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Electrical Discharge Machining (EDM) employing coated electrodes represents a relatively unexplored research avenue, with limited published findings to date. The choice of coating material significantly influences the EDM machining process, directly impacting the adjustment of technological parameters. Consequently, an in-depth investigation into the optimization of technological parameters for EDM with coated electrodes is imperative, aiming to propel the practical application of this innovative technique. This study focuses on determining the technological parameters for EDM utilizing an aluminum (Al) electrode coated with graphene for machining titanium alloy (Ti-6Al-4V). The research addresses a multi-objective optimization problem, with Material Removal Rate (MRR) and Tool Wear Rate (TWR) serving as key quality indicators. The integration of the Taguchi method with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is employed to address the multi-objective nature of the optimization challenge. The obtained results pinpoint optimal process parameters as U = 55 V, I = 5 A, and Ton = 1500 µs, resulting in an MRR of 6.57 mg/min. An in-depth analysis and evaluation of the machined surface quality with the coated electrode under optimal conditions are conducted. The TOPSIS method emerges as a fitting solution for this multi-objective optimization problem, offering simplicity in its computational steps.

The refurbishment of dies by the deposition welding of wear areas is an efficient and economical process. The aim of this study was to conduct a comparative analysis of the lifetimes of different types of dies for the manufacturing of wagon wheels. The analyzed dies were manufactured by conventional processes (Type I) and reconditioned through a deposition welding procedure using a dedicated electrode (Type II). The Anderson–Darling test was conducted to analyze the goodness of fit of the lifetime data specific to the die types. The maximum likelihood estimation method (MLE) with a 95% confidence interval (CI) was applied in order to estimate the lifetime distribution parameters. It was found that the lifetimes of type II dies were longer than those of type I dies. The mean time to failure (MTTF) recorded for reconditioned dies was 426 min, while the mean time to failure of dies manufactured by conventional processes was approximatively 253 min. In addition, an accentuated hazard rate for type I dies compared to type II dies was observed. The results of this analysis emphasized the fact that dies can be restored to their initial operating capacity by successfully using deposition welding procedures that confer a high resistance to operational loads. At the same time, the use of these procedures allows for the sustainable development of resources and waste management. [ABSTRACT FROM AUTHOR]

Micro-electrical discharge machining (micro-EDM) stands out as a transformative methodology, offering substantial progress in both technical and economic efficiency through the integration of coated electrodes. This study meticulously analyzes various technological parameters in micro-EDM, focusing specifically on Ti-6Al-4V, a widely employed titanium alloy. The application of a titanium nitride (TiN) coating material on a tungsten carbide (WC) electrode is investigated using the Taguchi method of experimental design. This study employs an ANOVA and factorial design methodology to scrutinize the influence of key parameters, namely voltage (V), capacitance (C), and spindle rotation (in revolutions per minute) (RPM) on the tool wear rate (TWR), overcut (OVC), and Z coordinate (depth) within the micro-EDM process. The findings unveil a noteworthy increase in the TWR with an elevated V, C, and RPM, with capacitance exerting a pronounced influence while voltage exhibits the least impact. OVC exhibits notable variations, revealing an inverse relationship with RPM. The Z coordinate (depth) is significantly affected by capacitance, with voltage and RPM each having a relatively negligible impact. A surface quality analysis exposes similarities and numerous defects in both coated and uncoated electrodes, emphasizing the need for further exploration into the effectiveness of coated electrodes in enhancing post-micro-EDM machined surface layers. This study contributes valuable insights to optimize and advance micro-EDM processes, laying groundwork for future innovations in precision machining. [ABSTRACT FROM AUTHOR]

In maintenance workshops, E6013 electrodes are used for hardfacing parts; therefore, the filler has low hardness and wear resistance. The problem addressed was to modify the chemical composition of the metal deposited by these electrodes by applying a peripheral coating. The objective was to evaluate the operational and melting behavior of E6013 electrodes, under a peripheral coating applied with a coated tape with variations in composition. By using a mix design, the composition of the tape coating was determined. Operational performance was evaluated by using expert criteria. In addition, the influence of the tape composition on the deposited metal chemical composition of the and the hardness was experimentally determined. Statistical processing was performed with the software for statistical analysis. E6013 peripherally coated electrodes demonstrated good operating properties. The chemical composition of the deposited metal was modified with contributions of C and Cr, from the chromite and graphite of the peripheral coating. During the fusion of the electrode with the peripheral coating, the carbothermic reduction of the chromite is guaranteed, from the heat provided by the electric arc, contributing to alloy the weld bead with Cr. [ABSTRACT FROM AUTHOR]

