Concentrations Of Nickel Chloride Research Articles

Electrodeposition of Ni-Ga Alloy Catalyst from BMIM-Otf Ionic Liquid Electrolyte for Electroreduction of Carbon Dioxide

To achieve a low-carbon economy, it is important to convert and use carbon-based energy sources efficiently. Electroreduction of CO2 to fuel and chemical feedstock is an attractive and prospective route for simultaneous conversion of CO2 and renewable power sources [1]. Ni5Ga3 compound was thought as the most active composition to take place of conventional Cu/ZnO/Al2O3 catalyst for the synthesis of methanol using CO2 and H2 [2,3]. Compared with chemical synthesis method, electrodeposition is an in-situ, convenient, chemical residue-free and easily controllable way to prepare catalyst. BMIM-OTF (1-Butyl-3-methylimidazolium trifluoromethanesulfonate) ionic liquid mixing with propyl alcohol in volume ratio of 6:1 was used as the electrolyte to electrodeposit Ni-Ga catalysts. The concentrations of nickel chloride and gallium chloride in the electrolyte are 50~80mmol/L and of 50~160mmol/L, respectively. Cyclic voltammetry (CV) of Ni, Ga and co-deposition of Ni-Ga alloy were scanned at speed of 100mV/s using a glassy carbon electrode (GCE) as working electrode, a platinum sheet as counter electrode and a platinum wire as reference electrode. The GCE was polished by Al2O3 powder of 1.0μm and ultrasonic washed in deionized water for 3 times before measuring. As seen from CV curves, the cathodic potential peak of Ni-Ga alloy is more positive than those of Ga and Ni, which indicates that the co-deposition of Ni-Ga is easier than that of single metal. The co-deposition of Ni-Ga is a diffusion controlled irreversible process. Gray-white deposits of Ni-Ga were electrodeposited at potential range of -1.4V to -2.0V vs. Pt. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were employed to observe the micromorphologies of Ni-Ga alloy. The Ni-Ga deposits are loose and composed by small particle clusters. The particle size of Ni-Ga alloy is about 100nm, which is bigger than that prepared by chemical synthesis method. There may be coexist of crystalline and amorphous structures in Ni-Ga alloy. The contents of Ni and Ga in the alloy were measured by Energy disperse spectroscopy (EDS). With the increase of concentration of gallium chloride in the electrolyte and the negative shift of potential, the contents of Ga in the Ni-Ga deposits increase. Catalytic activity of Ni-Ga alloy on conversion of CO2 were evaluated by CV curves measured in CO2 saturated KHCO3 aqueous solution of 0.1mol/L at scan rate of 100mV/S. Ni-Ga deposit shows a relative bigger catalytic activity compared to GC and nickel electrode. In conclusion, Ni-Ga alloy catalyst in size of 100nm were electrodeposited at -1.8V from the BMIM-OTF ionic liquid electrolyte, which has catalytic activity on electroreduction of CO2. The future work will focus on the preparation of nano size particles to present higher catalytic activity.

Effect of H2O on Corrosion of Ni in Molten Eutectic LiCl-KCl

In the absence of water and oxygen, it is known that molten chloride salts are relatively non-corrosive to a wide range of metals. Corrosion rates are expected to increase when water is present, however. To understand the threshold at which very small concentrations of water can cause corrosion of metals such as nickel and iron, a series of electrochemical measurements were made in molten eutectic LiCl-KCl and LiCl-KCl-UCl3. The presence of UCl3 is relevant for the use of this electrolyte in nuclear fuel electrorefining systems. Such systems are normally operated in inert atmosphere glove boxes or hot cells, where water concentration ranges from 1 to 50 ppm. In this study, argon gas containing up to 900 ppm H2O was bubbled into molten LiCl-KCl or LiCl-KCl-UCl3. Either a nickel or iron rod was inserted into the salt along with a Ag/AgCl reference electrode encased in a close-ended ceramic tube. The open circuit potential (OCP) was measured between the metal rod and the reference electrode as the gaseous Ar+H2O was bubbled into the salt. The temperature was held constant at 773 K. This is expected to result in formation of HCl, which will corrode the metal and cause a metal chloride to form and partition into the salt phase. Based on the Nernst Equation, this should cause a positive rise in the OCP. Based on changing OCP as a function of time, the rates of corrosion were compared for different concentrations of H2O in the gas stream. Cyclic voltammetry scans and samples of the salt were taken to verify the concentration of nickel and iron chloride in the salt at the end of each experiment. Noticeable corrosion was achieved in a time frame of 4 hours with water concentration as low as 120 ppm. This result demonstrates the importance of achieving a very high level of dryness in the salt prior to heating and melting it. Water concentration in the contacting atmosphere should also be well below 100 ppm to ensure long-term stability of the steels and similar metal alloys in molten LiCl-KCl or LiCl-KCl-UCl3. Implications and strategies for long term operation of electrorefiners using LiCl-KCl will be discussed.

