Platinum Metals Rev., 1967, 11, (4), 149
Performance of Platinised Titanium Anodes
The use of platinised titanium as a counter electrode in cathodic protection is well established, even though a detailed mechanism for the excellent performance of these anodes is not fully documented. A recent investigation of this subject by P. Van Laer and J. Van Muylder of CEBELCOR, presented as a paper to the CITCE colloquium on Corrosion and Electrochemical Thermodynamics held in Istanbul in September, is of some considerable help in this direction.
Anodic polarisation studies in synthetic seawater, using current densities in the range 0 to 600 mA/cm2, showed that if corrosion of the titanium is to be avoided the anodic potential must not exceed +7.0 VSCE. Further, the authors state that at potentials above +2.1 VSCE modification of the platinum surface occurs, and studies in the range +1.3 to 1.4 VSCE suggest that oxidation of platinic oxide PtO2 to perplatinic oxide PtO3 may take place.
It was concluded that the long life of platinised titanium anodes in sea-water is due to the titanium surface being protected from high current densities by the platinised areas, thus ensuring that the potential does not exceed the threshold of danger.