Effect of Aging Time on the Microstructural Characterization and Corrosion Resistance of Al-4.5Cu-1Li-0.4Mg-0.4Ag-0.4Mn-0.5Zn Alloys

Geothermal process equipment and accessories are usually manufactured from low-alloy steels which offer affordability but increase the susceptibility of the materials to corrosion. Applying erosion-corrosion-resistant coatings to these components could represent an economical solution to the problem. In this work, testing of two newly developed laser metal deposited high-entropy alloy (LMD-HEA) coatings—CoCrFeNiMo0.85 and Al0.5CoCrFeNi, applied to carbon and stainless steels—was carried out at the Hellisheidi geothermal power plant. Tests in three different geothermal environments were performed at the Hellisheidi site: wellhead test at 194 °C and 14 bar, erosion test at 198 °C and 15 bar, and aerated test at 90 °C and 1 bar. Post-test microstructural characterization was performed via Scanning Eletron Microscope (SEM), Back-Scattered Electrons analysis (BSE), Energy Dispersive X-ray Spectroscopy (EDS), optical microscopy, and optical profilometry while erosion assessment was carried out using an image and chemical analysis. Both the CoCrFeNiMo0.85 and Al0.5CoCrFeNi coatings showed manufacturing defects (cracks) and were prone to corrosion damage. Results show that damage in the CoCrFeNiMo0.85-coated carbon steel can be induced by manufacturing defects in the coating. This was further confirmed by the excellent corrosion resistance performance of the CoCrFeNiMo0.85 coating deposited onto stainless steel, where no manufacturing cracks were observed.

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Microstructural Characterization, Mechanical Properties, and Corrosion Resistance of Dental Co-Cr-Mo-W Alloys Manufactured by Selective Laser Melting

Journal of Materials Engineering and Performance ◽

10.1007/s11665-018-3520-6 ◽

2018 ◽

Vol 27 (10) ◽

pp. 5312-5320 ◽

Cited By ~ 6

Author(s):

Wei Wei ◽

Yanan Zhou ◽

Wenbo Liu ◽

Ning Li ◽

Jiazhen Yan ◽

...

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Selective Laser Melting ◽

Microstructural Characterization ◽

Laser Melting ◽

Mechanical Properties And Corrosion

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Characterization and Corrosion Resistance Behavior of Shape Memory Stainless Steel Developed by Alternate Routes

Metals ◽

10.3390/met10010013 ◽

2019 ◽

Vol 10 (1) ◽

pp. 13

Author(s):

David Dias ◽

Sandra Nakamatsu ◽

Carlos Alberto Della Rovere ◽

Jorge Otubo ◽

Neide Aparecida Mariano

Keyword(s):

Corrosion Resistance ◽

Shape Memory ◽

Dendritic Structure ◽

Microstructural Characterization ◽

Rolling Process ◽

Chloride Ions ◽

Secondary Phases ◽

Electrochemical Tests ◽

The Matrix ◽

Routing Methods

The microstructural characterization and corrosion resistance behavior of Fe-Mn-Si-Cr-Ni alloy with shape memory effect was studied under different mechanical processing conditions and heat treatments, which were produced using conventional casting and routing methods to reduce costs and make production viable. Microstructural characterization was performed with electron microscopy and x-ray diffraction techniques, electrochemical tests with polarization, and thermogravimetry techniques. The cast condition presented a dendritic structure and the presence of the secondary phases: ferrite-δ and Chi-X phase. The heat treatment eliminated phases, reincorporated elements in the matrix, and increased the austenitic grain. After the hot rolling process, the alloy exhibited a refined microstructure with recrystallized austenitic grains. The heat-treated condition presented better oxidation resistance than the other conditions, while the hot-rolled condition showed repassivation of the pits, raising them to higher levels. All conditions presented low corrosion resistance in environments containing chloride ions.

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Microstructural Characterization and Corrosion-Resistance Behavior of Dual-Phase Steels Compared to Conventional Rebar

Crystals ◽

10.3390/cryst10111068 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1068

Author(s):

Hany S. Abdo ◽

Asiful H. Seikh ◽

Biplab Baran Mandal ◽

Jabair A. Mohammed ◽

Sameh A. Ragab ◽

...

