scholarly journals Surface Modification of Ti-6Al-4V Alloy By Anodization Technique at Low Potential to Produce Oxide Layer

2020 ◽  
Vol 2 (3) ◽  
pp. 93-102
Author(s):  
Franciska Pramuji Lestari ◽  
Yeni Rian Sari ◽  
Fendy Rokhmanto ◽  
Talitha Asmaria ◽  
Andika Widya Pramono
Keyword(s):  
Corrosion Resistance ◽  
Oxide Layer ◽  
Electrochemical Impedance ◽  
Layer Growth ◽  
Electrochemical Anodization ◽  
Growth Surface ◽  
Tio2 Layer ◽  
Anodization Voltage ◽  
Definite Effect ◽  
Surface Alteration

        Due to their excellent biocompatibility, titanium alloys are tremendously as implants used, since relatively low modulus, corrosion resistance, and good fatigue strength. The biocompatibility, comes from the formation of natural Titanium dioxide (TiO2) layer. Therefore, TiO2 layer growth surface alteration is frequently applied to improve biological, chemical , and mechanical properties. TiO2 nanostructures are obtained under self-organization conditions by electrochemical anodization of Ti-6Al-4V. Parameters of anodization such as anodization time, voltage and addition of thiourea were evaluated in the composition of the H3PO4+NH4F solution. The morphology and elements of the Ti alloys surface were analyzed by Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS), whereas potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the TiO2 layer in corrosion resistance. The results showed that the anodized Ti-6Al-4V alloy E-corr imcreased as the anodization voltage increased. Titanium alloy anodized using 12 V during 2 hours with H3PO4 + NH4F without thiourea solution  had the thickest of oxide layer and highest corrosion resistance. Higher applied voltages have been shown to increase the deposition rate and coating thickness. Addition of thiourea has a definite effect on the inhibition of oxide layer of titanium. In order to produce the optimum titanium surface, the required applied anodization voltage and addition of volume thiourea is necessary.  

Material Property of a Passive Oxide Formed on Alloy 600

2007 ◽  
Vol 26-28 ◽  
pp. 937-940 ◽  
Author(s):  
Dong Jin Kim ◽  
Hyuk Chul Kwon ◽  
Seong Sik Hwang ◽  
Hong Pyo Kim
Keyword(s):  
Corrosion Resistance ◽  
Oxide Layer ◽  
Passive Film ◽  
Electrochemical Impedance ◽  
Oxide Films ◽  
Oxide Thickness ◽  
Solution Temperature ◽  
Alloy 600 ◽  
Pressurized Water ◽  
Electrochemical Behaviors

Alloy 600 is used as a material for a steam generator tubing in pressurized water reactors(PWR) due to its high corrosion resistance under a PWR environment. In spite of its corrosion resistance, a stress corrosion cracking(SCC) has occurred on the primary side as well as the secondary side of a tubing. It is known that a SCC is related to the electrochemical behaviors of an anodic dissolution and a passivation of a bare surface of metals and alloys. Therefore in the present work, the passive oxide films on Alloy 600 have been investigated as a function of the solution temperature by using a potentiodynamic polarization, electrochemical impedance spectroscopy and a TEM, equipped with EDS. Moreover the semiconductive property was evaluated by using the Mott-Schottky relation. It was found that the passivity depends on the chemical composition and the densification of the oxide film rather than the oxide thickness. As the solution temperature of 0.5M H3BO3 increased, the thickness of the passive film increased but the oxide resistance of the passive film was decreased, indicating that the measured current in the passive region of the potentiodynamic curve is closely related to the stability of the passive film rather than the oxide thickness. It was found that the oxide films were composed of an outer oxide layer with a lower resistance and an inner oxide layer with a relatively higher resistance. From the Mott-Schottky relation, the oxide formed at 300oC showed a p-type semiconductor property unlike the n-type oxide films up to 250oC.

scholarly journals Effects of Processing Parameters on the Corrosion Performance of Plasma Electrolytic Oxidation Grown Oxide on Commercially Pure Aluminum

