Nanoindentation and XPS Studies of Titanium TNZ Alloy after Electrochemical Polishing in a Magnetic Field.

Tadeusz Hryniewicz,Krzysztof Rokosz,Frédéric Prima,Ryszard Rokicki

doi:10.3390/ma8010205

Abstract

This work presents the nanoindentation and XPS results of a newly-developed biomaterial of titanium TNZ alloy after different surface treatments. The investigations were performed on the samples AR (as received), EP (after a standard electropolishing) and MEP (after magnetoelectropolishing). The electropolishing processes, both EP and MEP, were conducted in the same proprietary electrolyte based on concentrated sulfuric acid. The mechanical properties of the titanium TNZ alloy biomaterial demonstrated an evident dependence on the surface treatment method, with MEP samples revealing extremely different behavior and mechanical properties. The reason for that different behavior appeared to be influenced by the surface film composition, as revealed by XPS study results displayed in this work. The increase of niobium and zirconium in the surface film of the same titanium TNZ alloy after magnetoelectropolishing MEP treatment is meaningful and especially advantageous considering the application of this alloy as a biomaterial.

Highlights

Titanium and its alloys are advanced metallic materials possessing many interesting features and properties with outstanding corrosion resistance in a wide variety of environments [1,2,3,4,5,6,7,8,9,10,11,12,13]
The nanoindentation mechanical data recorded for titanium TNZ alloy samples in three groups, any treatments (AR), EP and MEP, vary concerning the magnitude and the range of changes
XPS Results In Figure 3, the titanium (Ti 2p), niobium (Nb 3d) and zirconium (Zr 3d) spectra of the passive layer formed after standard EP and MEP are shown

Summary

Introduction

Titanium and its alloys are advanced metallic materials possessing many interesting features and properties with outstanding corrosion resistance in a wide variety of environments [1,2,3,4,5,6,7,8,9,10,11,12,13]. CP Ti Grade 2 and NiTi alloys have been known for years for their application as biomaterials [1,7,8,9]. Other titanium alloys, such as Ti-6Al-4V, Ti-6Al-4V ELI, Ti-6Al-7Nb, have been used in prosthetic engineering [6,8,9,10], even if they contain carcinogenic vanadium and allergenic aluminum [6,14]. Some indentation and nanoindentation studies on stainless steels and titanium biomaterials were performed before [2,17,18,19], together with the significance of the quantitative determination of material hardness, stressed in the authors’ other work [15]

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Discussion

Conclusion