scholarly journals Fabrication of a Novel Ta(Zn)O Thin Film on Titanium by Magnetron Sputtering and Plasma Electrolytic Oxidation for Cell Biocompatibilities and Antibacterial Applications

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 649
Author(s):  
Heng-Li Huang ◽  
Ming-Tzu Tsai ◽  
Yin-Yu Chang ◽  
Yi-Jyun Lin ◽  
Jui-Ting Hsu

Pure titanium (Ti) and titanium alloys are widely used as artificial implant materials for biomedical applications. The excellent biocompatibility of Ti has been attributed to the presence of a natural or artificial surface layer of titanium dioxide. Zinc oxide and tantalum oxide thin films are recognized due to their outstanding antibacterial properties. In this study, high power impulse magnetron sputtering (HiPIMS) was used for the deposition of tantalum oxide and zinc-doped Ta(Zn)O thin films on Ti with rough and porous surface, which was pretreated by plasma electrolytic oxidation (PEO). Surface morphology, antibacterial property as well as cell biocompatibility were analyzed. The antibacterial effect was studied individually for the Gram-positive and Gram-negative bacteria Staphylococcus aureus (S. aureus) and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans). The deposited Ta (Zn)O coating was composed of amorphous tantalum oxide and crystalline ZnO. The antibacterial results on the tantalum oxide and Ta(Zn)O coated Ti indicated a significant inhibition of both S. aureus and A. actinomycetemcomitans bacteria when compared with the uncoated Ti samples. The deposited Ta(Zn)O showed the best antibacterial performance. The Ta(Zn)O coated Ti showed lower level of the cell viability in MG-63 cells compared to other groups, indicating that Zn-doped Ta(Zn)O coatings may restrict the cell viability of hard tissue-derived MG-63 cells. However, the biocompatibility tests demonstrated that the tantalum oxide and Ta(Zn)O coatings improved cell attachment and cell growth in human skin fibroblasts. The cytotoxicity was found similar between the Ta2O5 and Ta(Zn)O coated Ti. By adopting a first PEO surface modification and a subsequent HiPIMS coating deposition, we synthetized amorphous tantalum oxide and Ta(Zn)O coatings that improved titanium surface properties and morphologies, making them a good surface treatment for titanium-based implants.

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Ruzil Farrakhov ◽  
Olga Melnichuk ◽  
Evgeny Parfenov ◽  
Veta Mukaeva ◽  
Arseniy Raab ◽  
...  

The paper compares the coatings produced by plasma electrolytic oxidation (PEO) on commercially pure titanium and a novel superelastic alloy Ti-18Zr-15Nb (at. %) for implant applications. The PEO coatings were produced on both alloys in the identical pulsed bipolar regime. The properties of the coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The PEO process kinetics was modeled based on the Avrami theorem and Cottrell equation using a relaxation method. The resultant coatings contain TiO2, for both alloys, and NbO2, Nb2O5, ZrO2 for Ti-18Zr-15Nb alloy. The coating on the Ti-18Zr-15Nb alloy has a higher thickness, porosity, and roughness compared to that on cp-Ti. The values of the kinetic coefficients of the PEO process—higher diffusion coefficient and lower time constant for the processing of Ti-18Zr-15Nb—explain this effect. According to the electrochemical studies, PEO coatings on Ti-18Zr-15Nb alloy provide better corrosion protection. Higher corrosion resistance, porosity, and roughness contribute to better biocompatibility of the PEO coating on Ti-18Zr-15Nb alloy compared to cp-Ti.


2017 ◽  
Vol 17 (2) ◽  
pp. 41-54 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
K. Pietrzak ◽  
W. Malorny

AbstractThe SEM and EDS results of porous coatings formed on pure titanium by Plasma Electrolytic Oxidation (Micro Arc Oxidation) under DC regime of voltage in the electrolytes containing of 500 g zinc nitrate Zn(NO3)2·6H2O in 1000 mL of concentrated phosphoric acid H3PO4at three voltages, i.e. 450 V, 550 V, 650 V for 3 minutes, are presented. The PEO coatings with pores, which have different shapes and the diameters, consist mainly of phosphorus, titanium and zinc. The maximum of zinc-to-phosphorus (Zn/P) ratio was found for treatment at 650 V and it equals 0.43 (wt%) | 0.20 (at%), while the minimum of that coefficient was recorded for the voltage of 450 V and equaling 0.26 (wt%) | 0.12 (at%). Performed studies have shown a possible way to form the porous coatings enriched with zinc by Plasma Electrolytic Oxidation in electrolyte containing concentrated phosphoric acid H3PO4with zinc nitrate Zn(NO3)2·6H2O.


Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Viorel Malinovschi ◽  
Alexandru Horia Marin ◽  
Catalin Ducu ◽  
Sorin Moga ◽  
Victor Andrei ◽  
...  

In this study, the surface of commercially pure titanium (Cp-Ti) was covered by a 21–95 µm-thick aluminum oxide layer using plasma electrolytic oxidation. Coating characterization revealed the formation of nodular and granular α- and γ-Al2O3 phases with minor amounts of TiAl2O5 and Na2Ti4O9 which yielded a maximum 49.0 GPa hardness and 50 N adhesive critical load. The corrosion resistance behavior in 3.5 wt.% NaCl solution of all plasma electrolytic oxidation (PEO) coatings was found to be two orders of magnitude higher compared to bare Ti substrate.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1124
Author(s):  
Aqmar Zakaria ◽  
Hamdi Shukor ◽  
Masahiro Todoh ◽  
Kamaruzaman Jusoff

One way to improve the biofunctionality of titanium alloys is by implementing plasma electrolytic oxidation (PEO) to incorporate bioactive elements such as fluoridated hydroxyapatite, into surface coatings of orthopaedic and dental implants. Hydroxyapatite (HAp) is known as a bioactive coating while fluorapatite (FAp) has an antibacterial effect that would enhance the bio-functionality and reduce the failure rate of orthopaedic and dental implants. The purpose of this study was to develop fluoridated hydroxyapatite as a bio-functional coating on Ti6Al4V with electrolyte containing trisodium orthophosphate, potassium hydroxide, and calcium fluoride. The coating surface and cross-section morphologies were evaluated, and the species in the electrolyte solution were found, and irregular micropores shapes were observed by field emission scanning electron microscopy (FESEM) and energy dispersive spectrometer (EDS). The phase composition of the coating surface containing TiO2 (anatase and rutile), tricalcium orthophosphate, HAp, and FAp was characterized by X-ray diffractometer (XRD). The adhesive strength of the coating was analysed by a micro-scratch test. Simulated body fluid (SBF) immersion test was performed to investigate the bioactivity of the coating. In this study, we demonstrated that the PEO technique has a good potential to develop bio-functional surface modifications that can affect the chemical composition and roughness of the coating surface. The FAp coating may provide insights for subsequent bioactive coatings while improving the antibacterial properties for orthopaedic and dental implants. Future work shall investigate the optimal amount of fluoride in the coating layer that obtains excellent results without causing adverse effects on adjacent tissue.


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