operating modes of the magnetron at direct current during sputtering of a target composition (MoSi₂ + 20 wt % SiC) have been studied, and the influence of some parameters and modes of the technological process on the surface resistance R_S of the films has been studied. The value of the integral emissivity in the IR region of the film spectrum was determined to be 0.8. Using SEM analysis, the morphology of the surface and transverse cleavage of films deposited on a Si substrate was studied, and the quasi-amorphism of deposited films was established. It has been determined that the deposited films can be used as a resistive emitting medium in a thin-film IR emitter.

On the basis of previous studies, the efficiency of strengthening magnetic-pulse treatment of various metals and alloys, which is carried out within a very short time (approximately 0.001 s), has been shown. However, processing of refractory alloys requires the use of a very large magnetic energy, which leads to fast wear and breakage of some important working elements of the magnetic-pulse facility. To eliminate this drawback, a method of complex thermal and magnetic-pulse treatment of articles has been developed. A special electromagnetic device for preliminary induction heating was developed and manufactured. The regimes of complex processing that ensure improvement of the mechanical properties of the surface of specimens made of various grades of steels and hard alloys have been determined.

The structure, elemental composition, and mechanical and corrosion properties of (Zr, Nb)N, (Zr, Hf)N and (Zr, Nb, Hf)N vacuum-arc coatings deposited on the titanium alloy Ti–6Al–4V were studied. The X-ray diffraction analysis, scanning electron microscopy, microhardness measurement, adhesion, and corrosion tests were used as investigation techniques. It was found that the coatings were single-phase solid solutions based on ZrN. The highest microhardness value (17 GPa) was observed for the (Zr, Hf, Nb)N coating, and the lowest value (9 GPa) for the (Zr, Nb)N coating. The (Zr, Hf)N coating also possessed the highest critical force Lc3 during scratch tests. Comparison with the data obtained earlier showed that a decrease of the Nb concentration in the (Zr, Nb)N coating and an increase of the Hf concentration in the (Zr, Hf)N coating led to the growth of the critical force Lc3. Corrosion tests carried out in a 3% NaCl solution in the galvanostatic mode showed that the (Zr, Nb)N coating maintained continuity over the entire surface of the alloy in contrast to the coatings containing Hf atoms.

The influence of heating rate and sintering temperature on the mechanical characteristics of composite materials from iron–silicon carbide–sodium tetraborate and iron–silicon carbide–copper-phosphorous alloy systems synthesized using a high-frequency electromagnetic field is examined. It has been shown that the use of an induction heater allows for widely regulating the heating rate and the conditions of heat exchange between components of furnace charge and, thus, allows for controlling the properties of the resulting materials at the sintering stage. It has been established that subsequent annealing of the compacts for 5 and 10 min at a temperature equal to the sintering temperature increase the mechanical characteristics of the resulting materials.

Studies have been carried out of the elemental composition and mechanical properties of AlTiN and AlTiCN coatings obtained by conditions of separation of two-component plasma of a cathode-arc discharge using the magnetic optical system of the UVNIPA-1-001 vacuum machine. Separation makes it possible to reduce the number of macroparticles of micron and submicron sizes in coatings by half. In this case, large macroparticles (more than 5 microns) are removed almost completely, and the number of particles from 3 to 5 microns is reduced by an order of magnitude. A study of the elemental composition of AlTi(C)N coatings revealed a strong deficiency of aluminum in the absence of magnetic plasma separation. At the same time, magnetic separation makes it possible to obtain coatings with a relative content of aluminum and titanium close to the content of these metals in the cathode. As a result, under certain conditions of cathode arc combustion under conditions of magnetic separation of the plasma flow, a superhard AlTiN coating (HV 5400) was obtained. It has been shown that the adhesion of coatings during plasma separation can be increased several times by optimizing the nitrogen pressure during their deposition. A physical explanation is proposed for the phenomenon of changes in the elemental composition of coatings under separation conditions based on the nature of the propagation of light and heavy plasma ions in the presence of a curvilinear magnetic field.

The research of the pulsed magnetic field effect on the surface microhardness and residual microstresses of the samples made of titanium alloy VT-6 with ZrN, ZrNbN coatings are conducted. It is established that the mode with an energy of 10 kJ and a number of pulses equal to four are the most effective to change surface properties when magnetic-pulse effect with the use of high-frequency installation MPU-3 on researched samples is carried out. It is shown that the magnetic-pulse treatment of samples with ZrN coating leads to microhardness increase by 8–11% and up to 20% for samples with ZrNbN coating. When studying the pulsed magnetic field effect on residual stress, it is established that the treatment of studied samples with ZrN, ZrNbN coatings is followed by the compressive residual stresses. The treatment of studied samples under MPU 20–21 installation, where an increased exposure duration has been used, enables reducing the coefficient of microhardness values as well as to regulate residual microstresses on the surface and approximate them to zero.