Research on the Corrosion Behavior of TC4 Titanium Alloy by Scanning Kelvin Probe

The corrosion behavior and corrosion morphology of two typical TC4 titanium alloy with equiaxed structure and wicimanstatten structure in hydrochloric acid solution were studied using scanning Kelvin probe techniques and observed by scanning electron microscope, respectively. The results show that along with the ongoing of corrosion, surface potential of equiaxed structure alloy is moving to positive direction and that of widmanstatten structure alloy is moving to negative direction after positive direction movement. The surface potential of two kinds structure alloy all present cathode and anode region in the corrosion process, which shows the characteristic of selective corrosion. Surface potential difference of widmanstatten structure alloy is greater than that of equiaxed structure alloy and its corrosion resistance is inferior to that of equiaxed structure alloy. Corrosion preferentially occurs in alpha phase of the two kinds structure alloy through corrosion morphology observation analysis.