Micro-electrical discharge machining (micro-EDM) stands out as a transformative methodology, offering substantial progress in both technical and economic efficiency through the integration of coated electrodes. This study meticulously analyzes various technological parameters in micro-EDM, focusing specifically on Ti-6Al-4V, a widely employed titanium alloy. The application of a titanium nitride (TiN) coating material on a tungsten carbide (WC) electrode is investigated using the Taguchi method of experimental design. This study employs an ANOVA and factorial design methodology to scrutinize the influence of key parameters, namely voltage (V), capacitance (C), and spindle rotation (in revolutions per minute) (RPM) on the tool wear rate (TWR), overcut (OVC), and Z coordinate (depth) within the micro-EDM process. The findings unveil a noteworthy increase in the TWR with an elevated V, C, and RPM, with capacitance exerting a pronounced influence while voltage exhibits the least impact. OVC exhibits notable variations, revealing an inverse relationship with RPM. The Z coordinate (depth) is significantly affected by capacitance, with voltage and RPM each having a relatively negligible impact. A surface quality analysis exposes similarities and numerous defects in both coated and uncoated electrodes, emphasizing the need for further exploration into the effectiveness of coated electrodes in enhancing post-micro-EDM machined surface layers. This study contributes valuable insights to optimize and advance micro-EDM processes, laying groundwork for future innovations in precision machining.

Austempered ductile iron (ADI) offers a good combination of mechanical properties with low cost and successfully replaces cast and forged steel in many applications. Manual metal arc welding (MMAW) of such iron causes the formation of martensite in the heat-affected zone and an undesirable growth of iron carbide in the partial fusion zone. Although avoidance of hard products is accomplished at present by using Ni alloys as electrodes, they fail to satisfy the mechanical requirements apart from the high cost of Ni-based electrodes. Furthermore, such electrodes do not respond to austempering heat treatment. In the present study, an attempt has been made to develop a coated electrode with cost-effectiveness and response to austempering heat treatment by adjusting the alloying elements through flux coating on their ability to eliminate free carbides and response austemperability. The microstructures of different weld deposits and at different layers of each weld deposit have been evaluated in as-welded and after austempering treatment using an optical microscope, SEM with EDX. However, it has been possible to develop coated electrodes with shallow Ni content (0.71%), which responded to austempering resulting in a microstructure consisting of graphite nodules in a matrix of lower bainite. Microhardness of weldment (WM) was also carried out, which showed good agreement with microstructure characteristics. [ABSTRACT FROM AUTHOR]

The viscosity of 6% dispersions of Na-CMC in liquid Na- and K-glasses depending on temperature, as well as viscosity of pure liquid Na, K- and NaK-glasses depending on excess pressure and temperature was studied. Each of them represents a consistent medium of real electrode coating masses. Using the obtained results, by mathematical methods the functioning of the model of the joint effect of overpressure and dissipative heating on viscosity, velocity profile and stability of pressure flow of electrode coatings in the step channel under the conditions of coating formation by extrusion deposition on steel bars was verified. Although two competing sources of change in shear viscosity of the coating mass (temperature and pressure) are available, the calculations did not reveal situations with unstable (pulsating) flow modes through a suddenly narrowing channel, which could cause instability of the coating mass flow, and therefore electrode coatings with a thickness variation. At least, they were revealed in the studied range of capillary L/Rk <10 sizes and pressures, at which the electrodes are actually pressed. 10 Ref., 1 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

The viscosity of 6 % dispersions of Na-CMC in liquid Na- and K-glasses depending on temperature, as well as viscosity of pure liquid Na, K- and NaK-glasses depending on excess pressure and temperature was studied. Each of them represents a consistent medium of real electrode coating mixtures. With the use of the obtained results by mathematical methods, the functioning of the model of a joint effect of excess pressure and dissipative heating on viscosity, velocity profile and stability of pressure flow of electrode coating mixtures in the step channel under the conditions of coating formation by extrusion deposition on steel bars was verified. Although two competing sources of change in shear viscosity of the coating mass (temperature and pressure) are available, the calculations did not reveal situations with unstable (pulsating) flow modes through a suddenly narrowing channel, which could cause instability of the coating mixture flow and, therefore, electrode coatings with a thickness variation. At least, they were not revealed in the studied range of capillary sizes L/Rk < 10 and pressures, at which the electrodes are actually pressed. 10 Ref., 1 Table, 8 Figures. [ABSTRACT FROM AUTHOR]

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The objective of the research was to evaluate the potential of refractory chromites from Victoria I deposit (in Camagüey, Cuba) as a source of chromium for producing electrodes to recharge parts by manual electric arc welding. A mixture of rutile, graphite, refractory chromite, sodium silicate and AISI 1009 steel rods was used as raw material. The experimental electrodes were obtained by pressing the coating from a dosed mixture with the previous components. The mass balance predicts the weld bead can be alloyed with carbon and chromium by introducing refractory chromite and graphite in the rutile coating. The experimental results corroborated that the welding process allowed obtaining 2.3% carbon and 2.89% chromium in the metal deposited by the experimental electrodes. Results show that refractory chromites from Camagüey constitute a potential source of chromium for manufacturing rutile-coated electrodes for recharging parts by manual electric arc welding. [ABSTRACT FROM AUTHOR]

