Electric Current Values Research Articles

THE EFFECT OF ARC STUD WELDING PARAMETERS ON MECHANICAL PROPERTIES OF DOCOL 1500M ADVANCED HIGH STRENGTH STEEL WELDING JOINTS

Arc stud welding method is a welding method that takes advantage of the arc's ability to melt metals. Stud welding is an easy and fast welding method that is generally applied to surfaces where threading is problematic and welding is difficult. Docol 1500 martensite materials are high-strength steels with high tensile strength up to 1700 MPa and good ductility. These type of materials provide high efficiency, especially in the automotive industry, in terms of both vehicle lightness and advanced crash protection. In this study, the weldability of threaded studs made of 20MnB4 grade carbon steel was investigated using the arc stud welding process on Docol 1500M plate. The arc stud welding process was carried out using a ceramic ferrule at different combination values with electric current values ranging between 300A and 500A and different welding times ranging from 0.125 seconds to 0.300 seconds, as well as variable welding parameters such as 3mm plunge value and 5.9mm lift distance. With the experimental study, the most suitable welding parameters were try to determined according to the size and properties of the materials to obtain a quality welded. At the end of welding process, the effects of arc stud welding parameters such as welding current, welding time, plunge and lifting distance on mechanical and microstructural properties were experimentally investigated.

Electrical current-assisted reactive crucible melting technique: Case study of the Fe-Sn system

Modern materials science relies heavily on the advancement of combinatorial high-throughput experimental and computational methods to discover new advanced materials. Among these methods, the reactive crucible melting (RCM) technique stands out as particularly promising. However, a significant challenge in RCM combinatorial analysis is the occurrence of "missing" phases. In this study, we successfully addressed this limitation through the application of electrical current stressing. Furthermore, we investigate the influence of electric current stressing on diffusion rates and the phase formation processes within the reactive crucible. We employed Comsol Multiphysics modeling to analyze the experimental results in the framework of electromigration theory, focusing on the distribution of electrical field lines, temperature gradients, and current density values. Additionally, through the integration of finite element calculations with analysis of Electron Backscatter Diffraction (EBSD) and Magneto-Optical Kerr Effect (MOKE) data, we estimated the gradient of internal stresses along the boundaries of the crucible's reaction volume induced by the diffusion of electrically-induced vacancies and adatoms. Due to modest values of the current density in our experiment and the disparity between the rates of crucible body dissolution and vacancy diffusion, no compressive or tensile stresses were observed. Nonetheless, we propose that the developed electrical current-assisted reactive crucible melting technique holds promise for synthesizing metastable phases existing under high positive or negative pressures.

Development of MWCNTs@PDMS nanocomposites with enhanced hydrophobicity and thermo-oxidative stability

This paper presents the fabrication of hydrophobic polymer nanomaterials with improved thermal characteristics based on MWCNTs and poly(dimethylsiloxane). The samples were synthesized by physical adsorption of poly(dimethylsiloxane) onto P-MWCNTs surfaces in the amount from 5 to 20 wt%. The effect of different content of adsorbed polymer on the structure and properties of the prepared nanocomposites was studied in detail using ATR-FTIR, SEM, TEM, XRD and RS techniques. XPS results showed that with the increase of adsorbed PDMS onto the MWCNTs surfaces, the Si 2p atomic percentage increased from 1.5 to 5.0 at.%. The investigation of thermal properties using TGA/DSC techniques in air atmosphere revealed that polymer adsorption on the MWCNTs surfaces enhances the thermo-oxidative stability of the nanocomposites to a great extent. The WCA of MWCNTs@PDMS-1000(20) nanocomposite reached 138.9° while this value was 81.8° in the case of the P-MWCNTs. The electrical characterization of the examined samples demonstrated a non-linear current–voltage behaviour and the invariance of the electrical current value with the increasing polymer content in the nanocomposites. The results suggest that the obtained nanocomposites have multi-functional surfaces and are promising for integration into a silicon-based polymer matrix for the development of new materials for electronic devices.

