Surface Engineering and Applied Electrochemistry最新文献

Here, by the example of galvanostatic electrodeposition of Co–W coatings from a citrate bath, we demonstrate experimentally that when using the results on the deposition rate and the composition and properties (microhardness) of resulting coatings observed under laboratory conditions to develop this type of an electrodeposition process on a larger (industrial) scale the bath volume must be scaled in proportion to the increase in the cathode area. In this case, the current loading on the electrolyte, which is quantitatively expressed as the volume current density, does not increase.

The equations of magnetohydrodynamics (MHD) are presented as continual modeling for slow motions. The original equations of the MHD environment are linearized, reduced, and applied to the analysis of environments characterized by the phenomena of electrolysis and turbulence. A continual approach for electrolysis and turbulence is presented, and the real-life ongoing studies are considering local models. The formulation of the problem and its analysis are presented as the density of the MHD-field decreases from a flat wall. Experimental studies with respect to propulsion devices in sea water are characterized.

In asymptotic calculations of the first order of smallness in the dimensionless amplitude of water droplet oscillations, the effect of the dynamic surface tension on the oscillation parameters was investigated using a model of an ideal incompressible liquid. It was shown that the effect of the dynamic surface tension strongly manifests itself at frequencies of external influences that are inversely proportional to the water relaxation time. At such frequencies, under the action of external influences, the electrical double layer is destroyed (the ordering of water molecules in the near-surface layer is disrupted). As a result, the free energy of the surface increases, and so does the liquid surface tension. The dynamic surface tension affects the acoustic radiation from the droplet by altering the coefficient of surface tension. The contribution to the electromagnetic radiation of the oscillating droplet is made by the disruption of the order of near-surface water molecules in the electrical double layer.

The features of materials leading to the strong correlation effect and the phenomena realized in them are considered: the metal-insulator Mott transition and high-temperature superconductivity. The history of their study is traced. Particular attention is paid to studying the role of the interorbital correlation effect and the Hund’s coupling in multiorbital systems as well as the electron-phonon interaction in systems with strong Coulomb interaction. The development of the strong coupling diagram technique is analyzed and the results obtained based on the approach used are presented.

To improve the performance of the CompoNiAl-M5-3 alloy produced from nickel monoaluminide, protective coatings were applied by electrospark deposition (ESD) using electrodes made of the Zr–18%Ni eutectic alloy. The coatings were applied in an argon environment using tools for manual treatment both of vibrational and rotational types with the connection of direct and reverse polarities. It was determined that the maximum total deposition on the cathode of 11.17 × 10^–4 cm³ is achieved when using a tool of the rotational type with a direct polarity of connection. The obtained coatings are characterized by 100% continuity at a thickness of 20–25 μm, hardness of 11.6–14.6 GPa, and elastic modulus of 162–174 GPa. Electrospark treatment increases the hardness of the CompoNiAl-M5-3 alloy by a factor of 1.4 to 1.8, wear resistance by factor of 3.3 to 16.2, and heat resistance at a temperature of 1150°C for 5 h decreases coefficient of friction.

The corrosion process of steel St. 3 in water with the addition of a heteronuclear salicylate complex {[FeSr₂(SalH)₂(Sal)₂(NO₃)(DMA)₄]}_n by gravimetric, electrochemical, and physicochemical methods (X‑ray phase analysis, UV, IR and Mössbauer spectroscopy) has been studied. It has been shown that the introduction of the additive under study into a corrosive environment significantly reduces steel corrosion. Depending on the duration of the tests and the concentration of the inhibitor, the corrosion rate is reduced by 5.1–11.1 times with a degree of protection of 80.5–91.0%. A mechanism of inhibition has been proposed. The inclusion of products of interaction of ionized iron with the complex in the coating layers has been proven.

The prospects of utilizing electric current treatment of molten metal simultaneously with multiple types of current in foundry production were studied. This principle in combination with various designs of electrode systems allows the formation of a multivariant topology of the electromagnetic field in the molten metal, qualitatively and quantitatively shaping differently the thermomechanical load on the melt. Conditions for improving the performance of the cast metal were found. Simulation modeling methods identified treatment options capable of actively improving the incubation processes of crystallization. The results of simulation modeling were experimentally confirmed. It was determined that simultaneous treatment with two types of current at energy consumption three times lower than that in treatment with a single current source increases the tensile strength by 13% and the relative elongation by a factor of 1.5. The relative narrowing of the specimen was 4.4%, which cannot be achieved for an alloy in the Al–Si system by other treatment methods. The eutectic structure was modified, and α-Al grains acquired a rounded shape.

In this paper, an attempt to evaluate the effect of particles on the electrical conductivity of liquid dielectrics is made. For this purpose, a conductivity model is formulated taking into account the presence of relatively large charged microparticles in the dielectric. Based on calculations using the model, a comparative assessment of electrical conductivity was carried out. It is shown that in sufficient quantities, particles can significantly increase the electrical conductivity when forming double electric layers near their surface.

The purpose of this research was to enhance the wear behavior and hardness of cold work D5 tool steel by depositing a TiCrN multilayer nanocoating through the physical vapor deposition with a cathodic arc. A comparison was made between the properties of the applied coatings and the thin-film TiN and CrN nanolayer coatings produced using the same method. Various tests, including micro-hardness tests, surface wear tests, and corrosion examinations using the Tafel test, were conducted. The coating surfaces and the wear lines were analyzed using field emission scanning electron microscopy with energy dispersive X-ray spectroscopy. The results indicated that the TiN thin-film coating, the TiCrN multilayer nanocoating and the CrN coating exhibited higher hardness of 226, 205, and 165 HV, respectively than the less coated sample (101 HV). Additionally, friction coefficients were measured and found to be 0.35, 0.3, and 0.27 for TiN, TiCrN, and CrN coatings, respectively. Furthermore, the corrosion test results demonstrated that the TiCrN multilayer coating exhibited excellent corrosion resistance. The analysis of wear surfaces revealed abrasion wear mechanisms for the TiN and CrN coatings, while fatigue wear mechanisms were observed for the TiCrN coating. Those findings suggest that the TiCrN multilayer nanocoating has potential applications in the production of tool steel pieces, complementary parts, and machine tool components.

The present paper deals with a comprehensive investigation of the wettability of the platinum surface when subjected to water nanodroplets using molecular dynamics simulation. To evaluate the wettability of a solid-liquid interface, the contact angle was analyzed varied with respect to time, temperature, and energy between the atoms and the surfaces using large-scale atomic/molecular massively parallel simulator. It is worth noting here that the research reveals a significant change in the contact angle which goes from a prominent 147.158° to a more favorable 123.65° in an incredibly brief period of 2 to 200 fs. That dynamic change highlights the platinum surface significant improvement in wettability and sheds light on the kinetics of solid-liquid interactions. The result also shows that the ambient temperature reduced from 320 to 285.5 K, and the droplet temperature increased from 2.43 to 170 K in the same temperature range along with a decrease in the total energy. This study emphasizes the progressive aspect of wettability by revealing that, as time increases, the contact angle consistently reduces. This shows the perspective on how the platinum surface becomes increasingly amenable to wetting by H₂O nanodroplets.