Corrosion Behavior of Phosphate Conversion Coating on AZ31 Mg Alloy in 3.5% NaCl Solution

2014 ◽  
Vol 910 ◽  
pp. 27-30
Author(s):  
Xue Jun Cui ◽  
Chun Hai Liu ◽  
Rui Song Yang ◽  
Ming Tian Li ◽  
Xiu Zhou Lin
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Method ◽  
Immersion Time ◽  
Conversion Coating ◽  
Phosphate Coating ◽  
Nacl Solution ◽  
X Ray ◽  
Az31 Mg Alloy ◽  
Layered Phosphate ◽  
Scanning Electron

A duplex-layered phosphate conversion coating was obtained on AZ31Mg alloy through a phosphate bath with citric. Morphology, composition and corrosion behavior of the coating immersed into 3.5% NaCl solution for various time were investigated using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and electrochemical method. The results show that the coating is completely degraded after immersed in NaCl solution for 48h. The corrosion mediums mainly peel coating through the cracks among particles. The phosphate coating is damaged and falls out primarily, then the intermediate layer is degraded, and the substrate happens to dissolve with increasing of immersion time.

Study on Corrosion Behavior of Al-Zn-In and Al-Zn-Ga Alloys in NaCl Solution

2011 ◽  
Vol 284-286 ◽  
pp. 1701-1704
Author(s):  
Jing Ling Ma ◽  
Jiu Ba Wen ◽  
Gao Lin Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electrochemical Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Nacl Solution ◽  
X Ray ◽  
Inductive Loop ◽  
Capacitive Loop ◽  
Scanning Electron

The corrosion behavior of Al-5Zn-0.03In and Al-5Zn-0.03Ga alloys in 3.5 % NaCl solution has been examined by electrochemical methods, scanning electron microscopy, X-ray microanalysis, electrochemical impedance spectroscopy. The results demonstrate that the alloys differ in the microstructure, corroded morphology and electrochemical properties. For Al-5Zn-0.03In alloy, the precipitates enriched in Al and Zn initiates pitting. For Al-5Zn-0.03Ga alloy, corrosion occurs more uniformly, the corrosion of the alloy occurred via the formation of a surface Ga-Al amalgam alloy. The EIS of Al-5Zn-0.03In alloy contains a capacitive loop and an inductive loop; the inductive loop can be attributed to the presence of the pitting. The EIS of Al-5Zn-0.03Ga alloy contains only a capacitive loop.

Electrochemical Synthesis, Characterization and Corrosion Properties of POA−MoO42- Coating in 3.5% NaCl

2020 ◽  
Vol 22 (4) ◽  
pp. 263
Author(s):  
Ye.G. Bakhytzhan ◽  
A.M. Argimbayeva ◽  
G.S. Rakhymbay ◽  
R.Dzh. Jumanova ◽  
Kh. Avchukir ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electrochemical Method ◽  
Steel Grade ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Adhesion Properties ◽  
Protective Properties ◽  
X Ray ◽  
Scanning Electron

Polyanisidine (POA) and polyanisidine-molybdate (POA−MoO42-) coatings have been successfully synthesized on steel grade СТ3 from aqueous solutions of oxalic acid by electrochemical method using cyclic voltammetry. The morphology and composition of these films were characterized by scanning electron microscopy (SEM) and energydispersive X-ray (EDAX) methods. It was proven that the introduction of MoO42- into the polyanisidine matrix raised the corrosion resistance of the POA coating and also improved its adhesion properties. The protective properties of steel grade CT3 with POA and POA-MoO42- films were studied using potentiodynamic polarization in 3.5% NaCl solution. The results showed that ions improve anti-corrosion properties of POA films.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Detecting Critical Crevice Temperature for Duplex Stainless Steels in Chloride Solutions

