The Experts below are selected from a list of 8706 Experts worldwide ranked by ideXlab platform

Lai Zhu Jiang - One of the best experts on this subject based on the ideXlab platform.

  • quantification of texture induced ridging in Ferritic Stainless Steels 430 and 430lr during tensile deformation
    Journal of materials research and technology, 2019
    Co-Authors: Jingwei Zhao, Lai Zhu Jiang, Xin Zhang, Zhengyi Jiang
    Abstract:

    Abstract A comparative study has been carried out to assess the effect of rolling and annealing processes on ridging generation of Ferritic Stainless Steels (FSSs) 430 and 430LR after tensile deformation. The results show that FSS 430LR has better ridging resistance owing to the refinement of microstructure and crystallographic texture optimisation. A 30% reduction of ridging height can be achieved using FSS 430LR compared to FSS 430 after tension. Optimal reduction during cold rolling benefits the microstructural refinement and surface quality improvement of FSSs 430 and 430LR. Both theoretical calculations and experimental results indicate that the {1 1 2} and the {0 0 1} components are responsible for ridging in the FSSs after tension. Through preventing the formation of coarse bands and grains with the {0 0 1} component inside the FSSs, the ridging resistance of both FSSs 430 and 430LR can be improved.

  • Degradation of Ferritic Stainless Steels at 1200 °C in air
    Materials and Corrosion-werkstoffe Und Korrosion, 2017
    Co-Authors: Xiawei Cheng, Brian J Monaghan, Raymond J Longbottom, Zhengyi Jiang, Dongbin Wei, Ay Ching Hee, Lai Zhu Jiang
    Abstract:

    Three commercial Ferritic Stainless Steels were investigated at 1200 °C by a thermogravimetric analyser (TGA) in air. The oxidation kinetics of the Ferritic Stainless Steels differed significantly. The adhesion of the Cr2O3 scale, the morphology of the SiO2, with or without (Cr, Mn)3O4 spinel on the top can greatly influence the oxidation and the degradation behaviour of the Steels. Although the SUS430 steel had less Cr among the Ferritic Stainless Steels (16.2 wt% Cr), it did not show more degradation behaviour than the B443NT steel (21.0 wt% Cr). The spallation of the protective oxide scale on the B443NT steel was caused by vacancy condensation at the scale/substrate interface where the SiO2 particles were and the developed compressive stresses within the oxide scale during oxidation. (Cr, Mn)3O4 spinel on the top of the Cr2O3 scale on the B445J1M steel influenced its evaporation rate. The thermodynamic aspect of the chemical composition and oxidation atmosphere of the Fe–Cr–O system was also discussed.

  • breakaway oxidation behaviour of Ferritic Stainless Steels at 1150 c in humid air
    Corrosion Science, 2016
    Co-Authors: Xiawei Cheng, Brian J Monaghan, Raymond J Longbottom, Jingwei Zhao, Jianguo Peng, Zhengyi Jiang, Lai Zhu Jiang
    Abstract:

    Abstract The breakaway oxidation behaviour of Ferritic Stainless Steels 430, 443 and 445 has been investigated at 1150 °C in humid air. The oxidation kinetics exhibited significant differences among the three Ferritic Stainless Steels. A uniform and steady growing oxide scale was developed on the 430 steel with an even steel/oxide interface. Local breakdown of the initially protective oxide scale occurred and oxide nodules were developed on the 443 and 445 Stainless Steels, resulting in irregular and rough steel/oxide interfaces. The breakaway oxidation behaviour was significantly influenced by the microstructure and the composition of the oxide scale. The Mn-Cr spinel oxide formed on top of the Cr 2 O 3 scale in Mo alloying 445 steel can greatly minimise the Cr depletion.

  • texture microstructure and mechanical properties of aluminum modified ultra pure 429 Ferritic Stainless Steels
    Materials & Design, 2016
    Co-Authors: Xin Zhang, Lijun Fan, Xueshan Xiao, Lai Zhu Jiang
    Abstract:

    Abstract Effect of aluminum on texture, microstructure and mechanical properties of ultra-pure 429 Ferritic Stainless Steels has been investigated. Average grain size after annealing slightly increases with increased aluminum content because of the decreased recrystallization temperature and reduced area fraction of inclusions. Recrystallization texture of the surface and center layers evolves from α + γ-fiber to full γ-fiber, and the maximum intensity of γ-fiber increases with addition of 0.16 wt.% aluminum. However, the γ-fiber of {111} shifts to {223} and both the intensity of {111} and {111} decreases when aluminum content is further increased to 1.51 wt.%. The maximum texture intensity of γ-fiber in thickness direction can be significantly improved in steel with 0.16 wt.% aluminum but not in steel with 1.51 wt.% aluminum. Increased aluminum content benefits room temperature tensile properties, and steel with 0.16 wt.% aluminum exhibits plastic strain ratio of about 1.62. The TiN and MgO·Al2O3–TiN particles with a slightly increased average size and decreased area fraction may not suppress the growth of recrystallized grains and contribute to increased intensity of γ-fiber texture. The steel modified with 0.16 wt.% aluminum exhibits excellent formability due to the appearance of the strong γ-fiber texture.

  • improved oxidation resistance of 15 wt cr Ferritic Stainless Steels containing 0 08 2 45 wt al at 1000 c in air
    Corrosion Science, 2015
    Co-Authors: Xin Zhang, Lijun Fan, Xueshan Xiao, Lai Zhu Jiang
    Abstract:

    Abstract Improved oxidation resistance of 15 wt.% Cr Ferritic Stainless Steels at 1000 °C in air has been obtained. Weight gain per unit area is in parabolic relation to oxidation time and parabolic rate constant significantly decreases with increased Al content. Diffusion of Al is enhanced and the porous Cr 2 O 3 rich outer layer is replaced by a more compact Al 2 O 3 rich outer layer in Steels with higher Al contents. The appearance of continuous and compact Al 2 O 3 oxide scale contributes to the significantly improved oxidation resistance property and the oxidation mechanism has been suggested based on microstructural observations.

Jeffry W Stevenson - One of the best experts on this subject based on the ideXlab platform.

  • ce modified mn co 3o4 spinel coatings on Ferritic Stainless Steels for sofc interconnect applications
    Electrochemical and Solid State Letters, 2008
    Co-Authors: Zhenguo Yang, Guanguang Xia, Zimin Nie, Joshua D Templeton, Jeffry W Stevenson
    Abstract:

    This paper reports the development of a coating approach that simultaneously achieves the advantages of conductive (Mn,Co) 3 O 4 spinel coatings and of rare earth (RE) surface treatment on Ferritic Stainless Steels for solid oxide fuel cell (SOFC) interconnect applications. This approach involves the modification of (Mn,Co) 3 O 4 spinel coatings through addition of a RE element to the spinel composition. In particular, Ce-modified spinel coatings (Ce 0.05 Mn 1.475 Co 1.475 O 4 ) behaved similarly to unmodified Mn 1.5 Co 1.5 O 4 spinel coatings by acting as a Cr-outward and O-inward diffusion barrier, thus improving the surface stability and electrical performance of Ferritic Stainless steel. In addition, the RE addition appeared to alter the scale growth behavior beneath the coating, so that alloy samples with the Ce-modified spinel coating exhibited a more adherent scale/metal interface compared to samples with the unmodified spinel coating. As a result, it is anticipated that compared to unmodified spinel coatings, the RE-modified coatings may lead to improved structural stability and electrical performance for Ferritic Stainless steel-based SOFC interconnects.

  • effects of water vapor on oxidation behavior of Ferritic Stainless Steels under solid oxide fuel cell interconnect exposure conditions
    Solid State Ionics, 2005
    Co-Authors: Zhenguo Yang, Prabhakar Singh, Guanguang Xia, Jeffry W Stevenson
    Abstract:

    Abstract The oxidation of Ferritic Stainless Steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e., simultaneous exposure to air on one side of the sample, and fuel (hydrogen) on the other. It was found that, under the dual exposures, the oxidation behavior of the Stainless Steels at the airside differed significantly from that observed during exposure to air at both sides. Increased water vapor partial pressure in the air at the airside further accelerated the anomalous oxidation, resulting in nucleation and growth of hematite in the scale that led to a localized attack. The accelerated oxidation and growth of the hematite nodules was a result of combined effects of hydrogen transport from the fuel side to the airside and the presence of increased water vapor.