Introduction: There is a problem of recovering parts with large worn surfaces in industry. Filling is applied by manual electric arc welding for this, with low productivity when using small diameters cylindrical electrodes, operated with low current intensities. Objective: To evaluate operating and melting behavior of a coated electrode with a rectangular section core and a rutile coating. Materials and methods: Rutile coating was applied by pressing in molds. Operational performance was qualitatively evaluated by applying expert criteria. In addition, the consumption parameters were determined according to the standard (ISO 2401-72, 1972). The effect of core width and current intensity on consumption and dilution parameters was experimentally determined. Statistical processing was carried out with Statgraphics software. Results and Discussion: Electrodes have good operating properties as excellent arc stability is obtained in 77.8% of them, excellent slag detachment in 100%, good appearance and cord health in 77% and 88.9% respectively. The average deposition coefficient was 0.16 g/A*min, deposition efficiency of 80.6% and dilution of 30.5%. Conclusions: Obtained electrodes showed good operating behavior during welding tests, which allows the filling process in parts affected by wear. Dilution in deposited by these electrodes metal is less than in equivalent cylindrical electrodes, which constitutes a significant advantage in recharge processes. [ABSTRACT FROM AUTHOR]

Investigation of the effect of nitrogen alloying and yttrium and zirconium oxide additives to the weld pool on the structure of an austenitic weld and its microhardness in the zone of its fusion with pearlitic base metal was studied for the case of joints of dissimilar steels (austenitic with pearlitic), made by coated-electrode arc welding. It is shown that nitrogen alloying of weld metal of Kh20N9G6 type through the electrode coating practically does not affect the dendrite dimensions, but lower the microhardness (risk of martensite formation) in the zone of fusion with pearlitic base metal. In the case of yttrium or zirconium oxide additives to the austenitic metal of Kh15N25M6AG2 type through the coating, its dendrite structure is refined significantly, and metal microhardness in the fusion zone drops to the level that is indicative of martensite absence. [ABSTRACT FROM AUTHOR]

Investigation of the effect of nitrogen alloying and yttrium and zirconium oxide additives to the weld pool on the structure of an austenitic weld and its microhardness in the zone of its fusion with pearlitic base metal was studied for the case of joints of dissimilar steels (austenitic with pearlitic), made by coated-electrode arc welding. It is shown that nitrogen alloying of weld metal of Kh20N9G6 type through the electrode coating practically does not affect the dendrite dimensions, but lower the microhardness (risk of martensite formation) in the zone of fusion with pearlitic base metal. In the case of yttrium or zirconium oxide additives to the austenitic metal of Kh15N25M6AG2 type through the coating, its dendrite structure is refined significantly, and metal microhardness in the fusion zone drops to the level that is indicative of martensite absence. [ABSTRACT FROM AUTHOR]

Characterization of wave propagation on a switch line, which means a transmission line periodically loaded with electronic switches, is discussed for the generation of electrical continuous waves. We consider the case of a step pulse, which crosses the threshold voltage of loaded shunt switches, inputted to a switch line. Due to the effects of the electrode loss and the switch conductance, the forward pulse on a switch line is gradually attenuated, and finally dissappears. At this point, a stable exponential wave develops and then travels backward to the input port. At the input port, the pulse is reflected to travel forward again. This process continues permanently to give a method of generating electrical continuous waves. By designing the values of electrode loss, switch conductance, and the characteristic impedance of a switch line, the oscillation frequency covers a very wide range. [ABSTRACT FROM AUTHOR]

The thickness effect in ferroelectric thin films has been theoretically investigated using the Landau–Khalatnikov theory. Ferroelectric properties such as the hysteresis loop, and its associated coercive field and the remanent polarization of various film thicknesses have been numerically simulated. In this simulation, the thin film was modeled by the stacking of layers, each of which has unique parameters for the Landau free energy. Due to the interfacial effects near the electrodes, the parameters for the surface layers are different from those for the bulk. The simulated result shows that the coercive field decreases while the remanent polarization increases with thickness. Both of these trends qualitatively agree with experiments. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Results of sanitary-hygienic assessment of coated electrodes for welding high-alloyed chromium-nickel steels were used to study the influence of the composition of electrode coating binder on toxicity of aerosols, which form at application of these electrodes. Express-method of determination of cytotoxicity, levels of evolution and chemical composition of welding fumes, as well as their calculated hygienic values in accordance with international standard DSTU ISO 15011-4:2008 were applied for this purpose. It is shown that in order to develop new grades of welding electrodes with improved hygienic characteristics, it is reasonable to have not only initial sanitary-hygienic evaluation, but also the results of biological studies of the toxicity of welding fumes. It is found that application in electrode coating of a binder based on pure lithium or lithium-sodium-potassium liquid glass instead of potassium-sodium, enables reducing the level of welding fume evolution into the air, its content of highly toxic hexavalent chromium, and, lowering its general toxicity, due to that. [ABSTRACT FROM AUTHOR]

