Abstract
Sixteen alloys and five pure metals were used and the open circuit potentials (OCP) and the coupled potentials with titanium were measured in five kinds of solutions. All alloys and metals showed the maximum OCP in 1.3% lactic acid solution, and the minimum in 0.01% sodium sulfide solution. The coupled potential depended on the area ratio (alloy/titanium). This dependence was different in every solution. From the area ratio dependence of the coupled potential, the potassium fluoride solution was thought to be active with pure titanium. In contrast, sodium sulfide solution was thought to be active with the alloys and the metals. The effect of the co-existence of pure titanium was very small in the sodium sulfide solution.
