The use of pulse electrolysis for copper plating on steel and cast iron bases from citrate electrolyte

Process of electrochemical deposition of copper on a steel and iron substrate from citrate electrolytes was investigated. It is determined that the material of cathode greatly influences the kinetics of copper plating process. Influence of pulse electrolysis on a range of working density of current, a current efficiency of copper and porosity of coatings were investigated. It is determined that application of a pulse mode increases a range of working density of current and improves quality of the received coatings

Electrochemical deposition of nickel coatings from acetate-chloride electrolyte in pulse mode

The process of electrodepositing of nickel from acetate-chloride electrolyte at low temperature in a pulsed mode has been investigated. It is established that application of pulsed electrolysis mode allows to increase the working current density up to 9 A/dm2. A nanostructured nickel coating with a maximum size of crystallites of 200 nm is obtained. The results show that the use of pulsed electrolysis makes possible to reduce porosity of coating thicknesses up to 20 ?m.The process of electrodepositing of nickel from acetate-chloride electrolyte at low temperature in a pulsed mode has been investigated. It is established that application of pulsed electrolysis mode allows to increase the working current density up to 9 A/dm2. A nanostructured nickel coating with a maximum size of crystallites of 200 nm is obtained. The results show that the use of pulsed electrolysis makes possible to reduce porosity of coating thicknesses up to 20 ?m,Chemistry and Technology of Inorganic Materials and Substance

Cooperative localization-delocalization in the high Tc cuprates

The intrinsic metastable crystal structure of the cuprates results in local dynamical lattice instabilities, strongly coupled to the density fluctuations of the charge carriers. They acquire in this way simultaneously both, delocalized and localized features. It is responsible for a partial fractioning of the Fermi surface, i.e., the Fermi surface gets hidden in a region around the anti-nodal points, because of the opening of a pseudogap in the normal state, arising from a partial charge localization. The high energy localized single-particle features are a result of a segregation of the homogeneous crystal structure into checker-board local nano-size structures, which breaks the local translational and rotational symmetry. The pairing in such a system is dynamical rather than static, whereby charge carriers get momentarily trapped into pairs in a deformable dynamically fluctuating ligand environment. We conclude that the intrinsically heterogeneous structure of the cuprates must play an important role in this type of superconductivity.Comment: 14 pages, 8 figures, Proceedings of the "International Conference on Condensed Matter Theories", Quito, 2009 Int. J. Mod. Phys. B 2010 (Accepted

Superconductivity in charge Kondo systems

We present a theory of superconductivity in charge Kondo systems, materials with resonant quantum valence fluctuations, in the regime where the transition temperature is comparable to the charge Kondo resonance. We find superconductivity induced by charge Kondo impurities, study how pairing of a superconducting host is enhanced due to charge Kondo centers and investigate the interplay between Kondo-scattering and inter-impurity Josephson coupling. We discuss the implications of our theory for Tl-doped PbTe, which has recently been identified as a candidate charge Kondo system.Comment: 4 pages, 4 figures; revised version; detailed discussion on the physics of Tl-doped PbTe adde

Charge Kondo anomalies in PbTe doped with Tl impurities

We investigate the properties of PbTe doped with a small concentration $x$ of Tl impurities acting as acceptors and described by Anderson impurities with negative onsite correlation energy. We use the numerical renormalization group method to show that the resulting charge Kondo effect naturally accounts for the unusual low temperature and doping dependence of normal state properties, including the self-compensation effect in the carrier density and the non-magnetic Kondo anomaly in the resistivity. These are found to be in good qualitative agreement with experiment. Our results for the Tl s-electron spectral function provide a new interpretation of point contact data.Comment: 5 pages, 3 figures; published versio

Sedimentation of Ultradispersed Diamonds in the Citrate Copper-Plating Electrolyte