ANALISA PENGARUH ARUS LISTRIK PENGELASAN GMAW ALUMUNIUM 5052

Aluminum (Al) is a light metal that has corrosion resistance and good electrical conductivity. It is estimated that the use of aluminum in the future will still be wide open, both as a main material and as a supporting material, with the abundant availability of aluminum ore on earth. The welding process is one part of the manufacturing process. The welding process, which in principle is to connect two or more components, is more precisely indicated for assembling several components into a machine form. Welding Aluminum 5052 using GMAW welding with variations in welding electric current, namely 200A and 210 A, welding using the E4043 electrode. The aim of this research is to determine the strength of GMAW welded joints on Aluminum 5052 against the Charphy impact test. The GMAW welding electric current value at an electric current of 200 A produces a work force of 55.012 J and produces 0.678 J/????????2 impact charphy value, at an electric current of 210 A it produces a work force of 64.34 J and produces 0.804 J/????????2 impact charphy value. From the calculation results that have been obtained, the higher the GMAW welding electric current used causes the weld area to become more ductile, but on the contrary, the lower the GMAW welding electric current, the harder it is and tends to break easily.

An AuNPs-based electrochemical aptasensor for the detection of 25-hydroxy vitamin D3.

Vitamin D3 (VD3) is the main form of vitamin D and an essential nutrient for maintaining human life. Currently, traditional methods for detecting 25-hydroxyvitamin D3(25(OH)D3) are complex and expensive. In this study, we constructed an accurate, sensitive, simple, and cost-effective label-free biosensor based on an aptamer for the detection of 25(OH)D3. The aptamer-modified sulfhydryl adopted self-assembly as a way to stably immobilize at the glassy carbon electrode (GCE) surface modified by gold nanoparticles (AuNPs). Upon 25(OH)D3 binding to the aptamer, the complexes inhibit electron transfer at the electrode surface, leading to reduced [Fe(CN)6]3-/4- redox peak current. Consequently, the quantity of 25(OH)D3 that interacts with the electrode-bound aptamer correlates with the observed electric current response values. The Aptamer/AuNPs/GCE aptasensor achieved direct and highly sensitive detection of 25(OH)D3 over a wide concentration range (1.0-1000nM), with a limit of detection of 1.0nM. At the same time, other molecules with a similar structure, such as 25(OH)D2, Vitamin D3, and Vitamin D2, had lower response interference than 25(OH)D3. Therefore, this biosensor has great potential to become a portable diagnostic device for 25(OH)D3.

Copper and Aluminium Electrochemical Corrosion Investigation during Electrolysis and Heating from 20oC to 180oC

Our investigations show that electrochemical corrosion of copper is faster than electrochemical corrosion of aluminium at temperatures below 180°C and electric current density 3,000 A/m2 (or 30 A/dm2=3 mA/mm2). We have obtained that aluminium anodes (cylindrical or spherical) dissolve into concentrated NaCl solution during electrolysis more rapidly with temperature increasing while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C. Electric current value also increases with temperature increasing. Really, such result is unexpected. General quantity of the H+ and Cl- ions decreases during electrolysis at all temperatures since the H2 and Cl2 gases are formed near electrodes. It decreases electric current value on 1.3%. General quantity of the Cu+ and Cu2+ ions decreases with temperature increasing too. We guess that one reason only should be for electric current value increasing: average charge of copper ions increases from +1 at room temperature to +1.5 at 100°C and to +2 at 180°C while charge of aluminium ions remains the same +3. Corresponding mathematical model is proposed for the analysis, and literature experimental data are used too.

Copper, Iron and Aluminium Electrochemical Corrosion Investigation during Electrolysis and Temperature Increasing

An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1%, freezing point equals -22°C, pH 6.5–7.5) at room temperature and 100°C. The average charges of copper, iron, and aluminium ions were calculated using Faraday’s law of electrolysis at electric current density 3,000 A/m2 (or 30 A/dm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100°C. The main condition was zAl=3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl=3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50%/50%) dissolve into the solution at temperature 100°C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100°C (and, obviously, up to 180°C) like “zeroth Arrhenius law”. The spherical anode effect is greater than the cylindrical anode effect in 1.5 times.

