NaCl-HCl系溶液におけるチタンのすきま腐食挙動

抄録

The pitting potential of titanium is very high in NaCl-HCl solutions, and hence the pitting corrosion is not responsible for the initiation of corrosion in the crevice region.
Crevice corrosion of titanium takes place, when the pH within the crevice decreases so as to induce active dissolution of titanium. Measurement of buffer capacity of NaCl-HCl solutions suggests that concentrated Cl⁻ solutions give rise to a large decrease in pH with a small addition of H⁺, and that the Cl⁻ concentration in the crevice leads readily to a decrease in pH within the crevice to about 1-2. Once titanium is activated, corrosion propagates rapidly. During propagation of crevice corrosion, the potential of creviced specimen is about −0.6 V (vs.S.C.E).