Accumulation of nickel ions in seedlings of Vicia sativa L. and manifestations of oxidative stress.

The accumulation of nickel ions in the roots and shoots of vetch seedlings (Vicia sativa L.) at increasing concentrations of nickel chloride in the medium was studied. It was shown that the accumulation of nickel in the shoots was increased when the concentration of nickel chloride in the medium was more than 50μM. The bioconcentration factor and sustainability index for vetch seedlings were calculated under the experimental conditions. The obtained results were similar to parameters for other plants, grown on a nutrient medium or soil substrate. First, the obtained results allowed estimate the limits of nickel chloride concentrations for four of five zones, which correspond to the theoretical concept of dose-response curves in the studies on the influence of physiologically essential heavy metals on plants (Prasad 2010). Some parameters of oxidative stress caused by the presence of nickel chloride in the medium were shown. It seems that at low nickel concentrations in the medium in vetch seedlings the increase of several biochemical parameters (catalase activity and proline) caused by the high amylase activity in seeds.

The neuroprotective effects of taurine against nickel by reducing oxidative stress and maintaining mitochondrial function in cortical neurons

Previous studies have indicated that oxidative stress and mitochondrial dysfunction are involved in the toxicity of nickel. Taurine is recognized as an efficient antioxidant and is essential for mitochondrial function. To investigate whether taurine could protect against the neurotoxicity of nickel, we exposed primary cultured cortical neurons to various concentrations of nickel chloride (NiCl2; 0.5mM, 1mM and 2mM) for 24h or to 1mM NiCl2 for various periods (0h, 12h, 24h and 48h). Our results showed that taurine efficiently reduced lactate dehydrogenase (LDH) release induced by NiCl2. Along with this protective effect, taurine pretreatment not only significantly reversed the increase of ROS production and mitochondrial superoxide concentration, but also attenuated the decrease of superoxide dismutase (SOD) activity and glutathione (GSH) concentration in neurons exposed to NiCl2 for 24h. Moreover, nickel exposure reduced ATP production, disrupted the mitochondrial membrane potential and decreased mtDNA content. These types of oxidative damage in the mitochondria were efficiently ameliorated by taurine pretreatment. Taken together, our results indicate that the neuroprotective effects of taurine against the toxicity of nickel might largely depend on its roles in reducing oxidative stress and improving mitochondrial function. Taurine may have great pharmacological potential in treating the adverse effects of nickel in the nervous system.

The regulatory role of nickel on H3K27 demethylase JMJD3 in kidney cancer cells.

Nickel compounds are an important class of environmental pollutants and carcinogens. Chronic exposure to nickel compounds has been connected with increased risks of numerous cancers, including lung and kidney cancers. But the precise mechanism by which nickel compounds exert their carcinogenic properties is not completely understood. In this study, kidney cancer cells namely human embryonic kidney 293-containing SV40 large T-antigen (HEK293T) and 786-0 were incubated with various concentrations of nickel chloride for 24 h before analysing the expression of three histone H3K27 methylation-modifying enzymes and H3K27me3 using quantitative real-time polymerase chain reaction, Western blot and immunofluorescence analyses. Our results showed that incubation of nickel chloride upregulated the expression of H3K27me3 demethylase jumonji domain-containing protein 3 (JMJD3) in kidney cancer cells, which was accompanied by the reduction in the protein level of H3K27me3. Enhanced demethylation of H3K27me3 may represent a novel mechanism underlying the carcinogenicity of nickel compounds.

