Corrosion of titanium/cobalt-chromium alloy couples.

Because of the increasing use of dissimilar metal combinations in the human body, we undertook an in vitro study to determine the compatibility and tendency to accelerate crevice corrosion of galvanic couples of cobalt-chromium alloy with either titanium, titanium alloy, or stainless steel. We employed an electrochemical open-circuit potential measurement test and a potentiostatic passive film-corrosion measurement test. The results demonstrated that the chromium alloy/stainless-steel couple was unstable. The cobalt-chromium alloy/titanium alloy couple was stable.Cobalt-chromium alloys should not be used in combination with stainless steel but may be used in combination with titanium alloy. All usage of metal couples should be approached with the utmost caution.