This research involves study effect of
chloride ions in concentration range (0.01 – 0.50 mol.dm -3) on
the corrosion behavior of Al-Zn alloy in basic media of
1x10-3mol.dm-3NaOH at pH=11 and four different temperatures in
the range (298-313 K). Cathodic and anodic Tafel slopes (bc &ba)
and transfer coefficients (αc & αa) were calculated and the
results interprets according to the variation of the rate –
determining steps. The results also indicate that the chloride
ions are bonded chemically in the interface as an initial step
of formation of different mixed oxohydroxy – and chloro
complexes. Polarization resistance (Rp) is calculates and
interprets the different polarization behavior because
of addition of chloride ions to the basic media. |