Rates of cylindrical and spherical copper anodes dissolving into concentrated NaCl water solution calculation during electrolysis and temperature increasing

Our experimental investigations show that rate of copper anodes degradation decreases during electrolysis in concentrated NaCl solution in water (5 mol/kg or 23 %, freezing point equals −22°C, pH 6.5–7.5) at electric current density about 3000 A/m2 (or 30 A/dm2 = 3 mA/mm2) with temperature increasing from room temperature to 100 °C. Electric current value also increases with temperature increasing. Really, such result is unexpected. General quantity of the H+ and Cl− ions decreases during electrolysis at all temperatures since the H2 and Cl2 gases are formed near electrodes. General quantity of the Cu+ and Cu2+ ions decreases with temperature increasing too. We guess that one reason only should be for electric current value increasing: average charge of copper ions increases from +1 at room temperature to +1.5 at 100 °C and to +2 at 180°C. Corresponding mathematical model is proposed for the analysis. Literature experimental data are used too.

Magnetic particle separation using current-carrying plates: A novel geometry in magnetophoresis

This paper introduces a novel system designed for the separation and trapping of micro-magnetic particles in a microfluidic setup. The system employs two triangular-shaped current-carrying plates with different electrical currents beneath the microchannel to create a non-uniform magnetic field. This magnetic field efficiently separates and traps the magnetic particles, guiding them along distinct paths within the channel. The study includes a parametric analysis involving electrical current, particle size, magnetic susceptibility of particles, and carrier fluid, in order to identify optimal parameters for achieving maximum efficiency. Specifically, M-450 and Oligo(dT)25 magnetic particles are collected using current-carrying plates with electric currents of 50[mA] and 150[mA], respectively. Moreover, the system's efficiency is further boosted by setting the fluid velocity to 2[μm/s], leading to 99% efficiency in collecting and separating different types of particles. The proposed microchip demonstrates its versatility by enabling the trapping and separation of various particles, with the flexibility to adjust the electrical current value accordingly.

Solar thermoelectric generator and thermoelectric cooler performance: analysis and comparison using a different shape geometry

Abstract Thermoelectric devices are one of the technologies used either to generate electricity by applying a temperature difference using thermal energy or as a heating/cooling system by applying an electrical voltage. The number of materials required to produce a product is an important factor in determining its price. Production costs associated with these materials, as well as their availability and quality, play a crucial role in price determination by manufacturers. In this context, a method that employs a uniform volume distribution was implemented. This approach enabled the analysis to focus on other variables, thereby promoting a more precise and relevant evaluation of overall performance. Based on the finite element method, this study investigated the influence of geometric shape, including Rect-leg, Y-leg, Pin-leg and X-leg designs, on the performance of solar thermoelectric generators and thermoelectric coolers. The study was conducted considering the same hot alumina junction surface that receives solar radiation; however, the effective surface, which corresponded to the heat flow area and had a similar area near the exposed surface, varied depending on the chosen leg geometry, thus impacting the heat flux due to the variation in thermal resistance. In the case of a solar thermoelectric generator, the Rect-leg model, having the same effective surface area, presented the lowest heat loss value resulting from convection and radiation in the heat spreader and the hot alumina plate. Under the same conditions, the Y-leg showed the highest value. The Rect-leg design generated, by using thermal and optical concentration, the highest output power of 0.028 and 0.054 W, and efficiency of 3.47% and 4.7%, respectively, whereas the Y-leg generated lower values of 0.006523 and 0.018744 W for power, and 2.83% and 2.71% for efficiency, respectively. In the case of the thermoelectric coolers, the Y-leg generated the highest temperature difference between the hot and cold sides of 67.28 K at an electric current value of 1.8 A, whereas the Rect-leg, Pin-leg and X-leg generated ~66.25, ~67.02 and ~67.19 K at 6.1, 2.7 and 2.6 A.