Whole adult organism transcriptional profiling of acute metal exposures in male Zebrafish

BackgroundA convergence of technological breakthroughs in the past decade has facilitated the development of rapid screening tools for biomarkers of toxicant exposure and effect. Platforms using the whole adult organism to evaluate the genome-wide response to toxicants are especially attractive. Recent work demonstrates the feasibility of this approach in vertebrates using the experimentally robust zebrafish model. In the present study, we evaluated gene expression changes in whole adult male zebrafish following an acute 24 hr high dose exposure to three metals with known human health risks. Male adult zebrafish were exposed to nickel chloride, cobalt chloride or sodium dichromate concentrations corresponding to their respective 96 hr LC20, LC40 and LC60. Histopathology was performed on a subset of metal-exposed zebrafish to phenotypically anchor transcriptional changes associated with each metal.ResultsComparative analysis identified subsets of differentially expressed transcripts both overlapping and unique to each metal. Application of gene ontology (GO) and transcription factor (TF) enrichment algorithms revealed a number of key biological processes perturbed by metal poisonings and the master transcriptional regulators mediating gene expression changes. Metal poisoning differentially activated biological processes associated with ribosome biogenesis, proteosomal degradation, and p53 signaling cascades, while repressing oxygen-generating pathways associated with amino acid and lipid metabolism. Despite appreciable effects on gene regulation, nickel poisoning did not induce any morphological alterations in male zebrafish organs and tissues. Histopathological effects of cobalt remained confined to the olfactory system, while chromium targeted the gills, pharynx, and intestinal mucosa. A number of enriched transcription factors mediated the observed gene response to metal poisoning, including known targets such as p53, HIF1α, and the myc oncogene, and novel regulatory factors such as XBP1, GATA6 and HNF3β.ConclusionsThis work uses an experimentally innovative approach to capture global responses to metal poisoning and provides mechanistic insights into metal toxicity.

A simple and efficient method of nickel electrodeposition for the cyclotron production of 64Cu

Nickel targets for the cyclotron production of 64Cu were prepared by electrodeposition on a gold backing from nickel chloride solutions using boric acid as buffer. Parameters studied were nickel chloride and boric acid concentration, temperature and current density. All plating conditions studied were successful obtaining efficiencies of approximately 90% in 2–3h, reaching almost quantitative plating (>97%) in 10–20h depending on the current density. All plated targets withstood proton irradiations up to 40µA for 2h. Recovered nickel was successfully recycled and reused with an overall efficiency >95%.

Growth Responses, Metal Accumulation and Phytoremoval Capability in Amaranthus Plants Exposed to Nickel Under Hydroponics

The characterisation of plant responses to metal exposure represents a basic step to select a plant species for phytoremediation. In the present work, 3-week-old Amaranthus paniculatus L. plants were subjected to nickel chloride concentrations of 0 (control), 25, 50, 100 and 150 μM in hydroponic solution for 1 week to evaluate morphophysiological responses, such as biomass production and partitioning, nickel accumulation in plants and nickel removal ability from the polluted solutions. The results showed a progressive decrease in plant organ dry mass with the enhancement of nickel (Ni) concentration in the solution, suggesting a good metal tolerance at 25 μM Ni and a marked sensitivity at 150 μM Ni. The modification of biomass partitioning was particularly appreciated in leaves, analysing the organ mass ratio, the total leaf area and the specific leaf area. Amaranthus plants accumulated a significant amount of Ni in roots exposed to the highest Ni concentrations, while lower metal contents were observed in the aerial organs. The Ni uptake ratio was progressively reduced in plants exposed to increased Ni concentrations. The metal translocation from root to shoots, appreciated by the Ni translocation index, showed a far lower value in Ni-exposed plants than in controls. Moreover, by measuring the daily Ni content of the solutions, a lower Ni removal ability was found in Amaranthus plants at increasing Ni concentrations. Remarkably, plants exposed to 25 μM Ni succeeded in removing almost 60 % of the initial Ni content of the solution showing no stress symptoms. The potential of A. paniculatus for phytoremediation was discussed.

Physiological effects of nickel chloride on the freshwater cyanobacterium <i>Synechococcus</i> sp. IU 625

Harmful algal blooms (HABs) are a serious environmental problem globally. The ability of cyanobacteria, one of the major causative agents of HABs, to grow in heavy metal polluted areas is proving a challenge to environmental restoration initiatives. Some cyanobacteria secrete toxins, such as microcystin, that are potentially dangerous to animals and humans. In this study, the physiology of a cyanobacterium was assessed to nickel chloride exposure. Cell growths were monitored throughout the study with various nickel chloride concentrations (0, 10, 25 or 50 mg/L). Morphological abnormalities were observed with microscopic image analyses. Inductively coupled plasma mass spectrometry (ICP-MS) was carried out to trace the distribution of nickel during the growth period. This study provides insight on potential nickel response mechanisms in freshwater cyanobacteria, which may lead to effective HAB prevention strategy development.

