Copper Components Research Articles

AACVD processed binary amorphous NiVOx coatings on Cu substrates: Surface characterization and corrosion resistant performance in saline medium

Cu corrosion is a major issue affecting the structural integrity and efficient performance of Cu components in several applications. In recent years, the utilization of metal oxide thin films on copper components is fascinated cumulative consideration particularly in the field of energy and electronic related materials like micro-electromechanical, energy storage and memory device components. Herein, we report the use of a rapid and reproducible approach of aerosol-assisted (AA) CVD for depositing bimetallic nickel-vanadium oxide (NiVOx) thin films directly on Cu substrates. NiVOx coatings were produced by increasing the deposition period from 1 to 3 h at a fixed temperature of 480 °C and were structurally characterized through XRD analysis, XPS, SEM/EDS, and AFM. Detailed characterization was performed for the as-prepared amorphous NiVOx binary films having a compact and dense microstructure at an elemental stoichiometry of Ni/V in 1:1 ratio. Corrosion analyses, including electrochemical frequency modulation, Tafel plot analysis, and dynamic electrochemical impedance spectroscopy, were performed to assess the corrosion resistance performance of binary films on Cu substrates in saline medium. Moreover, scanning electrochemical microscopy was accomplished to estimate the electrochemical stability of the as-processed binary films during the 24-h immersion period in NaCl.

Joining and cycling performance of ultra-thick tungsten coatings on patterned steel substrates for fusion armour applications

Tungsten is the leading candidate to provide a critical protective coating for copper and steel-based plasma facing components in nuclear reactors. However, fabrication of thick tungsten coatings on copper or steel is challenged by the significant difference in the melting points and the thermal expansion coefficients of the materials, which leads to severe thermal expansion mismatch strains during manufacture and in service. This challenge is investigated using a new processing approach — field assisted sintering of tungsten nanopowders directly onto pre-sculptured steel component surfaces to induce controlled, vertical segmentation cracks that provide strain relief. Tungsten coatings up to 2 mm thick were fabricated with uniform density and with a microstructure consisting of ultrafine grains of ∼200 nm. The coatings showed outstanding thermal cycling durability and survived for at least 50 cycles under pulsed temperature cycles between 300 to 800 °C. Microscopy and in situ thermal imaging revealed that a previously unachievable thermal expansion mismatch strain tolerance was provided by a combination of enhanced tungsten coating adhesion and deliberate coating segmentation by vertical cracking. The approach should be readily adaptable to other dissimilar materials systems to facilitate a range of durable, ultra-thick low ductility coatings on metallic substrates.

A significant toughness enhancement, and microstructural evolution of an electric resistance welded (ERW) microalloyed steel

In this investigation, microstructural evolution and mechanical properties of an X52 microalloyed steel processed by a full scale industrial electric resistance welding (ERW) equipment was studied. The need for adequate level of mechanical properties, in particular toughness, in the welded pipes is discussed due to its industrial prominence. Optical microscopy (OM) and scanning electron microscopy (SEM) were used for microstructural evolution and fractography analysis. Results showed that employing a special annealing treatment of the welded pipe could enhance the mechanical properties and alleviate low toughness problem. Results also showed a significant variation in the microstructure of the pipe as a result of welding and its subsequent heat treatment processes. Electron backscatter diffraction (EBSD) results for the initial plate and the ERW processed cases showed a significant grain size refinement for the case of as weld and after the two-stage heat treatment. A fully random texture component was observed in {111} pole figure of the initial plate. A textured structure, with the components of Copper, Brass, S and Cube, was seen in the as weld condition. These texture characteristics remained in the system, though with lower intensity, after the normalizing stage heat treatment. Hence for its unpredictable toughness behavior. A completely weakened undesirable texture components was detected after the second stage of heat treatment together with smaller amount of second phase particles and smaller grain sizes. Finally, it was concluded that a proper mechanical properties combinations, particularly toughness value, could be attained as a result of this microstructural evolution.

CuO Quantum Dots Supported by SrTiO3 Perovskite Using the Flame Spray Pyrolysis Method: Enhanced Activity and Excellent Thermal Resistance for Catalytic Combustion of CO and CH4.