Iron, copper, and aluminium electrochemical corrosion in motionless and moving electrolytes investigation during electrolysis

An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1 %, freezing point equals −22 °C, pH 6.5–7.5) at room temperature and 100 °C. The average charges of copper, iron, and aluminium ions were calculated using Faraday's law of electrolysis at electric current density 3000 A/m2 (or 30 A/dm2 = 3 mA/mm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100 °C. The main condition was zAl = 3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl = 3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50 %/50 %) dissolve into the solution at temperature 100 °C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180 °C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100 °C (and, obviously, up to 180 °C) like “zeroth Arrhenius law”. The spherical anode effect is practically the same as the cylindrical anode effect. The galvanic current dependence on ratio of cathodic surface area to anodic surface area in the system Fe-chromium (Cr) stainless steel and the time of the iron anodes dissolution in motionless electrolyte and in moving electrolyte are also analysed using literature experimental data.

Thermal, mechanical and electrical performance of structural epoxy resins filled with carbon nanofibers

Carbon nanofibers (CNFs) were heat-treated at 1100 °C (CNF1100) and 2500 °C (CNF2500), respectively, and embedded as fillers at different mass percentages into an epoxy mixture. The paper aims at evaluating, through a comparison between the two different types of resulting nanocomposites, the influence of the CNF heat treatment on the thermal, mechanical, and electrical performance of the formulated samples. Thermogravimetric analysis (TGA) showed oxidative stability in the air of CNF2500 approximately 200 °C higher than the CNF1100 ones. The first oxidation stage of the resins embedding the two typologies of CNFs falls between 380 and 480 °C. This means that the temperature of the heat treatment of the nanofiller does not influence the temperature at which the thermodegradation of the nanocomposites starts. Differential Scanning Calorimetry (DSC) data show that the highest degree of cure (DC) was recorded for the epoxy samples filled with CNF2500. CNF thermal treatment increases the direct current (dc) conductivity of the nanocomposite by 3 orders of magnitude around the electrical percolation threshold (EPT) and increases the storage modulus of the CNF2500-based resins up to 60 °C compared with the unfilled resin. The peculiar wall structure of CNF1100 determines a further slight enhancement. Tunneling Atomic Force Microscopy (TUNA) reveals that the CNFs are evenly distributed on the nanodomains showing higher electric current values for samples loaded with CNF2500.

Analisis Struktur Lapisan Tanah Menggunakan Metode Geolistrik Resistivitas Konfigurasi Schlumberger Vertikal di Kompleks Perumahan Dosen Uncen Kali Acai, Kulurahan VIM, Distrik Abepura, Kota Jayapura

Research on the analysis of the structure of the soil layer using the Vertical Schlumberger Geoelectric method in the Lecturer Housing Complex of Uncen Kali Acai, VIM Village, Abepura District, Jayapura City. This study aims to determine the soil layer, determine the location and depth of the soft soil layer, determine the soft and hard soil. Data retrieval using geoelectric resistivity method with vertical Schlumberger configuration. The instrument used for subsurface surveys is the HV 500 AK resistivity meter. Field measurements obtained electric current and voltage values and then calculated the apparent resistivity values obtained from analysis using IP2win software to see the distribution profile, depth, and thickness of the soil layer.After doing research in the field, it can be seen that the subsurface structure at the research site is dominated by soft clay material with a resistivity value of 0.24 -692.00 Ωm. . In addition, there is a layer of hard rock in the form of a mixture of limestone with a resistivity value of 1181.00 - 8319.00 Ωm.. And the types of subsurface rocks found at the research site are clay, sandstone and limestone.

Multiple fields generated by two dissimilar conductive punches on thermoelectric material

Exposed to high load concentrations environments such as mechanical, thermal, and electrical, thermoelectric equipment may be damaged by the contact surface during operation, resulting in equipment failure. The effects of two dissimilar rigid punches on the thermoelectric material layer under mechanical force and thermoelectric loading are investigated in this article. Using the Fourier transform, the problem is turned into a system of three singular integral equations containing the thermoelectric effect, and the collocation methods are used to solve it numerically. The effects of thermoelectric load, thermoelectric material layer thickness, and the distance between two punches on the electric current density, energy flux, and surface normal stress distribution are thoroughly discussed. The results show that when the two punches are close to each other, below the two punches, the electric current density, energy flux, and contact stress values are larger near the distal end and lower at the inner edge. The stresses at the inner edge of the two indices show opposite characteristics with an increasing of total energy flow and total current, whereas they are consistent at the outer edge. The results aid in the measurement of the multifield coupling properties of finite-thickness thermoelectric material using indenter experiments.

