Sodium Aluminate Concentration Effects on Microstructure and Corrosion Behavior of the Plasma Electrolytic Oxidation Coatings on Pure Titanium

Molaei, Maryam; Fattah‐alhosseini, Arash; Gashti, Seyed Omid

doi:10.1007/s11661-017-4405-2

Cited by 48 publications

(9 citation statements)

References 36 publications

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“…The composition of the PEO coating is determined by the chemical composition of the electrolyte and substrate material [20]. The studies available in the published literature [1,9,12,21,22] have reported and confirmed that the chemical composition of the electrolyte has a major effect on the corrosion behavior of PEO coatings. Shokouhfar et al [22] concluded, for instance, that a change in electrolyte components, even when all other conditions remained constant, led to a change in the sparking voltage and, consequently, to a change in the size and uniformity of the surface pores.…”

Section: Introductionmentioning

confidence: 92%

Influence of different sodium-based additives on corrosion resistance of PEO coatings on pure Ti

Molaei

Fattah‐alhosseini

Keshavarz

2019

Journal of Asian Ceramic Societies

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In the present study, the plasma electrolytic oxidation method was used to form ceramic coatings on pure Ti substrates. For this purpose, five different aluminate-based electrolytes containing various sodium-based additives (sodium hydroxide, sodium phosphate, sodium silicate, sodium tetraborate and sodium fluoride) were used. The role of additives in the growth, macrostructure, surface and cross-sectional microstructure, phase composition and corrosion resistance of the coatings was evaluated. An X-ray diffractometer and scanning electron microscope were used to study the microstructure and phase composition of the coatings, respectively. The corrosion resistance of the coatings was investigated by applying electrochemical impedance spectroscopy and potentiodynamic polarization tests in a 3.5 wt. % NaCl solution. The results revealed that use of a sodium phosphate additive led to formation of a coating (4.33 µm thick) with the most suitable microstructure and highest corrosion resistance (4.36 × 10 6 Ω cm 2), which was 53 times higher than that of uncoated Ti.

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Section: Introductionmentioning

confidence: 92%

Influence of different sodium-based additives on corrosion resistance of PEO coatings on pure Ti

Molaei

Fattah‐alhosseini

Keshavarz

2019

Journal of Asian Ceramic Societies

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“…The larger semicircle appearing at lower frequencies is related to the dense inner layer, and the metal/coating interface and the smaller semicircle at higher frequencies are attributed to the outer porous layer. The dense internal layer is formed due to the applied voltage on the metal, and the porous layer is formed due to the reaction of the plasma with the metal and the coating bath during the process [ 2 , 50 , 51 ]. The Nyquist curve of Ti/TiO 2 -N has two time-constant elements in the proposed equivalent circuit, and the smaller semicircle at high frequencies corresponds to the outer porous nitrided layer, and the larger semicircle at lower frequencies is attributed to the outside dense TiO 2 coating and the double layer.…”

Section: Resultsmentioning

confidence: 99%

Corrosion and Wear Behavior of TiO2/TiN Duplex Coatings on Titanium by Plasma Electrolytic Oxidation and Gas Nitriding

et al. 2022

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In this study, corrosion and wear behavior of three kinds of coatings by two processes, namely, plasma electrolytic oxidation (PEO) coatings (Ti/TiO2), gas nitriding coating (Ti/TiN), and the duplex coating (Ti/TiO2-N) by combination of PEO and gas nitriding methods were systematically investigated. X-ray diffraction tests, field-emission scanning electron microscopy, and adhesion tests are employed for the coating characterization, along with the wear and electrochemical test for evaluating the corrosion and tribological properties. The morphology and structure of the coating consist of micro-cavities known as the pancake structure on the surface. The electrolytic plasma oxidation process produces a typical annealing behavior with a low friction coefficient based on the wear test. The coating consists of nitride and nitrate/oxides titanium for nitrided samples. The surface morphology of nitrided oxide titanium coating shows a slight change in the size of the crystals and the diameter of the cavities due to the influence of nitrogen in the titanium oxide coating. The tribological behavior of the coatings showed that the wear resistance of the duplex coating (Ti/TiO2-N) and Ti/TiO2 coatings is significantly higher compared to Ti/TiN coatings and uncoated Ti samples. The polarization resistance of the Ti/TiO2-N and Ti/TiO2 coatings was 632.2 and 1451.9 kΩ cm2, respectively. These values are considerably greater than that of the uncoated Ti (135.9 kΩ cm2). Likewise, impedance showed that the Ti/TiO2-N and Ti/TiO2 coatings demonstrate higher charge transfer resistance than that of other samples due to better insulating behavior and denser structure.

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“…Recently, the obtaining of advanced ceramic coatings by PEO on pure Ti substrate using aluminate-based electrolytes was investigated [3,[6][7][8][9]. The properties and structures of the coatings formed are determined by the PEO process parameters.…”

Section: Introductionmentioning

confidence: 99%

“…The properties and structures of the coatings formed are determined by the PEO process parameters. In [7], the PEO process was carried out in 10 g/L and 5 g/L aqueous solutions of NaAlO 2 at constant time and voltage (180 seconds and 420 V) and all the coatings formed consisted in rutile, anatase and a small number of TiAlO 5 phases. Some studies [8,9], described the oxidation process of Cp-Ti grade 2 substrates in galvanostatic regime, at constant current density j=0.36 A/cm 2 , employing a unipolar, pulsed, direct-current power source at a frequency of 150 Hz, in electrolytic bath containing NaAlO 2 with different concentrations (10 g/L, 15 g/L and 20 g/L), with or without the addition of NaOH 2 g/L; in addition, the period of the applied PEO treatments were 10, 20 and 30 min.…”

Section: Introductionmentioning

confidence: 99%

THE EFFECT OF ELECTROLYTE COMPOSITIONS ON THE STRUCTURE AND PROPERTIES OF PEO COATINGS ON PURE Ti SUBSTRATE

et al. 2023

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Plasma electrolytic oxidation method was used to form ceramic coatings on pure Ti substrates, using various aqueous solutions of sodium aluminate (15 g/L and 20 g/L, with or without the addition of NaOH, 2 g/L). The PEO process was carried out at constant time and voltage (300 seconds, 200 V). The ceramic coatings obtained by PEO were investigated by SEM, EDS, XRD, XPS and their corrosion behavior has been evaluated. The aim of the study was to understand the role of NaOH in the development of the PEO process and to evaluate the results obtained by short treatments in potentiostatc regime.

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Sodium Aluminate Concentration Effects on Microstructure and Corrosion Behavior of the Plasma Electrolytic Oxidation Coatings on Pure Titanium

Cited by 48 publications

References 36 publications

Influence of different sodium-based additives on corrosion resistance of PEO coatings on pure Ti

Influence of different sodium-based additives on corrosion resistance of PEO coatings on pure Ti

Corrosion and Wear Behavior of TiO2/TiN Duplex Coatings on Titanium by Plasma Electrolytic Oxidation and Gas Nitriding

THE EFFECT OF ELECTROLYTE COMPOSITIONS ON THE STRUCTURE AND PROPERTIES OF PEO COATINGS ON PURE Ti SUBSTRATE

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