scholarly journals Fabrication of a Protective Hybrid Coating Composed of TiO2, MoO2, and SiO2 by Plasma Electrolytic Oxidation of Titanium

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1182
Author(s):  
Tehseen Zehra ◽  
Mosab Kaseem ◽  
Shakhawat Hossain ◽  
Young-Gun Ko
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Sio2 Nanoparticles ◽  
Hybrid Coating ◽  
Structural Defects ◽  
Nacl Solution ◽  
Microstructural Observation ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

This work examined the influence of dual incorporation of MoO2 and SiO2 on the corrosion behavior of pure titanium treated via plasma electrolytic oxidation (PEO). To achieve this purpose, pure titanium substrate was treated via PEO in an alkaline-molybdate electrolyte without and with SiO2 nanoparticles. The microstructural observation revealed that the addition of SiO2 nanoparticles into the electrolyte during PEO helped to seal the structural defects in the PEO coating so that a rougher, thicker, and denser coating rich in SiO2 was successfully obtained. From the electrochemical measurements in a 3.5 wt.% NaCl solution, the TiO2-MoO2-SiO2 hybrid coating exhibited a higher corrosion resistance than the TiO2-MoO2 coating which was attributed to the sealing effect by stable SiO2 nanoparticles.

scholarly journals Development and characterization of bioglass incorporated plasma electrolytic oxidation layer on titanium substrate for biomedical application

2021 ◽  
Vol 60 (1) ◽  
pp. 678-690
Author(s):  
Nur Athirah Sukrey ◽  
Muhammad Rizwan ◽  
Abd Razak Bushroa ◽  
Siti Zuliana Salleh ◽  
Wan Jefrey Basirun
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Electrolyte Concentration ◽  
Biomedical Application ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Deposition Process ◽  
Voltage Response ◽  
Functional Coating ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Abstract In this research, the growth of bioglass (BG) (45S5) incorporated oxide layer via plasma electrolytic oxidation (PEO) method was studied with respect to different sodium hydroxide (NaOH) concentrations (0.1, 0.3, 0.5, and 0.7 M). The voltage response during the deposition process was highly dependent on the electrolyte concentration. Large sparks were recorded at the lowest electrolyte concentration. The result also showed that the increment of electrolyte concentration improved the thickness and mechanical properties of BG-coated pure titanium (TI) surfaces via the PEO process. However, the morphological investigation showed that the coating formation and the uniformity of coating distribution are dependent on the optimum concentration of the electrolyte. This study demonstrates the feasibility of the PEO method in producing a uniform bio-functional coating for biomedical applications.

scholarly journals Comparison of Biocompatible Coatings Produced by Plasma Electrolytic Oxidation on cp-Ti and Ti-Zr-Nb Superelastic Alloy

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Ruzil Farrakhov ◽  
Olga Melnichuk ◽  
Evgeny Parfenov ◽  
Veta Mukaeva ◽  
Arseniy Raab ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
X Ray ◽  
Kinetic Coefficients ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Cp Ti ◽  
Peo Coatings

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.

scholarly journals SEM and EDS Characterization of Porous Coatings Obtained On Titaniumby Plasma Electrolytic Oxidation in Electrolyte Containing Concentrated Phosphoric Acid with Zinc Nitrate

2017 ◽  
Vol 17 (2) ◽  
pp. 41-54 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
K. Pietrzak ◽  
W. Malorny
Keyword(s):  
Phosphoric Acid ◽  
Plasma Electrolytic Oxidation ◽  
Pure Titanium ◽  
Zinc Nitrate ◽  
Porous Coatings ◽  
Electrolytic Oxidation ◽  
Micro Arc Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

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.

scholarly journals Effect of Microstructure on the Localized Corrosion and Stress Corrosion Behaviours of Plasma-Electrolytic-Oxidation-Treated AA7075 Aluminum Alloy Forging in 3.5 wt. %NaCl Solution

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
A. Venugopal ◽  
Rajiv Panda ◽  
Sushant Manwatkar ◽  
K. Sreekumar ◽  
L. Ramakrishna ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Plasma Electrolytic Oxidation ◽  
Tensile Tests ◽  
Localized Corrosion ◽  
Nacl Solution ◽  
Uncoated Sample ◽  
Electrolytic Oxidation ◽  
Metallographic Observation ◽  
The One ◽  
Plasma Electrolytic