As a non-noble-metal catalyst, CuO has great potential in the catalytic combustion of CO and CH4. In this work, the influence of loading active copper components onto perovskites and essential operating parameters in flame aerosol synthesis has been experimentally and theoretically investigated to optimize the catalytic efficiency for the complete oxidation of lean CO and CH4. Herein, the CuO-SrTiO3 nanocatalysts are one-step-synthesized by flame spray pyrolysis with varied copper loadings and precursor feeding rates. The sample under the precursor flow rate of 3 mL/min and the CuO loading of 15 mol % demonstrates optimal catalytic performance. It is primarily attributed to the excellent low-temperature reducibility and improved activity of copper species originated by CuO quantum dots and metal-support interaction. Besides, SrTiO3 perovskite as a support can effectively inhibit the sintering of CuO quantum dots at high temperatures, which is responsible for the excellent sintering and water deactivation resistances.

Alternative manufacturing process of 3-dimensional interconnect device using thermoforming process

In early stages, the electronic circuits have been developed on simple printed circuit boards with multiple copper patterns and components interconnected by lead – free solder. Later on, these are converted to flexible circuits and molded interconnect devices (MID) because of high demand of complex circuit design. Laser machine is used to manufacture 3D MID circuits. An alternative manufacturing process has been introduced in this research. The method is to design functional circuits by using stretchable ink printed on a 2D substrate. Polycarbonate is selected as a substrate on the basis of its glass transition temperature (Tg). Thermoforming process is then applied to transfer 2D substrate into 3D shape. Reverse engineering technique is used to fabricate the mold through several steps. First, the dimensions of rear lighting is calculated by coordinate measuring machine (CMM), transferred to 3D drawing using SolidWorks. And finally the mold is produced using computer numerical control (CNC) machine. Screen printing technique is opted to print ink on a flat thermoplastic Polycarbonate substrate. The highly conductive circuit will be generated after heating printed ink in oven for about 30 min at 120 °C. The circuit with substrate is further transferred into 3D shape using the thermoforming process. All the light emitted diodes (LEDs) are then fixed on a circuit by dispensing conductive adhesive and cured again in an oven for 10 min at 120 °C, so strong bonds are formed at the joints. The reliability of the circuit is assessed by characterizing mechanical and electrical properties. The designed circuit is then compared with the existing design using scanning electron microscopy (SEM), universal testing, two-point probes multi-meter and spectrometer. The electrical performance of new circuit design shows promising results in terms of power consumption and luminous flux of LEDs and there is no major difference found between them. As a result, the new manufacturing process of printed circuit offers encouraging method in manufacturing the automotive lighting product.

How to Seal Hydraulic Fracturing Boreholes in the Large-Size HDR Rocks under HTHP Conditions

Abstract The hydraulic fracturing (HF) is a key technique to enhance the permeability and heat production of hot-dry-rock (HDR) geothermal reservoirs. Normally, laboratory HF tests should be preconducted to understand the HF characteristics of HDR samples. However, in the laboratory test, sealing failure between boreholes and injection pipes always limits the experimental efficiency and data accuracy, especially for the HF tests under high-temperature and high-pressure (HTHP) conditions. Traditional sealing methods, such as rubber and cement sealing, are easy to be failed because of their poor load and/or thermal bear performance under HTHP conditions. Therefore, in this study, we proposed a novel HTHP seal by using wedge-buckled copper components and steel rings. The sealing efficiency was verified by successfully conducting the HF tests of HDR rocks with a dimension of φ200×400 mm under various high temperatures ranging from 100°C to 400°C. As expected, the unfavorable factors such as HTHP and high injection pressure could be turned into favorable ones during the introduced seal method. By this investigation, we expect to provide some sealing solutions for researchers when conducting HF tests under HTHP environments.

Mechanisms of the copper third body as an interfacial media on copper matrix friction materials with different compositions

PurposeThis paper aims to reveal the effects of the copper third body on different copper matrix friction materials with a novel experimental way called “exogenous powder.”Design/methodology/approachAn accurate adding device of exogenous copper powder was designed to control the flow rate. The tribological properties with and without exogenous copper powder were investigated by a pin-on-disc tribometer during dry sliding.FindingsExperimental results indicate that the Cu addition tends to increase the friction coefficient. For pure Cu material, the exogenous copper third body exhibits poor fluidity on the friction surface, causing serious adhesive wear on the friction interface. For the Cu 90% + 10% Gr material, the plasticity of exogenous copper powder may intensify the deformation of the third body of the surface, presenting layered accumulation distribution. For the pure Cu and Cu 95% + 5% SiO2 material, the Cu addition makes the composition and density of the third body uneven in the direction of depth.Originality/valueThe role of the copper component on different materials is revealed from a new perspective, and the relationship between the third body structure and the friction properties is explored.