Effect of Nickel Chloride on Cell Proliferation

Objective:Metal alloys used in dentistry and in other biomedical fields may release nickel ions in the oral environment. The release of nickel might influence the normal biological and physiological processes, including tissue wound healing, cell growth and proliferation. The aim of this study was to evaluate in vitro the effects of nickel ions on cell cycle, viability and proliferation.Materials and Methods:Human osteosarcoma cells (U2OS) and human keratinocytes (HaCat) were exposed to different nickel chloride (NiCl2) concentrations (0 - 5mM) for various periods exposure. The viability of cultured cells was estimated by flow cytometry using Annexin V-FITC and Propidium Iodide (PI). Cell proliferation was evaluated by using carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and flow cytometry. Finally, the effects of NiCl2 on cell cycle were assessed and quantified by flow cytometry. Statistical analysis was performed by means of ANOVA followed by Tukey’s test.Results:NiCl2 induced a dose and time dependent decrease in cell viability. After 24h, 1mM NiCl2 caused a similar and significant reduction of viability in U2OS and HaCat cells, while higher NiCl2 concentrations and longer exposure times showed a reduced cytotoxic effect in HaCat as compared to U2OS cells. Exposure to NiCl2 caused a dose- and time-dependent inhibition of cell proliferation in both cell lines tested, with a prominent effect on U2OS cells. Furthermore, both cell lines exposed to NiCl2 exhibited significant changes in cell cycle distribution after 24h exposure 2mM NiCl2, as compared to untreated cells (p<0.05).Conclusion:Our results indicate that release of nickel ions may affect cell proliferation. The inhibition of cell growth by NiCl2 is mediated by both cell cycle arrest and by induction of cell death.

Efficacy of all-trans retinoid acid in preventing nickel induced cardiotoxicity in myocardial cells of rats

Nickel, a metal commonly found in battery plants and welding factories, has potential cardiotoxicity, while all-trans retinoid acid (atRA) can promote cardiovascular repair and myocardial recovery. The purpose of this study was to investigate whether atRA could prevent cardiotoxicity induced by nickel both in vitro and in vivo. In the study, a rat myocardial cell line (H9c2) exposed to different concentrations of nickel chloride (NiCl2) displayed apoptotic features accompanied by reactive oxygen species generation. In addition, NiCl2 also caused obvious apoptosis and systolic dysfunction in primary myocardial cells. Treatment with atRA efficiently attenuated the cytotoxicities triggered by NiCl2 as it significantly mitigated ROS generation and decreased MAP kinases activity in NiCl2-treated cardiomyocytes. Additionally, NiCl2 exposure caused obvious arrhythmia in Sprague–Dawley rats with the maximum tolerance dose of NiCl2 between 2 and 3mg/kg. A combinational intragastric administration of 40mg/kg atRA can partially reverse NiCl2-induced arrhythmia in rats. Our results suggested that atRA might have therapeutic potential in alleviating the adverse effects of nickel on the cardiovascular system.

Effect of Temperature on the Synthesis of Nano-Nickel Particles

<b> </b><b> </b>The focus of this study is to observe the effect of temperature on the size and morphology of nano-nickel particles. Nano-nickel particles have been prepared by a simple polymer-surfactant interaction of a cationic polymer poly vinyl pyrrolidone (PVP) with an anionic surfactant, sodium-dodecyl-sulphate SDS at different temperatures i.e. 60℃, 80℃ and 100℃. Nano-sized nickel particles were synthesized by using nickel chloride as the precursor, hydrazine as the reducing agent in the presence of SDS and PVP in a strong basic medium (pH-10.2). Our research shows that the rate of reduction increases as the reaction temperature was increased from 60℃ to 100℃. Finer particles of diameters less than 10nm were formed as the temperature was increased from 60 to 100℃. The morphology of the synthesized nano-nickel particles also varied as the temperature was increased. The concentration of nickel chloride and SDS/PVP was kept constant in all these experiments. The nano-sized nickel particles synthesized were characterized by using SEM and HRTEM.

