scholarly journals Improvement of Wear, Pitting Corrosion Resistance and Repassivation Ability of Mg-Based Alloys Using High Pressure Cold Sprayed (HPCS) Commercially Pure-Titanium Coatings

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 57
Author(s):  
Mohammadreza Daroonparvar ◽  
Ashish K. Kasar ◽  
Mohammad Umar Farooq Khan ◽  
Pradeep L. Menezes ◽  
Charles M. Kay ◽  
...  
Keyword(s):  
High Pressure ◽  
Pitting Corrosion ◽  
Electrochemical Impedance ◽  
Pure Titanium ◽  
Hysteresis Loops ◽  
Immersion Test ◽  
Mg Alloy ◽  
Commercially Pure Titanium ◽  
Titanium Coatings ◽  
Al Coating

In this study, a compact cold sprayed (CS) Ti coating was deposited on Mg alloy using a +high pressure cold spray (HPCS) system. The wear and corrosion behavior of the CS Ti coating was compared with that of CS Al coating and bare Mg alloy. The Ti coating yielded lower wear rate compared to Al coating and Mg alloy. Electrochemical Impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) tests revealed that CS Ti coating can substantially reduce corrosion rate of AZ31B in chloride containing solutions compared to CS Al coating. Interestingly, Ti-coated Mg alloy demonstrated negative hysteresis loop, depicting repassivation of pits, in contrast to AZ31B and Al-coated AZ31B with positive hysteresis loops where corrosion potential (Ecorr) > repassivation potential (Erp); indicating irreversible growth of pits. AZ31B and Al-coated AZ31B were most susceptible to pitting corrosion, while Ti-coated Mg alloy indicated noticeable resistance to pitting in 3.5 wt % NaCl solution. In comparison to Al coating, Ti coating considerably separated the AZ31BMg alloy surface from the corrosive electrolyte during long term immersion test for 11 days.

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.

Electrochemical Dissolution Characteristics of Magnesium Alloy Produced by Roll Compaction Process

2007 ◽  
Vol 561-565 ◽  
pp. 2143-2146 ◽  
Author(s):  
Satoshi Sunada ◽  
Takahito Kawamura ◽  
Katsuyoshi Kondoh ◽  
Hisakimi Notoya ◽  
Kazuhiko Majima
Keyword(s):  
Electrochemical Impedance ◽  
Immersion Test ◽  
Cathodic Current Density ◽  
Mg Alloy ◽  
Electrochemical Dissolution ◽  
Compaction Process ◽  
Cathodic Current ◽  
Structural Morphology ◽  
Polarization Test ◽  
Roll Compaction

The extruded AZ31B Mg alloy specimens using powders fabricated by roll compaction processing (RCP) was prepared, and their corrosion behavior has been investigated through the polarization test, electrochemical impedance spectroscopy test, immersion test and SEM observation in comparison to that of the conventional AZ31B Mg alloy, hereafter shortened as I/M specimen. The extruded AZ31B Mg alloys using RCP powder showed little change in Ecorr irrespective of number of pass cycles. Both anodic and cathodic current density suppression of the RCP specimens became larger with an increase in number of pass cycles. It was also confirmed that the corrosion characteristics of the RCP specimens depended strongly on their structural morphology and that the corrosion resistance of the RCP specimens subjected to 50 pass cycles was nearly same as that of the I/M specimen.

scholarly journals Slippage during high-pressure torsion of commercially pure titanium and application of accumulative HPT to it

2022 ◽  
Vol 1213 (1) ◽  
pp. 012003
Author(s):  
D V Gunderov ◽  
A A Churakova ◽  
A V Sharafutdinov ◽  
V D Sitdikov ◽  
V V Astanin
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Pure Titanium ◽  
Phase Changes ◽  
Phase Content ◽  
Commercially Pure Titanium ◽  
Micro Hardness ◽  
Ω Phase ◽  
Commercially Pure ◽  
First Time

