Pulsed laser cleaning of oxidized metallic surfaces in electrochemically controlled liquid confinement

Pulsed laser cleaning of oxidized metallic surfaces is studied. To our knowledge, for the first time, it has been demonstrated that the application of pulsed laser irradiation in a liquid confinement at controlled electrochemicaI potential enhances the oxide film removal from metal surfaces. Systematic studies on simulated corrosion product films using optical reflectance profile, energy dispersive X-ray spectroscopy, and piezoelectric transducer measurements, have revealed that efficient oxide film removal by laser irradiation is achieved if a basic electrolyte solution is used and a cathodic potential is imposed. The advantages of this novel technique against laser irradiation in air are demonstrated. The results indicate that hydrogen entrapment in the oxide film during the cathodic reduction process and the resulting defect formation is responsible for the observed effect.