Plasma-based low-energy ion implantation, including plasma source ion nitriding/carburizing and plasma source low-energy ion enhanced deposition of thin films, for surface engineering of metallic materials was emerged as low-temperature, low-pressure surface modification technique. Plasma source ion nitriding onto AISI 316L austenitic stainless steel produced a high nitrogen face-centered-cubic phase (gamma(N)) layer about 10 mu m thick at the temperature of 380 degrees C during 4 h with the high microhardness of HK0.1N 22.0 GPa. The microhardness of the nitrided surface from the titanium nitride phase [(Ti, Al, V)N] layer on Ti6Al4V alloy at 750 degrees C during 4 h achieved up to about HK0.5N 15.5 GPa. No pitting corrosion in the Ringer's solution at 37 degrees C was detected by electrochemical polarization measurement for the nitrided AISI 316L stainless steel and Ti6Al4V alloy, respectively. Plasma source ion nitriding of the metallic materials provided the engineering surfaces with combined improvement in hardness and corrosion resistance. (c) 2005 Elsevier B.V. All rights reserved.