ASTM D6208-97 Test for Repassivation Potential of Aluminum and Its Alloys by Galvanostatic Measurement

Scope:

ASTM D6208-97 test method determines the repassivation potential of aluminum alloy 3003-H14 as a measure of relative susceptibility to pitting corrosion by conducting a galvanostatic polarization. Galvanostatic polarization is a polarization technique that is used to measure corrosion rate. The specimens are visually examined to provide information about subtleties of the pitting and inhibition mechanisms. Inhibitor effectiveness is evaluated by recording the number of pits, pit depth, amount of deposit, presence of chloride, and surface discoloration.  

Test Procedure:

In ASTM D6208-97 test method, an aluminum alloy is placed in a solution of coolant and corrosive water containing chloride. For 20 min, the alloy is polarized at a fixed current density. The electric potential is recorded as a function of time.  The maximum potential, EB, reached upon polarization is determined. And the minimum potential following the maximum potential, EG, is also recorded. The aluminum alloy is visually examined using Guide G46 after disassembly and rinsing.

Data:

The following information is reported:

The aluminum alloy that is tested. Average EB and EG of all experimental runs. Type of curves obtained, A, B, or C. Visual observations made. And other relevant test parameters.