Electric Spark Discharge Method Research Articles

A Study of Nano-Tungsten Colloid Preparing by the Electrical Spark Discharge Method.

This study developed an energy-enhanced (ee)-micro-electric discharge machining (EDM) system for preparing nano-tungsten (nano-W) colloids. This system enables spark discharge using tungsten wires immersed in deionized water, to produce nano-W colloids. Compared with the chemical preparation method, the processing environment for preparing colloids in this study prevented nanoparticle escape. Among the nano-W colloids prepared using the ee-micro-EDM system and an industrial EDM system, the colloid prepared by the ee-micro-EDM system exhibited a more favorable absorbance, suspensibility, and particle size. The colloid prepared by the ee-micro-EDM system with a pulse on time and off time of 10-10 μs had an absorbance of 0.277 at a wavelength of 315 nm, ζ potential of -64.9 mV, and an average particle size of 164.9 nm. Transmission electron microscope imaging revealed a minimum particle size of approximately 11 nm, and the X-ray diffractometer spectrum verified that the colloid contained only W2.00 and W nanoparticles. Relative to industrial EDM applications for nano-W colloid preparation, the ee-micro-EDM system boasts a lower cost and smaller size, and produces nano-W colloids with superior performance. These advantages contribute to the competitiveness of the electrical spark discharge method in the preparation of high-quality nano-W colloids.

Optimized PID Controller in Micro-Electrical Discharge Machine to Prepare Nano-Ag Colloid by Electrical Spark Discharge Method

Optimized PID Controller in Micro-Electrical Discharge Machine to Prepare Nano-Ag Colloid by Electrical Spark Discharge Method

Characteristic of LED lighting the nanosilver colloid fabricated by electrical spark discharge method

This study determined the effects of visible light of various wavelengths on the characteristics of nanosilver colloids during and after fabrication. The colloids were fabricated using the electrical spark discharge method in a fabrication box, and silver wire was used as the electrode material. A nanosilver colloid fabricated in a dark environment was used as a control sample and featured a surface plasmon resonance (SPR) wavelength, absorbance, average radius, and zeta potential of 397 nm, 0.078, 34 nm, and −40.4 mV, respectively. The experimental colloids were irradiated with red, green, blue, and white light-emitting diodes, but the light resulted in nonsignificant effects on absorbance. After fabrication, the colloids continued to be irradiated; blue light significantly elevated absorbance after only 48 h, and green and white light significantly increased absorbance after 72 h. Red light failed to significantly increase absorbance. After irradiation with blue, green, or white light, the absorbance of the experimental colloids was respectively 1.885, 1.282, and 1.603 times that of the control. Blue light was the most likely to induce SPR because its wavelength was the closest to the nanosilver colloid SPR wavelength. Therefore, among visible light, irradiation with blue light can most increase the absorbance of nanosilver colloids.

Parameter configuration of the electrical spark discharge method for preparing graphene copper nanocomposite colloids and the analysis of product characteristics.

The electrical spark discharge method was used to prepare graphene copper nanocomposite (GNS-Cu) colloids under normal temperature and pressure. Cu and graphite were mixed in deionized water at a Cu : C mass ratio of 9 : 1 (99% purity), and the mixture was used to produce composite rods as the electrodes for spark machining. An electrical discharge machine with five settings of pulse cycle turn-on and turn-off times, namely 10–10, 30–30, 50–50, 70–70, and 90–90 μs, was used to prepare five different types of GNS-Cu colloids. The ultraviolet-visible spectroscopy results revealed that the highest absorbance (2.441) was observed when the turn-on and turn-off times were 30–30 μs, indicating that this configuration was most efficient for preparing GNS-Cu colloids. Transmission electron microscopy and X-ray diffraction analysis were also conducted to examine the surface characteristics and crystal structure of GNS-Cu colloids. The transmission electron microscopy results revealed that Cu particles in the GNS-Cu colloids were located within or on top of graphene sheets. The Cu particle size varied with the discharge efficiency, and the lattice spacing of the Cu particles was approximately 0.218 nm. The results of X-ray diffraction analysis revealed that no byproducts were formed from the preparation of GNS-Cu colloids, which had complete crystal structures.