The paper shows the favourable effect of nitrogen alloying of high-alloyed corrosion-resistant steels and weld metal on stabilization of the structure, prevention of grain boundary segregation in the HAZ and weld metal, and ensuring high corrosion resistance and technological strength of welded joints. 15 Ref., 2 Tabl., 10 Fig. [ABSTRACT FROM AUTHOR]

The paper shows the favourable effect of nitrogen alloying of high-alloyed corrosion-resistant steels and weld metal on stabilization of the structure, prevention of grain boundary segregation in the HAZ and weld metal, and ensuring high corrosion resistance and technological strength of welded joints. 15 Ref., 2 Tables, 10 Figures. [ABSTRACT FROM AUTHOR]

The finite element modulation of forming of coating at electric contact surfacing is provided. This model considers distribution of thermal properties and geometric parameters along the thermal deformation zone during the process of electric contact surfacing by tapes. It is found that the change of the value of the speed asymmetry factor leads to increasing of the friction coefficient in the zone of surfacing which is caused by the increasing of the tangential contact stresses in the zone of contact of the electrode tape with the surface of the part. This leads to the forming of the coating with higher adhesion strength, and thereby the higher quality of the restored part under the lower operating regimes such as current pulse, force of the roller electrode, and duration of the current pulse is achieved. Mentioned above allows to decrease the thermal influence on the structure of the material. [ABSTRACT FROM AUTHOR]

Abstract In this study, Iron doped Zinc oxide (Fe ZnO) nanoparticles (NPs) were synthesized and coated on carbon paper electrode. The NPs and NPs coated electrode physicochemical, antimicrobial, antibiofilm traits and MFC performances were investigated. The characterization results depicted that Fe ZnO NPs were hexagonal rod shape with hexagonal phase structure in size of 90–100 nm have 59 m2/g surface area. Antibiofilm results indicates concentration of 5 mg/L of NPs shows 39 and 42% inhibition for Lysinibacillus Sphaericus and Bacillus safensis. The antibacterial assay confirmed that test organism was more resistant against NPs and coated electrode. Impedance analysis of NPs coated anode shown decreased anodic charge transfer resistance. The MFC results confirmed that power density was increased for NPs coated electrode (134.7 mW/m2) as compared to uncoated electrode. Cyclic Voltammetry analysis reported that exoelectrogenesis was promoted by NPs. The NPs coated and bare electrode COD removal efficiency were found to be 72.8 and 63.8%. Graphical abstract Image 1 Highlights • Biogenic synthesis of leaf extract mediated Fe doped ZnO nanoparticles. • L. sphaericus and B. safensis bacteria was more resistant against NPs. • Fe ZnO NPs coated anode holds good hydrophilicity and unique electric property. • NPs coated anode enhances energy generation and waste water treatment efficiency. [ABSTRACT FROM AUTHOR]

One-dimensional hollow hexagonal ZnO rods (1-D HHZRs) were grown onto the SnO2: F (FTO) coated glass substrates by using two-step deposition techniques. Initially, the ZnO seed layer was coated onto the FTO which was followed by hydrothermal route in order to grow 1-D HHZRs. These 1-D HHZRs were decorated with Eosin-Y dye and CdS semiconductor nanoparticles (NPs) by using a chemical routes like dip coating and successive ionic layer absorption reaction (SILAR) technique, respectively to improve its photoelectrochemical (PEC) performance. The structural, morphological, optical and electrochemical characterizations of the thin films were analyzed by various sophisticated instruments. X-ray diffraction (XRD) pattern corroborated the phase formation of ZnO and CdS with the hexagonal and cubic crystal structure, respectively. 1-D HHZRs films were obtained by scanning electron microscopy (SEM) with rod diameter of about 1.47 μm. Furthermore, SEM image clearly showed the CdS NPs covered 1-D HHZRs. The direct optical bandgap energy of the samples were estimated to be 3.28, 3.24 and 3.03 eV. CdS NPs-sensitized 1-D HHZRs samples showed hydrophilic nature for water contact angle, which is advantageous for the better improvement in the PEC performance as compared with pristine and dye-sensitized 1-D HHZRs. [ABSTRACT FROM AUTHOR]