Keyword(s):

Corrosion Resistance ◽

Galvanic Corrosion ◽

Microstructural Characterization ◽

Carbon Steels ◽

Dual Phase ◽

Low Carbon ◽

Dp Steel ◽

Dp Steels ◽

Superior Corrosion Resistance ◽

Corrosive Environments

Dual-phase (DP) steels consist of a ferritic matrix dispersed with some percentage of martensite, which gives the material a good combination of strength and ductility, along with the capacity to absorb energy and enhanced corrosion protection properties. The purpose of this work was to study the microstructural and corrosion behavior (mainly pitting and galvanic corrosion) of DP steel compared with that of conventional rebar. To obtain DP steel, low-carbon steels were heat-treated at 950 °C for 1 h and then intercritically annealed at 771 °C for 75 min, followed by quenching in ice-brine water. The corrosion rates of DP steel and standard rebar were then measured in different pore solutions. Macro- and microhardness tests were performed for both steels. It was found that DP steels exhibited a superior corrosion resistance and strength compared to standard rebar. The reported results show that DP steels are a good candidate for concrete reinforcement, especially in aggressive and corrosive environments.

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Microstructure and Properties of Mg-Zn-Y Alloy Powder Compacted by Equal Channel Angular Pressing

Materials ◽

10.3390/ma11091678 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1678 ◽

Cited By ~ 5

Author(s):

Chun Chiu ◽

Hong-Min Huang

Keyword(s):

Mechanical Properties ◽

Corrosion Resistance ◽

Equal Channel Angular Pressing ◽

Volume Fraction ◽

Cast Alloy ◽

Milled Powder ◽

Microstructural Characterization ◽

Compressive Yield Strength ◽

Lpso Phase ◽

Angular Pressing

Mg97Zn1Y2 (at %) alloy with a long period stacking ordered (LPSO) phase has attracted a great deal of attention due to its excellent mechanical properties. It has been reported that this alloy could be fabricated by warm extrusion of rapid solidified alloy powders. In this study, an alternative route combining mechanical milling and equal channel angular pressing (ECAP) was selected to produce the bulk Mg97Zn1Y2 alloy. Microstructural characterization, mechanical properties and corrosion behavior of the ECAP-compacted alloys were studied. The as-cast alloy contained α-Mg and LPSO-Mg12Zn1Y1 phase. In the as-milled powder, the LPSO phase decomposed and formed Mg24Y5 phase. The ECAP-compacted alloy had identical phases to those of the as-milled sample. The compacted alloy exhibited a hardness of 120 HV and a compressive yield strength of 308 MPa, which were higher than those of the as-cast counterpart. The compacted alloy had better corrosion resistance, which was attributed to the reduced volume fraction of the secondary phase resulting in lower microgalvanic corrosion in the compacted alloy. The increase in Y content in the α-Mg matrix also contributed to the improvement of corrosion resistance.

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Evaluation for Properties of Anti-Corrosion Epoxy Coating after Photo-Oxidation Aging

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.795.200 ◽

2019 ◽

Vol 795 ◽

pp. 200-207 ◽

Cited By ~ 1

Author(s):

Bo Zhao ◽

Yu Xin Yu ◽

Tian Yu Zhou ◽

Shi Wen Zhou ◽

Jing Guo ◽

...

Keyword(s):

