Papers by Keyword: Electrochemical Characteristic

Abstract: The corrosion characteristic of Ti-6Al-4V alloy implanted by carbon was investigated in Hanks simulated body fluid. The results indicated that a disordered film, which was composed of TiC and Ti by XRD analysis, was formed on the surface of Ti-6Al-4V when Carbon was implanted. Electrochemical tests manifested, after implanted, the alloys corrosion potentials and increased, polarization resistance were increased, and anodic polarization current density decreased in Hanks simulated body fluid. The electrochemical properties were improved. The reason was that the disordered carbide film formed on alloys surface prevented alloying elements form dissolution and enhanced its corrosion resistance. For C implanted sample, the anodic polarization current density was increase when the alloy was abraded. It manifested that friction and abrasion conditions made corrosive environment more serious and accelerated the corrosion process. The alloys friction coefficient and abrasion rate were obviously decreased, and its hardness was increased when it was implanted C.

Abstract: A new type of micro super-capacitor with high working voltage, high over loading, small bulk, and low impedance was fabricated by a new process. The hydrous ruthenium oxide powder was prepared in a solution of RuCl₃·xH₂O and NaHCO₃. Different composites loaded with certain amount of carbon black were synthesized with this technique. Super-capacitor performance was assessed via cyclic voltammetry (CV), charge-discharge studies (DC), and impedance analysis (AC). The results show that the capacitance and resistivity of ruthenium oxide materials were dependent on the sample annealing temperature. The materials heated at 300°C exhibit the highest rate capacitance of 1080 F·g-1. Four to six cells of this capacitor was stacked up in series by conductive films in order to achieve higher working voltage. After packaged in resin, charge/discharge studies and impedance analysis were tested via the electrochemical test system. In the research, super-capacitors with a four-layer structure exhibited fine electrochemical characteristics with high working voltage over 5.5 V and low impedance under 1.5 ohm. Also, it had the ability of high-rate discharge performance and considerable large capacitance.

Abstract: The electrode alloys (Mg_1-xZr_x)₂Ni (x = 0, 0.3) were prepared by mechanical alloying (MA). Mg in the alloy was partially substituted by Zr in order to improve the electrochemical hydrogen storage characteristics of the Mg₂Ni-type alloy. The effects of substituting Mg with Zr as well as milling duration on the microstructures and electrochemical performances of the alloys were investigated in detail. The results showed that the substitution of Zr facilitates the formation of amorphous Mg₂Ni-type phase. The electrochemical measurement indicated that the substitution of Zr significantly enhances the discharge capacity and cycle stability of the alloys, and it markedly improved the discharge potential characteristic of the alloys. For a fixed alloy, the electrochemical performances, including the cycle stability and the discharge voltage characteristic as well as discharge capacity, of the alloys were markedly improved with prolonging of the ball-milling duration.

Abstract: By using electrochemical techniques, the electrochemical characteristic of Cr-based film coated 304 stainless steel (304SS) as proton exchange membrane fuel cell (PEMFC) bipolar plates, which was deposited by cathodic arc deposition technology, was studied. The results indicated that Cr, CrN, (TiCr)N and (TiN+Ti) film could not only decreased the steel’s contact resistance but also improved its corrosion resistance and the fuel cell stack’s performance. Since Cr, (CrN) and (TiCrN) film were more compact than (TiN+Ti) film, which contained the oxides of Ti, as bipolar plates, the performance for all film change in the following order: Cr film ≈(CrN) film ≈ (TiCrN) film >(TiN+Ti) film.