Commercial grade magnesium anodes are either high purity 99% magnesium or a magnesium, zinc and aluminium alloy.
Buckleys supply the Mg/Al/Zn alloy material for testing the BathyCorrometer. The aluminium content of the anode would be between 5.3 to 6.7 wt% and the Zinc content typically 2.5 to 3.5%. The open-circuit potential for the anode in seawater would be typically -1.5V vs Ag/AgCl/seawater.
Magnesium test blocks should not be considered as accurate reference electrodes as the potential can show significant variations with the potential range typically varying by +/-100mV. The readings obtained will also depend on the water temperature, salinity and the level surface contamination and corrosion products present on the test block surface..
The magnesium test block is provided to confirm that the BathyCorrometer can read structure to electrolyte potentials at the upper end of the expected potential range. The typical reading obtained when using a magnesium test block should be in the range of -1.4 to -1.70V when used to check silver-silver Chloride half cells.
For accurate calibration checks on the BathyCorrometer internal Ag/AgCl/seawater electrode, K-Cell calibration electrodes should be used.
Magnesium Test Block Details:
Size: 100mm x 60mm x 15mm
Includes a certificate of content analysis