Commercial success for proton exchange membrane fuel cell (PEMFC) requires manufacturing of its core component, membrane electrode assembly (MEA), with consistent and reliable performance. In this study, three common methods for the MEA manufacturing are investigated systematically for their impact on the cell performance under consistent preparation and cell test conditions, including catalyst coated substrate (CCS), catalyst coated membrane (CCM), and low temperature decal method (LTDM). The variations in each of these methods studied include applying an extra Nafion layer, hot press, and Pt loading. It is found that MEA manufacturing process has a significant impact on the cell performance, and this impact is significantly affected by the Pt loading. At the high Pt loading of 0.5 mg/cm 2 , CCM without hot press involving gas diffusion layers (GDLs), referred to as CCM-Wo, results in the best performance with the maximum power density of 0.95 W/cm 2 , although both LTDM and CCS with an extra Nafion layer (hence called N-LTDM and N-CCS) are just slightly less with the maximum power density of 0.91 W/cm 2 . Hot press with GDLs is essential for CCS method to achieve a good performance, while it is not the case for CCM and N-LTDM. Applying an extra layer of Nafion on catalyst layers as in N-LTDM and N-CCS methods has a positive impact on the cell performance; whereas it is negative when it is applied on the membrane as in the N-CCM method. When the Pt loading is reduced to 0.125 mg/cm 2 (75% reduction in the Pt loading), cell performance is reduced for all the MEAs made by the three methods, but significant reduction (about 75%) is observed for CCS method, while it is less than 30% for the other two methods. Therefore, care should be taken in the MEA manufacturing for MEAs with low Pt loadings. [ABSTRACT FROM AUTHOR]

In preparing switchable mirrors, palladium (Pd) was used as a catalyst for hydrogenation and dehydrogenation, and to prevent oxidation of the switchable layer. To reduce the cost, Pd was alloyed with ruthenium (Ru) and used as a catalytic layer, since the price of Ru is approximately one-tenth that of Pd. Switchable mirrors of magnesium-yttrium (Mg-Y) alloy thin films coated with a Pd-Ru layer were prepared by direct-current magnetron sputtering method. Their optical switching properties between reflective and transparent states were studied using gasochromic method. The mirrors coated with Pd 1- α Ru α of up to α  ≈ 0.6 showed nearly the same switching time from reflective to transparent state as those coated with pure Pd, while the mirrors coated with Pd 1- α Ru α of 0.2 ≤  α  ≤ 0.4 showed shorter switching times from transparent to reflective state than those coated with pure Pd. Furthermore, the alloy-coated mirrors with shorter switching times had approximately 2–3 times higher switching durability than those coated with pure Pd. These shorter time and higher durability may be because Pd-Ru alloy prevents oxidation of the underlying layers more effectively than pure Pd. Thus, Pd-Ru alloy is one of the most promising catalysts for switchable mirrors. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) are performed using C 3 N 4 post-treated TiO 2 particles as photoanode materials. The photoanode materials were synthesized via a simple method by which a thin layer of C 3 N 4 was coated onto the surface of TiO 2 particles after the TiO 2 was dipped in urea solution followed by calcination properly. The experimental results show that the photoelectric conversion efficiency of the TiO 2 DSSCs is remarkably improved. The measurements of I-V characteristic along with the analysis of electrochemical impedance spectroscopy indicate that the C 3 N 4 layer can expand the visible light absorption, suppress the recombination reaction of the e − -h + pair and increase both the open circuit voltage and the short-circuit photocurrent density. The mechanism of the improved performance of TiO 2 DSSCs by C 3 N 4 coating coating is proposed. The post-treatment method recorded in this work can be easily operated and achieve an enhanced photoelectric performance of DSSCs. [ABSTRACT FROM AUTHOR]

This study reports on the electrochemical characterisation of dioleoyl phospatidylcholine (DOPC) bilayer structures on a negatively polarised mercury (Hg) electrode. The bilayers are stable on the Hg surface between −1.0 and −1.3 V applied potential. The experimental approaches were:- (i) rapid cyclic voltammetry (RCV) to “fingerprint” the bilayers, (ii) potential step experiments to record Zn 2+ reduction and, (iii) electrochemical impedance. The results show the following. Both the specific capacitance (5 μF cm −2 ) and the specific resistance of the bilayer are higher and lower respectively than that of a defect-free free standing DOPC bilayer. This indicates the presence of water and ions in the bilayer within an applied negative field. The bilayer's resistance to electrolyte movement decreases with increase in negative potential to a minimum at −1.3 V. The DOPC bilayer is less permeable to Zn 2+ ions compared to the DOPC monolayer coated electrode at applied negative potentials and its permeability to Zn 2+ increases with an increase in negative applied potential. The specific capacitance of the bilayer increases to about 7.5 μF cm −2 with increase in applied negative potential showing the increasing significance of water in the bilayer commensurate with its increased permeability to ions. Adsorption of SiO 2 nanoparticles on the bilayer surface causes a step negative potential shift in the anodic capacitance current bilayer reformation peak indicating an acceleration of the bilayer reformation process. [ABSTRACT FROM AUTHOR]

