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Hybrid diffusive/PVD treatments to improve the tribological resistance of Ti-6Al-4V.
Biomed Mater Eng 2014; 24(1):581-92BM

Abstract

Titanium alloys are nowadays used for a wide range of biomedical applications thanks to their combination of high mechanical resistance, high corrosion resistance and biocompatibility. Nevertheless, the applicability of titanium alloys is sometimes limited due to their low microhardness and tribological resistance. Thus the titanium alloys cannot be successfully applied to prosthetic joint couplings. A wide range of surface treatments, in particular PVD coatings such as CrN and TiN, have been used in order to improve the tribological behaviour of titanium alloys. However, the low microhardness of the titanium substrate often results in coating failure due to cracks and delamination. For this reason, hybrid technologies based on diffusive treatments and subsequent PVD coatings may improve the overall coating resistance. In this work, conventional PVD coatings of CrN or TiCN, deposited on Titanium Grade 5, were characterized and then combined with a standard thermal diffusive nitriding treatment in order to improve the tribological resistance of the titanium alloys and avoid coating delamination. The different treatments were studied by means of scanning electron microscopy both on the sample surface and in cross-section. In-depth composition profiles were obtained using glow discharge optical emission spectrometry (GDOES) and localized energy dispersive X-ray diffraction on linear scan-lines. The microhardness and adhesion properties of the different treatments were evaluated using Vickers microhardness tests at different load conditions. The indentations were observed by means of SEM in order to evaluate delaminated areas and the crack's shape and density. The tribological behaviour of the different treatments was tested in dry conditions and in solution, in alternate pin-on-flat configuration, with a frequency of 0.5 Hz. After testing, the surface was investigated by means of stylus profilometry and SEM both on the surface and in cross-section. The standalone PVD coatings show a limited tribological resistance due to the low hardness of the substrate, which results in fractures and delamination. The combination of a diffusive process and a subsequent PVD coating shows a stronger effect in improving the tribological resistance of the substrate.

Authors+Show Affiliations

Department of Chemistry, Physics and Environment, University of Udine, Udine, Italy.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

24211942

Citation

Marin, E, et al. "Hybrid diffusive/PVD Treatments to Improve the Tribological Resistance of Ti-6Al-4V." Bio-medical Materials and Engineering, vol. 24, no. 1, 2014, pp. 581-92.
Marin E, Offoiach R, Lanzutti A, et al. Hybrid diffusive/PVD treatments to improve the tribological resistance of Ti-6Al-4V. Biomed Mater Eng. 2014;24(1):581-92.
Marin, E., Offoiach, R., Lanzutti, A., Regis, M., Fusi, S., & Fedrizzi, L. (2014). Hybrid diffusive/PVD treatments to improve the tribological resistance of Ti-6Al-4V. Bio-medical Materials and Engineering, 24(1), pp. 581-92. doi:10.3233/BME-130845.
Marin E, et al. Hybrid diffusive/PVD Treatments to Improve the Tribological Resistance of Ti-6Al-4V. Biomed Mater Eng. 2014;24(1):581-92. PubMed PMID: 24211942.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hybrid diffusive/PVD treatments to improve the tribological resistance of Ti-6Al-4V. AU - Marin,E, AU - Offoiach,R, AU - Lanzutti,A, AU - Regis,M, AU - Fusi,S, AU - Fedrizzi,L, PY - 2013/11/12/entrez PY - 2013/11/12/pubmed PY - 2014/6/24/medline KW - PVD KW - Ti-6Al-4V KW - TiN KW - nitridation KW - titanium hardening SP - 581 EP - 92 JF - Bio-medical materials and engineering JO - Biomed Mater Eng VL - 24 IS - 1 N2 - Titanium alloys are nowadays used for a wide range of biomedical applications thanks to their combination of high mechanical resistance, high corrosion resistance and biocompatibility. Nevertheless, the applicability of titanium alloys is sometimes limited due to their low microhardness and tribological resistance. Thus the titanium alloys cannot be successfully applied to prosthetic joint couplings. A wide range of surface treatments, in particular PVD coatings such as CrN and TiN, have been used in order to improve the tribological behaviour of titanium alloys. However, the low microhardness of the titanium substrate often results in coating failure due to cracks and delamination. For this reason, hybrid technologies based on diffusive treatments and subsequent PVD coatings may improve the overall coating resistance. In this work, conventional PVD coatings of CrN or TiCN, deposited on Titanium Grade 5, were characterized and then combined with a standard thermal diffusive nitriding treatment in order to improve the tribological resistance of the titanium alloys and avoid coating delamination. The different treatments were studied by means of scanning electron microscopy both on the sample surface and in cross-section. In-depth composition profiles were obtained using glow discharge optical emission spectrometry (GDOES) and localized energy dispersive X-ray diffraction on linear scan-lines. The microhardness and adhesion properties of the different treatments were evaluated using Vickers microhardness tests at different load conditions. The indentations were observed by means of SEM in order to evaluate delaminated areas and the crack's shape and density. The tribological behaviour of the different treatments was tested in dry conditions and in solution, in alternate pin-on-flat configuration, with a frequency of 0.5 Hz. After testing, the surface was investigated by means of stylus profilometry and SEM both on the surface and in cross-section. The standalone PVD coatings show a limited tribological resistance due to the low hardness of the substrate, which results in fractures and delamination. The combination of a diffusive process and a subsequent PVD coating shows a stronger effect in improving the tribological resistance of the substrate. SN - 1878-3619 UR - https://www.unboundmedicine.com/medline/citation/24211942/Hybrid_diffusive/PVD_treatments_to_improve_the_tribological_resistance_of_Ti_6Al_4V_ L2 - https://content.iospress.com/openurl?genre=article&id=doi:10.3233/BME-130845 DB - PRIME DP - Unbound Medicine ER -