Surface Layer Of Copper Research Articles

Effects of Laser Irradiation in High-Speed Gas Flow for Surface Treatments of Copper

In this study, the impacts of laser irradiation on the surface morphology and hardness of copper (Cu) are investigated under various environments, including air, vacuum, and high-pressure gas flow through a supersonic nozzle. After irradiating Cu targets with laser pulses with energy of 30, 60, and 90 mJ/pulse, the surface structures of the targets are analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The SEM analysis reveals diverse surface morphologies, including micro-cones, cavities, droplets, ripples, and island-like structures, depending on laser energy and environments. The XRD analysis provides insights into the structural changes induced by laser irradiation. The results indicate a significant enhancement in microhardness by a factor of 2.77, which is attributed to the surface and structural modifications incurred under various environments. In addition, the XRD analysis reveals a shift in the residual stress in the surface layers of copper from tensile before laser irradiation to compressive afterwards, highlighting the effectiveness of laser surface treatment in inducing favorable mechanical properties.

Regularities of Structure Formation, Morphology and Properties of Pure Copper Surface Layers Under Intensive Thermal Impact During Plasma Cutting

Regularities of Structure Formation, Morphology and Properties of Pure Copper Surface Layers Under Intensive Thermal Impact During Plasma Cutting

Теоретичне дослідження температурних полів міді при формуванні наноструктурних шарів у плазмовому середовищі

The subject of study is the mathematical model for thermal processes during the formation of nanostructures in a plasma medium. In previous studies, it was shown that for the appearance of nanostructures, it is necessary that there be a certain temperature, its rate of increase, and thermal stresses. The required depth of the near-surface layer of the processed material, which is most favorable for the formation of nanostructures, is determined where the highest temperature stress gradients occur. The current work determines the technological parameters for obtaining nanostructures during ion-plasma treatment of the copper surface, as an example. The task of this work, by changing the energy of the ions, is to choose the location of the fields along the depth of the material to generate the necessary high temperature gradients in the given planes of the material. Thus, significant thermal stresses, and hence nanostructures, can be created in a large volume of material. The method used is analytical. In our work, a mathematical model was developed to describe the generation of temperature fields during ion-plasma surface treatment and tested on the process of copper treatment with oxygen ions. In this model, the joint actions of plasma flows and flows of charged particles with materials are realized through thermophysical, thermomechanical, thermal fatigue, diffusion, thermochemical, plasma-chemical processes and collisions. Therefore, the developed model will contribute to a more accurate determination of technological parameters for the formation of conditions conducive to the stable growth of nanostructures in the surface layers of processed materials. Because of numerous calculations, the dependence of the temperature of the surface layer of copper on the energy of oxygen ions was determined. The temperature fields in the zone of action of ions for three levels of the plane of the surface layer are calculated depending on the depth of penetration of ions for different times of interaction and at different current densities from 2.7∙106 to 2.1∙108 A/m2. Studies have shown that the maximum surface temperature is reached at the end of the thermal action of the ion. Conclusions. The obtained values of thermal stresses showed the possibility of formation of nanostructures in the surface layer of copper under the action of oxygen ions at a depth of x=0.5λm at a current density of 2.7∙106 A/m2. For the x=0.5λm plane at a current density of 3∙107 A/m2, where the largest temperature gradients were found, the maximum temperature stresses were calculated, amounting to 5∙108 N/m, which confirms the creation of conditions for obtaining nanostructures. But at 2.1∙108 A/m2, the total temperature rises, and the temperature gradients decrease, which decreases temperature stresses and failure to meet the conditions for obtaining nanostructures. The results obtained can be used to develop a technology for the production of nanostructures in a plasma environment, for example, on copper by ion-plasma treatment in an oxygen environment.in a plasma environment, for example, on copper by ion-plasma treatment in an oxygen environment.

