Aluminum surface treatment by the RF plasma pencil

The effects of atmospheric RF plasma treatment on aluminum sheets were studied. The treatment was performed with the plasma pencil developed at Masaryk University, using Ar and Ar/O2 gas mixtures. The surface free energy of treated sheets increased up to 72.6 mJ/m2, which later resulted into higher adhesion between the STEEL industrial protective varnish and the plasma treated aluminum sheets. The adhesion properties were tested by ISO-certified Erichsen and bending tests. A set of IR spectroscopy measurements in ATR mode proved significant plasma surface cleaning, generation of OH groups and surface oxidation. The addition of O2 into the Ar flow resulted in stronger oxidation of aluminum, which was measured by the EDX technique. The surface of aluminum sheets became porous after the plasma treatment with Ar. The smoothening of pores occurred after adding a small amount of O2 into the Ar flow.