The Influence of the Prestressing Level of the Fully Threaded Anchor Bar on the Corrosion Rate

The article presents experimental research on the corrosion of prestressing steel bars with denotation CKT (fully threaded anchor bars), which are composed of high-quality prestressing steel of the grade Y 1050 (1050 MPa). The experiment was performed using an electrochemical accelerated test. The aspects of the electric current value influence, time dependence on the degree of corrosion, and especially the influence of the prestressing level in the prestressing steel bars on the degree of corrosion were observed and examined. The results of the experiment showed that if the sample was in a stressed state, its degree of corrosion increased. Specifically, for the maximal stress equal to 90% of the tensile strength, the corrosion degree was increased by approximately 7.3%, in comparison to the unstressed specimen. In this case, a 7.3% corrosion degree corresponds to a weight loss of 350 g. The theoretical degree of corrosion was calculated using Faraday’s Law, which allowed the prediction of a rough estimate of the corrosion degree obtained with known input data. The experimental results showed that there was no apparent difference in the corrosion morphology of the sample during the same time-dependent corrosion influence at the same prestressing level in the sample with the same electric current value.

The influence of ultrasonic processing on the structure and electrophysical properties of fruit in combined drying

The intensification of ultrasonic vibrations for the processing of agricultural products is becoming increasingly important in the food industry, as it can reduce energy consumption for the dehydration of raw materials. The research aims to study the effect of sonication on the change of electrophysical parameters and structure of apple raw materials in the process of combined drying using direct electric heating. Using scanning electron microscopy, images of the surface structure of dried apple samples were obtained at different combinations of sonication duration and methods of heat supply to the raw material during the drying process. Based on the experimental studies, the dependences of the current flowing through the sample in the process of combined drying using direct electric heating on the duration of raw material processing in an ultrasonic bath were obtained. The influence of preliminary sonication on the maximum values of the current strength during direct electric heating was determined. The dependences of changes in the resistivity of apple samples during dehydration at different pretreatment durations were investigated. The effect of ultrasound on the initial resistivity of apples, the duration of electro-plasmolysis, and the resistivity values at which the maximum values of the direct electric heating current are observed were determined. The results of the experiments show that the pretreatment of raw materials in an ultrasonic bath can reduce the peak current values by up to 27%. The initial values of the resistivity of the raw material after sonication are reduced by 7.8-13.8% compared to the control samples. The obtained images of the dried fruit surfaces showed an increase in the porosity and roughness of the samples. The obtained results of experimental studies can become a prerequisite for the development of an energy-efficient technical means of ultrasonic processing of fruit and vegetable raw materials before drying and the selection of optimal operating modes

Machine Learning Techniques Applied to the Harmonic Analysis of Railway Power Supply

Harmonic generation in power system networks presents significant issues that arise in power utilities. This paper describes a machine learning technique that was used to conduct a research study on the harmonic analysis of railway power stations. The research was an investigation of a time series whose values represented the total harmonic distortion (THD) for the electric current. This study was based on information collected at a railway power station. In an electrified substation, measurements of currents and voltages were made during a certain interval of time. From electric current values, the THD was calculated using a fast Fourier transform analysis (FFT) and the results were used to train an adaptive ANN—GMDH (artificial neural network–group method of data handling) algorithm. Following the training, a prediction model was created, the performance of which was investigated in this study. The model was based on the ANN—GMDH method and was developed for the prediction of the THD. The performance of this model was studied based on its parameters. The model’s performance was evaluated using the regression coefficient (R), root-mean-square error (RMSE), and mean absolute error (MAE). The model’s performance was very good, with an RMSE (root-mean-square error) value of less than 0.01 and a regression coefficient value higher than 0.99. Another conclusion from our research was that the model also performed very well in terms of the training time (calculation speed).