Study of apoptosis induction using fluorescent and higher harmonic generation microscopy techniques in Acartia tonsa nauplii exposed to chronic concentrations of nickel

In this study, we applied different fluorescent techniques to analyse the induction of apoptosis in the copepod Acartia tonsa nauplii exposed to low concentrations of nickel chloride (NiCl2). Newly hatched and later naupliar stages were exposed to increasing concentrations of NiCl2 (0.016, 0.025 and 0.063 mg·L−1) for 7 days and then stained with annexin V–FITC, a vital fluorescent probe commonly used to visualise apoptotic cells in live samples. Nauplii were also stained with TUNEL, a non-vital fluorescent probe used to detect apoptosis in fixed copepods. Moreover, we used for the first time, two-photon fluorescence (2PF) microscopy and higher harmonic generation microscopy (second SHG and third THG harmonic generation) to study apoptosis induction in A. tonsa nauplii without the use of fluorescent probes. 2PF and THG intensity increased in samples exposed to higher Ni concentrations, with respect to the control, whereas SHG signals were similar in all treated samples and visualised muscles. Future perspectives on the use of these new technologies to reveal apoptosis are discussed.

Optical Absorption of Polyvinyl Alcohol Films Doped with Nickel Chloride

Films of pure and doped Polyvinyl alcohol (PVA) with different concentration of Nickel Chloride (NiCl2) were prepared using the casting technique, in order to investigate the effect of NiCl2 additions on the optical properties of PVA host. The dispersion studies of pure PVA film and PVA films doped with NiCl2 were studied using complex refractive index in the wavelength range 190-1100 nm. The absorption spectral analysis showed that the optical energy band is due to the direct and indirect allowed optical transitions. The optical energy band gap Egopt of the films decreases with increasing NiCl2 contents, while the Urbach energy ∆Et called the width of localized states in the optical band gap decreases from 0.7414 to 0.1891 eV. The reductions of optical energy band gap were observed for all samples after annealing at temperatures 70oC for three hours.

Nickel exposure induces oxidative damage to mitochondrial DNA in Neuro2a cells: the neuroprotective roles of melatonin

Recent studies suggest that oxidative stress and mitochondrial dysfunction play important roles in the neurotoxicity of nickel. Because mitochondrial DNA (mtDNA) is highly vulnerable to oxidative stress and melatonin can efficiently protect mtDNA against oxidative damage in various pathological conditions, the aims of this study were to determine whether mtDNA oxidative damage was involved in the neurotoxicity of nickel and to assay the neuroprotective effects of melatonin in mtDNA. In this study, we exposed mouse neuroblastoma cell lines (Neuro2a) to different concentrations of nickel chloride (NiCl(2), 0.125, 0.25, and 0.5 mm) for 24 hr. We found that nickel significantly increased reactive oxygen species (ROS) production and mitochondrial superoxide levels. In addition, nickel exposure increased mitochondrial 8-hydroxyguanine (8-OHdG) content and reduced mtDNA content and mtDNA transcript levels. Consistent with this finding, nickel was found to destroy mtDNA nucleoid structure and decrease protein levels of Tfam, a key protein component for nucleoid organization. However, all the oxidative damage to mtDNA induced by nickel was efficiently attenuated by melatonin pretreatment. Our results suggest that oxidative damage to mtDNA may account for the neurotoxicity of nickel. Melatonin has great pharmacological potential in protecting mtDNA against the adverse effects of nickel in the nervous system.

Effect of Solvent on the Morphology of Nickel Localized Electrochemical Deposition

Localized electrochemical deposition (LECD) was performed by microanode-guided electroplating (MAGE) in two different baths to investigate the effect of solvent on the deposit morphology. One of the baths contained an ordinary aqueous solution prepared from distilled water and ionic liquid by mixing choline chloride with ethylene glycol; the other bath contained the same concentration of nickel chloride. A nonuniform micro deposit was obtained in the ionic liquid and it appeared as if it had been directly accumulated with huge nodular nickel particles; a uniform micro pillar was formed in the aqueous solution and this micro pillar exhibited a smooth appearance. The distinct deposit morphology is governed by the nature of the bath, which is characterized by the electrical resistivity and viscosity. The activation energy that arose from the electrical resistivity (Eρ) and viscosity (Eη) in the different baths was estimated. The sum of activation energies (i.e., Esum = Eρ + Eη) is much higher in the ionic liquid than in the aqueous solution. The higher activation energy in the ionic liquid bath leads to the formation of nodular deposits. The lower activation energy in the aqueous solution bath leads to the formation of a micro pillar with fine uniform particles that have a smooth appearance. Therefore, loosely-packed coarse particles grow in the ionic liquid bath to form nickel nodules whereas tiny dense particles are formed in the aqueous solution bath to form a micro pillar with a smooth surface.