TiO2–CU Thin Film Material for Optical Hydrogen Gas Sensor Applications

Purpose: Several scientific researches are underway to investigate the possibility of using various green energies. Hydrogen gas is a candidate of such research, since its use as a fuel in automobiles releases pure water, a recyclable biproduct. But, the leakages of the gas are detrimental to its application due to its low auto ignition energy of 20 μj, wider air flame limit of 4-75 % and high flame velocity of 3.46 ms-1. This study involved fabrication of an optical gas sensor for sensing the leakage levels of hydrogen gas to a surrounding.
 Methodology: Titanium dioxide thin films of thicknesses 47.7, 56.2, 82.3, 100.4 and 120.5 nm were deposited on both microscope and FTO glass slides using DC magnetron sputtering technique and characterized as primate and annealed at 400 and 500oC. Copper (Cu) catalytic layers of 5.6, 10.2, 17.3 and 21.0 nm were deposited using EDWARDS AUTO 306 Magnetron sputtering system on an optimized 100.4 nm TiO2 sample, annealed at 400oC. Optical properties were deduced from transmittance and absorbance spectra measured using 1800 Shimadzu spectrophotometer in the optimum range of 280-800 nm through simulation. The optical behavior of the films was generated using SCOUT software and analyzed using ORIGIN 9.1 64-bit software.
 Results: The energy band gap decreased with material thickness from 4.2±0.05 eV for 47.7 nm film to 3.9±0.05 eV for 100.4 nm films. 120.5 nm films showed higher energy gap of 4.0±0.05 eV. Transmittance decreased with increase in thickness probably due to agglomeration of film particles. The energy gap of the 100.4 nm, TiO2 thin films annealed at 400oC was 3.9±0.05 eV. This is a material quality of the anatase phase. The copper surface layer increased absorption in the higher wavelength region. The energy band gaps were reduced from 3.9 to 3.8±0.05 eV with increased coverage. Self-limiting at 17.3 nm copper overlayer realized increased energy gap to 4.1±0.05 eV. A lower energy band gap range of 3.9-3.8±0.05 eV was realized when FTO substrates were used. The transmittance decreased with increased H2 gas concentration. The optical energy gap reduced from 4.1±0.05 eV in 0 ccm to 3.9±0.05 eV in 50 ccm of hydrogen gas concentration. The sensitivity increased from 0.3 % in 0ccm to 3.9 % in 50 ccm hydrogen gas concentration. An average sensitivity of 2.0 % was realized for films fabricated on FTO substrate. This is higher than 1.7 % reported earlier. The material gas sensing potential was done at room temperature. The fabricated sensor material showed higher sensitivity and lower temperature operation and is furthermore, expected to be cheaper and safer
 Unique Contribution to Theory, Policy and Practices: Though, in order to realize a more portable stand-alone gas sensor, an investigation on an ideal photon type source that incorporates the material is recommended. Further, extension of this study on structure and morphology of the film is essential to understand its sensing behavior.

Investigation of the Implementation of Laser Surface Alloying of Cu with Cr-WC.

This paper presents research on the microstructure and mechanical properties of an alloyed composite copper (Cu) surface layer, reinforced with a mixture of chromium–tungsten carbide (Cr–WC) powders. Copper alloying was performed using a high-power diode laser (HPDL). In the tests, three mixtures of powders with different percentage contents (75%Cr 25%WC, 50%Cr 50%WC, 25%Cr 75%WC) were injected into the melting pool during the laser surface alloying process. Microstructural evolution and the properties of the surface layer of copper after laser alloying were investigated. Structural investigations were performed using light microscopy, scanning and transmission electron microscopy (SEM, TEM) and X-ray diffraction (XRD). Microhardness and wear resistance of the modified surface layer were examined as well. After laser treatment the applied powders appear as uniformly distributed particles in the alloyed zone as well as nanoscale precipitates in the Cu matrix. Several types of precipitate characteristics, in terms of morphology, structure and chemical composition, were observed. Laser alloying of the surface layer modified the microstructure, which resulted in an increase in the hardness of the surface layers compared to the base material.

STUDY OF CORROSION BEHAVIOR OF 1C45 STEEL COATED WITH ALUMINUM AND COPPER

In the context of the judicious use of natural resources, the obtaining of the mechanical, electrical or protection or resistance characteristics necessary for their use and the economic optimization, it is necessary to study new methods. The method of deposition of surface layers with the help of pulsed lasers offers new directions of development. The deposition of aluminum or copper on cheap basic materials is economically justified but it is necessary to study their corrosion behavior. The study was performed on a 1C45 base material and on samples of the same material with a surface layer of aluminum and copper. The immersion of the samples for a period of 195 days provided measurable results which led to conclusions on the behavior of these materials in the marine environment. Contrary to expectations, the corrosion was manifested in copper, and aluminum showed a high protection capacity. However, the effects of the environment on the strength of the treated surface must also be taken into account during use.

