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.

Corrosion Behavior of High-Strength Low-Alloy Steel in High-Temperature Water with Zinc and Aluminum Simultaneous Injection

CORROSION ◽  
10.5006/3545 ◽  
2020 ◽  
Vol 76 (10) ◽  
pp. 918-929
Author(s):  
Shenghan Zhang ◽  
Chenhao Sun ◽  
Yu Tan
Keyword(s):  
Oxide Film ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Oxide Films ◽  
High Strength ◽  
Corrosion Current ◽  
Pressurized Water ◽  
Simultaneous Injection ◽  
Primary Water ◽  
Photocurrent Measurement

Oxide films were formed on A508-3 steel in simulated pressurized water reactor (PWR) primary water at the temperature of 561 ± 1 K for 168 h with zinc and/or aluminum injection. Corrosion behaviors of oxide films were analyzed by electrochemical polarization, electrochemical impedance spectroscopy, Mott-Schottky plots, photocurrent measurement, scanning electronic microscopy, and x-ray diffraction. The results showed that zinc and aluminum simultaneous injection technology decreased the corrosion current density, increased the impedance value, made the oxide film more compact, and affected the semiconductor properties of the oxide film. The increase in zinc concentration improved the corrosion resistance to some extent. ZnAl2O4 phase, with extremely low solubility and high stability, had been detected in the oxide film; this substance changed the composition of the oxide film and affected the corrosion behavior of A508-3 steel.

The passive properties of TA10 in Coca-Cola containing oral environment

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ming Liu ◽  
Jun Li ◽  
Danping Li ◽  
Lierui Zheng
Keyword(s):  
Corrosion Resistance ◽  
Passive Film ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Content Type ◽  
Passive Behavior ◽  
Tooth Demineralization ◽  
Oral Environment

Purpose At present, carbonated drinks such as cola are especially favored by the younger generation. But because of its acid, it often leads to tooth demineralization, resulting in “cola tooth”. However, the influence of cola on the corrosion resistance of passive film of TiA10 alloy restorative materials is rarely reported. The purpose of this study was to analysis the corrosion resistance, composition of the passive film of TA10 alloy in different concentrations of Cola. Design/methodology/approach The passive behavior of TA10 alloy in artificial saliva (AS) and Cola was studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy, cyclic voltammetry, Mott-Schottky techniques and combined with X-ray photoelectron spectroscopy and Auger electron spectroscopy (AES) surface analysis. Findings With the increase of cola content, the self-corrosion current density of the alloy increases sharply, and the corrosion resistance of the passive film is the best in AS, while Rp in cola is reduced to half of that in AS. The thickness of the passive film in AS, AS +cola and cola is about 9.5 nm, 7.5 nm and 6 nm, respectively. The passive film in cola has more defects and the carrier density is 1.55 times as high as that in AS. Cola can weaken the formation process of the protected oxide, promote the formation of high valence Ti-oxides and increase the content of Mo-oxides in the passive film. Originality/value These results have important guiding significance for the safe use of the alloy in the complex oral environments.

Corrosion Behavior of Zr53.5Cu26.5Ni5Al12Ag3 Bulk Amorphous Alloy in 3.5% NaCl Solution

2011 ◽  
Vol 299-300 ◽  
pp. 427-431
Author(s):  
Yun Li ◽  
Shi Zhi Shang ◽  
Ming Cheng ◽  
Liang Xu ◽  
Shi Hong Zhang
Keyword(s):  
Corrosion Resistance ◽  
Amorphous Alloy ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Bulk Amorphous Alloy ◽  
Nacl Solution ◽  
Current Densities ◽  
Resistance Decrease

The corrosion behavior of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution was investigated by using potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results show that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the better corrosion resistance than its corresponding crystal alloy. During the bath in the 3.5% NaCl solution at 25°C, Zr53.5Cu26.5Ni5Al12Ag3 alloy has the lower corrosion current density than the corresponding crystal alloy. After 100h, the corrosion current densities of Zr53.5Cu26.5Ni5Al12Ag3 and the corresponding crystal alloy are 3.8415×10-8A/cm2 and 5.2827×10-7A/cm2, respectively. The results of EIS test indicate that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the excellent corrosion resistance because passive film with stable structure formed on the surface in 3.5% NaCl solution. With an increase in the immersion time, the passive film becomes thicker. It leads to impedance resistance and corrosion resistance decrease. The surface of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution for 100h was analyzed by SEM and EDS. The results show that the corrosive pitting can be found at both the amorphous alloy and the corresponding crystal alloy. However, the amorphous alloy has the better corrosive pitting resistance than the crystal one because the corrosion products formed by selective dissolving of Zr and Al elements. Moreover, the addition of Ag element helps to improve the corrosion resistance of the amorphous alloy greatly.

