HCl-メタノール溶液中におけるTiおよびZrの応力腐食割れについて

抄録

Recently the phenomenon that Ti was easily attacked by stress corrosion cracking in methanol containing HCl was found by the present authors. And now a study was accomolished quantitatively on the stress corrosion cracking of Ti in alcohol solutions. The stress corrosion cracking of Zr was also studied considering its similarity in chemical behavior to Ti.
The stress corrosion cracking of Ti occurs in methanol solution containing HCl or H₂SO₄, and that of Zr is observed in methanol containing HCl, H₂SO₄ or HCOOH and in ethanol containing HCl.
In HCl-alcohol solutions it is also observed that the larger the molecular weight of alcohol is, the longer life the metals have.
Addition of water to HCl-methanol solution prevents the stress corrosion cracking of Ti and Zr. Critical concentration of water in 0.4% HCl-methanol solution is about 1.5% for Ti, and about 3% for Zr. To prevent the stress corrosion cracking by stress relief, annealing temperature should be selected higher than 500°C for Ti and 450°C for Zr.