%0 journal article
%@ 0257-8972
%A Lutz, J., Diaz, C., Garcia, J.A., Blawert, C., Maendl, S.

%D 2011
%J Surface and Coatings Technology
%N 8-9
%P 3043-3049 
%R doi:10.1016/j.surfcoat.2010.11.017
%T Corrosion behaviour of medical CoCr alloy after nitrogen plasma immersion ion implantation
%U https://doi.org/10.1016/j.surfcoat.2010.11.017
8-9 
%X Surface treatment of medical CoCr alloys L605 by nitrogen plasma immersion ion implantation (PIII) leads to the formation of a hard and wear resistant surface layer, consisting of nitrogen in solid solution. However, a detailed investigation of the corrosion properties by potentiodynamic polarization and electrochemical impedance spectroscopy shows that even at processing temperatures of 350 °C, where no CrN precipitates are observed, no complete passivation of the surface by formation of a protective Cr2O3 layer is possible leading to enhanced corrosion rates further increasing with increasing PIII processing temperature. It is postulated that the enhanced affinity of chromium for nitrogen leads to a reduced mobility inside the alloy, thus prohibiting a timely surface passivation. Nevertheless, a surface modification where a moderate decrease in corrosion resistance coupled with a significant reduction in generated wear particles should be feasible for biomedical applications.