Acetic acid - Direct corrosive mediator in SCC of titanium/ethanol system

Although so many researchers paid attention on stress corrosion mechanism of titanium/ethanol system, few papers explained why ethanol, a very weak corrosive mediator, caused severe anodic solution. We found that the anodic polarization process of the titanium/ethanol system produced lots of acetic acid, which caused the pH value decreased rapidly. Maybe the acetic acid was the direct reason of stress corrosion susceptibility of titanium alloy in ethanol. And SSR tests proved that acetic acid could accelerate SCC of this system seriously. Also we found that in this system when the specimen was in the yield region, its corrosion potential fluctuated and PDS analysis showed this fluctuation was not a pure random process but a random fluctuation superposed with a definitive quasisine wave. We thought that it was acetic acid made the passive film unstable and this unstable state was the main reason caused SCC in this system.