Self-Organized Anodic Oxides on Titanium Alloys Prepared from Glycol- and Glycerol-Based Electrolytes

Marta Michalska-Domańska; Magdalena Łazińska; Justyna Łukasiewicz; Johannes M C Mol; Tomasz Durejko

doi:10.3390/ma13214743

Self-Organized Anodic Oxides on Titanium Alloys Prepared from Glycol- and Glycerol-Based Electrolytes

Materials (Basel). 2020 Oct 23;13(21):4743. doi: 10.3390/ma13214743.

Authors

Marta Michalska-Domańska^{1

2}, Magdalena Łazińska³, Justyna Łukasiewicz³, Johannes M C Mol¹, Tomasz Durejko³

Affiliations

¹ Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands.
² Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw, Poland.
³ Faculty of Advanced Technology and Chemistry, Institute of Materials Science and Engineering, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw, Poland.

Abstract

The anodization of commercially pure Ti alloy (99.5 wt %) and two biomedical titanium alloys, Ti6Al7Nb and Ti6Al4V, was performed, and the resulting anodic oxides were studied. The biomedical alloys were made by Laser Engineered Net Shaping. The glycol-based and glycerol-based electrolytes with 0.3 M ammonium fluoride and 2 wt % of deionized water content were tested. It was found that electrolyte type as well as the chemical composition of the base substrate affected the final morphology and chemical composition of the anodic oxide formed. A higher current density, ionic mobility, and oxide growth rate were obtained in glycol-based electrolyte as compared to those obtained in glycerol-based electrolyte for all tested alloys. A self-organized nanotubular and nanoporous morphology of the anodic oxide in both types of electrolyte was obtained. In each electrolyte, the alloy susceptibility to oxidation increased in the following order: Ti6Al4V < Ti 99.5% < Ti6Al7Nb, which can be correlated to the oxidation susceptibility of the base titanium alloy. It was observed that the more impurities/alloying elements in the substrate, the lower the pore diameters of anodic oxide. There was a higher observed incorporation of electrolyte species into the anodic oxide matrix in the glycerol-based electrolyte compared with that in glycol-based electrolyte.

Keywords: anodization; biomedical alloys; current density; electrolytes viscosity; ions incorporation; oxidation susceptibility; titanium anodic oxide.