scholarly journals Carburization effect of Austenitic alloys with various Cr and Al additions under the methane/hydrogen atmosphere on the corrosion behaviors of steels

2021 ◽  
Vol 3 (1) ◽  
pp. 165-174
Author(s):  
Shu Liu ◽  
◽  
Jing Cui ◽  
Keyword(s):  
Corrosion Resistance ◽  
Optical Microscope ◽  
Hydrogen Atmosphere ◽  
Alumina Scales ◽  
Cr Content ◽  
Stability Diagrams ◽  
Austenitic Alloys ◽  
Corrosion Behaviors ◽  
Diffusion Paths ◽  
Al Additions

The corrosion behaviors of six Fe-19Ni-13/21Cr-xAl (x = 0, 2, 6 at. %) alloys in 10% CH4/H2 at 800oC were investigated. 2 at. % Al did not affect the corrosion resistance obviously, while 6 at. % Al reduced the carbon attack completely for Fe-19Ni-13Cr-6Al but was still insufficient to form protective alumina scales for alloys with 21 at. % Cr. An increase of Cr content changed the appearance of the internal carburization zone under the optical microscope. Stability diagrams of M-C-O system（M= Cr, Fe）were established to estimate the diffusion paths of carbon in the alloys.

Characteristic and Corrosion Studies of Rare Earth (REE) Based Anodizing on AZ91D Magnesium Alloy

2013 ◽  
Vol 594-595 ◽  
pp. 571-574
Author(s):  
Mat Akhir Khalid Azadi ◽  
M.Z.M. Zamzuri ◽  
S. Norbahiyah ◽  
Mohd Nazree Derman
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Immersion Test ◽  
Optical Microscope ◽  
Oxide Coatings ◽  
Az91d Magnesium Alloy ◽  
Β Phase ◽  
Corrosion Studies ◽  
Corrosion Behaviors ◽  
Scanning Electron

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing Mg (NO3)2 with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly.

Characteristic and Corrosion Studies of Rare Earth (Ree) Based Anodizing on AZ91D Magnesium Alloy

2014 ◽  
Vol 879 ◽  
pp. 38-42
Author(s):  
Mat Akhir Khalid Azadi ◽  
M.Z.M. Zamzuri ◽  
S. Norbahiyah ◽  
M.R.N. Liyana ◽  
M. Marina ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Immersion Test ◽  
Optical Microscope ◽  
Oxide Coatings ◽  
Az91d Magnesium Alloy ◽  
Β Phase ◽  
Corrosion Studies ◽  
Corrosion Behaviors ◽  
Scanning Electron

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing La (NO3) and Mg (NO3),with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

scholarly journals Chemical Composition and Corrosion Behavior of a-C:H/DLC Film-Coated Titanium Substrate in Simulated PEMFC Environment

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Beibei Han ◽  
Mengyuan Yan ◽  
Dongying Ju ◽  
Maorong Chai ◽  
Susumu Sato
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Metal Ion ◽  
Ion Beam ◽  
Titanium Substrate ◽  
Corrosion Current ◽  
Ion Concentration ◽  
Bipolar Plates ◽  
High Adhesion ◽  
Corrosion Behaviors

The amorphous hydrogenated (a-C:H) film-coated titanium, using different CH4/H2 and deposition times, was prepared by the ion beam deposition (IBD) method, which has the advantage of high adhesion because of the graded interface mixes at the atomic level. The chemical characterizations and corrosion behaviors of a-C:H film were investigated and evaluated by SEM, AFM, Raman spectroscopy, EPMA, TEM and XPS. An a-C:H film-coated titanium was corroded at 0.8 V, 90 °C in a 0.5 mol/L H2SO4 solution for 168 h. The metal ion concentration in the H2SO4 corrosion solution and the potentiodynamic polarization behavior were evaluated. Results indicate that a higher CH4/H2 of 1:0 and a deposition time of 12 h can result in a minimum ID/IG ratio of 0.827, Ra of 5.76 nm, metal ion concentration of 0.34 ppm in the corrosion solution and a corrosion current of 0.23 µA/cm2. The current density in this work meets the DOE’s 2020 target of 1 µA/cm2. Electrical conductivity is inversely proportional to the corrosion resistance. The significant improvement in the corrosion resistance of the a-C:H film was mainly attributed to the increased sp3 element and nanocrystalline TiC phase in the penetration layer. As a result, the a-C:H film-coated titanium at CH4/H2 = 1:0 with improved anti-corrosion behavior creates a great potential for PEMFC bipolar plates.

scholarly journals Susceptibility to Stress Corrosion of Laser-Welded Composite Arch Wire in Acid Artificial Saliva

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Chao Zhang ◽  
Xinhua Sun
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Shape Memory Alloy ◽  
Artificial Saliva ◽  
Steel Wire ◽  
Niti Shape Memory Alloy ◽  
Solution Ph ◽  
Corrosion Behaviors ◽  
Cu Interlayer

The corrosion resistance of laser-welded composite arch wire (CoAW) with Cu interlayer between NiTi shape memory alloy and stainless steel wire in artificial saliva with different acidities and loads was studied. It was found that both the solution pH and the stress had a significant influence on the corrosion behaviors of the CoAW samples. Decreasing the solution pH or increasing the loading stress caused the increase of Cu release and weight loss. The corroded morphology formed on the surfaces of the CoAW was the consequence under the combined effect of corrosion and stress.

