scholarly journals Annealing of Al-Zn-Mg-Cu Alloy at High Pressures: Evolution of Microstructure and the Corrosion Behavior

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2076
Author(s):  
Chuanjun Suo ◽  
Pan Ma ◽  
Yandong Jia ◽  
Xiao Liu ◽  
Xuerong Shi ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Electrochemical Impedance ◽  
Extrusion Direction ◽  
Corrosion Properties ◽  
Cu Alloy ◽  
The Matrix ◽  
Annealing Pressure ◽  
Corrosion Pits ◽  
Evolution Of Microstructure

Extruded Al-Zn-Mg-Cu alloy samples with grains aligned parallel to the extrusion direction were subjected to high-pressure annealing. The effects of annealing pressure on the microstructure, hardness, and corrosion properties (evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) were investigated. Phase analysis showed the presence of MgZn2 and α-Al phases, the MgZn2 phase dissolved into the matrix, and its amount decreased with the increasing annealing pressure. The recrystallization was inhibited, and the grains were refined, leading to an increase in the Vickers hardness with increasing the annealing pressure. The corrosion resistance was improved after high-pressure treatment, and a stable passivation layer was observed. Meanwhile, the number of corrosion pits and the width of corrosion cracks decreased in the high-pressure annealed samples.

Corrosion Behavior of X52 Steel in High Pressure CO2 Environment

2013 ◽  
Vol 686 ◽  
pp. 234-243 ◽  
Author(s):  
Abdel Hafiz Mustafa ◽  
Bamban Ariwahjoedi ◽  
M.C. Ismail
Keyword(s):  
High Pressure ◽  
Corrosion Behavior ◽  
High Pressures ◽  
Electrochemical Impedance ◽  
Co2 Corrosion ◽  
Corrosion Mechanism ◽  
Corrosion Rates ◽  
High Pressure Co2 ◽  
X52 Steel ◽  
Co2 Environment

Research in high pressure CO2 environment is important in oil and gas industry due to potential development of high pressure CO2 gas fields. Current understanding limits the use of carbon steel pipeline material in this high pressure CO2 environment due to excessive corrosion rates predicted by corrosion prediction software. The aim of this work is to elucidate the corrosion behavior of X52 steel in high pressure CO2 environment. Electrochemical methods of linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were employed to study the CO2 corrosion mechanism at high pressures of 10-60 bar at ambient temperature. Surface morphology and chemical composition of corrosion film was studied by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results obtained showed that the corrosion rates at high pressures were significantly influenced by CO2 pressure. However FeCO3 and F3C were the main component of the corrosion product film.

scholarly journals High Performance Anti-Corrosion Coatings of Poly (Vinyl Butyral) Composites with Poly N-(vinyl)pyrrole and Carbon Black Nanoparticles

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2307 ◽  
Author(s):  
Lu Hao ◽  
Guowei Lv ◽  
Yaqian Zhou ◽  
Kaiming Zhu ◽  
Mochen Dong ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Black ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Corrosion Properties ◽  
The Matrix ◽  
Superior Corrosion Resistance ◽  
Vinyl Butyral

Zinc is widely used in battery negative electrodes and steel coatings for automotive industries. The anti-corrosion property of zinc is the most important factor determining the performance and lifetime of the products. In this paper, both size-controlled poly N-(vinyl)pyrrole (PNVPY) nanoparticles and carbon black (CB) nanoparticles were compounded with poly (vinyl butyral) (PVB) binder developing a series of composite coatings covered on the zinc substrates using a spin-coating technique. The morphologies of the surface and cross section of the PNVPY/CB/PVB coatings indicate that the PNVPY and CB nanoparticles are uniformly distributed in the matrix. The corrosion resistance of the composite coatings was tested by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization in a 3.5% NaCl solution. It is found that the coating with 1.9 wt.% PNVPY and 2.3 wt.% CB nanoparticles shows a remarkably high resistance value (Rc) and corrosion protection efficiency (99.99%). Meanwhile, the immersion results also reveal its superior corrosion resistance. It is considered that the nanoscale dispersion of PNVPY and carbon in PVB matrix and the strong interface action between the nanoparticles and PVB result in the uniform microstructure of the composites which endues the superior corrosion properties of the coatings.