Micromachining of Al2O3 thin films via laser drilling and plasma etching for interfacing copper

Due to their chemical inertness and high-temperature stability, atomic layer deposited (ALD) oxide thin films emerged as an attractive copper encapsulation, passivation, and protection technology. Several types of high-k dielectrics, which are robust insulators, can be deposited by ALD. Hence, a successful encapsulation process electrically isolates the underlying film and active elements from the environment, as a side effect. To electrically interface such encapsulated structures, a reliable method that selectively and locally removes the encapsulation film is required. Here, the study focused on the effectiveness of laser drilling and plasma etching of Al2O3 thin films deposited via ALD, both in silico and experimentally. Results have shown that the CO2 laser drilling alone is insufficient to remove the Al2O3 thin films. However, plasma etching successfully removes the encapsulation layer, providing a clean interface for conductive vias. Results are essential for future ALD layer applications in the encapsulation of copper and other critical components in semiconductor fabrication processes.

Fabrication and Characterization of Ni60A Alloy Coating on Copper Pipe by Plasma Cladding with Induction Heating

Plasma cladding coupled induction heating was developed and successfully used to fabricate Ni60A coating on the surface of copper pipe. By matching the swing arc with the rotating copper pipe, the cladding efficiency was as high as 32.72 mm2/s. From the head to the tail of the coating, the wear resistance changed from 4.5 to 1.8 times that of pure copper. During the cladding process with constant current, the surface temperature of the cladding zone and the bath depth gradually increased. The corresponding dilution ratio increased, accompanied by the widening of the interface transition zone and the growth of precipitated phases (CrB and Cr23C6). Due to the gradient change of composition, the coating can be regarded as an in situ synthesized gradient coating. The critical point of sudden change of temperature in cladding zone was 850 °C, at which point the wear mechanism changed from abrasive wear to adhesive wear. The proper surface temperature of cladding zone should be controlled within 600–850 °C, which can be achieved by matching the cladding current and induction heating power. Results indicated that plasma cladding coupled induction heating is a potentially effective method to prepare high-quality coating on the surface of a large-complex-curved copper component.

A texture study of nanostructured Al–Cu multi-layered composite manufactured via the accumulative roll bonding (ARB)

In this study, texture development during the accumulative roll bonding (ARB) of Al–Cu multilayered composite was investigated using X-ray diffraction. Microstructural investigations were also conducted using optical and transmission electron microscopy. The results of textural investigation of the rolled specimens indicated that a strong β-fiber was developed and dominated mainly by the Brass and Copper components in both the Al and Cu layers during the early stages of the ARB process. Moreover, the intensity of the most textural components in both of the metallic layers decreased in the last two ARB cycles. No component other than a weak Rotated Cube was found in the Al layer after the last ARB cycle. In the Cu layer, on the other hand, a Cube component, known as the "recrystallization texture ", was developed which was accompanied by a "rolling texture" represented by the β fiber. Furthermore, the increased misorientation between the grains at high ARB cycles confirmed the formation of high angle grain boundaries in both of the metallic layers. Microstructural investigations showed that the average grain size of the final specimens (after 7 ARB cycles) was less than 500 nm in both Al and Cu layers.