  • mn1 5co1 5 o 4 spinel protection layers on Ferritic Stainless Steels for sofc interconnect applications
    Electrochemical and Solid State Letters, 2005
    Co-Authors: Zhenguo Yang, Guanguang Xia, Jeffry W Stevenson
    Abstract:

    In intermediate solid oxide fuel cells, the use of cost effective chromia forming alloy interconnects such as Ferritic Stainless Steels can lead to severe degradation in cell performance due to chromium migration into the cells at the cathode side. To protect cells from chromium poisoning and improve their performance, a Mn1.5Co1.5O4 spinel barrier layer has been developed and tested on the Ferritic Stainless steel Crofer22 APU. Thermal and electrical tests confirmed the effectiveness of the spinel protection layer as a means of stopping chromium migration and decreasing oxidation, while promoting electrical contact and minimizing cathode/interconnect interfacial resistance. The thermally grown spinel protection layer was well-bonded to the Crofer22 APU substrate and demonstrated stable performance under thermal cycling.

  • oxidation behavior of Ferritic Stainless Steels under sofc interconnect exposure conditions
    Journal of The Electrochemical Society, 2004
    Co-Authors: Zhenguo Yang, Matthew S Walker, Prabhakar Singh, Jeffry W Stevenson, Truls Norby
    Abstract:

    The oxidation of Ferritic Stainless Steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e. simultaneous exposure to air on one side of the sample, and moist hydrogen on the other side. This paper focuses on the oxidation behavior of Ferritic Stainless Steels during the isothermal oxidation in the dual environments. It was found that scales grown on the air side under these dual exposure conditions can be significantly different from scales grown on samples exposed to air on both sides. In contrast, no substantial difference was observed between the scales grown on the fuel side of the dual atmosphere samples and scales grown on samples exposed to moist hydrogen on both sides. AISI430, with 17% Cr, suffered localized attack via formation of Fe2O3 hematite-rich nodules on the air side of dual exposure samples, while the spinel top layer of the air side scale of Crofer22 APU (23% Cr) was enriched in iron. For E-brite, with the highest Cr content (27%), no unusual phases were found in the scale on the air side, but it was noticed the air side scale was less dense and appeared to be more prone to defects than the scalemore » grown in air only. The anomalous oxidation behavior of Ferritic Stainless Steels on the air side of dual exposure specimens is related to the transport of hydrogen through the steel and its subsequent presence in the air side scale.« less

Zhenguo Yang - One of the best experts on this subject based on the ideXlab platform.

  • ce modified mn co 3o4 spinel coatings on Ferritic Stainless Steels for sofc interconnect applications
    Electrochemical and Solid State Letters, 2008
    Co-Authors: Zhenguo Yang, Guanguang Xia, Zimin Nie, Joshua D Templeton, Jeffry W Stevenson
    Abstract:

    This paper reports the development of a coating approach that simultaneously achieves the advantages of conductive (Mn,Co) 3 O 4 spinel coatings and of rare earth (RE) surface treatment on Ferritic Stainless Steels for solid oxide fuel cell (SOFC) interconnect applications. This approach involves the modification of (Mn,Co) 3 O 4 spinel coatings through addition of a RE element to the spinel composition. In particular, Ce-modified spinel coatings (Ce 0.05 Mn 1.475 Co 1.475 O 4 ) behaved similarly to unmodified Mn 1.5 Co 1.5 O 4 spinel coatings by acting as a Cr-outward and O-inward diffusion barrier, thus improving the surface stability and electrical performance of Ferritic Stainless steel. In addition, the RE addition appeared to alter the scale growth behavior beneath the coating, so that alloy samples with the Ce-modified spinel coating exhibited a more adherent scale/metal interface compared to samples with the unmodified spinel coating. As a result, it is anticipated that compared to unmodified spinel coatings, the RE-modified coatings may lead to improved structural stability and electrical performance for Ferritic Stainless steel-based SOFC interconnects.

  • effects of water vapor on oxidation behavior of Ferritic Stainless Steels under solid oxide fuel cell interconnect exposure conditions
    Solid State Ionics, 2005
    Co-Authors: Zhenguo Yang, Prabhakar Singh, Guanguang Xia, Jeffry W Stevenson
    Abstract:

    Abstract The oxidation of Ferritic Stainless Steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e., simultaneous exposure to air on one side of the sample, and fuel (hydrogen) on the other. It was found that, under the dual exposures, the oxidation behavior of the Stainless Steels at the airside differed significantly from that observed during exposure to air at both sides. Increased water vapor partial pressure in the air at the airside further accelerated the anomalous oxidation, resulting in nucleation and growth of hematite in the scale that led to a localized attack. The accelerated oxidation and growth of the hematite nodules was a result of combined effects of hydrogen transport from the fuel side to the airside and the presence of increased water vapor.