Морфологічна структура гальваноосаджених в неоднорідних режимах прошарків міді

The microstructure of copper layers obtained by electrodeposition in stationary, pulsed and stochastic modes on copper substrates was studied by means of scanning electron microscopy. It was found that the shape of the applied grains differs significantly in the case of pulsed and stationary application modes. The technology of production of electrodeposited layers in stationary, pulse and stochastic modes of copper on copper substrates is worked out in the work. The developed automated software and hardware complex was used to control the electrodeposition process. The effect of electrodeposition in different modes on the structure of copper surface layers was investigated using scanning electron microscopy. Qualitative examination of SEM images of electrodeposited surfaces showed that in the case of stochastic and stationary modes of electrodeposition, a coating with a larger grain size is formed than in the case of pulsed deposition. It should also be noted that the shape of the applied grains is significantly different in the case of pulsed and stationary application modes. In the process of electrodeposition in the stationary mode, sediment is formed in the form of conglomerates of grains of different sizes, while in the pulse mode, a uniform grain structure is formed. The shape of the grains formed in the process of electrodeposition in the stochastic mode is different in that the coating has areas with evenly distributed grains and conglomerates of grains. The average grain size in the electrodeposited layers obtained using the pulse mode increases with increasing pulse period. It was also found that the average grain size is smaller in the case of the stochastic application method than in the case of the pulsed method, for the same average current density

Influence of the Structural-Phase State of a Copper Substrate upon Modification with Titanium Ions on the Thermal Cyclic Resistance of a Coating Based on Zr-Y-O

The results of investigation of the surface of a copper substrate modified with titanium ions are presented. The phase composition, the structure, and the morphology of the surface of the copper alloy modified by titanium ions have been investigated by X-ray, SEM, and TEM. It has been established that there are the intermetallic phases of the Cu-Ti equilibrium diagram in the surface layer during the treatment of copper by the titanium ions. A multilevel micro- and nanoporous structure is formed in the modified layer. It has been established that the structure-phase state and morphology of the surface layers of copper directly effects on the thermocycler resistance and adhesion of the Zr-Y-O coating. The thermocyclic resistance of the Zr-Y-O coating increases by an order of magnitude, the adhesion to the substrate is 2 times if the substrate surface is treated with titanium ions for 6 min.

Effects of ultrasonic shot peening process parameters on nanocrystalline and mechanical properties of pure copper surface

In this paper, the effects of ultrasonic shot peening (USP) and various process parameters on grain refinement, surface hardness, and tensile properties of pure copper surface layers were studied. USP was employed to obtain a grain-refined strengthening layer on the surface of pure copper, and the grains size of the strengthening layer were less than 10 nm, and the thickness of the grain-refined strengthening layer can reach 338 μm. The influence law of process parameters on microstructure was acquired. The hardness of surface increased by 233.5%, from 42.6 HV to 142.1 HV, the influence law of process parameters on surface hardness was grained. Obviously, it was found that the tensile strength was increased from 263 MPa to 308 MPa, which was 17.1% higher than that of the original pure copper specimens by using USP stretch on both sides of the tensile specimens. The influence law of process parameters on tensile strength was obtained. When the peening duration was 120 s, the optimal tensile strength can be obtained, sufficient plasticity can be retained meanwhile.

Damage and Deformation Effects in the Surface Layers of Copper and Copper–Gallium Alloy under Pulsed Irradiation in a Plasma Focus Unit

Damage and Deformation Effects in the Surface Layers of Copper and Copper–Gallium Alloy under Pulsed Irradiation in a Plasma Focus Unit

Microstructure and Properties of the Copper Alloyed with Ag and Ti Powders Using Fiber Laser.

The scope of the work covers the development of the relationship between the chemical composition of surface-modified copper and the diffusion of alloy elements as well as the microstructure and mechanical properties. This article presents the impact of laser alloying with titanium and silver powders on the microstructure and mechanical properties of copper. In order to investigate the phenomena occurring during the laser alloying process, microstructural studies were performed using scanning electron microscopy (SEM), optical microscopy, and energy dispersive x-ray spectroscopic (EDS) analysis of the chemical composition in micro-areas. In addition, to test the properties of the resulting alloy, abrasion resistance, hardness measurement at low loading force, and conductivity measurements were performed. As a result of alloying with Ag and Ti powders, three distinct zones were indeed recognized: re-melting zone (RZ), diffusion zone (DZ), and heat affected zone (HAZ). The surface modification that results from laser alloying increases the hardness as well as the abrasion resistance of the material. Overall, it was found that laser alloying with Ti powder increased the strength of the copper surface layer due to the formation of intermetallic phases (Cu3Ti2). It was also found that laser alloying with Ag powder changed the mechanical properties of the surface layer due to the solid solution strengthening.