CORROSION ◽  
2011 ◽  
Vol 67 (2) ◽  
pp. 025004-1-025004-7 ◽  
Author(s):  
D. Han ◽  
Y. Jiang ◽  
B. Deng ◽  
L. Zhang ◽  
J. Gao ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Electrochemical Method ◽  
Duplex Stainless Steels ◽  
Good Reproducibility ◽  
X Ray ◽  
Initiation Step ◽  
Critical Pitting Temperature ◽  
Preferential Dissolution ◽  
Scanning Electron

Abstract A simple and rapid electrochemical method for the evaluation of crevice corrosion in duplex stainless steels (DSS) is described. Three types of DSS—namely, UNS S32101, UNS S31803, and UNS S32750—were tested in 1 mol/L sodium chloride (NaCl) solutions. Results showed good reproducibility with a typical standard deviation of below 3°C. The critical pitting temperature (CPT) for the same specimens was also investigated in 1 mol/L NaCl solutions. An approximately 20°C decrease from CPT to critical crevice temperature (CCT) was observed and subsequently explained. Then, the morphologies of crevice corrosion were studied using scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDS) method. The SEM/EDS study revealed that the ferrite phase was the site where preferential dissolution took place at the initiation step of crevice corrosion, which was in accordance with the prediction by calculating the critical crevice index. Moreover, repassivation was detected with the development of crevice corrosion. The reason was clarified by combining the results obtained with a successful diffusion model, and eventually the crevice corrosion progress was illustrated schematically.

Electrochemical Synthesis and Photocatalytic Activity of Differently Shaped CuOx Particles

2017 ◽  
Vol 13 ◽  
pp. 330-333
Author(s):  
Anna Ulyankina ◽  
Igor Leontyev ◽  
Nina Smirnova
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Electrochemical Method ◽  
Spherical Particles ◽  
Photocatalytic Efficiency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyhedral Particles ◽  
Copper Electrodes ◽  
Scanning Electron

CuOx powders with diff erently shaped particles were firstly prepared via an electrochemical method by oxidation and dispersion of copper electrodes in an electrolyte solution under pulse alternating current (PAC). By means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) the current density is found to have an influence on the morphology and composition of CuOx particles. Photocatalytic efficiency of CuOx towards methyl orange (MO) degradation under visible light was investigated. The prepared polyhedral particles show the best photocatalytic activity of 81 % towards MO comparing to octahedral and spherical particles with 70 and 61 %, respectively.

Microstructural and Corrosion Studies by Immersion in 3.5% NaCl Solution on Aged Mg-9Al-1Zn-XCa Alloy

2019 ◽  
Vol 969 ◽  
pp. 93-97
Author(s):  
S. Manivannan ◽  
B. Narenthiran ◽  
A. Sivanantham ◽  
S.P. Kumaresh Babu
Keyword(s):  
Corrosion Behaviour ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
Corrosion Attack ◽  
X Ray ◽  
Α Phase ◽  
Corrosion Studies ◽  
Different Temperatures ◽  
Xrd Techniques ◽  
Scanning Electron

The experimatal alloys were aged at different temperatures of 180°C, 200°C, 220°C, and 240º C with calcium addition levels of (X=0.5, 1, 1.5, 2%) on Mg-6Al-1Zn-XCa alloy were investigated in 3.5% NaCl solution. All the experimatal alloys were immersed in 3.5% NaCl solutions and the resulted surface were analyzed to study the corrosion behaviour and its surface topography by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersed spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The result shows that corrosion attack occurred predominantly on ß phase and α phase exhibit relatively minor corrosion. In addition to that the increased aging temperature coarsens the intermetallic as well as α- Mg grains, which shows adverse effect to corrosion resistances and the best result were obtained at composition of 0.5wt.% Ca aged at 200°C.

scholarly journals Microstructure and Corrosion Behavior of Friction Stir-Welded 6061 Al/AZ31 Mg Joints with a Zr Interlayer