  • mn1 5co1 5 o 4 spinel protection layers on Ferritic Stainless Steels for sofc interconnect applications
    Electrochemical and Solid State Letters, 2005
    Co-Authors: Zhenguo Yang, Guanguang Xia, Jeffry W Stevenson
    Abstract:

    In intermediate solid oxide fuel cells, the use of cost effective chromia forming alloy interconnects such as Ferritic Stainless Steels can lead to severe degradation in cell performance due to chromium migration into the cells at the cathode side. To protect cells from chromium poisoning and improve their performance, a Mn1.5Co1.5O4 spinel barrier layer has been developed and tested on the Ferritic Stainless steel Crofer22 APU. Thermal and electrical tests confirmed the effectiveness of the spinel protection layer as a means of stopping chromium migration and decreasing oxidation, while promoting electrical contact and minimizing cathode/interconnect interfacial resistance. The thermally grown spinel protection layer was well-bonded to the Crofer22 APU substrate and demonstrated stable performance under thermal cycling.

  • oxidation behavior of Ferritic Stainless Steels under sofc interconnect exposure conditions
    Journal of The Electrochemical Society, 2004
    Co-Authors: Zhenguo Yang, Matthew S Walker, Prabhakar Singh, Jeffry W Stevenson, Truls Norby
    Abstract:

    The oxidation of Ferritic Stainless Steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e. simultaneous exposure to air on one side of the sample, and moist hydrogen on the other side. This paper focuses on the oxidation behavior of Ferritic Stainless Steels during the isothermal oxidation in the dual environments. It was found that scales grown on the air side under these dual exposure conditions can be significantly different from scales grown on samples exposed to air on both sides. In contrast, no substantial difference was observed between the scales grown on the fuel side of the dual atmosphere samples and scales grown on samples exposed to moist hydrogen on both sides. AISI430, with 17% Cr, suffered localized attack via formation of Fe2O3 hematite-rich nodules on the air side of dual exposure samples, while the spinel top layer of the air side scale of Crofer22 APU (23% Cr) was enriched in iron. For E-brite, with the highest Cr content (27%), no unusual phases were found in the scale on the air side, but it was noticed the air side scale was less dense and appeared to be more prone to defects than the scalemore » grown in air only. The anomalous oxidation behavior of Ferritic Stainless Steels on the air side of dual exposure specimens is related to the transport of hydrogen through the steel and its subsequent presence in the air side scale.« less

Douglas G Ivey - One of the best experts on this subject based on the ideXlab platform.

  • The effect of surface treatment on the oxidation of Ferritic Stainless Steels used for solid oxide fuel cell interconnects
    Journal of Power Sources, 2008
    Co-Authors: L Cooper, S. Benhaddad, Anthony Wood, Douglas G Ivey
    Abstract:

    Abstract Ferritic Stainless Steels are candidate interconnect materials for solid oxide fuel cells (SOFC); however, the oxidation resistance of commercial Stainless Steels within the operating temperature range of 700–800 °C is not adequate. A relatively thick, poorly conducting oxide layer forms on the surface of the Stainless steel interconnect, decreasing cell performance. One way of modifying the oxidation behaviour of an alloy is through surface treatment. The aim of this work is to perform a systematic study of the effect of surface treatment (sandblasting and cold rolling) on the oxidation behaviour of three different Ferritic Stainless Steels at 800 °C in air. Oxidized specimens are characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, specimens oxidized under the same conditions for 15 min are examined using secondary ion mass spectrometry (SIMS) depth profiling and X-ray photoelectron spectroscopy (XPS) depth profiling. For all three Steels, the as-is (undeformed) specimens have a lower mass gain than the deformed specimens. The steel with the highest Cr content has significantly higher mass gains than the other two Steels, which have similar mass gains. X-ray diffraction and electron microscopy results indicate that the oxide scale formed on all the specimens consists of an inner layer of chromia and an outer spinel layer. The relative amounts of the two oxide phases present depends on both the steel and treatment condition. The presence of insulating oxides at the metal/oxide interface is detected with both surface science techniques and electron microscopy.