Periodic Open Cellular Raney‐Copper Catalysts Fabricated via Selective Electron Beam Melting

Herein, the possibility of generating Raney‐Copper catalysts with high geometric complexity is demonstrated. For this, periodic open cellular structures (POCS) composed of a highly brittle Al–Cu alloy containing 29.4 at% copper are fabricated by selective electron beam melting (SEBM) for application in chemical reaction engineering. After selective leaching of aluminum in an NaOH solution, the POCS show a core–shell structure with a nanoporous copper surface layer and a solid core. The fabrication and dealloying processes as well as the microstructure are studied. Moreover, the SEBM‐processed Raney‐type copper catalysts show a high catalytic activity in methanol synthesis.

О механизме понижения адгезионного износа медной пары трения в инертной атмосфере методом имплантации ионов азота

The mechanisms of increasing the resistance of copper samples treated with a high-energy beam of nitrogen ions to adhesive wear during friction together with a copper counterbody in an argon atmosphere are studied. It was shown that the increase in wear resistance is complex and is associated with the action of mechanisms such as solid-solution hardening, grinding of copper grains, precipitation of the finely dispersed CuN3 phase, increase in the density of dislocations and internal stresses of the second kind in the surface layer . The maximum increase in wear resistance and microhardness (~ 4 and ~ 2.6 times, respectively, compared with the original copper) is observed about ion fluence of ~ 9×1017 ion/cm2. A further increase in fluencies leads to a decrease in wear resistance and microhardness due to the enlargement of the pores formed in the surface layer of copper as a result of implantation of nitrogen ions.

The influence of the crystallographic orientation of the copper catalytic substrate crystallites on the mechanical transfer of graphene

In this paper, we studied the dependence of adhesion between CVD graphene and copper substrate on different crystallographic orientations of copper grains. It was determined that the adhesion between graphene and copper surface increases for grains with low-index crystallographic orientations. This phenomenon is explained by the surface microrelief formation during the crystallization of the copper surface layer, molten at the stage of annealing and graphene growth. During the liquid layer cooling and crystallizing, partial exfoliation of graphene from the copper surface occurs. Graphene exfoliation leads to an increase in defectiveness of the graphene layer. However, graphene peeling from copper grains with high-index crystallographic orientations can significantly reduce damage to graphene during the transfer process to a polymer surface.

Formation of Oxide Layers on the Surface of Copper and its Alloys Modified by a High-Power Ion Beam

The change in the phase and elemental composition of the surface layers of copper and its alloys, brasses LS59-1, L63, and bronze BrAZh9-4, preliminarily irradiated with a high-power ion beam, after oxidation in air at 400°C is studied. It is shown that depletion of the brass surface by zinc under irradiation with a high-power ion beam does not lead to a noticeable increase in the oxidation of brass during thermal annealing in air due to the diffusion of Zn from the volume to the surface. The annealing of high-power ion-beam-irradiated copper under similar conditions does not change the composition of oxidation products, and the phase ratio is determined by the duration of annealing. For BrAZh9-4 bronze irradiated by a high-power ion beam, enrichment of the surface with copper leads to the intensification of oxidative processes. Possible mechanisms for the observed changes in copper and its alloys are considered.

Laser-induced surface activation and electroless metallization of polyurethane coating containing copper(II) L-tyrosine

In this work copper(II) L-tyrosine was firstly reported as effective precursors for laser-induced selective activation and electroless metallization of polyurethane coating. The compound in the form of powder was mixed at amount of 20 wt% with polyurethane resin to form the coating on the polycarbonate substrate. The coating was irradiated with excimer ArF laser which generated UV radiation of about 193 nm wavelength. Various laser fluences and number of laser pulses were applied to determine physicochemical changes of the coating surface layer. After irradiation coatings were electrolessly metallized. It was found that laser irradiation resulted in formation of cone-like surface geometrical structure. The high of the cones was dependent on the dose of irradiation, whereas their tops were covered with copper. The external surface layer of precipitated copper was oxidized. This, however, did not affect the possibility of the surface to be electrolessly metalized. The irradiated coatings was effectively metallized and thus deposited copper layer characterized with high adhesion strength.

