Electrodeposition of Copper / Cuprous Oxide Nanocomposites

1996 ◽  
Vol 451 ◽  
Author(s):  
Jay A. Swrrzer ◽  
Eric W. Bohannan ◽  
Teresa D. Golden ◽  
Chen-Jen Hung ◽  
Ling-Yuang Huang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Cuprous Oxide ◽  
Nanocomposite Films ◽  
Constant Current ◽  
Oxide Content ◽  
Copper Metal ◽  
Solution Ph ◽  
Mole Percent ◽  
Strong Function ◽  
Current Densities

ABSTRACTNanocomposite films of copper metal and cuprous oxide were electrodeposited at room temperature from an alkaline copper(11) lactate solution. The electrode potential oscillated spontaneously during constant-current deposition of the composites. The oscillations were periodic in a stirred solution, but became chaotic in unstirred solution. For a given current density the phase composition was a strong function of solution pH. As the pH was increased, the cuprous oxide content increased. At pH 12, no oscillations were observed, and pure cuprous oxide was deposited. At pH 9, the phase composition varied from pure cuprous oxide at current densities below 0.1 mA/cm2 to 96 mole percent copper at 2.5 mA/cm2.

scholarly journals Mechanical Properties of Graphene Oxide–Copper Composites

2016 ◽  
Vol 61 (2) ◽  
pp. 863-868 ◽  
Author(s):  
P. Duda ◽  
R. Muzyka ◽  
Z. Robak ◽  
S. Kaptacz
Keyword(s):  
Graphene Oxide ◽  
Tribological Properties ◽  
Low Voltage ◽  
Electrical Equipment ◽  
Oxide Content ◽  
Large Current ◽  
Current Densities ◽  
Materials Used ◽  
System Disk ◽  
Positive Effect

Abstract Due to their characteristics, sintered Cu-C composites are materials used in electrical equipment. These characteristics include high electrical conductivity, thermal conductivity and excellent resistance to abrasion. Currently, graphite nanopowder is used successfully as a carbon material. Metal-graphite, which is created on its basis, exists in different proportions of graphite to metal. A larger graphite content has a positive effect on smaller wear of commutators and rings. In contrast, a material with a higher copper content is used at high current densities. An example of such machines is a DC motor starter characterized by low voltage and large current. Tribological properties of Cu-C composites depend on the form of carbon they include. Owing to the capability to manufacture graphene, it has become possible to produce composites with its content. The present study tested the effect of a graphene oxide content on tribological properties in contact with steel. Tests were conducted on a ball-on-disk apparatus in conditions of dry friction. Microscopic observation was performed on the Hitachi SU70 field emission electron microscope. EDS analyses were performed using the Thermo Scientific X-ray Microanalysis system. Disk wear and surface geometrical structure parameters (SGP) of the samples after tribological tests were determined on the basis of measurements made on the Talysurf 3D contact profilometer from Taylor Hobson.

scholarly journals Importance of the pyrolysis for microstructure and superconducting properties of CSD-grown GdBa2Cu3O7−x-HfO2 nanocomposite films by the ex-situ approach

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pablo Cayado ◽  
Hannes Rijckaert ◽  
Els Bruneel ◽  
Manuela Erbe ◽  
Jens Hänisch ◽  
...  
Keyword(s):  
Processing Parameters ◽  
Nanocomposite Films ◽  
Ex Situ ◽  
Superconducting Properties ◽  
Critical Temperatures ◽  
Solution Deposition ◽  
Nanoparticle Distribution ◽  
Current Densities ◽  
First Time ◽  
Lower Heating

Abstract For the first time, GdBa2Cu3O7−x nanocomposites were prepared by chemical solution deposition following the ex-situ approach. In particular, ~ 220 nm GdBa2Cu3O7−x-HfO2 (GdBCO-HfO2) nanocomposite films were fabricated starting from a colloidal solution of 5 mol% HfO2 nanoparticles. Hereby, one of the main challenges is to avoid the accumulation of the nanoparticles at the substrate interface during the pyrolysis, which would later prevent the epitaxial nucleation of the GdBCO grains. Therefore, the effect of pyrolysis processing parameters such as heating ramp and temperature on the homogeneity of the nanoparticle distribution has been investigated. By increasing the heating ramp to 300 °C/h and decreasing the final temperature to 300 °C, a more homogenous nanoparticle distribution was achieved. This translates into improved superconducting properties of the grown films reaching critical temperatures (Tc) of 94.5 K and self-field critical current densities ($${J}_{\mathrm{c}}^{\mathrm{sf}}$$ J c sf ) at 77 K of 2.1 MA/cm2 with respect to films pyrolyzed at higher temperatures or lower heating ramps.

scholarly journals Modification of large area Cu2O/CuO photocathode with CuS non-noble catalyst for improved photocurrent and stability

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Panzeri ◽  
M. Cristina ◽  
M. S. Jagadeesh ◽  
G. Bussetti ◽  
L. Magagnin
Keyword(s):  
Surface Modification ◽  
Cuprous Oxide ◽  
Small Area ◽  
Low Cost ◽  
Compositional Analysis ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution ◽  
Large Area ◽  
Solution Ph ◽  
Sulfur Atmosphere