Aging behavior of Cu-rich precipitates in Fe-3% Si-Cu alloy

Fe-3%Si-Cu alloys with different Cu content were aging treated at 500 ∼ 800 °C. In order to study the dynamic behavior of the aging precipitations, the microstructure and the aging precipitation behavior of copper-rich phase in these alloys under different aging heat treatment were tested by OM, TEM technology and Vickers hardness. The results show that the amount of the copper-rich precipitates in the two alloys are gradually increase with the aging time going after aging treated at 600 °C. Within the 103 s aging time, the size of the copper-rich precipitates of the two samples is below 20 nm. When it reaches 105.5 s, the copper-rich precipitates have obvious cluster phenomenon and the size are not more than 100 nm. After being treated with different aging temperature, the hardness of Fe-3% Si-Cu alloys with different copper component increases first and then decreases with time going, with obvious aging hardening peaks. When the aging temperature is 500 °C and the aging time is 104.5 s, the hardness of the two alloys reaches the maximum and they are 264 HV and 238 HV, respectively. The precipitation kinetics curve of the copper-bearing Fe-3% Si-Cu alloy is in the shape of ‘C’, and there is a certain precipitation incubation period. When the aging temperature is 600 ∼ 650 °C, the precipitation incubation period is the shortest. The increase of the copper content in the alloy will shorten the incubation period of the precipitation kinetic curve, increase the precipitation tendency of copper and cause the curve shifted to the left obviously.

Photothermocatalytic Removal of CO and Formaldehyde with Excellent Water Vapor Stability over Dual‐Functional Copper Loading on TiO2 Synthesized via Flame Spray Pyrolysis

Photothermocatalytic (PTC) oxidation is a high‐efficient, low‐temperature, and green approach to eliminate the air pollutant, but its application is drastically restricted by lack of low‐cost, active, and superior water‐resistance catalysts. Herein, the influence of bifunctional copper components on TiO2 is experimentally and theoretically investigated to optimize PTC efficiency for the CO and HCHO oxidation via flame spray pyrolysis. Both the abundant lattice doping and highly dispersed nanocluster modification of hybrid CuO x remarkably enhance charge separation, maintain a dynamic Cu+/Cu2+ balance, and decrease oxygen vacancy formation energy. The satisfactory PTC CO and HCHO oxidation on the CuO x −TiO2 samples is mainly attributed to higher lattice oxygen activity and less reaction intermediates under irradiation. In addition, the essential synthesis parameters, such as the increasing precursor flux, are assessed to further enhance the PTC performance. Interestingly, photocatalysis effectively removes the surface H2O or hydroxyl group of catalysts, which is responsible for the excellent water vapor stability in the lean CO PTC oxidation.

Solvent-free partial oxidation of cyclohexane to KA oil over hydrotalcite-derived Cu-MgAlO mixed metal oxides

A highly efficient and stable hydrotalcite-derived Cu-MgAlO catalyst was developed for the partial oxidation of cyclohexane with molecular oxygen. The physical–chemical properties of Cu-MgAlO catalysts were studied, and the results indicated that the copper component had been successfully introduced into the hydrotalcite unit layer structure. The catalytic reaction results showed that copper as the active species could activate CH bond and effectively promote the decomposition of cyclohexyl hydroperoxide (CHHP) to the mixture of cyclohexanol and cyclohexanone (KA oil). 8.3% of cyclohexane conversion and 82.9% of selectivity for KA oil were obtained over 9%Cu-MgAlO catalyst at 150 °C with 0.6 MPa of oxygen pressure for 2 h. Especially, its catalytic performance was still stable after five runs.

Copper additive manufacturing using MIM feedstock: adjustment of printing, debinding, and sintering parameters for processing dense and defectless parts

In the present study, an additive manufacturing process of copper using extrusion 3D printing, solvent and thermal debinding, and sintering was explored. Extrusion 3D printing of metal injection moulding (MIM) feedstock was used to fabricate green body samples. The printing process was performed with optimized parameters to achieve high green density and low surface roughness. To remove water-soluble polymer, the green body was immersed in water for solvent debinding. The interconnected voids formed during solvent debinding were favorable for removing the backbone polymer from the brown body during thermal debinding. Thermal debinding was performed up to 500 °C, and ~ 6.5% total weight loss of the green sample was estimated. Finally, sintering of the thermally debinded samples was performed at 950, 1000, 1030, and 1050°C. The highest sintering temperature provided the highest relative density (94.5%) and isotropic shrinkage. Micro-computed tomography (μCT) examination was performed on green samples and sintered samples, and qualitative and quantitative analysis of the porosity confirmed the benefits of optimized printing conditions for the final microstructure. This work opens up the opportunity for 3D printing and sintering to produce pure copper components with complicated shapes and high density, utilizing raw MIM feedstock as the starting material.

