Polarization curve of Magnesium alloy

Experiment setup:

Instrument: Potentiostat/galvanostat model CS350M

Solution: 3.5% NaCl (25 ℃)

Reference electrode: saturated calomel electrode 

Auxiliary/counter electrode: Pt

Working electrode: sample #1: Mg alloy with film

Sample #2: Mg alloy substrate without passivation film 

Technique: Potentiodynamic 

The effective exposure area: 1.7 cm2

Scan rate: 5 mV/s

We can see that there is no significant difference in the anodic polarization behavior of the two samples, and no obvious passivation appears in either sample. From the calculation, the corrosion rate of the sample#1 is 3.02 mm/a, and that is 21.5 mm/a for sample#2, indicating that the deposited film effectively inhibits the corrosion of the magnesium alloy.