The influence of metallurgical heterogeneities such as coring and intermetallic phases on the corrosion and stress corrosion cracking behaviours of AA7075 aluminium alloy forging was examined in 3.5 wt. % NaCl solution with and without plasma electrolytic oxidation coating. Electrochemical test results demonstrated significant improvement in the corrosion resistance of the alloy after PEO coating. Stress corrosion results show that the metallurgical heterogeneities resulted in a loss in elongation of the uncoated sample in NaCl (11.5%) when compared to the one tested in air (12.9%). The loss in elongation of the uncoated sample was shown to be due to localized corrosion-assisted mechanical cracking rather than true stress corrosion based on preexposure tensile tests followed by posttest metallographic observation of the stress corrosion tested samples. This was further confirmed by the fractographic examination of the failed samples, which exhibited a typical ductile cracking morphology for all the coated and uncoated specimens.

scholarly journals Improvement of Mechanical and Corrosion Properties of Commercially Pure Titanium Using Alumina PEO Coatings

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Viorel Malinovschi ◽  
Alexandru Horia Marin ◽  
Catalin Ducu ◽  
Sorin Moga ◽  
Victor Andrei ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Corrosion Properties ◽  
Commercially Pure ◽  
Electrolytic Oxidation ◽  
Aluminum Oxide Layer ◽  
Plasma Electrolytic ◽  
Cp Ti ◽  
Peo Coatings

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.

scholarly journals Characterization of Porous Phosphate Coatings Created on CP Titanium Grade 2 Enriched with Calcium, Magnesium, Zinc and Copper by Plasma Electrolytic Oxidation

2018 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Steinar Raaen ◽  
Sofia Gaiaschi ◽  
Patrick Chapon ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Plasma Electrolytic Oxidation ◽  
Titanium Substrate ◽  
Porous Coating ◽  
Phosphate Coatings ◽  
Electrolytic Oxidation ◽  
Calcium Magnesium ◽  
Titanium Grade ◽  
Plasma Electrolytic ◽  
Peo Coatings

In the paper, the effect of voltage increasing (from 500 VDC up to 650 VDC) on the structure and chemical composition of porous coating on titanium made by Plasma Electrolytic Oxidation, is presented. In the present paper, phosphates based coatings enriched with calcium, magnesium, zinc and copper in electrolyte based on 1 L of 85% concentrated H3PO4 with additions of Ca(NO3)2·4H2O, and Mg(NO3)2∙6H2O, and Zn(NO3)2∙6H2O, and Cu(NO3)2∙3H2O, are described. The morphology, chemical and phase composition, are evaluated using SEM, EDS, XRD, XPS, GDOES. Based on all the analyses, it was found out that the PEO coatings are porous and enriched with calcium, magnesium, zinc and copper. They consist mainly of the amorphous phase, which is more visible for higher voltages, and it is correlated with the increasing of the total PEO coating thickness (the higher the voltage, the thicker the PEO coating). However, for 650 VDC an amorphous phase and titanium substrate was also recorded with a signal from Ti2P2O7 crystalline, that was not observed for lower voltages. It was also found out that all the obtained coatings may be divided in three sub-layers, i.e. porous, semiporous, and transition one.

scholarly journals Metal Ions Supported Porous Coatings by Using AC Plasma Electrolytic Oxidation Processing

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3838 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Steinar Raaen ◽  
Sofia Gaiaschi ◽  
Patrick Chapon ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Orthophosphoric Acid ◽  
Titanium Substrate ◽  
Oxidation States ◽  
Phosphate Coatings ◽  
Cathodic Voltage ◽  
Electrolytic Oxidation ◽  
Anodic Voltage ◽  
Plasma Electrolytic ◽  
Calcium Phosphate Coatings

Coatings enriched with zinc and copper as well as calcium or magnesium, fabricated on titanium substrate by Plasma Electrolytic Oxidation (PEO) under AC conditions (two cathodic voltages, i.e., −35 or −135 V, and anodic voltage of +400 V), were investigated. In all experiments, the electrolytes were based on concentrated orthophosphoric acid (85 wt%) and zinc, copper, calcium and/or magnesium nitrates. It was found that the introduced calcium and magnesium were in the ranges 5.0–5.4 at% and 5.6–6.5 at%, respectively, while the zinc and copper amounts were in the range of 0.3–0.6 at%. Additionally, it was noted that the metals of the block S (Ca and Mg) could be incorporated into the structure about 13 times more than metals of the transition group (Zn and Cu). The incorporated metals (from the electrolyte) into the top-layer of PEO phosphate coatings were on their first (Cu+) or second (Cu2+, Ca2+ and Mg2+) oxidation states. The crystalline phases (TiO and Ti3O) were detected only in coatings fabricated at cathodic voltage of −135 V. It has also been pointed that fabricated porous calcium–phosphate coatings enriched with biocompatible magnesium as well as with antibacterial zinc and copper are dedicated mainly to medical applications. However, their use for other applications (e.g., catalysis and photocatalysis) after additional functionalizations is not excluded.

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