Surface modification of SAE 1070 by chromium using plasma immersion ion implantation and deposition

It is well known that chromium content above 12% in Fe alloys increases their corrosion resistance significantly. In order to obtain this improvement, we studied the incorporation of chromium atoms into the surface of SAE 1070 steel by plasma immersion ion implantation and deposition (PIIID) method, in which an RF magnetron sputtering (MS) device is used as the metal source. Chromium films were deposited by RF magnetron sputtering only and compared with one formed by PIIID with respect to corrosion resistance, tribological properties, surface morphology and elemental profile. Potentiodynamic scans showed that the presence of chromium film leads to a decrease in the corrosion current density, promoting higher corrosion resistance. Tribology tests, of pin-on-disk type, showed an increase in the coefficient of friction and wear for PIIID samples, but the film was not totally removed from the wear scar. SEM images showed rougher surfaces for the PIIID samples. GDOES depth profiles showed the increase of film and mixing layer thicknesses with the increase of PIIID processing time.