Electrochemical behaviour of passive film formed on the surface of Ti-6Al-4V alloys fabricated by electron beam melting

Gai, Xin; Bai, Yun; Ji, Li; Li, Shujun; Hou, Wentao; Hao, Yulin; Zhang, Xing; Yang, Rui; Misra, R.D.K.

doi:10.1016/j.corsci.2018.09.010

Cited by 170 publications

(64 citation statements)

References 60 publications

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“…The surface of the specimen, as well as the spontaneously formed oxide film (i.e., TiO 2 ) of the titanium alloy, would not be very flat. [ 47 ] Therefore, the thickness of the oxide film ( d film ) formed on selective laser‐melted Ti6Al4V–5Cu alloy and forged TC4 specimens can be calculated by [ 47 ] :

d_{f i l m} = \frac{ε ε_{0} A}{C_{normale normalf normalf}},

where ε, ε 0 , A , and C eff denote the permittivity of vacuum (i.e., 8.85 × 10 −14 F/m), the dielectric constant of the oxide (e,g., TiO 2 is 60 [ 48 ] ), the effective surface area (m 2 ), and the effective capacitance, that is, the CPE value from EIS fitting result. The calculated thickness of the oxide film formed on the selective laser‐melted Ti6Al4V–5Cu alloy and forged TC4 specimens was estimated to be 0.162 and 0.123 nm, respectively.…”

Section: Resultsmentioning

confidence: 96%

Design and characterization of selective laser‐melted Ti6Al4V–5Cu alloy for dental implants

Zong

Zha

Zhang

et al. 2020

Materials & Corrosion

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Ti6Al4V-5Cu alloys have potential biomedical applications due to their adequate antibacterial properties. However, the wear and corrosion properties of these alloys are also crucial for dental implants. In the present study, Ti6Al4V-5Cu alloys were fabricated by selective laser melting (SLM). The microstructure and composition of Ti6Al4V-5Cu alloys by SLM were evaluated. The wear properties of the alloys in the simulated saliva environment and the atmospheric environment, as well as the electrochemical properties in the simulated saliva environment, were systematically investigated. The results showed that the crystal structure of Ti6Al4V-5Cu alloys was mainly composed of α-Ti and Ti 2 Cu. In the SLM process, no preferred texture was observed due to the complex direction of the heat flux. The formation of Ti 2 Cu can improve the strength of the material and make the titanium copper alloy have higher microhardness. Ti6Al4V-5Cu alloy showed a satisfactory wear resistance in both wear media. The addition of Cu reduced the second-phase content of the alloy. Meanwhile, the number of microcells was reduced, which was a positive factor to improve the corrosion resistance of the alloys.

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d_{f i l m} = \frac{ε ε_{0} A}{C_{normale normalf normalf}},

Section: Resultsmentioning

confidence: 96%

Design and characterization of selective laser‐melted Ti6Al4V–5Cu alloy for dental implants

Zong

Zha

Zhang

et al. 2020

Materials & Corrosion

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“…It has been widely reported that the current density of the sample decreases quickly within the first 30 s and then slowly decreases to a nearly stable value due to the formation of the passive film (Gai et al, 2018). Therefore, the growth kinetics of passive film follows the Macdonald model (Lakatos-Varsányi et al, 1998), which can be expressed as the following equation:…”

Section: Potentiostatic Polarization Testsmentioning

confidence: 99%

Characteristics of Passive Films Formed on As-Cast Ti–6Al-4V in Hank’s Solution Before and After Transpassivation

et al. 2021

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In this work, the characteristics of passive films formed on as-cast Ti-6Al-4V before and after transpassivation by electrochemical methods will be studied. A simulated body fluid of Hank’s solution was used as the electrolyte in this work. According to the potentiodynamic polarization test, the passivation range, transpassive range, and repassivation range of as-cast Ti-6Al-4V were obtained. Afterward, the potentiostatic polarization was employed to passivate the Ti-6Al-4V in both passivation and repassivation ranges. Electrochemical impedance spectroscopy (EIS) was used to analyze the characteristics of formed passive films. Different electrochemical behavior of as-cast Ti–6Al-4V is found in passivation and repassivation ranges. The passivation current density of the sample in the repassivation range is significantly larger than that in the passivation range. Meanwhile, the growth rate of passive film in the repassivation range is also greater than that in the passivation range. Although the sample shows a higher charge transfer impedance in the repassivation range, metastable pitting corrosion is also observed, indicating the formation of the unstable passive film. Such results advance the understanding of as-cast Ti-6Al-4V polarized under different potentials for potential biomedical applications.

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“…De Damborenea et al (2017) [11] have characterised Ti-6Al-4V surgical pins using a DMLS technique and highlighted the formation of voluminous oxides that lead to serious drawbacks related to the corrosion resistance of the parts. Bai et al (2017) and Gai et al (2018) [12,13] have investigated the electrochemical behaviour of Ti-6Al-4V fabricated by an EBM technique, revealing a better corrosion resistance of the EBM-produced specimen compared to that of wrought Ti-6Al-4V. The reasons were deemed to be a large fraction of β phase and refined lamellar α/β phases and, also, the formation of a thinner and more compact passive film than traditionally produced specimens.…”

Section: Introductionmentioning

confidence: 99%

As-Built EBM and DMLS Ti-6Al-4V Parts: Topography–Corrosion Resistance Relationship in a Simulated Body Fluid

Acquesta

Monetta

2020

Metals

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Machined devices made of titanium or titanium alloys are widely used in biomedical applications. Recently, additive manufacturing technologies (AM) were proposed to reduce the cost of parts and customise their shape. While several researchers have studied the characterisation of the machined surfaces of AM products, less attention has been focused on the study of the surfaces of as-produced parts. The aim of this study was to compare the surface and bulk properties of Ti-6Al-4V alloy products obtained using two types of AM—i.e., electron beam melting and direct metal laser sintering—in comparison to the wrought material and analyse their metallographic, crystallographic, topographic, and electrochemical properties. The metallographic and crystallographic, as well as topographic, analysis showed different microstructures and surface area extensions between the tested specimens. Potentiodynamic polarisation tests highlighted the complex electrochemical behaviour of additively manufactured parts if compared to that of the traditionally fabricated ones. The tests performed on mechanically polished parts underlined similar electrochemical performance between them, even if the additive manufactured ones exhibited a certain instability. Although the as-produced additive manufactured parts present exciting surface shapes, useful in the biomedical field, significant drawbacks remain. A more in-depth study of the device surface modifications, to improve their electrochemical behaviour, is needed.

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Electrochemical behaviour of passive film formed on the surface of Ti-6Al-4V alloys fabricated by electron beam melting

Cited by 170 publications

References 60 publications

Design and characterization of selective laser‐melted Ti6Al4V–5Cu alloy for dental implants

Design and characterization of selective laser‐melted Ti6Al4V–5Cu alloy for dental implants

Characteristics of Passive Films Formed on As-Cast Ti–6Al-4V in Hank’s Solution Before and After Transpassivation

As-Built EBM and DMLS Ti-6Al-4V Parts: Topography–Corrosion Resistance Relationship in a Simulated Body Fluid

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