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 394 ◽  
Author(s):  
Getinet Asrat Mengesha ◽  
Jinn P. Chu ◽  
Bih-Show Lou ◽  
Jyh-Wei Lee
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Layer Thickness ◽  
Surface Engineering ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Corrosion Performance ◽  
Commercially Pure ◽  
Peo Coatings

The plasma electrolyte oxidation (PEO) process has been considered an environmentally friendly surface engineering method for improving the corrosion resistance of light weight metals. In this work, the corrosion resistance of commercially pure Al and PEO treated Al substrates were studied. The PEO layers were grown on commercially pure aluminum substrates using two different alkaline electrolytes with different addition concentrations of Si3N4 nanoparticles (0, 0.5 and 1.5 gL−1) and different duty cycles (25%, 50%, and 80%) at a fixed frequency. The corrosion properties of PEO coatings were investigated by the potentiodynamic polarization and electrochemical impedance spectroscopy test in 3.5 wt.% NaCl solutions. It showed that the weight gains, layer thickness and surface roughness of the PEO grown oxide layer increased with increasing concentrations of Si3N4 nanoparticles. The layer thickness, surface roughness, pore size, and porosity of the PEO oxide layer decreased with decreasing duty cycle. The layer thickness and weight gain of PEO coating followed a linear relationship. The PEO layer grown using the Na2B4O7∙10H2O contained electrolyte showed an excellent corrosion resistance and low surface roughness than other PEO coatings with Si3N4 nanoparticle additives. It is noticed that the corrosion performance of PEO coatings were not improved by the addition of Si3N4 nanoparticle in the electrolytic solutions, possibly due to its detrimental effect to the formation of a dense microstructure.

The Influence of Heat Treatment and Plastic Deformation on the Bio-Degradation of a Mg–Y–RE Alloy

2009 ◽  
Vol 618-619 ◽  
pp. 71-74 ◽  
Author(s):  
Petra Gunde ◽  
Angela Furrer ◽  
Anja C. Hänzi ◽  
Patrik Schmutz ◽  
Peter J. Uggowitzer
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Human Body ◽  
Electrochemical Impedance ◽  
Essential Element ◽  
Heat Treatments ◽  
Protective Oxide ◽  
Degradation Behaviour ◽  
Polarisation Resistance

Magnesium has become an interesting candidate in the field of bioabsorbable implant materials; it is an essential element in the human body, biocompatible and degradable due to its low corrosion resistance in a pH range below 11.5. However, in the human body (pH  7.4) a magnesium implant might degrade too quickly and lose its mechanical strength before the tissue has fully healed. However, the corrosion resistance can be improved for example by the choice of a suitable Mg alloy containing corrosion-inhibiting elements such as yttrium or by the deployment of surface heat treatments at high temperatures causing protective oxide layers to form. We studied the bio-degradation behaviour of a Mg–Y–RE alloy in different heat treatment states by electrochemical impedance spectroscopy and immersion testing in simulated body fluid. The heat treatments caused a change in microstructure and also the formation of a thermal oxide layer on the sample surface, which consisted mainly of Y2O3 and which slowed the degradation and increased the polarisation resistance significantly compared to the polished state. However, in some specimens localised corrosion attacks occurred which drastically weakened the protective effect of the oxide. Because the implant might be deformed during implantation resulting in the oxide cracking, we intentionally strained the samples and investigated the degradation performance. These cracks led to a decrease in polarisation resistance compared to the non-strained oxidised state, but in comparison to the polished state they still perform better. Macroscopically, the degradation process occurred in a homogeneous way without localised corrosion attacks. Microscopically, corrosion attacks started at the cracks and undermined the oxide layer with time.

scholarly journals Atomic Layer Deposition of aTiO2 Layer on Nitinol and Its Corrosion Resistance in a Simulated Body Fluid

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 659
Author(s):  
Rebeka Rudolf ◽  
Aleš Stambolić ◽  
Aleksandra Kocijan
Keyword(s):  
Corrosion Resistance ◽  
Simulated Body Fluid ◽  
Atomic Layer Deposition ◽  
Body Fluid ◽  
Electrochemical Impedance ◽  
Atomic Layer ◽  
Tio2 Layer ◽  
High Tendency ◽  
X Ray ◽  
Layer Deposition