Abstract A new efficient method was used to find that in the case of high-pressure torsion of commercially pure titanium, accumulation of shear strain in Ti does not occur due to slippage of anvils. Despite this, micro-hardness increases as the number of turns n increases, and Ti structure is refined more intensively. High-pressure torsion is accompanied by a high-pressure ω-phase formation. However, the content of ω-phase changes non-monotonously with an increase in the number of turns. First, while number of turns is less than n=5, the ω-phase content reaches 50%. Upon further deformation, the ω-phase content decreases to 15% for n=20. A new accumulative high-pressure torsion method is applied to commercially pure titanium for the first time. Accumulative high-pressure torsion leads to the strongest transformation of the structure and an increase in hardness, since stronger real deformation occurs due to composition of compression and torsion strain cycles.

scholarly journals Electrochemical Behaviour of Ti and Ti-6Al-4V Alloy in Phosphate Buffered Saline Solution

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7495
Author(s):  
Senka Gudić ◽  
Ladislav Vrsalović ◽  
Dario Kvrgić ◽  
Aleš Nagode
Keyword(s):  
Oxide Film ◽  
Barrier Layer ◽  
Saline Solution ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Corrosion Stability ◽  
Cp Ti ◽  
Phosphate Buffered Saline

The electrochemical behavior of commercially pure titanium (CP Ti) and Ti-6Al-4V (Grade 5) alloy in phosphate buffered saline solution (PBS, pH = 7.4) at 37 °C (i.e., in simulated physiological solution in the human body) was examined using open circuit potential measurements, linear and potentiodynamic polarization and electrochemical impedance spectroscopy methods. After the impedance measurements and after potentiodynamic polarizationmeasurements, the surface of the samples was investigated by scanning electron microscopy, while the elemental composition of oxide film on the surface of each sample was determined by EDS analysis. The electrochemical and corrosion behavior of CP Ti and Ti-6Al-4V alloys is due to forming a two-layer model of surface oxide film, consisting of a thin barrier-type inner layer and a porous outer layer. The inner barrier layer mainly prevents corrosion of CP Ti and Ti-6Al-4V alloy, whose thickness and resistance increase sharply in the first few days of exposure to PBS solution. With longer exposure times to the PBS solution, the structure of the barrier layer subsequently settles, and its resistance increases further. Compared to Ti-6Al-4V alloy, CP Ti shows greater corrosion stability.

Effect of carbides on sensitivity of pitting corrosion in Inconel 718 alloy

2020 ◽  
Vol 67 (2) ◽  
pp. 158-165
Author(s):  
Xianping Wei ◽  
Wen Jie Zheng
Keyword(s):  
Pitting Corrosion ◽  
Inconel 718 ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Immersion Test ◽  
Nacl Solution ◽  
Inconel 718 Alloy ◽  
Content Type ◽  
Corrosion Susceptibility ◽  
Dynamic Electrochemical Impedance Spectroscopy

Purpose This paper aims to expand the application area of Inconel 718 alloy in marine environment, the sensitivity of pitting corrosion should be analyzed and discussed, especially the effect of block carbides. Design/methodology/approach Effect of carbides on the sensitivity of pitting corrosion for Inconel 718 alloy was carried out at 30°C in 3.5% NaCl solution using dynamic electrochemical impedance spectroscopy and anodic polarization techniques. In addition, the initiation of pitting corrosion was investigated by immersion test in 0.05 M HCl + 6% FeCl3 solution. Findings As a result, the precipitation of carbides, as the initiation of pitting corrosion, increased pitting corrosion susceptibility, especially the block carbides could lead to deep-spalling. Within that process, temperature and potential acted as the main controlling factors, and the effect of the latter was more distinct. Originality/value The initiation of pitting corrosion was revealed by the immersion test. The mechanism of pitting corrosion was analyzed and discussed.

scholarly journals Corrosion Resistance of the CpTi G2 Cellular Lattice with TPMS Architecture for Gas Diffusion Electrodes

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Bożena Łosiewicz ◽  
Joanna Maszybrocka ◽  
Julian Kubisztal ◽  
Grzegorz Skrabalak ◽  
Andrzej Stwora
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Pure Titanium ◽  
Total Porosity ◽  
Complex Surface ◽  
Potential Method ◽  
Gas Diffusion ◽  
Open Circuit ◽  
Commercially Pure Titanium ◽  
Titanium Grade

