Surface free energy changes of stainless steel after one atmospheric pressure plasma treatment

Stainless steel plates (AISI 304L) were treated by an atmospheric pressure plasma treatment at room temperature in order to modify the surface properties. After plasma treatment, the surface wettability and the surface free energy were both improved. The wettability and the surface free energy of stainless steel plates before and after plasma treatment were measured from the results of contact angle test. Through the results of contact angle and surface free energy, optimum plasma treatment conditions were obtained, such as the treatment time of 60 sec and the treatment power of 120 W. In addition to this, the optimum aging time was 3 to 5 min in air.