Corrosion Behavior of Al-Si-Cr-Cu Bearing Low Carbon Steel in A Cyclic Dry/Wet Laboratory Test

2009 ◽  
Vol 79-82 ◽  
pp. 1017-1020 ◽  
Author(s):  
Hui Shu Zhang ◽  
Dong Ping Zhan ◽  
Song Lian Bai ◽  
Zhou Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
Rust Layer ◽  
Electrochemical Behaviors ◽  
Corrosion Rates ◽  
The Matrix ◽  
Corrosion Behaviors

The corrosion behaviors of Al-Si-Cr-Cu bearing low carbon steel and a reference steel Q235 were tested in a cyclic dry/wet environment containing 0.01mol/L NaHSO3 in laboratory. Rust layers were observed by optical microscope (OM), scanning electron microscopy (SEM) and XRD. The electrochemical behaviors of the steels were studied on the polarization curves and electrochemical impedance spectroscopy (EIS). The results indicate that after 120h corrosion test, the annual corrosion rates of the designed steels reduce 42 % than Q235 at least. The corrosion products are generally iron oxyhydroxides and oxides such as FeOOH, γ-FeOOH, α-FeOOH, γ-Fe2O3, Fe3O4. The α-FeOOH possesses good stabilization mainly exits and can improve the corrosion resistance. There are the enrichments of Cu, Cr, Si and Al in the rust layer close to the matrix, which make the rust layer be more compact and protected. The corrosion currents of the two designed steels are lower than that of Q235, the corrosion potentials are higher than that of Q235 after Tafel fitting. The rust layer impedances of the designed steels are higher than that of Q235.

Understanding the low corrosion potential and high corrosion resistance of nano-zinc electrodeposit based on electron work function and interfacial potential difference

RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 97606-97612 ◽  
Author(s):  
Qingyang Li ◽  
Hao Lu ◽  
Juan Cui ◽  
Maozhong An ◽  
Dongyang (D. Y.) Li
Keyword(s):  
Corrosion Resistance ◽  
Work Function ◽  
Corrosion Potential ◽  
Electron Work Function ◽  
Coarse Grained ◽  
High Corrosion Resistance ◽  
Corrosion Behaviors ◽  
Interfacial Potential ◽  
Nano Zinc ◽  
Zinc Coatings

The corrosion behaviors of coarse-grained and nanocrystalline zinc coatings and correlated the corrosion potential with electron stability are investigated.

Study on the Corrosion Behaviors of MAO Coated on TC4 Titanium Alloy

2012 ◽  
Vol 518-523 ◽  
pp. 632-636
Author(s):  
Jian Jun Xi ◽  
Jun Zhao
Keyword(s):  
Dielectric Constant ◽  
Corrosion Resistance ◽  
Titanium Alloy ◽  
Ac Impedance ◽  
Compact Layer ◽  
Soaking Time ◽  
Tc4 Titanium Alloy ◽  
Pore Area ◽  
Corrosion Behaviors ◽  
Loose Layer

This paper provides the method of calculating the film pore area and comparing the density of the looser and compact layer by AC impedance, then to compare the corrosion resistance of the film by comparing the pore area and the dielectric constant. The resistance of the film decreases fellow the soaking time extending, the capacitance of the loose and compact layer increases with the soaking time extending. The capacitance of the compact layer is smaller than that of the loose layer.

scholarly journals Improved Mechanical Properties and Corrosion Resistance of Mg-Based Bulk Metallic Glass Composite by Coating with Zr-Based Metallic Glass Thin Film

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1212
Author(s):  
Pei-Hua Tsai ◽  
Chung-I Lee ◽  
Sin-Mao Song ◽  
Yu-Chin Liao ◽  
Tsung-Hsiung Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Substrate Surface ◽  
Bending Test ◽  
Corrosion Behaviors ◽  
Lightweight Structure ◽  
Mechanical Properties And Corrosion

Mg-based bulk metallic glass (BMG) and its composite (BMGC) can be excellent candidates as lightweight structure materials, but lack of anti-corrosion ability may restrict their application. In order to enhance the natural weak point of Mg-based BMGC, a 200-nm thick Zr-based metallic glass thin film (MGTF) ((Zr53Cu30Ni9Al8)99.5Si0.5) was applied and its mechanical properties as well as its corrosion resistance were appraised. The results of a 3-point bending test revealed that the flexural strength of the Mg-based BMGC with 200-nm thick Zr-based MGTF coating can be greatly enhanced from 180 to 254 MPa. We propose that the Zr-based MGTF coating can help to cover any small defects of a substrate surface, provide a protecting layer to prevent stress concentration, and cease crack initiation from the specimen surface during bending tests. Moreover, the results of anti-corrosion behavior analysis revealed a similar trend between the Mg-based BMG, Mg-based BMGC, and Mg-based BMGC with Zr-based MGTF coating in 0.9 wt.% sodium chloride solution. The readings show a positive effect with the Zr-based MGTF coating. Therefore, the 200-nm thick Zr-based MGTF coating is a promising solution to provide protection for both mechanical and anti-corrosion behaviors of Mg-based BMGC and reinforce its capability as structure material in island environments.

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