Papers by Keyword: Electrochemistry

Abstract: CuO nanorods were fabricated by a facile microwave-assisted synthesis method and applied to pseudo-capacitor. The CuO nanorods were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The capacitive behavior of nanorods was investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. Electrochemical experiments reveal that CuO nanorods demonstrate better capacitance performance than granular CuOs prepared by chemical precipitation method. The CuO nanorods have a high specific capacitance of 317 F/g at a current density of 1 A/g and a fairly good cyclic stability.

Abstract: Basing on the study of adsorption behavior of glycidoxypropyl-trimethoxy-silane (GTMS), pretreatment method of AA2024-T3 aluminum alloy for sol-gel films was optimized. The morphology, composition and corrosion protective performance of alloy coated with the films were investigated by using FE-SEM, EDS, AFM and EIS. The results showed that the Al matrix exhibited better ability to adsorb GTMS molecules than the second phase particles, especially at lower concentration of GTMS. Further, the 5% GTMS films cover the whole surface, but the selective adsorption behaviors still exist. It was concluded that less second phase particles and smoother surface were benefit to the sol-gel films on aluminum alloy. Depending on this conclusion, the pretreatment method for sol-gel films was optimized. The optimized surface condition conducted with 50 g•L^-1 sodium hydroxide and ultrasound at 60 oC for 30 s was obtained. These samples coated with the sol-gel films revealed good anti-corrosion performance. The coverage degree of the films was up to 97.95 %.

Abstract: The crystal morphology and geometry may play a role in electronic dissemination transition, and they would lay the foundation for the assembly about various accessories. The main aim of our research is to investigate a variety of factors which had an impact on the types and morphologies of the final products during the Co(OH)₂ crystal formation process, such as substrate material, reaction concentration and reaction time. In this paper, Co(OH)₂ microspheres are successfully prepared by a facile hydrothermal synthesis method, using cobalt nitrate hexahydrate and ammonium fluoride as the raw material, ammonia as the complexing agent and a clean nickel or copper foam as the base material. The structure and morphology of samples are characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM).

Abstract: The paper presents the results of tribotechnical studies of anti-wear properties of iron-based coatings for light-alloy drill pipes made of aluminum alloys. The description of the tribotechnical stand simulating real processes of drilling in a wide range of conditions is given. Also, the analysis of corrosion resistance of coatings by electrochemical analysis was carried out. The results showed that there is a potential for the use of this type of coating.

Abstract: Porous Ti-Nb-Ta-Zr alloys for biomedical applications were successfully fabricated by PM. The microstructure, cycle compressive and electrochemistry behavior were studied. It results that the porous structure of Ti-Nb-Ta-Zr with 0.8 GPa Young’s modulus, 2.7% pseudoelastic strain ratio and-0.44 V corrosion potential in SBF, can be applied to the trabecular bone prosthesis or bone substitute for spinal vertebral body.

Abstract: Copper-Nickel alloy pipes in marine engineering have been suffering severe seawater corrosion and erosion-corrosion. In this work, six kinds of Cu-Ni alloy pipes with different service lives delivered by two manufacturers were used to clarify the relationship between corrosion resistance and microstructure. The corrosion behaviors of the samples in 3.5 wt.% NaCl solution were studied by electrochemical measurements. Chemical composition, grain size distribution, crystallographic orientation, and grain boundary characterization distribution (GBCD) were investigated by energy-dispersive spectrometry (EDS), metallography and electron backscattered diffraction (EBSD) technology. There were no obvious differences in chemical composition and GBCD in contrast with size and uniformity of grains. Pipes with large grains and a broader grain size distribution had better corrosion resistance. It was also found that the accuracy of experimental data greatly depended on the quality of the sample surface in EBSD analysis. The scratches and contamination during sample preparation have a strong impact on the imaging quality and the calculation of GBCD.

Abstract: The low density and high strength/weight ratio of magnesium (Mg) and magnesium alloys make them promising candidate materials in light-weight vehicle industries, such as automobile and aerospace, where poor corrosion resistance is a major obstacle in many of their wide-spread applications. Addition of alloying elements with production of wrought Mg alloys with finer microstructure results in enhanced mechanical properties and corrosion resistance. The aim of this research is to study the changes in microstructure caused by addition of alloying elements (zinc (Zn), and tin (Sn)) to new wrought Mg-5Al alloy, and their influence on the alloy's corrosion behavior. The microstructure was investigated using optical and electron microscopy and EDS. The corrosion behavior was analyzed through electrochemical measurements and immersion test. It was found that the corrosion resistance of Mg-5Al alloy was improved by addition of alloying elements, and the amounts of these elements strongly influenced the corrosion behavior of the alloys. Nevertheless, the influence of alloying elements is different for short-term and long-term immersion periods, since the mechanisms of corrosion initiation and corrosion propagation are different.

Abstract: The wet-chemical etching of ruthenium in acidic solutions of cerium (IV) has been investigated using electrochemical methods. Etch rates were determined using Rutherford backscattering spectroscopy (RBS) and post-etching surface roughness was investigated using atomic force microscopy (AFM). Low-k material is compatible with the etchant, however, residues were formed.

Abstract: There were many advantages for functional materials production using Sol-gel method, such as low operating temperature and easy doping. So, it was widely used in materials preparation, such as nano powders, films, functional glass, nanoceramic and modified electrode. The sol-gel modified electrode has extensive application in electrochemical analysis and electrochemical sensors. In addition, the film by electrodeposition can be tightly assembled on electrode substrate and its structure and shape can be easily regulated. So, The two methods are combined to make better use of their respective advantages. Up to now, the film materials using electrochemically induced sol-gel had been used in electrochemistry analysis and functional films preparation. In this paper, it was summarized that the progress of combined application of sol-gel and electrochemistry. Mainly including sol-gel materials, modified electrodes, electrochemical analysis and sensors, and electrochemical induction sol-gel method for the preparation of thin film materials.

Abstract: Spherical cupric oxide (CuO) was grown on copper (Cu) foil by a facile, low-temperature chemical bath deposition (CBD) under alkaline conditions. This method enables direct contact between the active materials and the cathode which is advantageous for attaining higher capacitance. The Cu products were spherical in shape and have a uniform morphology due to self-assembly and Ostwald ripening. The fabricated CuO exhibit a specific capacitance in the range of 700–800 F/cm².