Nickel Wire Research Articles

Effects of Unidirection/Bidirection Torsional Thermomechanical Processes on Grain Boundary Characteristics and Plasticity of Pure Nickel.

The “torsion and annealing” grain boundary modification of pure nickel wires with different diameters was carried out in this paper. The effects of torsional cycles as well as unidirectional/bidirectional torsion methods on grain boundary characteristic distribution and plasticity were investigated. The fraction of special boundaries, grain boundary characteristic distributions and grain orientations of samples with different torsion parameters were detected by electron backscatter diffraction. Hardness measurement was conducted to characterize the plasticity. Then, the relationship between micro grain boundary characteristics and macro plasticity was explored. It was found that the special boundaries, especially Σ3 boundaries, are increased after torsion and annealing and effectively broke the random boundary network. The bidirectional torsion with small torsional circulation unit was the most conducive way to improve the fraction of special boundaries. The experiments also showed that there was a good linear correlation between the fraction of special boundaries and hardness. The plasticization mechanism was that plenty of grains with Σ3 boundaries, [001] orientations and small Taylor factor were generated in the thermomechanical processes. Meanwhile, the special boundaries broke the random boundary network. Therefore, the material was able to achieve greater plastic deformation. Moreover, the mechanism of torsion and annealing on the plasticity of pure nickel was illustrated, which provides theoretical guidance for the pre-plasticization of nickel workpieces.

Deteksi Level Ketinggian Air Dengan Nikelin, Encoder dan Sensor Tekanan Untuk Sistem Peringatan Dini Banjir

Floods and their problems show an increasing indication when rainfall is high. Data from BNPB shows that floods, landslides and tornadoes contributed to the total disasters in Indonesia in a decade. The existence of an early warning flood disaster can help evacuate before a disaster strikes. The system requires a water level detector as the basic data for determining flood predictions. In order to get the water level value, a touch water method can be used using electrodes or without touching the water with the help of pressure sensors, ultrasonic and imaging. Each method has advantages over the other. In this study, the effectivity and accuracy of detecting water levels were investigated using 3 methods: the direct touch of water through nickel wire, buoys with encoder, and pressure sensors. Detection of water levels can be used as a reference to obtain river water level data which is then connected via an IoT or internet connection as a reference for the Early Warning System for the arrival of floods. This study found that changes in water level of less than 30 cm can utilize buoys and encoders with an accuracy of detecting 5 to 6 counts per 1 mm increase in water level. Meanwhile, the measurement of less than 30 cm water level using nickel wire resulted in a non-linear value. The utilization of nickel wire can be used for a height of more than 30 cm where the change in resistivity has started to be linear. ADC change value is 2.93 mV/cm using 10 bit ADC at 5 Volt reference voltage. For water level heights of 50 cm and above, a pressure sensor can use a pressure sensor that can detect changes in pressure of 0.002 in Hg/mm or 0.05 mmHg/mm.

Morphology and Growth Region Analysis of Carbon Nanotubes Growth in Water-Assisted Flame Synthesis

ABSTRACT Water has been proven to be an effective additive to enhance the growth rate and purity of the synthesized carbon nanotubes (CNTs) in the chemical vapor deposition (CVD) method. Due to similar CNT growth parameters in CVD and flame environment, it is expected that a similar effect can be replicated in CNT flame synthesis to a certain degree. The present study analyzes the effect of water addition to the fuel stream toward the CNT growth in methane diffusion flame under atmospheric conditions. Water vapor was introduced into the fuel gas by passing the methane gas through a water bubbler, and the growth condition was analyzed based on a cross-sectional analysis of the grown CNT on top of nickel wire. The water addition to the fuel reduces the axial extent of the growth region due to the reduction in flame height. Even though the spatial distribution of the growth region in the flame with water additive changes compared to that of the flame without water, the average growth region temperature is relatively identical for both flames at a similar height above the burner. The synthesized CNT morphology did not change with the addition of water due to similar temperatures within the growth region and inhomogeneity of catalyst nanoparticle formation. Remarkably, the thickness of the amorphous carbon layer in the growth region decreases by almost 20% in water-assisted flame due to the reduction of carbon supply caused by the modification of gas-phase chemical reaction and water vapor etching effects that happen within the growth region. Numerical simulation of the flame structure shows that addition of water vapor in the fuel stream lowers the methane concentration within the CNT growth region and simultaneously promotes water etching effects on the amorphous carbon layer.

