Electrochemical behavior of the Ti6Al4V alloy implanted by nitrogen PIII

SURFACE & COATINGS TECHNOLOGY

卷:206

Article

Savonov, G. S.^1,2  Ueda, M.¹  Oliveira, R. M.¹  Otani, C.² 

[1] INPE, BR-12227010 Sao Jose Dos Campos, SP, Brazil

[2] ITA, BR-12228900 Sao Jose Dos Campos, SP, Brazil

关键词: Plasma immersion ion implantation;    Corrosion;    Polarization;    Electrochemical impedance spectroscopy;    Titanium alloy;    Titanium nitride;   

DOI  :  10.1016/j.surfcoat.2011.09.007

来源: Elsevier

【 摘 要 】

Plasma surface treatments have been used very often to enhance the surface properties of metallic materials. In this work, Ti6Al4V titanium alloy was treated by nitrogen plasma immersion ion implantation (NPIII) in order to obtain improvements in its surface properties, such as corrosion resistance evaluated here. The microstructure and corrosion behavior of the implanted and unimplanted samples were evaluated, using, XRD, GDOES and potentiodynamic polarization and impedance electrochemical spectroscopy tests in 0.6 M NaCl solution. It was verified that the NPIII created resistant layers to corrosive attacks. In corrosion tests by polarization, the implanted samples showed corrosion current density reduction of about 10 times compared to the Ti6Al4V alloy without treatment. Besides that, it was also observed a reduction of the passive current density of one order of the magnitude. In all the studied cases, the polarization curves were shifted to more positive values of potentials, indicating a lower tendency of these PIII treated surfaces to corrosion. The implantation process produced a thin TiN surface layer followed by Ti(2)N and then a layer with nitrogen in solid solution, all detected by GDOES combined with X-ray diffraction. These layers promoted an excellent polarization resistance of the Ti6Al4V surfaces on impedance spectroscopy tests also. This better performance in these tests can be correlated with the formation of continuous nitride layer, which could retard chloride ions ingress into the substrate. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

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