Assessment of atmospheric plasma treatment cleaning effect on steel surfaces

The present study deals with the ability of an atmospheric pressure air plasma torch (APPT) treatment to remove lubricant pollutants coming from machining processes on steel surfaces. This effect has been characterized by contact angle measurements, gravimetric analysis and reflection absorption infrared reflectance spectroscopy (RAIR-FTIR). Attending to the initial results of the investigation, further surface analysis has been done by means of X-ray photoelectron spectroscopy (XPS). In order to define the benefits of cleaning for adhesive bonding processes, pull-off tests were performed on all the coupons. Experimental data show the effectiveness of APPT to achieve not only a high rate of surface lubricant layer elimination, thus cleaning the metal samples by means of a solvent free and fast treatment, but also a remarkable improvement on the substrate adhesive bonding strength.