Electrochemical measurement and analysis of YCl3, ScCl3, GdCl3 and MgCl2 in molten eutectic LiCl-KCl

Electrochemical measurements of YCl3, ScCl3, GdCl3 and MgCl2 were obtained in molten LiCl-KCl eutectic at 773 K using a three-electrode configuration. Tungsten rods were used as the working and counter electrodes. Two quasi- and one reference electrode(s) (glassy carbon, nickel wire, and Ni/NiO) were used to collect electrochemical measurements of the analyte salts. Cyclic voltammetry data were analyzed to calculate values of diffusion coefficient, exchange current density, and charge transfer resistance and were determined to be on the order of 10−5 cm2 s−1, 10−2 A cm−2, and 100 Ω; respectively. In general, the values of diffusion coefficients were found to be consistent with those reported of high-temperature molten salts. Relatively large values of exchange current density corresponded with smaller values of charge transfer resistance. These values were found to be reasonable in comparison to results available in the literature. The measured cyclic voltammograms were normalized with respect to both lithium reduction and chloride ion oxidation potentials. Such a normalization technique is effective for comparing experimentally obtained cyclic voltammetry data to those that have been published. An analysis of experimentally obtained results indicates the relation of electrode reactions (e.g., differences of reduction potentials) are independent of the choice of reference electrode. Additionally, the choice of reference electrode did not affect the electrochemical window, exchange current density, or diffusion coefficient values.

Unravelling the Anisotropic Behavior of Nickel—Wires Prepared through External Magnetic Field Assisted Hydrazine Reduction Method

Ni wires, prepared through a hydrazine reduction, were exposed to external magnetic fields of different geometrical shape and configuration during the synthesis denoted as Ni-Non-Magnetic, Ni-Double, Ni-Single, Ni-Ring. Their effect on the wire morphology, magnetization and magnetic anisotropy was then investigated via various characterization techniques viz. X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (HR-FESEM), and vibrating sample magnetometer (VSM). The polycrystalline single phase of the Ni-wires with face centered cubic symmetry was confirmed through the analysis of XRD patterns. Analysis of HR-FESEM images revealed that the Ni-particles were aligned in form of wire-like morphology. The Ni-single sample formed the wires with minimum diameter compared to the parent sample. The magnetization measurements performed at 300 K and 50 K demonstrated the ferromagnetic behavior of all the samples. The room temperature saturation magnetization (MS) and anisotropy constant (K) of the Ni-wires were reduced upon providing the external field during synthesis. However, the low temperature (50 K) magnetization behavior was rather opposing, indicating enhanced values of MS and K. Among all, Ni-ring sample showed maximum anisotropy with a value of 3.84 × 104 erg/cm3 at 50 K. The ambiguous nature of the anisotropic constant and saturation magnetization ascribed partly to the variation in diameters of Ni-wires and to the intermittent spin-spin exchange interactions of unaligned/partially aligned particles during the synthesis. Briefly, in the present study, it was established that the morphology and magnetic anisotropy of the Ni-wires could be tailored through the external magnetic field assisted synthesis method.

Formation technology and structure of titanium nickelide-based alloys in double-arc melting