This study increased the surface area of a membrane by forming patterns on the Nafion resin membrane using a stainless steel mesh to enhance the performance of a direct methanol fuel cell (DMFC) because the triple-phase boundary is extended. Nafion resin (F-form ( SO 3 F)) was used which has melt-moldability to form a stable surface pattern and to directly coat the catalyst layer by the bar-coating method. The performance (polarization and power density curves) and the resistance of the membrane-electrode assembly (MEA) were analyzed with a single cell and an impedance analyzer. The surface area of the patterned membranes was increased 1.99, 2.10, and 2.12 times compared to the flat membrane, and the power density also increased 12.9, 18.6, and 24.2% at 0.4 V, respectively. The performance of the MEA with the patterned membrane had a lower concentration polarization than that of the MEA with the flat membrane. The performance of the MEAs with the patterned membranes had a greater impact on the cathode side of the membrane than on the anode side. The results of these experiments offer a solution to the problem of a low performance of MEA, which is one of the disadvantages of DMFCs. [ABSTRACT FROM AUTHOR]

For several years it has been possible to measure the uniaxial strain dependence of the critical current density JC (ε) of (RE)BCO coated conductors [(RE)BCO tapes] and a parabolic strain dependence of JC (ε) has been observed. To improve our understanding of how strain affects the electrical and mechanical properties of a SuperPower APC SCS4050 (RE)BCO tape, we have created a biaxial sample holder that can apply arbitrary strains along both the x- and y-axes of a (RE)BCO tape simultaneously. It can be used to measure JC for independently controllable applied x and y strains ranging from -0.50% ⩽ εx ⩽ 0.30% to -0.15% ⩽ εy ⩽ 0.20%, respectively, at 77 K. We present the results of JC measurements over this strain range at 77 K in magnetic fields of up to 0.7 T. We show that we obtain the standard parabolic relationship for JC (εx), with a peak in JC occurring at εxP = -0.01%. We also show that when we apply an additional y strain of εy = -0.08% the peak in JC moves to εxP = 0.4%, which cannot be explained by considering the differential strains produced by nonsuperconducting components of the tape and sample holder. In addition, the value of JC at the peak increases considerably by 11%. [ABSTRACT FROM AUTHOR]

The paper gives the results of studying the influence of the parameters of the process of submerged-arc surfacing of steel with flux-cored wire of PPBrOF10-1 grade and with coated electrodes ANBO-2, providing deposited metal of the composition, corresponding to cast bronze of BrO10F1L grade, on formation of intercrystalline penetrations of bronze into steel. It is shown that formation of intercrystalline penetrations is the most significantly influenced by values of current and deposition rate. Based on metallographic studies, it is found that absence of intercrystalline penetrations of bronze into steel is achieved at limitation of effective heat input of the process of arc surfacing both with flux-cored wire and with coated electrodes to the value of 450 kJ/m. 8 Ref., 2 Tabl., 2 Fig. [ABSTRACT FROM AUTHOR]

To evaluate the effectiveness of arc bubble, the influences of controllable arc bubble on the process stability and microstructural evolution of welded joint under different welding conditions were investigated. The main welding conditions, including onshore welding, conventional underwater wet welding (UWW) and mechanical constraint assisted UWW (MC-UWW), were characterized and compared. The exerted mechanical constraint resists the arc bubble detachment and keeps the larger arc bubble attached to the weld pool surface for providing better protective effect of welding region. The adverse effect of surrounding water with its higher heat conduction is not negligible compared with onshore welding, and the mechanical coupling between arc bubble and constraint device plays a vital role in affecting the arc stability and joint quality. Microstructure analyses revealed that under the same welding parameters, the proportion of brittle microstructure in weld metal follows the order: UWW > MC-UWW > onshore welding. A more stable wet welding process can be realized by controlling the arc bubble detachment, which provides a new orientation for wet welding technique application. [ABSTRACT FROM AUTHOR]

In this work the chemical and metallographic characterization of the deposit without dilution obtained with an experimental tubular electrode (CIS 3), developed for hardfacing through manual welding with a coated electrode (SMAW) of surfaces under abrasive wear conditions, using a combined Fe-Cr-Mn-Si-C ferroalloy resulting from pyro-metallurgical processing of Cuban chromite and pyrolite minerals, is carried out. The deposit was obtained as specified in the AWS A5.13 standard, for hardfacing SMAW electrodes. As characterization techniques: optical and electron microscopy, phase microanalysis, volumetric hardness and micro hardness studies were used, as well as chemical composition analysis using atomic emission spectroscopy. As a result it was determined that the material of the deposit without dilution belongs to the white irons system, alloyed with Cr, Mn and Si. This material presents a hypereutectic microstructure. These results show the CIS 3 tubular electrode with favorable characteristics in terms of its application as a hardfacing consumable of pieces subjected to abrasive wear conditions as main mechanism of damage. [ABSTRACT FROM AUTHOR]