A study of preparing silver iodide nanocolloid by electrical spark discharge method and its properties

This study employed an electric discharge machine (EDM) and the Electrical Spark Discharge Method (ESDM) to prepare silver iodide nanocolloid (AgINC). Povidone–iodine (PVP-I) was dissolved in deionized water to create a dielectric fluid. Silver material was melted using the high temperature generated by an electric arc, and the peeled-off material was reacted with PVP-I to form AgI nanoparticles (AgINPs). Six discharge pulse wave parameter combinations (Ton–Toff) were employed, and the resultant particle size and suspension of the prepared samples were examined. The results revealed that AgINPs were successfully created using the ESDM. When Ton–Toff was set at 90–90 μs, the zeta potential of the AgINC was − 50.3 mV, indicating excellent suspension stability. The AgINC particle size was 16 nm, verifying that the parameters yielded AgINPs with the smallest particle size distribution and highest zeta potential. Ultraviolet–visible spectrum analyser was performed to analyse the samples, and the spectra indicated that the characteristic wavelength was 420 nm regardless of the Ton–Toff values. X-ray diffraction analysis determined that the AgINPs exhibited two crystal structures, namely β-AgI and Ag. Transmission electron microscopy was performed and revealed that the particles were irregularly shaped and that some of the larger particles had aggregated. The crystal structure was determined to be a mixture of Ag and β-AgI, with a lattice spacing of 0.235 nm and 0.229 nm, respectively. The lattice spacing of the Ag was 0.235 nm. X-ray diffraction analysis indicated that the prepared AgINC were composed of only Ag and I; no additional chemical elements were detected.

Implementation of a micro-electrical discharge machining system to fabricate TiO2 nanocolloid

This study implemented a micro-Electrical Discharge Machining (micro-EDM) system based on Electrical Spark Discharge Method (ESDM) with real-time monitoring system to fabricate TiO2 nanocolloid. This system is relatively small size and low cost compared with industrial EDM machine. The real-time monitoring and control function of this system was achieved with VisSim software, an RT-DAC4/PCI card, and a designed servo circuit. Among the colloid prepared by micro-EDM system with two PID parameters, the colloid prepared using the PID parameters to get absorbance, average particle size, and suspensibility. The experimental results indicated that the colloid had absorbance of 0.187, ζ potential of -27.4 mV, average particle size of 223.9 nm, and percentage of colloidal particles smaller than 91.28 nm of 78.7% when the micro-EDM system Ton–Toff pulse period was set to 30–30 µs, the colloid production time was set to 20 min, and the PID controller parameter were set to Kp = 0.88, Ki = 0.045, and Kd = 0.035. TiO2 nanocolloid preparation in this study was completed in DW. The preparation process did not cause dust dissipation and was thus a green preparation method with low energy consumption.

Preparing Cuprous Iodide Nanocolloid by the Electrical Spark Discharge Method

Preparing Cuprous Iodide Nanocolloid by the Electrical Spark Discharge Method

A Study of Nanosilver Colloid Prepared by Electrical Spark Discharge Method and Its Antifungal Control Benefits.

This is a study of an antimicrobial test, including yeast, Aspergillus Niger, and Aspergillus Flavus, on a nanosilver colloid solution. The antibiosis is compared with a standard silver ion solution at the same concentration as in the experimental process. This study proved that the nanosilver colloid prepared by the electrical spark discharge method (ESDM) is free of any chemical additives, has a microbial control effect, and that the effect is much better than the Ag+ standard solution at the same concentration. 3M Count Plate (YM) is used to test and observe the colony counts. The microbial control test for yeast, Aspergillus Niger, and Aspergillus Flavus is implemented in the nanosilver colloid. In addition to Aspergillus flavus, an Ag+ concentration of 16 ppm is enough to inhibit the growth of the samples. At the same concentration, the nanosilver colloid has a much better microbial control effect than the Ag+ standard solution, which may be because the nanoparticle can release Ag+ continuously, so the solution using the ESDM has a more significant microbial control effect.

Characteristics of Nano-metal Colloid Prepared by Electrical Spark Discharge Method

Background: This study used Electrical Spark Discharge Method (ESDM) to fabricate the nano-Au, nano-Ag and nano-Cu colloid. The spark wears down the surface of the electrodes and gets nano-metal particles at standard temperature and pressure and without adding any other chemical materials in the deionized water. Methods: The nano-metal particles are examined by UV-Visible Spectroscopy, Zetasizer, Transmission Electron Microscope, and Energy Dispersive X-ray Analysis and are proven to be nano-metal colloid. Under the comparison of different parameters (discharge pulse width, HV, Ip), the size of nano-metal particles increases with the level of Ip. Results: Under the experiment of light or dark, most of the Absorbance of the nano-Au and nano-Ag colloid is higher than that of the environment under strong light irradiation as long as it is prepared in a pure black environment. The nano-Au and nano-Ag colloid prepared by ESDM have a zeta potential exceeding the absolute value of 30 mV, no matter which parameter is applied or whether there is illumination or not. Conclusion: It represents a good suspension stability of the nano-Au and nano-Ag colloid, but the nano-Cu colloid does not have this feature. The suspension stability is not good.

