One set of painted panels with a vertical scribe of 1 mm
×
50 mm
were exposed in triplicate in a salt spray chamber according to
ASTM B117 Standard Practice (NaCl concentration: 50 g/L and pH
between 6.5 and 7.2). The tested panels were inspected visually
(ASTM standard D-610-01) at regular intervals up to 560 h of exposure.
To evaluate scribe creep corrosion, the surface was scrubbed
thoroughly with xylene using a stiff brush. ImageTool program was
used to calculate the corroded area. The average value of the three
measurements was reported.