Corrosion Resistance ◽

Aging Time ◽

Electrochemical Impedance ◽

Epoxy Coating ◽

Xenon Lamp ◽

Neutral Solution ◽

Solution Ph ◽

Adhesion Properties ◽

Time Constants ◽

Nyquist Plots

In this article, a set of aging anti-corrosion epoxy coating was prepared in Xenon lamp light chamber of 0h, 72h, 144h, 216h, 288h, 360h and 432h. Meanwhile, the changes of coating thickness, adhesion properties, functional groups, and corrosion resistance properties increasing with aging time were determined. The results showed that the thickness of epoxy coating was increased more than 50% as the aging time increased to 432h, and reached 32μm. The adhesion reduced significantly, which was 0 grade in cross-cut test at 0h, but decreased to 2 grade after been aged for 432h. Meanwhile, the value of adhesive force declined more than 56% in pull-off test. The corrosion resistance properties were investigated by electrochemical impedance spectra (EIS) in both 3.5% NaCl neutral solution (pH=7) and acid solution (pH=2). The Nyquist plots in neutral solution transferred from single time constant to two time constants in neutral solution. The capacitive impedance loop became shorter, while coating resistance Rf declined more rapidly as the aging time increasing. Meanwhile, the Nyquist plots possessed three time constants in acid solutiondue to the dissolution of zinc in the coating. The FT-IR spectrum showed that the peak value of C-O-C and C-H declined with aging time increasing, and the peak of C=O becamemore significantly. The results showed that the protective properties of epoxy coating declined while the aging reaction going on, with chain broken of C-O-C and C-H bond and hydrophilicity enhancing.

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Microstructural Characterization and Corrosion-Resistance of Borided Rebar

El-Cezeri Fen ve Mühendislik Dergisi ◽

10.31202/ecjse.892342 ◽

2021 ◽

Author(s):

Tayfun UYGUNOĞLU ◽

İbrahim GÜNEŞ ◽

Atila Gürhan ÇELİK ◽

Emriye ÇINAR

Keyword(s):

Corrosion Resistance ◽

Microstructural Characterization

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CORROSION BEHAVIOUR OF TEMPERED 42CrMo4 STEEL

Materiali in tehnologije ◽

10.17222/mit.2021.014 ◽

2021 ◽

Vol 55 (3) ◽

Author(s):

Sunčana Smokvina Hanza ◽

Lovro Štic ◽

Lovro Liverić ◽

Vedrana Špada

Keyword(s):

Corrosion Resistance ◽

Corrosion Behaviour ◽

Microstructural Characterization ◽

Open Circuit ◽

Medium Carbon Steel ◽

42Crmo4 Steel ◽

Double Quenching ◽

Quenched And Tempered Steel ◽

Quenching And Tempering ◽

Tempered Steel

Low-alloy 42CrMo4 steel (AISI 4140) is a medium carbon steel, commonly used as a quenched and tempered steel. Because of its good mechanical properties, high tensile strength and toughness, 42CrMo4 is one of the widely used and investigated steels. In order to increase ductility even more, in addition to standard quenching and tempering, steel is often hardened by double quenching and tempering and austempering. The aim of this paper was to investigate the corrosion behaviour of 42CrMo4 steel after quenching and tempering, double quenching and tempering and austempering. For this purpose, microstructural characterization and electrochemical investigation after different hardening processes were performed. Microstructure of specimens was observed using optical microscopy and scanning electron microscopy. Open circuit potential and potentiodynamic polarization measurements of tempered specimens were carried out using computer-controlled potentiostat with three electrode set-up in 0.6 M NaCl naturally aerated solution. It was concluded that applied heat treatment processes increase the corrosion resistance of 42CrMo4 steel in comparison to normalized steel. In comparison to quenched and tempered steel, double quenching and tempering, as well as austempering, do not significantly change corrosion resistance of steel.

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Effect of heat treatment on microstructure and corrosion resistance of extruded ZK80 Mg alloy

Materials Express ◽

10.1166/mex.2019.1585 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1092-1099

Author(s):

Fenghong Cao ◽

Chang Chen ◽

Zhenyu Wang

Keyword(s):

Heat Treatment ◽

Corrosion Resistance ◽

Corrosion Rate ◽

Aging Time ◽

Room Temperature ◽

Aging Treatment ◽

Corrosion Process ◽

Corrosion Mechanism ◽

Nacl Solution ◽

Corrosion Properties

The corrosion characteristics and corrosion mechanism of the extruded ZK80 alloy with different states soaking in 3.5% NaCl solution at room temperature were analyzed via OM, SEM, EDS, XRD and static weightlessness method and other experimental analysis methods. The results show that when the aging temperature is constant, and the corrosion rate decreases with the lengthen of aging time, while when the corrosion time is constant, the corrosion rate increases with the increase in aging time. Appropriate aging treatment not only refines the grain of the alloy, but also precipitates the Mg–Zn phase which can effectively prevent the corrosion process and improve the anti-corrosion properties of the alloy. The main corrosion characteristics of the alloy are filamentary corrosion and pitting corrosion.

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