Alloys based on titanium nickelides have high mechanical properties, as well as a set of special properties: shape memory effect, superelasticity, high level of damping and corrosion resistance, biocompatibility. To obtain titanium nickelides, various technologies are used: smelting in arc and induction vacuum furnaces, electrolysis of molten media, sintering, selfpropagating high-temperature synthesis, which are distinguished by high energy consumption of processes and significant cost. To reduce the cost of obtaining alloys based on titanium nickelide, a technology of double-arc melting in argon using electrode wires made of titanium and nickel was proposed, which makes it possible to obtain not only blanks and parts of the required shape from these alloys, but also deposited layers on the surface of finished products. The conducted studies of processes of titanium nickelides formation by double-arc melting showed that the chemical composition of samples is determined by modes of electric arc melting of electrode wires and, first of all, by the ratio of the feed rates of nickel and titanium wires. The nickel content in obtained samples varied within 34.1–60.1%. The structure of the samples was determined by the ratio of feed rates of electrode wires and was represented by phases: α(Ti); NiTi2; NiTi. The structure based on NiTi2 and Ti is formed when the ratio of the nickel wire feed rate to thetitanium wire feed rate is equal to 0.38. With the feed rate ratio in the range of 0.44–0.86, the structure of samples is represented by phases NiTi2 + NiTi. A single-phase structure based on titanium nickelide (NiTi) during double-arc melting in an argon atmosphere is formed at the feed rate ratio of the order of 1–1.14 of nickel and titanium wires with the same diameter.

English

BACKGROUND Orthodontic metallic appliances in the oral cavity are constantly in contact with biological fluids or tissues thereby releasing particulate masses. They can be common causes of contact allergies and should be considered as a critical issue in determining properties of biomaterials. Nickel ions in various forms and compounds have been known to cause carcinogenic, mutagenic, cytotoxic and allergenic reactions. Pattern of metal ions released from different stainless steel orthodontic appliances in vitro could provide valuable information to consider their application in clinical scenarios. The purpose of the present study was to evaluate metal ions released under different ph levels, immersion period time and using different archwire orthodontic appliances. METHODS Orthodontic appliances were constructed consisting of five brackets from central incisor to the second premolar, a buccal tube welded molar band and an archwire that were used as samples. Total of twelve appliances were constructed; using stainless steel, Ni - Ti, and Thermal Ni - Ti wires (N = 4 each). Half of these samples were immersed in artificial saliva at pH 3.5 and the other half were immersed in artificial saliva at pH 6.75. The samples were stored in an incubator at a temperature of 37 degrees Celsius. Saliva samples from these bottles were collected at the end of 1, 7, 14 and 28 days and subjected to spectrophotometric analysis for estimation of nickel content. RESULTS Nickel release was maximum during the first week of immersion from orthodontic appliances comprising of Ni - Ti wires compared to Stainless steel and thermal Ni - Ti. A gradual decline in the nickel release was observed in the subsequent weeks. Ion release was increased by 30 times in the acidic pH medium, as compared to neutral pH conditions. CONCLUSIONS There is a definite release of nickel ions from orthodontic appliances when exposed to oral environment; however, the amounts are much lower than the daily dietary intake and don’t pose risk of toxicity. Care should be taken in patients with nickel hypersensitivity and wires such as beta - titanium or epoxy coated wires can be substituted. As there is an increase in ion release under acidic conditions the patients need to maintain hygienic oral environment thereby limiting corrosion of appliances. KEY WORDS NitiAlloy, Archwires, pH, Hypersensitivity

Codeposition of Platinum and Gold on Nickel Wire Electrodes via Galvanic Replacement Reactions for Electrocatalytic Oxidation of Alcohols.

Codeposition of Pt and Au on Ni wire was performed using a simple treatment of immersing Ni wire in aqueous solutions containing both K2PtCl4 and HAuCl4. For evaluating the electrochemical properties of the thus-prepared electrodes, cyclic voltammograms (CVs) of 1.0 M ethanol in 1.0 M NaOH aqueous solutions were recorded. Compared with Pt- or Au-deposited Ni wire electrodes prepared by treating Ni wire in aqueous solutions of a single component, e.g., 1.0 mM K2PtCl4 or 1.0 mM HAuCl4, a noteworthy increase in the electrocatalytic current was observed for the oxidation of ethanol with a PtAu-codeposited Ni (PtAu/Ni) wire electrode even when it was prepared in an aqueous solution containing both 0.10 mM K2PtCl4 and 0.10 mM HAuCl4. In addition, the shape and the peak potentials of CVs recorded using PtAu/Ni wire electrodes were found to be different from those recorded with the Pt- or Au-deposited Ni wire electrodes. Because the CV responses typical of the PtAu/Ni wire electrodes were observed even when a PtAu/Ni wire electrode was prepared in an aqueous solution containing both 0.010 mM K2PtCl4 and 1.0 mM HAuCl4, it is considered that a small amount of Pt was effectively modified or incorporated and affected the electrochemical properties significantly. The CV results for ethanol oxidation were compared with those for the electrocatalytic oxidations of methanol, 1-propanol, and 2-propanol. Besides, the CV results recorded with the present PtAu/Ni wire electrodes are discussed in comparison with some previous results obtained using other PtAu nanoelectrocatalysts.

