The paper presents preliminary studies of the corrosion behavior in NaCl solution of a composite made up of a conversion coating of alumina obtained by sulphuric anodization and chitosan biopolymer. The results obtained from the electrochemical studies (potentiodynamic polarization, electrochemical impedance spectroscopy) indicate a decrease of the corrosion current density for alumina-chitosan composite and a corrosion resistance improvement comparing to untreated aluminum. The presence of the alumina-chitisan composite stabilizes the passivation behavior of the anodized samples due to the sealing of the alumina pores with chitosan biopolymer.
This paper discusses the properties of some Ni-Cu deposits obtained on a steel substrate, which may be employed as supercapacitor plates. In order to achieve plates with different properties, one has varied the parameters of the deposition process such as deposition time, current density and temperature. Scanning electron microscopy and dispersive energy spectrometry were employed for the determination of the structure and composition of the Ni-Cu deposits. The plates with the Ni-Cu deposits were used to create supercapacitors and their capacitance values were also determined.
This paper discusses the importance of the temperature drying process on some silane films in order to obtain a coating with specific properties (stability in time, resistance to corrosion attack and compactness) that would make them appropriate to be used as anticorrosive protection layers. Electrochemical techniques such as open circuit potential and electrochemical impedance spectroscopy were employed in order to characterize the investigated deposited silane films on aluminium substrate. The validation of the experimental electrochemical impedance spectroscopy data was carried out using the comparison of the validation coefficient versus the Pearson coefficient computed for a a=0.05.
This paper introduces a method of reconditioning lithium-polymer batteries which are no longer performing as expected. The reconditioning process consists of consecutive charging/discharging steps at controlled currents and is followed by an evaluation procedure, in order to determine the actual performances of the reconditioned batteries. For the evaluation of the characteristics of the Li-polymer batteries, one has measured the charging capacity, the discharging capacity and the internal resistance. However, after the reconditioning stage, one must look for a new application for these batteries, as the reconditioned batteries are seldom behaving as the new ones to be used for the same initial designated application. We manufactured and tested a cold jump-start system, particularly useful in the case of cars flat batteries or cars batteries starting failure. The advantages of this system consist in their reduced mass and volume and a very powerful starting current, comparable to that of high capacity lead acid batteries, the system being able to act as multiple starting aids.
Nickel-Copper metallic layers were deposited onto a steel substrate by using the electrochemical method. The morphology and the chemical composition of the deposited layers were studied by scanning electron microscopy. The electrical capacitance was measured on a functional supercapacitor made of two Ni-Cu deposited layers and a Nafion 117� membrane hydrated with distilled water, which served as a dielectric separator.
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