Synthesis and Electrophoretic Concentration of Ag–Cu Nanoparticles of the Core–Shell Type in an AOT Microemulsion in n-Decane

Stable organosols of silver and copper bimetallic nanoparticles were obtained in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles in the emulsion and microemulsion variants and characterized by physicochemical methods. The adsorption layer of nanoparticles in AOT solutions in n-decane was found to have a complex multilayer structure; an increase in the mole fraction of copper led to an increase in the hydrodynamic diameter of nanoparticles from 14 to 23 nm and a decrease in the electrokinetic potential from 18 to 7 mV. The surface charge of nanoparticles can be increased by diluting the sols with chloroform, and electrophoretic concentration can be performed with concentration factors of 30–50 depending on the composition. Based on the XRD data for solid composites in AOT, it was concluded that the structure of nanoparticles is most likely of the “core–shell” type with a silver metal core and a surface layer of X-ray amorphous copper.

Study of laser cutting of copper and copper alloys

The processes of interaction of laser radiation with a surface layer of copper under laser irradiation, as well as the main factors affecting the absorption capacity of copper during surface treatment with a laser beam, are considered.

Phase composition and mechanical properties of Cu–Ti alloys synthesized in the surface layer of copper by plasma impact on the Ti/Cu system

Cu–Ti alloys synthesized in the surface layer of copper by means of preliminary Ti coating deposition and subsequent treatment by compression plasma flows have been investigated in this work. X-ray diffraction, scanning electron microscopy, energy-dispersion X-ray microanalysis, Auger electron spectroscopy, Vickers microhardness measurements and tribological tests were used for Cu–Ti alloys characterization. The findings showed that the increase of the energy absorbed by the surface layer during plasma treatment from 57 to 74 J/cm2 per pulse resulted in the growth of the alloyed surface layer thickness from 15 to 19 μm, more homogeneous distribution of Ti in the alloyed layer and the decrease of Ti average concentration from 13.1 to 9.7 at.% in it. The supersaturated solid solution of titanium in copper was the main phase constituent of the alloyed layer after treatment at 74 J/cm2. The synthesized surface of the Cu–Ti alloy possessed enhanced strength and tribological properties.

ВПЛИВ ОБРОБКИ ПОВЕРХНІ ЗА ТЕХНОЛОГІЄЮ SMAT НА МЕХАНІЧНІ ВЛАСТИВОСТІ ПОВЕРХНЕВИХ ШАРІВ МІДІ

Nanostructured materials are characterized by a specific structure compared to polycrystalline materials. Nanostructured materials are created in way of strong deformations. SMAT (surface mechanical attrition treatment) technology consists in the treatment of the surface of a material with steel balls accelerated by a generator of high-frequency oscillations (about 20 kHz). This changes the mechanical properties of the materials. The size of graines in such materials decreases in the direction from the volume of the crystal to the surface. As a result of SMAT processing, graines become nanosized near the surface of the samples. Such materials have a large number of subsurface defects formed as a result of intense plastic deformation, which determines their thermodynamic and diffusion characteristics. The purpose of this work is to develop the device of high-frequency (20 kHz) surface machining by attrition using SMAT technology and its application to the treatment of surfaces, both polished copper plates and electrodeposited in a stationary mode to copper plates with copper layers. In this work, the device is developed and the technology of high-frequency mechanical surface treatment of SMAT is described. The design features and technical characteristics of the experimental plant are presented. In the work, the surfaces of copper substrates were processed by different methods: grinding and polishing of copper polycrystalline plates, electrolytic deposition of copper surface layers on these plates, processing of prototypes by SMAT technology. The microhardness was measured in the surface layers of the linings made using different technologies and their comparative characteristics were performed. It is established that high-frequency surface treatment of plates by SMAT technology increases the microhardness of the surface of copper plates of different types, both polished and with electrolytically deposited copper. The results of the research showed that the sample, which was subjected to electrolytic deposition of copper, has a high defectiveness of the surface and reduced microhardness. After processing such a sample using SMAT technology, it is obtained a hardness higher than the reference polycrystalline copper sample.