The industrial experience on development of requirements to the analysis of granulometric composition of consumables, applied in the electrode coatings was described. The importance of selecting the method of analysis and the applied equipment was noted. The conclusion on importance of unification of analysis procedures at the manufacturers of consumables and suppliers of powders was made. [ABSTRACT FROM AUTHOR]

Information about PJSC «PlazmaTek», the leading manufacturer of welding consumables in Ukraine and CIS, history and plans of development, products being manufactured, as well as some peculiarities of the technology of their manufacture is described. [ABSTRACT FROM AUTHOR]

A mathematical model of convective evaporation of metal from the melt surface was proposed for prediction of the composition of fumes formed in manual arc welding. Numerical analysis of the characteristics of the flow of multicomponent metal vapour in welding with high-alloyed chromium-nickel electrodes was performed. Rates of evaporation of welding fume components at application of electrodes for high-alloyed steel welding were established. Obtained mathematical model enables calculation of not only the relative mass fraction of toxic component in the fume, as it was possible up to now, but also of convective flows of welding fume components. [ABSTRACT FROM AUTHOR]

Oscillographic and mathematical statistics methods were applied to study the regularities of formation of coating thickness variation in experimental electrodes UONI 13/55 with 4 mm rod diameter at their manufacture in angle hydraulic press under the conditions maximum close to production ones. It is found that coating thickness variation is a continuous, multistage, nonmonotonic (wavelike) and harmonic process, in which disturbances, arising at the starting stage, can be felt in subsequent stages of electrode pressing. Coating thickness variation is caused, primarily, by violation of elasticity and viscosity balance, on which the consistency of electrode coating masses depends. At the same time the probability of appearance of coating thickness variations is essentially influenced by the features of forming path of electrode coating press. [ABSTRACT FROM AUTHOR]

It is proved that introduction of up to 53.4 % of exothermal mixture in electrode coating results in increase of the following coefficients, i.e. core melting, deposition, rate of electrode melting and melting of electrode coating. Increase of thickness of electrode coating, containing 44.4 % of exothermal mixture, from 0.5 to 2.6 mm results in rise of amount of exothermal mixture and deposition coefficient, decrease of value of core melting coefficient, increase of mass rate of coating melting. It is proved that an efficient method for increase of electroslag processes efficiency is application of exothermal flux, namely scale, ferroalloys, aluminum powder and standard flux (ANF-6 etc.) in the amounts sufficient for exothermal reaction passing. This provides for emission of additional heat in a start period of exothermal processes and promotes for accelerated formation of slag pool of necessary volume on «solid» start on monofilar as well as bifilar schemes of process instead of «liquid» start. The electroslag processes using exothermal alloyed flux on «solid» start allow (in comparison with existing methods of slag pool formation) rising metal yield by 2-10 %; 1.2-1.4 kW·h economy of melting of 1 kg of standard flux; 25 % reduction of time of ESR process start period. It is determined that introduction of aluminum as a deoxidizing agent in the exothermal fluxes rises content of aluminum oxide (Al2O3) in a weld pool, its resistance, and increases efficiency of electroslag process. [ABSTRACT FROM AUTHOR]

The results of investigations of the properties of electrode compounds, coatings and electrodes of rutile-basic type were set forth and analyzed. These electrodes are designed for welding of high-strength Cr-Ni steels depending on composition of lithium-containing liquid glass. It is shown that application of Li-Na-K liquid glass for manufacture of such electrodes allows significantly improving their hygiene and sanitary properties due to reduction of specific emissions of hexavalent chromium high-toxic compounds. Simultaneously, application of Li-Na-K glass results in significant decrease of hygrosorption capacity of the coating, at that its strength and crack resistance in welding do not deteriorate, and ductility and impact toughness of weld metal is somewhat improved. The workability indices and welding-technological characteristics of compared electrodes are at the same level. The results of the investigations allowed upgrading coating composition and production technology of ANV-35 electrodes. [ABSTRACT FROM AUTHOR]

Investigations were carried out to determine the degree of non-uniformity of the melting rate of coated electrodes as a result of preheating with passing current. The increase in the melting rate with time can be described with high accuracy by a linear dependence. The melting rate increases at the end of combustion of the electrode in comparison with the initial rate by up to 42% in comparison with the initial rate, with the average rate being up to 17.7% higher than the initial rate. A method for calculating the initial melting rate of the coated electrodes using the data on the melting rate of the electrode wire in automatic submersion-arc welding is proposed. [ABSTRACT FROM AUTHOR]