The corrosion of materials used in the design of metal-air batteries may shorten their cycle life. Therefore, metal-based materials with enhanced electrochemical stability have attracted much attention. The purpose of this work was to determine the corrosion resistance of commercially pure titanium Grade 2 (CpTi G2) cellular lattice with the triply periodic minimal surfaces (TPMS) architecture of G80, D80, I-2Y80 in 0.1 M KOH solution saturated with oxygen at 25 °C. To produce CpTi G2 cellular lattices, selective laser melting technology was used which allowed us to obtain 3D cellular lattice structures with a controlled total porosity of 80%. For comparison, the bulk electrode was also investigated. SEM examination and statistical analysis of the surface topography maps of the CpTi G2 cellular lattices with the TPMS architecture revealed much more complex surface morphology compared to the bulk CpTi SLM. Corrosion resistance tests of the obtained materials were conducted using open circuit potential method, Tafel curves, anodic polarization curves, and electrochemical impedance spectroscopy. The highest corrosion resistance and the lowest material consumption per year were revealed for the CpTi G2 cellular lattice with TPMS architecture of G80, which can be proposed as promising material with increased corrosion resistance for gas diffusion in alkaline metal-air batteries.

Electrochemical Behavior of Titanium in Artificial Saliva: Influence of pH

2014 ◽  
Vol 40 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Savithri Abey ◽  
Mathew T. Mathew ◽  
Damian J. Lee ◽  
Kent L. Knoernschild ◽  
Markus A. Wimmer ◽  
...  
Keyword(s):  
Passive Film ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Pure Titanium ◽  
Corrosion Current ◽  
Nyquist Plot ◽  
Commercially Pure Titanium ◽  
Ph Values ◽  
Film Layer

Titanium is the most common material chosen for dental implants because it is highly corrosion resistant because it constantly reforms a protective passive film layer. The formation and composition of the passive film layer is dependent on the environmental conditions. If the stable oxide layer is damaged, the titanium surface underneath can corrode. The purpose of this study was to determine if basic corrosion of commercially pure titanium (CpTi) alloy in artificial saliva was affected by pH and to understand the corrosion kinetics/mechanisms of CpTi as a function of pH. In this study, titanium alloy discs were subjected to corrosion tests. Before the tests, all samples were cleaned and polished using standard metallographic preparation methods. Artificial saliva was used as the testing medium. The following pH values were tested: 3.0, 4.5, 6.0, 6.5, 7.5, and 9.0. Different pH values were achieved by adding lactic acid (acidic) or NaOH (basic) in appropriate amounts. Potentiodynamic curves indicated behavior change at each pH. In addition, the corrosion current density value determined from the potentiodynamic curve exhibited the poorest corrosion resistance for pH 7.5. The Nyquist plot (from the electrochemical impedance spectroscopy results) indicated that pH 7.5 had the poorest resistance. Scanning electron microscopy images indicated that pH levels of 6.5, 7.5, and 9.0 had considerable surface corrosion. The results showed that the media's pH significantly influenced the corrosion behavior of CpTi. The poor corrosion behavior at the neutral pHs invites some concerns and highlights the need for further study.

scholarly journals EFFECT OF THERMAL OXIDATION ON THE CORROSION RESISTANCE OF CP-TI

2017 ◽  
Vol 23 (2) ◽  
pp. 135
Author(s):  
Shijing Lu ◽  
Kunxia Wei ◽  
Yan Wang ◽  
Jing Hu
Keyword(s):  
Corrosion Resistance ◽  
Thermal Oxidation ◽  
Pure Titanium ◽  
Immersion Test ◽  
Commercially Pure Titanium ◽  
X Ray Diffraction ◽  
X Ray ◽  
Commercially Pure ◽  
Different Temperatures ◽  
Cp Ti

<p class="AMSmaintext">Commercially pure titanium (CP-Ti) was subjected to thermal oxidation at different temperatures and times for determining the optimum oxidation conditions to obtain the optimum corrosion resistance. The phase constituents of the samples were determined by X-ray diffraction (XRD), the morphology of the surface was observed by SEM, and the corrosion behavior was investigated using immersion test by exposing the samples in HCl solutions with a concentration of 37%. The results showed that Rutile TiO<sub>2</sub> layer was formed on the surface of CP-Ti after thermal oxidation and the thickness of the TiO<sub>2</sub> layer increased with the treating temperature. Meanwhile, It was found that the optimum corrosion resistance to HCl was obtained while oxidizing at 700℃ for 330min～500min.</p>

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