Agradecimentos: The authors are grateful F.L. Bernardes for fabrication of the samples. Experimental support of L.H.M. Antunes at Unicamp, Campinas in addition to Mr. L. Wu, Dr. F.E. Montoro and Dr. A.L. Gobbi (projects ME 22425 and LMF 20869) at Brazilian Nanotechnology National Laboratory-LNNano is acknowledged. The authors acknowledge the LNNano and the Brazilian Synchrotron Light Laboratory-LNLS for the use of the XTMS installation at the XRD-1 beamline. Microstructural characterisation was performed at Analytical Centre - UFC/CT-INFRA/MCTI-SISNANO/Pró-Equipamentos CAPES and LNNano. Financial support was provided by CAPES, Brazil (Project 50/2011), CNPEM, Brazil (Project 20170618) and the São Paulo Research Foundation FAPESP, Brazil (grant numbers 2016/09350-2 and 2007/54829-5) Ver menos

Abstract: CoCrMo alloys have been used for several decades in implantable devices due to their favourable mechanical properties, low wear rate in addition to good biocompatibility and high corrosion resistance. These alloys are conventionally produced via casting and/or forging route, however additive manufacturing techniques being recently employed in their fabrication. In this work, CoCrMo samples were produced by direct metal laser sintering additive manufacturing process. The microstructure and surface composition were examined employing scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The corrosion resistance was measured in 0.14 M sodium chloride solution and in phosphate buffered solution (PBS) both with and without addition of albumin at pH 7.4 and 37 degrees C. For this, potentiodynamic tests in addition to electrochemical impedance spectroscopy were employed. The studied CoCrMo alloy exhibits a good corrosion resistance in solutions tested being the highest in PBS solution without albumin addition. The XPS analysis showed that the passive film composition and its thickness are not modified by the adsorbed layer. Microstructural analysis revealed occurrence of strain-induced martensitic transformation Ver menos