Hydrothermal facile fabrication of superhydrophobic magnetic nanospiky nickel wires: Optimization via statistical design

In the present research, novel superhydrophobic magnetic nanospiky nickel wires via a controlled one-step hydrothermal method were fabricated using Taguchi L16 statistical design. The effects of independent factors including concentration of NiCl2 .6H2O (50-125 mM), the concentration of N2H4.H2O (450-1650 mM), reaction temperature (80-100 ºC), and reaction time (6-12 h) on the wettability properties of octadecyl trichlorosilane (ODTS)-modified samples were investigated. Based on ANOVA and the main effect analyses, despite all factors affecting the wettability response, hydrazine solution concentration with a contribution percent of 47.22% had the most significant effect on the samples' hydrophobicity and growth mechanism as a reducing agent and bridging bidentate ligand. Under the predicted optimum conditions (A1¯,B3¯,C2¯,D2¯), the water contact angle (WCA) and contact angle hysteresis (CAH) were 162.78°±2.4º and 4.32°±0.9º, respectively. Morphological aspects and chemical composition of the as-prepared samples were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), and Vibrating Sample Magnetometer (VSM) analyses. According to the FESEM images, the length and spike diameters were ranged 500-800 nm and 50-90 nm, respectively. The conical nanospikes' growth on the nickel wires was not dependent on the external magnetic field. It just promoted the formation of straight wires along the present magnetic field. The coercivity (Hc) and remnant magnetism (Mr) in the presence of the magnetic field were 103.077 Oe and 7.80 emu/g, respectively, due to the crystallite arrangement anisotropy.

Synchronization Patterns of Two Coupled Oscillators in a Closed Electrochemical Bipolar Cell

We investigate the dynamical behavior of the oscillatory electrodissolution of two nickel and hydrogen reduction reaction in a closed electrochemical bipolar cell. In the bipolar setup, two half U cells are separated by an epoxy plate with two embedded nickel wires; the oxidation and reduction reactions take place at the two ends of the same wire. By tuning the concentration of electrolyte in the anode and cathode compartments, the current level and the dynamics of the oscillatory range can be varied without any external resistance. Phase analysis of the chronopotentiometric measurements showed that the potential oscillations of the two nickel anodes are completely in-phase synchronized, and thus strongly coupled, when 1.00 mm diameter electrodes were employed. The complete in-phase synchronization and strong coupling effect was lost as the electrode diameter was decreased from 1.00 mm to 0.25 mm. The synchronization effects were interpreted by the charge transfer resistance of the hydrogen reduction reaction as the main coupling element in the cell. The experiments demonstrate the use of bipolar electrochemical cells for the investigation of coupling and synchronization in chemical oscillatory processes.

Efficient phenol degradation by laccase immobilized on functional magnetic nanoparticles in fixed bed reactor under high-gradient magnetic field.

Enzymatic degradation of emerging contaminants has gained great interest for the past few years. However, free enzyme often incurs high costs in practice. The immobilized laccase on the polyethylenimine (PEI)‐functionalized magnetic nanoparticles (Fe3O4–NH2–PEI–laccase) was fabricated to efficiently degrade phenolic compounds continuously in a newly fixed bed reactor under a high‐gradient magnetic field. The degradation rate of continuous treatment in the bed after 18 h was 2.38 times as high as that of batch treatment after six successive operations with the same treatment duration. Under the optimal conditions of volume fraction of nickel wires mesh, flow rate of phenol solution, phenol concentration, and Fe3O4–NH2–PEI–laccase amount, the degradation rate of phenol kept over 70.30% in 48 h continuous treatment. The fixed bed reactor filled with Fe3O4–NH2–PEI–laccase provided a promising avenue for the continuous biodegradation of phenolic compounds for industrial wastewater in practice.