Abstract In this work, a three-layered heterostructure Cu2O/CuO/CuS was obtained through a low-cost and large-area fabrication route comprising electrodeposition, thermal oxidation, and reactive annealing in a sulfur atmosphere. Morphological, microstructural, and compositional analysis (AFM, SEM, XRD, EDS, XPS) were carried out to highlight the surface modification of cuprous oxide film after oxidation and subsequent sulfurization. Impedance, voltammetric, and amperometric photoelectrochemical tests were performed on Cu2O, Cu2O/CuO, and Cu2O/CuO/CuS photocathodes in a sodium sulfate solution (pH 5), under 100 mW cm−2 AM 1.5 G illumination. A progressive improvement in terms of photocurrent and stability was observed after oxidation and sulfurization treatments, reaching a maximum of − 1.38 mA cm−2 at 0 V versus RHE for the CuS-modified Cu2O/CuO electrode, corresponding to a ~ 30% improvement. The feasibility of the proposed method was demonstrated through the fabrication of a large area photoelectrode of 10 cm2, showing no significant differences in characteristics if compared to a small area photoelectrode of 1 cm2.

Effect of Growth Conditions on the Reliability of Ultrathin MOS Gate Oxides

1996 ◽  
Vol 428 ◽  
Author(s):  
Tien-Chun Yang ◽  
Krishna C. Saraswat
Keyword(s):  
Gate Oxide ◽  
Interface State ◽  
Growth Conditions ◽  
Physical Stress ◽  
Constant Current ◽  
Strong Function ◽  
Oxidation Rates ◽  
Mos Devices ◽  
State Generation ◽  
Mos Gate

AbstractIn this work we demonstrate that in MOS devices the reliability of ultrathin (< 100Å) gate oxide is a strong function of growth conditions, such as, temperature and the growth rate. In addition, for constant current gate injection the degradation of SiO2 is enhanced as the thickness is reduced. We attribute this to physical stress in SiO2 resulting from the growth process. The degradation is always more for those growth conditions which result in higher physical stress in SiO2. Higher temperatures and slower oxidation rates allow stress relaxation through viscous flow and hence result in SiO2 of better reliability. We also found that for constant current stressing, the interface damage is more at the collecting electrode than at the injecting electrode. ΔDit (stress induced interface state generation) can be reduced after a high temperature Ar post anneal after the gate oxide growth.

Preparation of Chitosan - Hydroxyapatite Nanocomposites

2011 ◽  
Vol 284-286 ◽  
pp. 1760-1763
Author(s):  
Jing Xian Zhang ◽  
Dong Liang Jiang ◽  
Qing Ling Lin ◽  
Zhong Ming Chen ◽  
Zheng Ren Huang
Keyword(s):  
Mechanical Properties ◽  
Fourier Transform ◽  
Phase Composition ◽  
Fourier Transform Infrared ◽  
Chitosan Solution ◽  
Precipitation Method ◽  
Solution Ph ◽  
Cylindrical Form ◽  
Infrared Spectrometer ◽  
Co Precipitation

Chitosan/Hydroxyapatite composites with a homogeneous nanostructure have been prepared by a co-precipitation method. Initially, a chitosan solution was prepared and mixed with the (NH4)2HPO4 solution. After homogenizing, the obtained chitosan/ (NH4)2HPO4 solution was gradually dropped into the Ca (NO3)2.4H2O solution under stirring. The solution pH was adjusted to 9 using NH3.H2O. The precipitate was compressed into a cylindrical form followed by post treatment. The microstructure, phase composition and mechanical properties of the resulting chitosan-HAp composites were characterized. In the presence of chitosan, HAp crystallites were found to be well aligned along the c-axes in the respective aggregates. Fourier transform infrared spectrometer results indicated that an intermolecular bridging complexes might have been developed between the chitosan and HAp. The compact composites obtained were mechanically flexible, the highest strength was found to be 38.4 MPa for chitosan/HAp samples with a 20 wt% of chitosan.

scholarly journals Differential Pulse Voltammetry as an Alternative Method for Tracking Hydrochlorothiazide Electrolytic Degradation

2021 ◽  
Vol 4 (3) ◽  
pp. 70-77
Author(s):  
Mohammad Khanfar
Keyword(s):  
Differential Pulse Voltammetry ◽  
Model Compound ◽  
Differential Pulse ◽  
Degradation Process ◽  
Constant Current ◽  
Solution Ph ◽  
Tracking Method ◽  
First Order Kinetics ◽  
Voltammetric Techniques ◽  
Pulse Voltammetry

This study aims to compare differential pulse voltammetry as a tracking method with chromatography and photometry. The three methods were used to track the degradation of the model compound hydrochlorothiazide (HCT) where 250ml of 0.50mM HCT solution (pH of 3.50 and ionic strength of 0.010M) was electrolyzed with 50.0mAmp constant current. The degradation process demonstrated great fit (R2 >0.99) with pseudo-first-order kinetics when the three tracking methods were utilized. However, different rate constants were reported for these methods: 0.032min-1, 0.016 min-1, and 0.0052min-1 for the chromatographic, photometric, and voltammetric techniques, respectively. The observed variation was attributed to the nature of the utilized probing methods. The differential pulse voltammetry is promising as an electrolytic decomposition tracking method; however, the working probe to target pollutants needs to be improved.

