Development of copper-enriched porous coatings on ternary Ti-Nb-Zr alloy by plasma electrolytic oxidation

Abstract

In this paper, a preparation method and characteristics of porous coatings enriched in copper distributed in the whole volume on a ternary Ti-Nb-Zr alloy biomaterial obtained by plasma electrolytic oxidation (PEO) in an electrolyte containing H 3 PO 4 within Cu(NO 3 ) 2 at potentials of 180 and 450 V are presented. It has been shown that the PEO potential has impact on the thickness of the coatings, i.e., the higher the potential used, the thicker the coating obtained. Using XPS study, it was shown that copper inside the coating appears as Cu + and Cu 2+ ions, while titanium, niobium, and zirconium appear as Ti 4+ , Nb 5+ , and Zr x+ (x ≤ 2), respectively. It was also found that the roughness of PEO coating formed at 450 V is higher than the one obtained at 180 V, and it is well correlated with bigger pores after the PEO treatment. Additionally, in this paper two PEO coating models composed of three sub-layers are presented. The thickness of the outer top porous sub-layer obtained after PEO oxidation at both 180 and 450 V equals to about 2 μm, while the semi-porous as well as transition sub-layers are thicker after PEO processing at 450 V (5 μm) than those obtained at 180 V (4 μm thick). The creation of the top porous and transition compact sub-layer of PEO coating may be explained by switch-on and switch-off of the PEO potential, while the middle and semi-porous sub-layers are most likely formed during the stable voltage conditions of PEO treatment.

Characterisation of Calcium- and Phosphorus-Enriched Porous Coatings on CP Titanium Grade 2 Fabricated by Plasma Electrolytic Oxidation

“…Nowadays, light metals such as titanium [1][2][3][4], niobium [5][6][7][8][9], tantalum [10][11][12][13][14][15], and their alloys [16][17][18][19][20][21][22], after electrochemical treatment (electropolishing and/or plasma electrolytic oxidation), may be used as biomaterials (implant materials) because of their mechanical properties [23][24][25][26][27], good corrosion resistance [28][29][30][31] in body fluids, and osteointegration [32][33][34]. The electropolishing…”

Fabrication and characterisation of porous, calcium enriched coatings on titanium after plasma electrolytic oxidation under DC regime

“…To prepare the nano-layers with expected chemical composition and mechanical properties, the electropolishing (EP) [1], magnetoelectropolishing (MEP) [2], and high-current density electropolishing (HDEP) [3] processes are employed, while for obtaining the micro scale layers, the Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO) [4][5][6], should be used. That method may be used to oxidize inter alia the titanium [7][8][9][10], its alloys (Ti6Al4V [11][12], Ti6Al7Nb [13], NiTi [14], TiNbZr [15], TiNbZrSn [16]) as well as niobium [18] and tantalum [19]. In addition, it has to be pointed that PEO coatings may be enriched also in other elements, i.e.…”

SEM, EDS and XPS analysis of nanostructured coating formed on NiTi biomaterial alloy by Plasma Electrolytic Oxidation (PEO)

“…Carbon contamination layer formed on the NiTi surface consists of about 80 at% of carbon and 20 at% of oxygen. Additionally, the Cu/P, Cu/Ti, Ti/P and Cu/(Ti+Ni+P) coefficients were found to allow comparing the obtained coating with other ones proposed by the other researchers [19,20]: Based on the spectra shown in Fig. 9, it is possible to note that the binding energies of Ti 2p 3/2 and Ti 2p 1/2 , are equaling to 460,4 eV and 466 eV, respectively.…”

“…9, it is possible to note that the binding energies of Ti 2p 3/2 and Ti 2p 1/2 , are equaling to 460,4 eV and 466 eV, respectively. Those binding energies suggest in fact the presence of titanium on the fourth stage of oxidation (Ti 4+ ) in the surface layer [18,19]. On the basis of P 2p spectrum, where the maximum is observed at 134,1 eV, one can assume the presence of titanium and/or copper and/or nickel phosphates in the PEO coating.…”