Investigation of the Thermal State of Parts to Justify the Possibility of Additive Forming of Nitinol Blanks <i>In Situ</i>

In this paper, the substantiation of the possibility of additive forming of nitinol billets by simultaneous surfacing of two titanium and nickel wires with an electron beam in vacuum is given. The method of mathematical modeling shows the possibility of forming several molten pools of liquid metal on the bead being deposited immediately behind the main pool for remelting the formed material. The modes of the electron beam for the formation of the main and two additional remelting pools due to the deflection of the beam are determined taking into account the technological capabilities of the installation. The residence time of the metal in the liquid state is calculated for various additive forming modes. Remelting makes it possible to increase the residence time in the liquid state by a multiple of the molten pools number. This significantly improves the conditions for mixing the raw materials and reduces the heterogeneity of the material.

Контроль главного разъёма реактора при помощи автоматизированной системы

Traditionally, on reactors of the VVER type, a manual measuring tool is used to inspect the sealing surfaces of the main joint. To automate testing, a PGR-59 system was developed, which was successfully applied to three new power units of type VVER-1200.
 The purpose of the application is to measure the geometric characteristics of the main joint and determine the filling factor of the sealing grooves with nickel wire. Measurement is performed by laser scanning. Additionally, the article has a television camera for searching for defects with the possibility of measuring their dimensions.
 The result of the work was the obtaining of actual profiles of seating surfaces of the main joint of the reactor. The use of the PGR-59 system allows you to monitor the change in the profile of the seating surfaces, which constantly changes due to mechanical impact on the seating surfaces, predict its condition and plan the necessary repairs in advance. Based on the measurement results, new data were found on the nature of the main connector seal.
 The information obtained during the actual measurements made it possible to improve the operational and ergonomic characteristics of the system.

Corrosion Resistance of Dissimilar GTA Welds of Pipeline Steel and Super Duplex Stainless Steels in Synthetic Brine

The effect of weld passes and single V grove designs on the corrosion resistance of dissimilar welds of a low alloy steel and a super duplex stainless steel was studied in synthetic brine. Welds were manufactured in argon by the gas tungsten arc technique and joined by a high nickel wire of super duplex stainless steel. Samples of weld regions were characterized by composition scans, electrochemical measurements, microhardness, and scanning electron microscopy. In X52/ER2594, a transition region of grain boundaries type II and a band of martensite were formed. The base metal of X52 underwent the highest corrosion rate and localized corrosion occurred in the heat affected zone. Interface ER2594/25Cr7Ni and 25Cr7Ni showed the presence of pitting near intermetallics.

High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations.

Modern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the Heat Affect Zone, the region in which cracks occur. Another disadvantage is connected with differences in values of ultimate strength of parent and weld material. The differences can be diminished using the correct welding process, which employs nickel and molybdenum electrode wires at much lower sulfur content. The weld metal deposit contains mainly martensite and bainite with coarse ferrite, while the parent material contains mainly martensite and rather fine ferrite. New technology, micro-jet cooling after the joining process enables to obtain the microstructure of weld metal deposit at acceptable parameters. Welding with micro-jet cooling could be treated as a very promising welding Docol steels process with high industrial application. Results of non-destructive inspections on macro samples corresponded with further destructive test results (tensile strength, hardness, fatigue, metallographic structure analyses). This article aims to verify fatigue behavior of Docol 1200 M steel after welding supported by the cooling using the micro-jet technique. For the first time, micro-jet cooling was used to weld this kind of steel to check the mechanical properties of the joint, especially to determine the fatigue limit. This study is formulated as follows: investigating fatigue resistance of the Docol 1200 M weld manufactured at the cooling process with micro-jets. The joints were produced in the MAG (Metal Active Gas) technology modified by micro-jet cooling. The results collected in the fatigue test were processed in the form of the Wöhler’s S–N diagram following the fatigue limit of the weld examined. All data have indicated the possibility of obtaining a new method of welded joints with high fatigue limit minimum of 480 MPa. It could be important to achieve a tensile strength of 700 MPa while maintaining the best relative elongation at the level of the base material.

