Atmospheric pressure microwave plasma for aluminum surface cleaning

An atmospheric pressure, 2.45 GHz microwave plasma operating in ambient air was used to clean and activate aluminum surfaces. The effect of processing parameters on surface chemistry of aluminum has been studied to determine the minimal power and time needed to create clean surfaces. The contact angle measurements showed that the hydrophilicity greatly increases with increasing power and decreasing substrate speed. Fourier transform infrared spectroscopy shows that oxidative and thermal degradation is present during the plasma cleaning process. The authors' system using atmospheric pressure air plasma proves to be an efficient method for cleaning and activating metal surfaces without generating chemical waste and can be used to increase the adhesion of subsequent protective coatings.