Abstract
The corrosion behaviors of die cast AZ91D and AXJ530 magnesium alloys have been investigated by using electrochemical noise technique. Chloride ions have been used as corrosive agent to induce different forms of corrosion in neutral and alkaline media. The data transformed from the time domain to the frequency domain involve the calculation of power spectral density (PSD). The slope of PSD gives information about the type of corrosion process. The analysis in frequency domain has allowed to quote specific slopes and transition frequencies as being characteristic of a particular type of corrosion occurring in these magnesium alloys. The relevant slope for each form of corrosion has been established by experiment (sampling frequency and measurement time). The influence of chemical composition and microstructure upon frequency electrochemical noise parameter has been investigated. Different localized attacks such as pitting, intergranular and filiform corrosion have been identified and quantitatively described using characteristic slope values and magnitudes of power spectral density.