Ionic Conduction Mechanisms in CaF2 and CaF2-Al2O3 Nanocomposite Films on Al2O3 Substrates

1993 ◽  
Vol 318 ◽  
Author(s):  
F. A. Modine ◽  
D. Lubben ◽  
J. B. Bates
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Ionic Conduction ◽  
Electrical Conductance ◽  
High Conductivity ◽  
Nanocomposite Films ◽  
Second Phase ◽  
Mole Percent ◽  
Interdigital Electrodes

ABSTRACTThin films of pure CaF2 and nanocomposite mixtures of Al2O3 with CaF2 were sublimated on Al2O3 substrates. Interdigital electrodes allowed in situ measurements of the electrical conduction of films as a function of thickness, deposition rate, composition, time, and temperature. The electrical conductivity in pure CaF2 adjacent to an Al2O3 interface sometimes exceeded the bulk CaF2 conductivity (i.e., value at more than 50 nm distance) by as much as a factor of 6700 at 200°C. The high conductivity is characterized by an activation energy of 0.6 ± 0.1 eV, which is significantly lower than the activation energy of about 1.0 eV for conduction in the bulk. However, this high conductivity is thermally unstable and diminishes in time. A high but stable conductivity was obtained in CaF2 films containing about 10 mole percent Al2O3 as a dispersed second phase. At 200°C, a 2-phase film gave a factor of 360 enhancement over the measured bulk CaF2 conductivity and a factor of 7 improvement over the best previously reported conductivity for CaF2-Al203 composite materials. The origin of enhanced conduction in CaF2 is attributed to ion transport along dislocations. Dislocations anneal with a characteristic log of time dependence that is recognizable in the annealing behavior of the electrical conductivity. Presumably, the addition of a dispersed second phase of Al2O3 to CaF2 serves both to generate and to pin dislocations; the electrical conductance is thereby enhanced and stabilized.

scholarly journals Yellow 2G dye degradation by electro-Fenton process using steel electrode as catalysis and its phytotoxicity effect

2020 ◽  
Author(s):  
Amel Benhadji ◽  
Mourad Taleb Ahmed
Keyword(s):  
Dye Degradation ◽  
Batch Reactor ◽  
Reaction Times ◽  
Fenton Process ◽  
Optimum Conditions ◽  
Germination Test ◽  
Solution Ph ◽  
Steel Electrode ◽  
Initial Ph ◽  
Current Densities

Abstract The heterogeneous electro-Fenton process degradation of Yellow 2G from wastewater was studied using a batch reactor. The COD of the wastewater used in treatment experiments was 163 mg O2·L−1 and the BOD5 was 17 mg O2·L−1 (hardly biodegradable). The treatment of the wastewater at different current densities (2.5 mA·cm−2–12.5 mA·cm−2), solution pH (3 and 6.6), reaction times (5–25 min), electrolyte nature (NaCl, Na2SO4) and electrolyte concentrations (0.15 g·L−1–1 g·L−1) was investigated. According to the results, the heterogeneous electro-Fenton process was suitable for the decolorization of wastewater containing Yellow 2G. The optimum conditions were current density of 12.5 mA·cm−2, initial pH of the wastewater neutral, 25 min of electrolysis treatment using an additive steel electrode as a source of catalysis and in the presence of 1 g NaCl·L−1. We obtained easily biodegradable water with a mineralization rate equal to 85% and non-toxicity confirmed by the pea grain germination test.

Study on Energy-Saving Mode of High-Quality Anti-Corrosion Micro Arc Oxidation Coatings on Magnesium

2010 ◽  
Vol 33 ◽  
pp. 479-482
Author(s):  
J.J. Xi ◽  
Pei Nian Wu ◽  
Jun Zhao ◽  
Wei Wang
Keyword(s):  
Phase Composition ◽  
Ceramic Coating ◽  
Salt Spray ◽  
Current Mode ◽  
Constant Current ◽  
Alkaline Solutions ◽  
Coating Film ◽  
High Quality ◽  
Micro Arc Oxidation ◽  
Smooth Film

In this paper, micro-arc oxidation process on magnesium alloy anode in three models alkaline solutions are considered under conditions of low power. The excellent morphology of ceramic coating is dense smooth film-like structure of the whole. The phase composition of ceramic coating film is MgO, Al2O3, and a kind of phase composition of the main salt. In the constant current mode in a high frequency of small duty cycle of research methods, the corrosion performance (salt spray test) is successfully developed that achieve 800~ 1000 hours of high quality film, under electric current density less than 1A/dm2.

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