In previous research [1–5] we have successfully performed the design and application of thermoelectric nanowire characterization platforms (TNCPs). These chip-based measurement platforms are used to characterize single nanowires from a structural, electrical and thermoelectric point of view. For this purpose, a TNCP must carry electrical contacts in a tight spacing, exhibit a long and very small gap over which a nanowire is suspended. Chip height is limited for integration into a TEM holder, which would allow for a structural investigation of the nanowire under test. This calls, in total for a complex MEMS fabrication process with associated high costs. However, as one TNCP chip is suitable to perform measurements with only one nanowire, questions arise in general, how cleanroom costs and efforts can be reduced in the production of such single-use MEMS devices, while keeping their performance high. These challenges have given rise to the study presented in this paper. A new method for silicon microstructuring, based on direct silicon laser ablation is proposed. To improve surface quality of the laser-ablated areas, chemical post-processing is implemented in addition to the laser ablation. Additionally the development of low temperature indium based solders is reported in detail, with the aim to employ automatic formation of individual solder contacts on a micron spacing. For this purpose, the measurement electrodes are covered with our proposed low temperature solder through an adapted physical vapor deposition (PVD) and lift off process. [ABSTRACT FROM AUTHOR]

The electrocatalytic reduction of carbon dioxide to formic acid on metallic electrodes is known to suffer from low current density and rapid surface contamination by electrolyte impurities. Gas diffusion electrodes (GDE) can overcome these problems due to their high specific surface area. In this work, we show a simple method to prepare indium coated gas diffusion electrodes (GDE-In/C) and their physical and electrochemical characterization. Indium is chosen for its ability to reduce CO 2 to formic acid at relatively low overpotential compared to other metals. The catalytic performance of the GDE-In/C is compared to an indium foil using identical operating conditions. During electrolysis in homogeneous aqueous media (dissolved CO 2 ) at −1.65 V vs. Ag/AgCl, the partial current density toward HCOOH on the GDE-In/C is 7 times higher than on the indium foil with a faradaic efficiency of 45%. The production of formic acid increases by 15% when a continuous flux of CO 2 gas is applied through the GDE-In/C. In addition, the GDE-In/C shows a good resistance to electrolyte impurities and allows to achieve higher current densities. These promising results are a key milestone in the development of a zero gap cell for gas phase CO 2 electroreduction [ABSTRACT FROM AUTHOR]

We have successfully employed a double-sided process to deposit MgO buffer layers on both sides of amorphous Y 2 O 3 surface for double-sided YBa 2 Cu 3 O 7 − δ (YBCO) coated conductors (CCs) for the first time, the structure of which is of great prospect to improve the performance and cut the production cost. The biaxial textures of MgO buffer layer are noticeably affected by the ion energy and film thickness, which is demonstrated by X-ray diffraction. The best biaxial texture of double-sided MgO films shows ω -scan of (002) MgO and Φ -scan of (220) MgO yield full width at half maximum values of 4° and 7.8° for one side, respectively, as well as 3.5° and 6.7° for the other side. The subsequent double-sided YBCO films are deposited on the as-prepared MgO template with entire critical current of over 300 A/cm for both sides. [ABSTRACT FROM AUTHOR]

The present work was conducted to assess the weldability of duplex stainless steel in underwater conditions. Metal manual arc welding (MMA) with the use of coated electrodes was used in the investigations. Tekken weldability tests were performed underwater at 0.5 m depth and in the air. Nondestructive tests, metallographic examinations of welds, ferrite content assessment in microstructure and hardness test were performed. The good weldability at underwater conditions of duplex stainless with the use of MMA method was confirmed, however difficulties in stable arc burning were revealed. [ABSTRACT FROM AUTHOR]

Herein, we report a tailored Ag mesh electrode coated with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer on a flexible polyethylene terephthalate (PET) substrate. The introduction of this highly conductive polymer solves the existing problems of Ag mesh-type transparent conductive electrodes, such as high pitch, roughness, current inhomogeneity, and adhesion problems between the Ag mesh grid and PEDOT polymer or PET substrate, to result in excellent electron spreading from the discrete Ag mesh onto the entire surface without sacrificing sheet conductivity and optical transparency. Based on this hybrid anode, we demonstrate highly efficient flexible polymer solar cells (PSCs) with a high fill factor of 67.11 %, which results in a power conversion efficiency (PCE) of 6.9 % based on a poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′] dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl}):[6,6]-phenyl-C71-butyric acid methyl ester bulk heterojunction device. Furthermore, the PSC device with the Ag mesh electrode also exhibits a good mechanical bending stability, as indicated by a 70 % retention of the initial PCE after 500 bending cycles compared with the PSC device with a PET/indium tin oxide electrode, which retained 0 % of the initial PCE after 300 bending cycles. [ABSTRACT FROM AUTHOR]