Nitinol is a group of nearly equiatomic alloys composed of nickel and titanium, which was developed in the 1970s. Its properties, such as superelasticity and Shape Memory Effect, have enabled its use, especially for biomedical purposes. Due to the fact that Nitinol exhibits good corrosion resistance in a chloride environment, an unusual combination of strength and ductility, a high tendency for self-passivation, high fatigue strength, low Young’s modulus and excellent biocompatibility, its use is still increasing. In this research, Atomic Layer Deposition (ALD) experiments were performed on a continuous vertical cast (CVC) NiTi rod (made in-house) and on commercial Nitinol as the control material, which was already in the rolled state. The ALD deposition of the TiO2 layer was accomplished in a Beneq TFS 200 system at 250 °C. The pulsing times for TiCl4 and H2O were 250 ms and 180 ms, followed by appropriate purge cycles with nitrogen (3 s after the TiCl4 and 2 s after the H2O pulses). After 1100 repeated cycles of ALD depositing, the average thickness of the TiO2 layer for the CVC NiTi rod was 52.2 nm and for the commercial Nitinol, it was 51.7 nm, which was confirmed by X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscope (SEM) using Energy-dispersive X-ray (EDX) spectroscopy. The behaviour of the CVC NiTi and commercial Nitinol with and without the TiO2 layer was investigated in a simulated body fluid at body temperature (37 °C) to explain their corrosion resistance. Potentiodynamic polarisation measurements showed that the lowest corrosion current density (0.16 μA/cm2) and the wider passive region were achieved by the commercial NiTi with TiO2. Electrochemical Impedance Spectroscopy measurements revealed that the CVC NiTi rod and the commercial Nitinol have, for the first 48 h of immersion, only resistance through the oxide layer, as a consequence of the thin and compact layer. On the other hand, the TiO2/CVC NiTi rod and TiO2/commercial Nitinol had resistances through the oxide and porous layers the entire immersion time since the TiO2 layer was formatted on the surfaces.

scholarly journals Effect of Iron Content on Corrosion Properties of Pure Titanium as Grain Refiner

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7193
Author(s):  
Bosung Seo ◽  
Hyeon-Tae Im ◽  
Ki-Beom Park ◽  
Kwangsuk Park ◽  
Hyung-Ki Park
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Pure Titanium ◽  
Open Circuit ◽  
Tio2 Layer ◽  
Grain Refiner ◽  
Corrosion Properties ◽  
Acid Environment ◽  
Titanium Cathode

Microstructures and corrosion properties of pure titanium were characterized when iron was used as a grain refiner. The added Fe element acted as a strong grain refiner for pure titanium by forming β Ti phase at grain boundaries, and 0.15 wt% Fe was revealed to be a sufficient amount to make the grain size of pure titanium below 20 μm, which was the requirement for the desired titanium cathode. However, corrosion resistance was decreased with the Fe amount added. From the open circuit potential (OCP) results, it was obvious that the TiO2 stability against the reducing acid environment was deteriorated with the Fe amount, which seemed to be the main reason for the decreased corrosion resistance. Electrochemical impedance spectroscopy (EIS) results showed that both the decrease in the compact oxide film’s resistance (Rb) and the appearance of the outer porous film occurred as a result of the dissolution of the TiO2 layer, whose phenomena became more apparent as more Fe was added.

scholarly journals The Influence of Microstructure on the Passive Layer Chemistry and Corrosion Resistance for Some Titanium-Based Alloys

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1233 ◽  
Author(s):  
Nader El-Bagoury ◽  
Sameh I. Ahmed ◽  
Ola Ahmed Abu Ali ◽  
Shimaa El-Hadad ◽  
Ahmed M. Fallatah ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Photoelectron Spectroscopy ◽  
Volume Fraction ◽  
Electrochemical Impedance ◽  
Passive Layer ◽  
Layer Growth ◽  
Uniform Corrosion ◽  
Cyclic Polarization ◽  
X Ray

