3.3. Corrosion resistance
Fig. 6 presents the potentiodynamic polarization test results of
bare aluminum, Samples 1 and 3 in a 1 M H2SO4 þ 2 ppm HF
solution at 70 C purged with H2 and O2. The bare aluminum
showed a general metallic corrosion curve while the composite
coated samples recorded much lower current density than bare
aluminum. In the anodic condition in PEM fuel cells, the current
density of Samples 1 and 3 measured at 0.1 V with H2 purging was
5.6 107 A cm2 and 3.6 107 A cm2
, respectively. The
difference in current density between Samples 1 and 3 was negligible
compared to the difference between bare aluminum and the
composite coated samples. Under the cathodic condition, the
current density of Samples 1 and 3 measured at þ0.6 V with O2
purging was 1.2 107 A cm2 and 3.3 107 A cm2
, respectively.
These values satisfy the DOE targets [10].
F