TITLE:
Nanomodificated Surface CoCr Alloy for Corrosion Protection of MoM Prosthesis
AUTHORS:
Cristina Díaz, Stephan Mändl, Rosario Pereiro, Beatriz Fernández
KEYWORDS:
Plasma Immersion Ion Implantation, THR, Nanoparticles, Ion Release
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.6 No.2,
March
24,
2015
ABSTRACT: Problems in metal-on-metal (MoM) hip replacement systems still persist due to high wear rates,
low corrosion resistance and release of toxic ions and nanoparticles. As a consequence of these
effects, failure, infections, loosening or bone resorption is the typical problems in the hip prosthesis.
In order to reduce failure due to corrosion and/or releasing ions and particles, this study presents
some works in a novel nanoscale surface modification of cobalt-chromium alloy (CoCr) for
obtaining improved surface conditions in these alloys for these applications. Improving corrosion
resistant of these alloys and achieving a low wear rate are possible to reduce the total released
ions and particles released from the surface of this material. According to it, three different treatments
using oxygen at temperatures of 300°C, 350°C and 400°C were carried out by plasma immersion
ion implantation technique (PI3). X-ray diffraction (XRD) analysis shows an increase in
the formation of chromium oxides in the outer surface of the CoCr alloy. It allows improving in
corrosion resistant in CoCr alloys. Moreover, total quantity of released Co, Cr and Mo ions have
been reduced. Wear rate studies showed a very similar behaviour after the treatments in relation
to untreated CoCr alloy and release rate from the treated surface of CoCr alloys was reduced in
comparison with untreated CoCr alloy.