Volatile metal emissions from volcanic degassing and lava\u2013seawater interactions at K\u012blauea Volcano, Hawai\u2019i

Volcanoes represent one of the largest natural sources of metals to the Earth’s surface. Emissions of these metals can have important impacts on the biosphere as pollutants or nutrients. Here we use ground- and drone-based direct measurements to compare the gas and particulate chemistry of the magmatic and lava–seawater interaction (laze) plumes from the 2018 eruption of Kīlauea, Hawai’i. We find that the magmatic plume contains abundant volatile metals and metalloids whereas the laze plume is further enriched in copper and seawater components, like chlorine, with volatile metals also elevated above seawater concentrations. Speciation modelling of magmatic gas mixtures highlights the importance of the S2− ligand in highly volatile metal/metalloid degassing at the magmatic vent. In contrast, volatile metal enrichments in the laze plume can be explained by affinity for chloride complexation during late-stage degassing of distal lavas, which is potentially facilitated by the HCl gas formed as seawater boils.

A small copper carrier in blood plasma: purification, characterization, and metabolism

In mammals, concentrations of copper in tissues and fluids are kept very constant. The main mechanism underlying this constancy is the ability of the liver to modulate excretion of copper by varying the amounts entering the bile – which end up in the feces. When biliary excretion of copper is hindered, as occurs when one of the proteins involved is defective, copper accumulates in the liver and later in other organs, with fatal consequences if untreated. Major examples are the copper “pump”, ATP7B, defective in Wilson Disease, and COMMD1, which also aids biliary excretion. With copper overload, there is increased copper in the urine, which normally is very low. Studies by Gray et al.[1] with the mouse Atp7b knockout model of Wilson disease determined that the increase in urine is due to a small copper carrier (SCC) of about 2 kDa, which our laboratory then determined was also in the blood plasma of these mice. Moreover, canines with defective ATP7B also had large increases in SCC-Cu in their blood and urine. We have been researching ways of purifying significant amounts of SCC, using commercially available porcine plasma, so it can be further characterized. Based on size exclusion chromatography (SEC) of 3 kDa ultrafiltrates in small pore gels, we know that usually most of the Cu is in a single component (SCC), which by ESI-MS appears to have a mass/charge ratio of 845, one atom of Cu(II) – detected in EPR as bound to N and O ligands, and a pI in the range of 3-4. New ways of purifying SCC beyond the ultrafiltration stage have been developed, involving concentration by lyophilization and special forms of dialysis using very small pore membranes. Hydrophilic interaction chromatography and additional SEC are providing much purer SCC, with more reasonable yields. Meanwhile, we have also been investigating the secretion and uptake of SCC-Cu, using cultured cells. SCC is secreted by hepatic cells as well as those modeling intestinal and kidney epithelium, particularly when preloading with Cu(II)-diHis. Intestinal (Caco2) cell monolayers with tight junctions secreted SCC mainly across the apical membrane (representing the gut lumen), but this was dramatically reversed when albumin was present in the basal medium (which is more physiological). Kidney epithelial cells also secreted SCC-Cu and some additional copper components mainly into the apical fluid. Other studies, with 67Cu-labeled SCC from hepatic secretions, confirmed not only that SCC was secreted, but showed that it was also taken up by all cell types examined. These findings suggest that metabolism of SCC and its copper is very active, and that SCC may play an important role in mammalian copper homeostasis. [1]Gray et al. PLoS ONE 7(6): e38327.

Penta band single negative meta-atom absorber designed on square enclosed star-shaped modified split ring resonator for S-, C-, X- and Ku- bands microwave applications

This paper represents a penta band square enclosed star-shaped modified split ring resonator (SRR) based single negative meta-atom absorber (MAA) for multi-band microwave regime applications. FR-4 low-cost material has been used as a substrate to make the MAA unit cell with 0.101λ0 × 0.101λ0 of electrical size, where λ0 is the wavelength calculated at the lower resonance frequency of 3.80 GHz. There are two outer square split ring and one inner star ring shape resonator of 0.035 mm thickness of copper placed on the one side, and another side of the substrate has full copper to construct the desired unit cell. The MAA unit cell provides five absorption peaks of 97.87%, 93.65%, 92.66%, 99.95%, and 99.86% at the frequencies of 3.80, 5.65, 8.45, 10.82, and 15.92 GHz, respectively, which covers S-, C-, X-, and Ku- bands. The properties of MAA have been investigated and analyzed in the E-, H-fields and surface current. The EMR and highest Q factor of the designed MAA is 9.87 and 30.41, respectively, and it shows a single negative (SNG) property. Different types of parametric analysis have been done to show the better performance of absorption. Advanced Designed System (ADS) software has been used for equivalent circuit to verify the simulated S11 result obtained from the CST-2019 software. Experimental outcomes of the MAA unit cell have a good deal with the simulated result and measured result of the 24 × 20 array of unit cells also shown. Since the unit cell provides superior EMR, excellent Q-factor, and highest absorption so the recommended MAA can be effectively used as a penta band absorber in microwave applications, like notch filtering, sensing, reducing the unintended noise generated with the copper component of the satellite and radar antennas.

