Surface Engineering and Applied Electrochemistry最新文献

The possibility of the formation of structures such as compounds of elements between chalcogenides and the transition group of metals in the crystal lattice of silicon is studied. This is an urgent problem in electronics. It is shown that, under certain technological conditions, a sufficient concentration of unit cells is formed, which leads to a change in the band structure of silicon itself; i.e., a micro- and nanoscale inclusion in silicon with a direct-gap structure is obtained. The possibilities of creating a fundamentally new class of photocells with an extended spectral sensitivity region, as well as light-emitting devices, light-emitting diodes, and lasers based on them, are shown.

A study was made of the interaction of the first azimuthal modes of capillary waves on the surface of an elliptic jet in a homogeneous electrostatic field that is perpendicular to the axis of the jet. The interaction is nonlinear in the product of two independent small parameters. The interaction arises due to the ellipticity of the perpendicular cross-section of the jet and involves three azimuthal modes: either even or odd. The stability of the jet in the perpendicular homogeneous electrostatic field is lower than that of a jet in a radial electrostatic field. The characteristic destabilization time decreases with increasing initial amplitudes of the interacting modes and intensity of the external electrostatic field, and also depends on the wavenumber.

Cryogenic treatment is the process of cooling a material to extremely low temperatures to generate enhanced mechanical and physical properties. The present investigation examines the effect of a deep cryogenic treatment on the enhancement of mechanical properties, such as the wear resistance, the corrosion resistance, the tensile strength, and the impact strength of the plunger material 100Cr6 bearing steel. An improvement in those properties of the deep cryogenically treated samples over the conventionally heat treated ones was found to be 50, 26, 13, and 27%, respectively. This study suggests that the formation of very small carbides dispersed in the tempered martensite structure can be the main reason for the enhancement of certain mechanical properties, along with the retained austenite transformations.

The polarizable continuum model was used for four different compounds to investigate the impact of substituent groups, of the number of π-electrons, of the electron-accepting and electron-donating properties on the corrosion inhibiting properties in both aqueous and gas phases for the neutral and cationic forms of the studied subsdtances. Measures for the corrosion prevention of metals are of great importance in the industrial, environmental (or ecologic), aesthetic, and economic fields. The use of inhibitors is the best way to preserve metals and alloys from corrosion. The purpose of this study was to apply quantum chemical calculations in the research of the corrosion inhibition and adsorption properties of four compounds with various heteroatoms or substituent groups but with similar chemical skeleton structures: 2-mercaptoimidazole, 2-mercapto-5-methyl benzimidazole, 2-mercaptobenzoimidazole, and 2-mercapto-5-nitrobenzimidazole, shown in Figs. 1 and 2 and designated as A, C, B, and D, respectively. The quantum chemical computations sector of the study gives complete calculation details and discussion on the correlation between corrosion inhibition and global reactivity descriptors such as the energy of the highest occupied molecule orbital, the energy of the lowest unoccupied molecule orbital, total energy, ionization energy, electron affinity, electronegativity, energy gap, hardness, softness, dipole moment, electron transfer, chemical potential, electrophilicity, nucleophilicity, and back-donation energy. The calculations were carried out using the general purpose computational chemistry software package Gaussian 09. The total calculations have been done based on the density functional theory at 6-311++G(d, p) basis set and applying the hybrid functional B3LYP level taking into account the exchange and the correlation with three parameters defining the hybrid Becke’s functional (Becke—the exchange part, and Lee, Yang and Parr—the correlation part). Based on the calculations performed in this paper, the following summary ranking was obtained for the corrosion inhibition efficiency: A > B > C ≈ D for neutral forms and A > B > C > D for cationic forms in the gas phase, A > C ≈ D > B for neutral forms and A ≈ B > C > D for cationic forms in the aqueous phase. Thus, inhibitor A should be considered to be the best one in all cases.