Modification with platinum of silver-deposited nickel wire electrodes for electrocatalytic oxidation of alcohols

A silver-deposited nickel (Ag/Ni) wire electrode was prepared via a galvanic replacement reaction between Ag+ and Ni wire in aqueous solution. It was then found that the Ag/Ni wire electrode could be modified with Pt simply by treating it in an aqueous solution of K2PtCl4. Although the deposition of Ag on Ni wire was limited in amount, forming Ag deposits less than 100 nm in size, a considerable increase in the electrocatalytic currents for the oxidation of alcohols could be observed after further modification of the Ag/Ni wire electrodes with Pt. This is in contrast to the fact that it was difficult to produce sufficient electrocatalytic response by modifying Ni wire with Pt directly via a simple galvanic replacement between PtCl42− and Ni wire. Thus, the prior deposition of Ag was found to strongly promote modification with Pt via a simple stepwise treatment using AgNO3 and K2PtCl4. This approach should be effective in modifying various Ni materials with Pt, including Ni microparticles.

Enhanced performance of mesoporous NiCo 2 S 4 nanosheets fibre‐shaped electrode for supercapacitor

Here, mesoporous NiCo2S4 nanosheet fibre-shaped electrode was prepared using Ni–Co layered double hydroxide (LDH) grown on nickel wire as precursor. NiCo2S4 nanosheet electrode displayed excellent electrochemical properties with specific capacitance of 1974.55 mF/cm2 at 2 mA/cm2 and 86.2% capacitance retention after 5000 cycles, which were far higher than those of Ni-Co LDH precursor. Our work provides new strategy to improve the performance of LDH used for supercapacitor.

Исследование структуры и свойств наплавленных покрытий на основе никелида титана

The conditions for formation of coatings based on titanium nickelide under the argon double-arc surfacing of titanium and nickel electrode wires on the titanium samples were shown. Results of evaluating the quality of formation and geometric parameters of the weld at the double-arc surfacing were presented. Relationship between the ratio of feed rates of nickel and titanium wires and chemical composition of the deposited coatings has been established. Investigations of the structure of the surfaced metal at the surfacing modes was carried out. It has been shown that argon double-arc surfacing formed coatings based on the Ti2Ni and TiNi. Mechanical and operational properties of surfaced coatings were studied — hardness, resistance to abrasion and heat resistance at 800 °С. Relative wear resistance of surfaced coatings is higher than that of titanium samples. Dependence of the relative wear resistance of the coatings on the chemical and phase composition was shown. Dependence of heat resistance of the surfaced coatings on the modes of surfacing and the chemical composition of the weld metal is established.

Effect of the ember element in increasing the efficiency of liquefied petroleum gas stoves

The purpose of this study was to determine the effect of use ember element from woven nickel wire to increasing the efficiency of the LPG stoves. It is supposed that high-temperature embers can burn more fuel around the wire, thereby increasing the area of complete combustion. The test was conducted by means of a Water Boiling Test (WBT) and the number of ember layers varied from one to four. It was found that the use of elements of fire without reflectors could increase efficiency by 8.32%, with the highest efficiency being with the use of a single layer ember element of the fire, of 61.71%. However, the use of elements of fire in the finned heat reflectors causes efficiency to decrease, as the pattern to put elements of fire interfere with the reflectivity. This means the heat reflection is blocked by the pattern and trapped between the reflector and pattern elements. As a result, the heat energy from the reflector reflection cannot be forwarded to the combustion zone. The test results also show that the temperature distribution from ember element use can increase the area of complete combustion.

Studies on Energy Cells Based on Si-, Si-Ge- and Ge-Air Systems

Silicon metal may be used as a fuel in Si-Air fuel cells. The most important characteristics of theseenergy cells is its thermodynamic reversibility. The Silicon-air energy cell is highly promising for electric vehicles due to its high theoretical energy density (8470 Wh kg-1) and its discharge products are non-toxic. For the first time, pure silicon and germanium powders are used as anode material. Nickel wire mesh embedded with charcoal and manganese dioxide powder as cathode and concentrated potassium hydroxide is used as electrolyte. Voltage-time curves have been presented in this study for pure silicon and germanium powder, and 5% and 10% germanium with silicon powder.