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.  

scholarly journals Electrochemical Corrosive Behaviors of Fe-Based Amorphous/ Nanocrystalline Coating on Stainless Steel Prepared by HVOF-Sprayed

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 226 ◽  
Author(s):  
Jifu Zhang ◽  
Chunming Deng ◽  
Jinbing Song ◽  
Changguang Deng ◽  
Min Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Passive Film ◽  
Pitting Corrosion ◽  
Electrochemical Impedance ◽  
Corrosion Mechanism ◽  
Corrosive Media ◽  
Active Dissolution ◽  
Nanocrystalline Coating ◽  
Alkaline Conditions

In this study, FeCrMnWMoSi amorphous/nanocrystalline coating was prepared on stainless steel by high-velocity oxygen fuel (HVOF) spraying. In order to thoroughly evaluate this novel material, the corrosion behaviors and corrosive film characteristics of the amorphous/nanocrystalline coating in NaCl corrosive media were studied using electrochemical measurement technologies such as potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). It was found that the corrosion resistance of Fe-based amorphous/nanocrystalline coating could be attributed to the passive film formed, which consisted of Fe, Cr, Mo, and W oxides. pH has an important influence on the corrosion resistance of amorphous/nanocrystalline coating by changing the pitting corrosion mechanism. Under neutral and acidic conditions, the corrosion mechanism of Fe-based amorphous/nanocrystalline coating was mainly local pitting corrosion. However, under strong alkaline conditions, the amorphous/nanocrystalline coating not only had pitting corrosion, but also had the active dissolution of the passive film. Therefore, the anti-corrosion performance of Fe-based amorphous/nanocrystalline coating under alkaline conditions was not as good as neutral and acidic corrosive medium.

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 Effect of fluoride on the thickness, surface roughness and corrosion resistance of titanium anodic oxide films formed in a phosphate buffer solution at different applied potentials

2020 ◽  
Vol 9 (11) ◽  
pp. e95791110689
Author(s):  
Gláucia Domingues ◽  
Michele de Almeida Oliveira ◽  
Nayne Barros Gonzaga Ferreira ◽  
Bhetina Cunha Gomes ◽  
Elivelton Alves Ferreira ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Oxide Film ◽  
Phosphate Buffer ◽  
Electrochemical Impedance ◽  
Oxide Films ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Titanium Film ◽  
Small Surface

The anodizing process and anions type present in the electrolyte during anodic oxidation are important parameters to improve oxide biocompatibility. From these parameters, it is possible to control the thickness and surface roughness of the oxide film. This control is of major importance, once blood clots can be avoided when the oxide film on the metal substrate has a small surface roughness (Ra ≤ 50 nm). In this paper, the thickness, surface roughness, and corrosion resistance of the anodized titanium film were studied in a phosphate buffer solution containing fluoride anions (0.6 w.t % NaF), at 20 V, 40 V, 60 V, and 80 V, using atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and electrochemical impedance spectroscopy (EIS) techniques. It was observed that thickness and roughness tend to increase as the applied potential rises. For oxides grown in the solution without NaF, the growth rate is roughly 1.3 ± 0.2 nm/V. Surface roughness generally presents the same behaviour. Moreover, EIS and SE thickness measurements agree at 20 V and 60 V but disagree at 80 V. This may be associated with a possible dielectric breakdown at 80 V. The oxide film formed at 60 V showed the best corrosion resistance in relation to the other studied potentials. Globular structures were also observed using AFM on surfaces at 40 V, 60 V, and 80 V, which suggests oxide film nucleation. Oxide films formed in solution with NaF presented lower thickness, excellent corrosion resistance, and low surface roughness (Ra ≤ 50 nm).

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