Experimental investigation of PV/T and thermoelectric systems using CNT/water nanofluids

This study investigated experimentally the thermal performance of a Photovoltaic-thermal (PV/T) and thermoelectric (TE) system using the application of two nanofluids. Single-walled Carbon nanotube/water (SWCNT/water) and multi-walled Carbon nanotube/water (MWCNT/water), with a mass fraction of 0.02% were assessed as the working fluid of the PV/T system. Examinations were done from 10:00 to 16:30 daily in November 2021 at Tarbiat Modares University, Tehran, Iran. Different parameters were measured during the experimental tests including fluid inlet and outlet temperatures, volume flow rate, solar irradiance, and ambient and cell surface temperatures. The results showed that the highest performance of the solar system was measured using the application of SWCNT/water nanofluid. The PV/T surface temperature decreased using nanofluids compared to pure water. It was found that the output generated power and efficiency improved using nanofluid application whereas application of SWCNT/water was more effective compared to MWCNT/water nanofluid. Also, the application of the two nanofluids improved the performance of the TE module compared to pure water. The highest values of TE electric current, voltage, generated power, and efficiency were obtained using the application of SWCNT/water nanofluid.

Formation of Protective and Hardening Coatings on Reinforcing Steels

A technique for applying a protective and hardening coating on steel 18G2S by electrodeposition from ionic melts has been developed. Melt in the triple eutectic point of salts NaF - 30%, NaCl - 16.6% and AlF3 - 53.4% is used as an electrolyte. During electrolysis, a graphite crucible was used as an anode, samples of reinforcing steel (18G2S) cleaned of corrosion and other contaminants were used as a cathode. The temperature of the ionic melt during electrolysis was 1120 ± 5K. In the process of electrolysis, the value of the electric current and voltage were controlled, the change in the mass of the deposited aluminium over a given time was measured. The current output during the deposition of aluminium was kept in the range of 89 ... 96 %. During electrolysis, aluminium diffuses into the surface layers of steel and with iron form solid solutions, intermetallic compounds and eutectics. At the same time, crystals of the FeAl3 compound (59.18% Al) appear in the structure. A further aluminium content decrease in the depth of the surface layer entails the appearance of chemical compounds of the following compositions: Fe2Al7, Fe2Al5, FeAl2 , FeAl. The elasticity limit and ultimate tensile strength of aluminium-coated samples compared to uncoated samples increased by 7.9% and 7.8% respectively. Electrochemical oxidation of samples with aluminium coating of reinforcing steel in sulfuric acid electrolyte was carried out. The oxidation rates for aluminium are set within (7.1... 8.3) 10-6 g / (s mm2) and iron (7.6 10.4) 10-6 g / (s mm2). Experimental assessment of samples oxidation rate under conditions of sulfuric acid electrolyte was carried out at an electric current value of 11 to 18 A.

Numerical analysis of direct-current (DC) plasma processing for high-efficient steel surface modification

Nowadays, direct-current (dc) non-transferred arc plasma torch has drawn significant interest from both academia and industry due to the capability to process products in an efficient and convenient way. The core of this technology is to clarify and manipulate the arc behavior at the interior of the dc plasma torch to produce ideal plasma jets for processing. To solve this problem, a quasi-steady axisymmetric model is built to simulate and compare the arc characteristics in different operating conditions and different nozzle structures of the plasma torch. The results uncover distinct aspects of the study on arc characteristics, including the detection of the primary arc attachment region and its spatial features caused by the choking effect of torch structure. The thermal efficiency focused on processing substrate is also calculated in this paper for estimating the performance of plasma processing. The calculated results show that increasing the mass flow rate brings better thermal efficiency and the greatest promotion is at least 6% in the same current value, whereas improving the arc current value causes the opposite result. Meanwhile, two types of nozzle are compared to the original design in thermal efficiency, where the wide nozzle is chosen for torch optimization due to its best power efficiency. The secondary arc attachment on the metal substrate is discovered though its impact scope is only within a radius of 10 mm from the torch axis, its effect on the processing could be ignored for the extremely low electric current value.