Study on the Characteristics of Zinc Oxide Nanocolloid Prepared Using Electrical Spark Discharge Method

In this study, zinc oxide (ZnO) nanocolloids (ZnONCs) were prepared in an electrical discharge machine using the electrical spark discharge method. ZnONCs comprising ZnO nanoparticles (ZnONPs) and zinc nanoparticles (ZnNPs) could be successfully prepared using metal electrodes with 99.97%-purity zinc (Zn) wire and deionized water as the dielectric fluid at normal temperature and pressure; chemical substances were not required in the preparation. According to the results of ultraviolet–visible spectroscopy, the ZnONP characteristic peak value was 345 nm. X-ray diffraction results indicated that ZnONCs had both Zn and ZnO crystallite orientations. Transmission electron microscopy results revealed that ZnONPs and ZnNPs exhibited elongated crystals measuring 30–50 nm, a ZnO d-spacing of 0.25 nm, and a Zn d-spacing of 0.21 nm. Raman and photoluminescence imaging results indicated favorable structural quality and crystallinity.

Parameters and properties for the preparation of Cu nanocolloids containing polyvinyl alcohol using the electrical spark discharge method

Through the use of an electric discharge machine, this study performed the electrical spark discharge method in deionised water under normal temperature and pressure for Cu nanocolloid (CuNC) preparation. The CuNCs had a zeta potential of 12.3 mV, indicating poor suspension stability. The suspension stability was effectively increased (zeta potential 32.5 mV) through the addition of polyvinyl alcohol (PVA) to form PVA-containing CuNCs PVA/CuNCs. Next, the following pulse-width modulation (Ton:Toff) parameters were tested to determine the optimal setting for PVA/CuNC preparation: 10:10, 30:30, 50:50, 70:70 and 90:90 µs. The optimal preparation parameter was then determined according to the absorbance, zeta potential and size distribution results. Finally, the surface properties and crystal structure of the PVA/CuNCs were characterised through transmission electron microscopy (TEM) and X-ray diffraction (XRD). When the Ton:Toff was set to 30:30 µs, preparation efficiency was optimal, as was suspension stability, as indicated by the absorbance value (0.534), zeta potential (32.5 mV) and size distribution (85.47 nm). Transmission electron microscopy revealed that Cu nanoparticles that were more dispersed in the PVA/CuNCs had a diameter smaller than 10 nm and a crystal line width of 0.2028 nm. X-ray diffraction showed that the PVA/CuNCs contained intact Cu crystal structures.

Parameter optimization of nanosilver colloid prepared by electrical spark discharge method using Ziegler-Nichols method

This study adopted a self-developed real-time monitoring micro electrical discharge machine (micro-EDM) system for nanosilver colloid preparation through the electrical spark discharge method (ESDM). The developed system relies on the parameters modulated through a closed-loop proportional-integral-derivative (PID) controller and optimized through the Ziegler–Nichols method to get modulated PID parameters, affect the process duration of ESDM. In the present study, samples were prepared under varying process durations and pulse modulation (TON–TOFF) duty cycles. Various instruments were applied to compare the absorbance values, discharge success rates, and particle size distributions of these samples. The results indicated that, compared with the samples prepared through the closed-loop PID controller, the samples prepared through the modulated PID parameters exhibited substantially higher absorbance, discharge success rates, and smaller particle size distribution. The improved discharge success rate is increased to an average of 129% compared to the original parameters. The particle size distributions of samples based on the empirical data averaged 10–20 nm, whereas the samples based on the parameters modulated through the Ziegler–Nichols method were primarily smaller than 10 nm, with the averaged size being 7.068 nm. These confirmed the effectiveness of the Ziegler–Nichols method in optimizing ESDM nanosilver colloid preparation.