  • yttrium cobalt and yttrium cobalt oxide coatings on Ferritic Stainless Steels for sofc interconnects
    Journal of Power Sources, 2006
    Co-Authors: Li Jian, Douglas G Ivey, Josephine M Hill
    Abstract:

    Abstract Ferritic Stainless Steels are being considered as potential interconnect materials for SOFCs, in part because of their low cost relative to alternatives. These materials are, however, susceptible to degradation over time. A primary source of degradation is an increase in the area specific resistance (ASR), which is due to the formation of poorly conducting oxides (Mn–Cr spinel and Cr 2 O 3 ) on the surface. In this work, the influence of Y, Co and Y/Co oxide coatings on the oxidation behaviour of a Ferritic Stainless steel (16–18 wt% Cr) has been investigated. Samples were oxidized in air for up to 500 h at temperatures ranging from 700 to 800 °C. Coated and uncoated samples were characterized, before and after heat treatment, using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG) analysis and four-point probe resistance measurements. Surface morphology investigations of coated and uncoated Stainless Steels showed differences for Y and Co in terms of oxide formation. In all cases, Cr–Mn spinel and Cr 2 O 3 were the two main surface oxides; however, the morphology of the spinel phase was dependent on the type of coating. The lowest resistances were obtained for the Y/Co-coated samples, which had ASR values up to seven times lower than corresponding uncoated Ferritic Stainless Steels.

Xin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • quantification of texture induced ridging in Ferritic Stainless Steels 430 and 430lr during tensile deformation
    Journal of materials research and technology, 2019
    Co-Authors: Jingwei Zhao, Lai Zhu Jiang, Xin Zhang, Zhengyi Jiang
    Abstract:

    Abstract A comparative study has been carried out to assess the effect of rolling and annealing processes on ridging generation of Ferritic Stainless Steels (FSSs) 430 and 430LR after tensile deformation. The results show that FSS 430LR has better ridging resistance owing to the refinement of microstructure and crystallographic texture optimisation. A 30% reduction of ridging height can be achieved using FSS 430LR compared to FSS 430 after tension. Optimal reduction during cold rolling benefits the microstructural refinement and surface quality improvement of FSSs 430 and 430LR. Both theoretical calculations and experimental results indicate that the {1 1 2} and the {0 0 1} components are responsible for ridging in the FSSs after tension. Through preventing the formation of coarse bands and grains with the {0 0 1} component inside the FSSs, the ridging resistance of both FSSs 430 and 430LR can be improved.

  • texture microstructure and mechanical properties of aluminum modified ultra pure 429 Ferritic Stainless Steels
    Materials & Design, 2016
    Co-Authors: Xin Zhang, Lijun Fan, Xueshan Xiao, Lai Zhu Jiang
    Abstract:

    Abstract Effect of aluminum on texture, microstructure and mechanical properties of ultra-pure 429 Ferritic Stainless Steels has been investigated. Average grain size after annealing slightly increases with increased aluminum content because of the decreased recrystallization temperature and reduced area fraction of inclusions. Recrystallization texture of the surface and center layers evolves from α + γ-fiber to full γ-fiber, and the maximum intensity of γ-fiber increases with addition of 0.16 wt.% aluminum. However, the γ-fiber of {111} shifts to {223} and both the intensity of {111} and {111} decreases when aluminum content is further increased to 1.51 wt.%. The maximum texture intensity of γ-fiber in thickness direction can be significantly improved in steel with 0.16 wt.% aluminum but not in steel with 1.51 wt.% aluminum. Increased aluminum content benefits room temperature tensile properties, and steel with 0.16 wt.% aluminum exhibits plastic strain ratio of about 1.62. The TiN and MgO·Al2O3–TiN particles with a slightly increased average size and decreased area fraction may not suppress the growth of recrystallized grains and contribute to increased intensity of γ-fiber texture. The steel modified with 0.16 wt.% aluminum exhibits excellent formability due to the appearance of the strong γ-fiber texture.

  • improved oxidation resistance of 15 wt cr Ferritic Stainless Steels containing 0 08 2 45 wt al at 1000 c in air
    Corrosion Science, 2015
    Co-Authors: Xin Zhang, Lijun Fan, Xueshan Xiao, Lai Zhu Jiang
    Abstract:

    Abstract Improved oxidation resistance of 15 wt.% Cr Ferritic Stainless Steels at 1000 °C in air has been obtained. Weight gain per unit area is in parabolic relation to oxidation time and parabolic rate constant significantly decreases with increased Al content. Diffusion of Al is enhanced and the porous Cr 2 O 3 rich outer layer is replaced by a more compact Al 2 O 3 rich outer layer in Steels with higher Al contents. The appearance of continuous and compact Al 2 O 3 oxide scale contributes to the significantly improved oxidation resistance property and the oxidation mechanism has been suggested based on microstructural observations.