The effect of microstructure and chemistry on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys, was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing dynamic electrochemical impedance spectroscopy (DEIS). Corrosion studies were performed in 0.9% NaCl solution at 37 °C, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron spectroscopy (XPS) analysis. For all studied alloys, the microstructure consisted of α matrix, which was strengthened by β phase. The highest and the lowest values of the β phase’s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The susceptibility of the investigated alloys toward pitting corrosion was enhanced following the sequence: Ti-6Al-7Nb < Ti-6Al-4V << TC21. Ti-6Al-7Nb alloy recorded the lowest pitting corrosion resistance (Rpit) among studied alloys, approaching that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in the corrosion behavior of these materials.

scholarly journals Exploring the Influence of the Microstructure on the Passive Layer Chemistry and Breakdown for Some Titanium-Based Alloys in Normal Saline Solution

2019 ◽  
Author(s):  
Nader El-Bagoury ◽  
Sameh Ibrahim ◽  
Ola Ahmed Abu Ali ◽  
Shimaa El-Hadad ◽  
Ahmed M. Fallatah ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Volume Fraction ◽  
Electrochemical Impedance ◽  
Beta Phase ◽  
Passive Layer ◽  
Layer Growth ◽  
Uniform Corrosion ◽  
X Ray

The effect of microstructure and chemistry of passive films on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing Tafel extrapolation and dynamic electrochemical impedance spectroscopy. Corrosion studies were performed in 0.9% NaCl solution at 37 oC, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction and scanning electron microscopy. Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron analysis. For all studied alloys, the microstructure consisted of &alpha; matrix, which was strengthened by &beta; phase. The highest and the lowest values of the &beta; phase&rsquo;s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The uniform corrosion rate and pitting corrosion resistance (Rpit) of the studied alloys were enhanced following the sequence: Ti-6Al-7Nb &lt; Ti-6Al-4V &lt;&lt; TC21. The corrosion resistance of Ti-Al-Nb alloy approached that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in their corrosion rates.

scholarly journals Improvement of Corrosion Resistance of Stainless Steel Welded Joint Using a Nanostructured Oxide Layer

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 838
Author(s):  
Jun Heo ◽  
Sang Yoon Lee ◽  
Jaewoo Lee ◽  
Akram Alfantazi ◽  
Sung Oh Cho
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Electrochemical Impedance ◽  
304 Stainless Steel ◽  
Gas Tungsten Arc ◽  
Nanostructured Oxide ◽  
Corrosion Behaviors ◽  
Surface Morphologies ◽  
Type 304

In this study, we fabricated a nanoporous oxide layer by anodization to improve corrosion resistance of type 304 stainless steel (SS) gas tungsten arc weld (GTAW). Subsequent heat treatment was performed to eliminate any existing fluorine in the nanoporous oxide layer. Uniform structures and compositions were analyzed with field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD) measurements. The corrosion resistance of the treated SS was evaluated by applying a potentiodynamic polarization (PDP) technique and electrochemical impedance spectroscopy (EIS). Surface morphologies of welded SS with and without treatment were examined to compare their corrosion behaviors. All results indicate that corrosion resistance was enhanced, making the treatment process highly promising.

MODELING THE NORMAL SPECTRAL EMISSIVITY OF BRASS H62 AT 800–1100 K DURING OXIDE LAYER GROWTH

2018 ◽  
Vol 49 (15) ◽  
pp. 1445-1458
Author(s):  
Deheng Shi ◽  
Fenghui Zou ◽  
Zunlue Zhu ◽  
Jinfeng Sun
Keyword(s):  
Oxide Layer ◽  
Spectral Emissivity ◽  
Layer Growth ◽  
Normal Spectral Emissivity

scholarly journals Hydrophobic Modification of Graphene Oxide and Its Effect on the Corrosion Resistance of Silicone-Modified Epoxy Resin

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 89
Author(s):  
Wei Yuan ◽  
Qian Hu ◽  
Jiao Zhang ◽  
Feng Huang ◽  
Jing Liu
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
X Ray ◽  
Modified Graphene Oxide ◽  
Modified Epoxy

This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2.

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