The Influence of Deformation the Corrosion Resistance of Titanium Grade2

2015 ◽  
Vol 227 ◽  
pp. 27-30 ◽  
Author(s):  
Marta Zwolińska ◽  
Agata Sotniczuk ◽  
Krzysztof Topolski ◽  
Andrzej Królikowski ◽  
Halina Garbacz
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Extrusion Direction ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Transmission Electron

Severe Plastic Deformation (SDP) processes including Hydroextrusion (HE) causes the change of the mechanical properties by the introduction of a large number of defects and significant refinement of the microstructure. During the initially stages of HE microstructure becomes more elongated according to the extrusion direction. Only after a certain deformation, grains become more equiaxed. Present studies are intended to determine the influence of the titanium Grade2 microstructure and grain size distribution on its corrosion properties. All corrosion tests were conducted in a 0.9 % NaCl solution at room temperature. Electrochemical Impedance Spectroscopy (EIS) was measured after 2 and 24 hours. Also Potentiodynamic Polarization was conducted after 24 hours. Microstructures were reviled using Scanning Electron Microscopy and Transmission Electron Microscopy. Grain size distribution was determined using the program Micrometer . The results confirmed formation of titanium dioxide and very good corrosion properties of titanium Grade2 at all stages of hydrostatic extrusion.

Investigation of Microstructure and Properties of an Al-Zn-Mg-Cu Alloy

2013 ◽  
Vol 668 ◽  
pp. 885-889
Author(s):  
Xi Wu Li ◽  
Bai Qing Xiong ◽  
Yon Gan Zhang ◽  
Zhi Hui Li ◽  
Feng Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fatigue Testing ◽  
Conductivity Measurement ◽  
Corrosion Properties ◽  
Microstructure And Properties ◽  
Depth Direction ◽  
Cu Alloy ◽  
The Matrix ◽  
Toughness Testing ◽  
Quench Method

In this study, the microstructure and properties of an Al-7.5Zn-1.7Mg-1.4Cu-0.12Zr alloy in T74 condition have been investigated using TEM, tensile properties testing, conductivity measurement, fracture toughness testing, fatigue testing, corrosion testing and soaking quench method etc. The results indicate that When T74 tempers are performed, the alloy can obtain a good comprehensive performance with GPII zones, η' phases and η phases as the major precipitates in the matrix and coarser and discontinuous precipitates on the grain boundaries. The alloy also exhibits a good combination of tensile strength, fracture toughness, fatigue and corrosion properties. And the alloy has a good quench performance, after soaking quenched in water, the strength of the forging with 210mm thickness is stable and varies less than 10% along the depth direction.

Electrochemical Impedance Characteristics of Sintered 7075 Aluminum Alloy Under Ssrt Condition

2013 ◽  
Vol 58 (2) ◽  
pp. 505-508 ◽  
Author(s):  
S. Sunada ◽  
N. Nunomura
Keyword(s):  
Aluminum Alloys ◽  
Complex Shape ◽  
Electrochemical Impedance ◽  
Ingot Metallurgy ◽  
View Point ◽  
Corrosion Properties ◽  
Electrochemical Tests ◽  
Impedance Characteristics ◽  
Polarization Test ◽  
Conventional Ingot

Powder metallurgy (P/M) process has the advantage of better formability to fabricate complex shape products without machining and welding. And recently this P/M process has been applied to the production of aluminum alloys. The P/M aluminum alloys thus produced also have received considerable interest because of their fine and homogeneous structure. Many papers have been published on the mechanical properties of the aluminum alloys produced by P/M process while there have been few on their corrosion properties from the view point of electrochemistry. In this experiment, therefore, two kinds of 7075 aluminum alloys prepared by the conventional ingot metallurgy (I/M) process and P/M process were used, I/M material is commercially available. and their corrosion behavior were investigated through the electrochemical tests such as potentiodynamic polarization test, slow rate strain tensile (SSRT) test and electrochemical impedance spectroscopy (EIS) measurement under SSRT test in the corrosion solution and the deionized water.

Peculiarities of high-pressure hydrogen adsorption on Pt catalyzed Cu-BTC metal–organic framework

2021 ◽  
Vol 23 (7) ◽  
pp. 4277-4286
Author(s):  
S. V. Chuvikov ◽  
E. A. Berdonosova ◽  
A. Krautsou ◽  
J. V. Kostina ◽  
V. V. Minin ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Hydrogen Adsorption ◽  
Metal Organic Framework ◽  
Pt Catalyst ◽  
Metal Organic ◽  
Pt Catalyzed ◽  
Pressure Hydrogen ◽  
Organic Framework

Pt-Catalyst plays a key role in hydrogen adsorption by Cu-BTC at high pressures.

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

scholarly journals Crystal and electronic structure engineering of tin monoxide by external pressure

2021 ◽  
Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Band Gap ◽  
High Pressures ◽  
Low Pressure ◽  
Widespread Application ◽  
Space Group ◽  
Tin Monoxide ◽  
High Possibility ◽  
Pressure Phase

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.

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