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1115 ◽  
Author(s):  
Yang Zheng ◽  
Xiaomeng Pan ◽  
Yinglei Ma ◽  
Shuming Liu ◽  
Libin Zang ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Stir Zone ◽  
Thermal Barrier ◽  
Al Alloy ◽  
X Ray ◽  
Friction Stir ◽  
Base Materials ◽  
Dissimilar Alloys ◽  
Scanning Electron

Friction stir welding (FSW) with a Zr interlayer was employed to join dissimilar alloys of 6061 Al and AZ31 Mg. The microstructures of Al/Mg and Al/Zr/Mg joints were investigated by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDS). The results showed that the central part of the Zr interlayer was smashed and intermixed with the base materials in the stir zone, whereas the undamaged part remained stable at the Al/Mg interface. The formation of Al–Mg intermetallic compounds (IMCs) was suppressed by the Zr interlayer due to its synergetic effects of chemical modification and thermal barrier. The electrochemical measurements revealed a differentiated corrosion behavior for each joint, where the corrosion rate of representative regions increased in the order of Al alloy < Mg alloy < heat-affected zone < stir zone. The immersion tests indicated an enhancement in corrosion resistance for the Al/Zr/Mg joint compared with the Al/Mg joint, which is owing to the mitigated galvanic corrosion between the base materials by the Zr interlayer.

Corrosion of High Zn Content Al-Zn-Mg-Cu Alloy in 3.5 wt.% NaCl Solution

2014 ◽  
Vol 703 ◽  
pp. 21-28
Author(s):  
Fan Qing Ran ◽  
Zi Yong Chen ◽  
Li Hua Chai
Keyword(s):  
Corrosion Process ◽  
Localized Corrosion ◽  
Nacl Solution ◽  
X Ray ◽  
Second Stage ◽  
Cu Alloy ◽  
Zn Content ◽  
The Matrix ◽  
Two Stages ◽  
Scanning Electron

In this paper, the polished specimens of high Zn content Al-Zn-Mg-Cu alloy after various aging treatments were immersed in 3.5 wt.% NaCl for up to 240 mins. The development of corrosion was monitored using scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). There are two stages during the corrosion process, the first stage of attack started with localized corrosion of trenching around the Al-Zn-Mg-Cu particles. In the second stage the pitting corrosion appeared at the grain boundaries, and then developed into intergranular corrosion. This phenomenon is related to the potential difference between the matrix and the precipitates.

Zinc Oxide Nanorods Characteristics Prepared by Sol-Gel Immersion Method Immersed at Different Times

2013 ◽  
Vol 667 ◽  
pp. 375-379 ◽  
Author(s):  
M. Awalludin ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Z. Mohamad ◽  
Mohamad Rusop
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Immersion Time ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Zinc Oxide Nanorods ◽  
Immersion Method ◽  
X Ray ◽  
Oxide Nanorods ◽  
Scanning Electron

This paper focus on zinc oxide (ZnO) nanorods prepared using sol-gel immersion method immersed at different time. Immersion times have been varied 1~24 hr and the characteristics of each sample have been observed. The effects of immersion time on ZnO nanorods thin films have been studied in surface morphology and structural properties using Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD), respectively.

Corrosion Protection of Mg Alloy by a TiO2 Coating Prepared by Sol-Gel Method

2013 ◽  
Vol 740 ◽  
pp. 473-477
Author(s):  
Yi Zhang ◽  
Cai Li Zhang ◽  
Xiang Meng ◽  
Guo Qin Cao ◽  
Chuan Shuai Li
Keyword(s):  
Orthogonal Experiment ◽  
Sol Gel ◽  
Mg Alloy ◽  
Orthogonal Experiment Design ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Az31 Mg Alloy ◽  
Hydrolysis Temperature ◽  
Scanning Electron

TiO2 films were prepared on the AZ31 Mg alloy substrate by sol-gel method. The morphology was characterized via X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy disperses spectroscopy (EDS). The corrosion rate of the coated AZ31 mg alloy was tested with the method of orthogonal experiment design. The influence of the hydrolysis temperature, coating times, calcinations temperature and time was investigated.

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