Fabrication of nano-bismuth colloids in deionized water using an electrical discharge machine

Bismuth (Bi) is used to treat certain diseases, however the Bi powder or colloids used in medicine must be nonpolluting and safe. The use of electrical discharge machines (EDMs) to produce nano-Bi powder is a green process. A nonpolluting and safe nano-Bi colloid can be produced swiftly and easily in deionized water using the electrical spark discharge method, adjusting the discharge pulse width Ton, Toff and the discharge current IP of the EDM. Transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy, the Zetasizer technique, ultraviolet–visible spectroscopy (UV–Vis), and other techniques were used to analyze a nano-Bi colloid prepared under various discharge parameters to optimize the preparation of Bi nanoparticles (Bi-NPs) using EDMs. The results of this study indicated that Bi-NP colloids were successfully prepared using EDM. TEM images revealed that the NPs were smaller than 50 nm with only the Bi element in the colloid. Furthermore, the zeta potential of the nano-Bi colloid exceeded 30 mV, which indicated that the suspension of the colloid was excellent. A UV–Vis absorption peak was observed at approximately 234–237 nm.

Deriving Optimized PID Parameters of Nano-Ag Colloid Prepared by Electrical Spark Discharge Method.

Using the electrical spark discharge method, this study prepared a nano-Ag colloid using self-developed, microelectrical discharge machining equipment. Requiring no additional surfactant, the approach in question can be used at the ambient temperature and pressure. Moreover, this novel physical method of preparation produced no chemical pollution. This study conducted an in-depth investigation to establish the following electrical discharge conditions: gap electrical discharge, short circuits, and open circuits. Short circuits affect system lifespan and cause electrode consumption, resulting in large, non-nanoscale particles. Accordingly, in this study, research for and design of a new logic judgment circuit set was used to determine the short-circuit rate. The Ziegler–Nichols proportional–integral–derivative (PID) method was then adopted to find optimal PID values for reducing the ratio between short-circuit and discharge rates of the system. The particle size, zeta potential, and ultraviolet spectrum of the nano-Ag colloid prepared using the aforementioned method were also analyzed with nanoanalysis equipment. Lastly, the characteristics of nanosized particles were analyzed with a transmission electron microscope. This study found that the lowest ratio between short-circuit rates was obtained (1.77%) when PID parameters were such that Kp was 0.96, Ki was 5.760576, and Kd was 0.039996. For the nano-Ag colloid prepared using the aforementioned PID parameters, the particle size was 3.409 nm, zeta potential was approximately −46.8 mV, absorbance was approximately 0.26, and surface plasmon resonance was 390 nm. Therefore, this study demonstrated that reducing the short-circuit rate can substantially enhance the effectiveness of the preparation and produce an optimal nano-Ag colloid.

A Study of a PID Controller Used in a Micro-Electrical Discharge Machining System to Prepare TiO2 Nanocolloids

This study developed a micro-electrical discharge machining (micro-EDM) system for producing TiO2 nanocolloids. When a proportional–integral–derivative controller designed using the Ziegler–Nichols method was adopted to control the interelectrode gap, TiO2 nanocolloids were obtained from spark discharges generated between two titanium wires immersed in deionized water. For a pulse on time–off time of 40–40 μs and a colloid production time of 100 min, TiO2 nanocolloids were produced that had an absorbance of 1.511 at a wavelength of 245 nm and a ζ potential of −47.2 mV. They had an average particle diameter of 137.2 nm, and 64.2% of particles were smaller than 91.28 nm. The minimum particles were spherical. The characteristics of colloids confirmed that the micro-EDM system can produce TiO2 nanocolloids with excellent suspension stability. The colloid production method proposed in this study has the advantages of low equipment cost and no dust diffusion in the process environment. These advantages can improve the competitiveness of the electric spark discharge method for high-quality TiO2 nanoparticle production. The colloids produced in this study did not contain elements other than titanium and oxygen, and they may prevent secondary environmental pollution.

Parameter control and property analysis in the preparation of platinum iodide nanocolloids through the electrical spark discharge method.

This study employed the electrical spark discharge method to prepare platinum iodide nanocolloids at normal temperature and pressure. Wires composed of 99.5% platinum were applied as the electrodes, and 250 ppm liquid iodine was employed as the dielectric fluid. An electric discharge machine was applied to generate cyclic direct current pulse power between the electrodes. Five sets of turn-on and turn-off time (Ton–Toff) parameters, namely 10–10, 30–30, 50–50, 70–70, and 90–90 μs, were implemented to identify the optimal nanocolloid preparation conditions. An ultraviolet-visible spectroscope, a Zetasizer, and a transmission electron microscope were used to examine the nanocolloids' properties. The results revealed that the Ton–Toff parameter set of 10–10 μs was the most ideal setting for platinum iodide nanocolloid preparation. With this parameter set, the characteristic wavelengths of the nanocolloid were 285 and 350 nm, respectively; its absorbance values were 0.481 and 0.425, respectively; and its zeta potential and particle size were −30.3 mV and 61.88 nm, respectively. This parameter set yielded maximized absorbance, satisfactory suspension stability, and minimized nanoparticle sizes for the nanocolloid.