Tube Drawing with Tilted Die: Texture, Dislocation Density and Mechanical Properties

Anisotropic behavior is a key characteristic for understanding eccentricity in tubes. In this paper, the effect of using a tilted die during tube drawing on eccentricity, texture, dislocation density, and mechanical properties is shown. Copper tubes were drawn with a ±5° tilted die for two passes. The increase or decrease in eccentricity can be controlled by controlling the angle of the tilted die. Two types of textures have been developed during tube drawing, namely plane strain and uniaxial types. Plain strain type texture is mainly characterized by the β fiber with a dominant copper component {112}<111>. The uniaxial deformation type is dominated by the <111> fiber, as commonly found by wire drawing. Texture sharpness increases with increasing drawing strain, and the texture varies significantly between the maximum and minimum wall thickness. This texture variation between maximum and minimum wall thickness has no significant influence on mechanical properties, which are more or less similar, but the increase in strength after each drawing pass is apparent. The dislocation density is low for the as-received tubes due to recovery and recrystallization. This is consistent with the as-received texture dominated by the cube component {001}<100>. During tube drawing, dislocation density increases as a function of the deformation strain. The variation of dislocation density between the maximum and minimum wall thickness in the tube deformed with −5° tilted die is higher than the variation in the tube deformed with +5° tilted die.

Defect Analysis on VMC Machined Copper Components through Statistical Tools in Quality Control Process

Defect Analysis on VMC Machined Copper Components through Statistical Tools in Quality Control Process

CREATION OF COMPOSITE ELECTRICALLY CONDUCTIVE COATINGS BY GAS DYNAMIC SPRAYING

The article presents the results of research of spraying processes of composite electrically conductive coatings using copper C01-11 and aluminum A20-11 powders in order to determine the effect of components on each other in the formation of cold gas-dynamic spraying (CGDS) and the development of recommendations for the introduction of additional component to obtain a composite coating with a given ratio of different components. For example, when at a working air temperature of 300 ° C the copper sputtering coefficient is almost zero, it is a search for the experimental dependence of the sputtering coefficient change depending on the percentage of components of copper and aluminum powders in the sprayed mixture and determination of their residual content in the coating. based on the obtained data of the sputtering coefficients of copper and aluminum. The CGDS method obtained blanks with composite coatings from mixtures of powders of aluminum A20-11 and copper C01-11 at different initial concentrations of aluminum by weight (from 0 to 100% with a step of 10%) under otherwise equal conditions (air pressure 0,6 MPa, temperature air heating 300 ° C). The sputtering coefficient of a mixture of copper and aluminum and the residual content of components in the sprayed composite coatings were found. Data on the residual content of the individual components in the sprayed coating allows to determine the composition of the source powder required for spraying a given content of each of the components in the coating. The dependences of the spraying coefficients of copper C01-11 and aluminum A20-11 on the mass content of aluminum in the sprayed mixture were found. When the initial concentration of aluminum is less than 66%, the coefficient of copper deposition is greater than the coefficient of deposition of aluminum. Both increase with increasing concentration of aluminum until it reaches 61%. At high concentrations of aluminum (more than 66%) the spray coefficients of copper, aluminum and their mixtures coincide. The results obtained on the residual content of the components in the coating allow you to select the composition of the source powder required to obtain the desired content of components in the coating. For example, the maximum residual copper content (~ 95%) can be obtained by adding 30-40% aluminum to the starting powder. The obtained results prove the influence of the components on each other and justify the amount of introduction of an additional component for spraying a composite coating containing a component that is difficult to spray.