L-carnitine protects against nickel-induced neurotoxicity by maintaining mitochondrial function in Neuro-2a cells

Mitochondrial dysfunction is thought to be a part of the mechanism underlying nickel-induced neurotoxicity. L-carnitine (LC), a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine in all mammalian species, manifests its neuroprotective effects by improving mitochondrial energetics and function. The purpose of this study was to investigate whether LC could efficiently protect against nickel-induced neurotoxicity. Here, we exposed a mouse neuroblastoma cell line (Neuro-2a) to different concentrations of nickel chloride (NiCl 2) (0.25, 0.5, 1, and 2 mM) for 24 h, or to 0.5 mM and 1 mM NiCl 2 for various periods (0, 3, 6, 12, or 24 h). We found that nickel significantly increased the cell viability loss and lactate dehydrogenase (LDH) release in Neuro-2a cells. In addition, nickel exposure significantly elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels, disrupted the mitochondrial membrane potential (ΔΨ m), reduced adenosine-5′-triphosphate (ATP) concentrations and decreased mitochondrial DNA (mtDNA) copy numbers and mtRNA transcript levels. However, all of the cytotoxicities and mitochondrial dysfunctions that were triggered by nickel were efficiently attenuated by pretreatment with LC. These protective effects of LC may be attributable to its role in maintaining mitochondrial function in nickel-treated cells. Our results suggest that LC may have great pharmacological potential in protecting against the adverse effects of nickel in the nervous system.

Spectroscopic investigations and electrical properties of PVA/PVP blend filled with different concentrations of nickel chloride

Films of PVA/PVP blend (50/50) filled with different concentrations of NiCl 2 were prepared by casting method. The prepared films were investigated by different techniques. XRD scans demonstrated that the peak intensity at 2 θ≈20° decreased and the band width increased with increase in the concentrations of NiCl 2 content, which implied decrease in the degree of crystallization and hence causes increase in the amorphous region. UV–vis analysis revealed that the values of the optical band gap are affected with increase in NiCl 2 content. This indicates the formation of charge transfer complexes between the polymer blend and the filler. The rise of conductivity is significant with increased concentration of NiCl 2 filler; this reveals an increase in degree of amorphosity. AC conductivity ( σ ac ) behavior of all the prepared films was investigated over the frequency range 42 Hz–5 MHz and under different isothermal stabilization in the temperature range 313–393 K. It suggests that the hopping mechanism might be playing an important role in the conduction process in high frequency region. The dielectric behavior was analyzed using dielectric permittivity ( ε´, ε″) dielectric loss tangent (tan δ) and electric modulus ( M″). The decrease in dielectric permittivity was observed with increase in the concentration of NiCl 2 filler. This suggests the role of NiCl 2 as filler to improve the electrical conductivity of PVA/PVP blend.

Synthesis of nano-aggregated nickel particles by a chemical process

The focus of this study is in the synthesis of nanoalloy/composites and powders for industrial gas turbines applications. Nanosized nickel particles have been prepared by a simple polymer–surfactant interaction of a cationic polymer polyvinylpyrrolidone with an anionic surfactant, sodium dodecyl sulphate (SDS). These particles were synthesised using nickel chloride as the precursor and hydrazine as the reducing agent in the presence of SDS in a strong basic medium. Our research shows that the rate of reduction increases as the reaction temperature was increased from 60 to 100°C. Finer particles of diameters <10 nm were formed as the temperature was increased from 60 to 100°C. The concentration of nickel chloride was kept constant in all these experiments. The nanosized nickel particles synthesised were characterised using SEM and HR TEM. The combination of SDS/polyvinylpirrolidone reaction produced nanosized nickel particles, which were much finer than the reactions where SDS was used on its own.

Sharpening Mechanism Using Composite Electro-Plating In-Process Sharpening Technique

The in-process sharpening mechanism of the grinder during the grinding process of a CVD diamond film surface is investigated using the composite electro-plating in-process sharpening (CEPIS) technique. The bath concentration is employed to investigate the variation of coating structure deposited on the grinder. Results show that the land area ratio increases with increasing nickel chloride concentrations (NiCl2．6H2O) of the plating bath from 10 to 30 g/L, and the coating structure becomes very smooth without porous area at the nickel chloride concentration of 75 g/L. Therefore the coating structure becomes compact to hold the diamond particles rigidly. Consequently, the grinding ability of the grinder can be significantly improved, where the mirror-like surface of the CVD diamond film can be achieved.