Parameter control and concentration analysis of graphene colloids prepared by electric spark discharge method

AbstractIn this study, graphene colloids were prepared using the electric spark discharge method (ESDM) with graphite rods (99.9% purity) in deionized water (DW) at a normal temperature and pressure. Five different types of graphene colloids were prepared using an electrical discharge machine (EDM) with five different pulse cycle switching times (Ton:Toff) = 10:10, 30:30, 50:50, 70:70, and 90:90 μs. According to the Ultraviolet-visible spectra (UV-Vis) and Zetasizer analysis, the results showed that the 10:10 μs parameter was the most suitable for the preparation of graphene colloids. UV-Vis was also used to detect the concentration of the graphene colloids; a comparison with a graphene oxide (GO) confirmed that this method could be used to calculate the discharge time needed to produce graphene colloids with different concentrations in the ESDM process.

Novel Preparation of Reduced Graphene Oxide-Silver Complex using an Electrical Spark Discharge Method.

This study used an electrical discharge machine (EDM) to perform an electrical spark discharge method (ESDM), which is a new approach for reducing graphene oxide (GO) at normal temperature and pressure, without using chemical substances. A silver (Ag) electrode generates high temperature and high energy during gap discharge. Ag atoms and Ag nanoparticles (AgNP) are suspended in GO, and ionization generates charged Ag+ ions in the Ag plasma with a strong reducing property, thereby carrying O away from GO. A large flake-like structure of GO was simultaneously pyrolyzed to a small flake-like structure of reduced graphene oxide (rGO). When Ag was used as an electrode, GO was reduced to rGO and the exfoliated AgNP surface was coated with rGO, thus forming an rGOAg complex. Consequently, suspensibility and dispersion were enhanced.

Fabricating Tungsten and Tungsten-Trioxide Nanocomposite Colloid in Deionized Water by Electric Spark Discharge Method

In this study, the electric spark discharge method was used to prepare tungsten (W) and tungsten-trioxide (WO3) nanocomposite colloid. A high-energy arc was used to melt a W rod, and the W ions were then ionized with a medium arc to prepare W and WO3 nanocomposite colloid at a high temperature. This preparation method was simple, fast, and effective. The particle size and zeta potential of the samples were measured with a Zetasizer and the shape, size, distribution, and crystal lattice of the W (0.225 nm) and WO3 (0.355 nm) nanoparticles were observed and compared using a Transmission Electron Microscope. The optical properties of the nanocomposite colloids were measured with a UV–visible spectrophotometer (UV–Vis). X-ray diffraction and a Raman Spectrometer were used to detect the crystal properties of the W and WO3 nanoparticles. The results showed that the components of the nanocomposite colloid were W and WO3. The average size of the nanoparticles was 79.65 nm and the zeta potential was − 52.5 mV; thus, the W and WO3 nanoparticles had the suspension effect. There was a peak at 320 nm according to UV–Vis, which is the characteristic absorbance of W and WO3.

Stability analysis of platinum nanoparticles prepared by ESDM in deionised water

Electrical discharge machine was used to prepare platinum nanocolloid by electric spark discharge method (ESDM) at room temperature. Preparation of platinum nanocolloid needed only traditional electrical discharge machine, platinum wire (99.5%) and magnet mixer. Then verify whether platinum nanoparticles be could successfully prepared under different preparation and their suspension stability. The optical properties and zeta potential were measured by UV–vis and Zetasizer, and their characteristic peaks (surface plasmon resonant), while suspension stability was analysed. The results of transmission electron microscope showed size, shape and dispersibility of platinum nanoparticles with a size of mostly <10 nm. X-ray diffraction was used to measure crystal lattice structure and component of platinum nanoparticles. In this work, platinum nanocolloid in conditions of normal and centrifuge were analysed. Zeta potential of normal colloid was decreased from −29.5 to −18.8 mV after precipitation, while zeta potential of the centrifuged colloid still maintained at −40 mV, confirming the good suspension stability of platinum nanocolloid prepared by ESDM after centrifugation.