Abstract—The aggregation and sedimentation of ultradispersed diamonds (UDDs) in a citrate copper-plating electrolyte (CCPE) used to fabricate composite electrochemical coatings are investigated. The sedimentation and aggregation stability is investigated in order to select the UDD concentration in the CCPE. This is necessary to fabricate composite copper coatings with improved operational characteristics (increased hardness, wear resistance, and corrosion resistance), as well as impart them new properties (antifriction and catalytic). The UDD content in the electrolyte varies in limits from 0.2 to 2.0 g/L. The size distribution of the UDD particles in the electrolyte immediately after the suspension preparation and after the 10-day holding is determined using a Malvern Mastersizer 2000 laser diffraction analyzer. The aggregation and sedimentation stability of the UDD suspension in the CCPE is investigated by the gravimetric method with the continuous weighing of a quartz small cap immersed into this suspension. The quartz cap is associated with a Sartorius R200D analytical balance with the help of a quartz wire. The experimentally determined time dependence of the weight of settling UDD particles is Q = f(t). The relative size distribution of the particles is determined from this dependence. It is established that the sedimentation stability is substantially affected by the aggregation of the particles, the intensity of which increases with an increase in the UDD concentration. The results satisfying the requirements on the aggregation and sedimentation stability are found for the UDD suspension in the CCPE with a concentration of 1.0 g/L. In this case, the high content of the dispersed phase is combined with aggregation and sedimentation stability, which makes it possible to fabricate copper composite coatings with improved operational properties. © 2019, Allerton Press, Inc

Optimization of PET ion-track membranes parameters

Nowadays polymer ion-track membranes are used for a wide range of practical applications, which include various levels of filtration (micro-, ultra-, nanofiltration and osmosis), the creation of flexible electronic circuits and sensors based on polymer substrate, and using as templates for shape-controlled nanostructures synthesis. New applications demand clear understanding of the processes that occur during track membranes formation. For high-precision control of the end-product parameters, it is necessary to establish the correlation between etching conditions and track membranes characteristics (pores dimensions, porosity and membranes thicknesses). For this purpose, in the paper it is considered the technique of membranes formation with 10 nm - 10 μm cylindrical pores and correlation between their parameters and processing modes is studied. © 2019 Elsevier Ltd

Влияние цитратного электролита меднения, его компонентов и добавок ультрадисперсных алмазов на поверхностные свойства стали

The state of the steel substrate (steel 3) was studied before the application of composite copper coatings from citrate copper-plating electrolyte. The properties of steel base in the investigated copper-plating electrolyte with the addition of ultradispersed diamonds (UDD) have been studied. A component-by-component analysis of the citrate copper-plating electrolyte was carried out, and the effect of each component on the properties of the steel electrode was evaluated. The possibility of using the considered electrolyte for coating directly on steel is shown, which significantly distinguishes it from currently used ethylenediamine, pyrophosphate, acid and other electrolytes. Electrochemical impedance spectroscopy and cathodic polarization were used as research methods. It was found that the lowest resistance of the steel surface (about 15 Ω) corresponded to the sample immersed in citrate copper-plating electrolyte with the addition of 1.0 g/l of UDD. Diffusion current density for suspensions with 1.0 g/l UDD in citrate copper-plating electrolyte was 2.6 A/dm2. Ultradispersed diamonds in citrate copper-plating electrolyte shielded the surface of the steel sample, while reducing the total resistance of the passive layer of steel 3. Equivalent electrical circuits of the surface of steel samples immersed in citrate copper-plating electrolyte and its components are also presented.  Проведены исследования состояния стальной подложки (Ст 3) перед нанесением композиционных медных покрытий из цитратного электролита меднения. Изучены свойства стальной основы в исследуемом электролите меднения с добавкой ультрадисперсных алмазов (УДА). Проведен покомпонентный анализ цитратного электролита меднения и оценено влияние каждого компонента на свойства стального электрода. Показана возможность применения рассматриваемого электролита для нанесения покрытий непосредственно на сталь, что значительно отличает его от используемых в настоящее время этилендиаминовых, пирофосфатных, кислотных и других электролитов. В качестве методов исследования применяли электрохимическую импедансную спектроскопию и катодную поляризацию. Установлено, что наименьшее сопротивление поверхности стали (около 15 Ом) отвечало образцу, погруженному в цитратный электролит меднения с добавлением 1,0 г/л УДА. Диффузионная плотность тока для суспензий с 1,0 г/л УДА в цитратном электролите меднения составила 2,6 А/дм2. Ультрадисперсные алмазы в цитратном электролите меднения экранировали поверхность стального образца, при этом снижая общее сопротивление пассивного слоя стали Ст 3. Также представлены эквивалентные электрические схемы поверхности стальных образцов, погруженных в цитратный электролит меднения и составляющие его компоненты.