4.2. The relationship between the corrosion rate and potential

Experiment 1/2 in Table 2 suggests that in case of very damaging corrosion, the potential of titanium is low. To confirm this hypothesis, corrosion rates of the unalloyed titanium (Grade 2) were compared to the potentials in 36 different simulated alkaline hydrogen peroxide environments. The results in Fig. 7 reveal that low potential of titanium clearly indicated high corrosion rates, but it must be noted that high corrosion potentials did not guarantee that titanium is protected. Platinum electrode was added to some systems to indicate whether the low potentials during rapid corrosion rates resulted from surface reactions. With three exceptions, the potential of titanium was clearly below that of platinum suggesting that the corrosion occurred by mechanisms presented in equations (4.1), (4.2) and (4.3). (When no corrosion was observable, there were four additional cases, in which the potential of platinum was lower than that of titanium.)