Showing 3 results for Mott–schottky
A. Fattah-Alhosseini, H. Farahani,
Volume 10, Issue 4 (12-2013)
Abstract
The effects of H2SO4 concentration on the electrochemical behaviour of passive films formed on AISI 304 stainless steel were investigated using by potentiodynamic polarization, Mott–Schottky analysis and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization indicated that the corrosion potentials were found to shift towards negative direction with an increase in solution concentration. Also, the corrosion current densities increase with an increase in solution concentration. Mott–Schottky analysis revealed that the passive films behave as n-type and p-type semiconductors at potentials below and above the flat band potential, respectively. Also, Mott– Schottky analysis indicated that the donor and acceptor densities are in the range 1021 cm-3 and increased with solution concentration. EIS data showed that the equivalent circuit Rs(Qdl[Rct(RrQr)]) by two time constants is applicable.
A. Fattah-Alhosseini, O. Imantalab,
Volume 11, Issue 2 (6-2014)
Abstract
In this study, effect of immersion time on the electrochemical behaviour of AISI 321 stainless steel (AISI 321)
in 0.1 M H
2SO
4
solution under open circuit potential (OCP) conditions was evaluated by potentiodynamic
polarization, Mott–Schottky analysis and electrochemical impedance spectroscopy (EIS). Mott–Schottky analysis
revealed that the passive films behave as n-type and p-type semiconductors at potentials below and above the flat band
potential, respectively. Also, Mott–Schottky analysis indicated that the donor and acceptor densities are in the range
1021 cm-3 and increased with the immersion time. EIS results showed that the best equivalent circuit presents two time
constants: The high-medium frequencies time constant can be correlated with the charge transfer process and the low
frequencies time constant has been associated with the redox processes taking place in the surface film. According to
this equivalent circuit, the polarization resistance (interfacial impedance) initially increases with the immersion time
(1 to 12 h), and then it is observed to decreases. This variation is fully accordance with potentiodynamic polarization
results
A Fattah-Alhosseini, M Asadi Asadabad,
Volume 11, Issue 4 (12-2014)
Abstract
Four compositions of austenitic Mn-Cr steels have been developed successfully for in-vessel component materials in power plant industry. The phase stability of these Mn-Cr steels was studied by and X-ray diffraction (XRD) patterns. XRD patterns have shown that the matrix of these Mn-Cr steels is a single γ-phase structure. The potentiodynamic polarisation curves suggested that these fabricated Mn-Cr steels showed passive behaviour in 0.1M H2SO 4solution. Therefore, semiconducting behaviour of passive film formed on these fabricated Mn-Cr steels in 0.1M H2SO 4 solution was evaluated by Mott–Schottky analysis. This analysis revealed that passive films behave as n-type and p-type semiconductors. Based on the Mott–Schottky analysis, it was also shown that donor and acceptor densities are in the order of 1021 cm -3 and are comparable for other austenitic stainless steels in acidic environments
