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Conrath Elodie - One of the best experts on this subject based on the ideXlab platform.
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Oxidation behavior of chromium-rich Fe-based alloys containing HfC carbides at 1100 degrees C
'Wiley', 2015Co-Authors: Conrath Elodie, Berthod PatriceAbstract:International audienceThree HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 27wt% Cr, 0.25 or 0.50wt% C and 4 to 6wt% Hf, are composed of a dendritic matrix and of HfC carbides of two types: pre-eutectic blocky carbides and interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry tests in air at 1100 degrees C for 46 h. The presence of Hafnium led to oxidation kinetics globally parabolic and low mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia. Iron Oxides or (iron, chromium) Oxides were also present. Some particles of Hafnium Oxides were noticed in the subsurface and in the external scales. These particles obviously pegged the external oxide scale on the alloy surface. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. For the alloys in which they were present in the as-cast state, the eutectic chromium carbides played an important role. They dissolved and helped to supply chromium by enriching the interdendritic spaces which act as fast diffusion paths. In the alloy containing 0.50wt% Cr and 4wt% Hf, a parabolic constant of only 2.5 x 10(-10) g(2) x cm(-4) x s(-1) was thus obtained, which is a very low value for 1100 degrees C
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High Temperature Oxidation of HfC-Containing Chromium-Rich Iron-Based Alloys
'Springer Science and Business Media LLC', 2014Co-Authors: Berthod Patrice, Conrath ElodieAbstract:International audienceThree HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 25wt.%Cr, 0.25 or 0.50wt.%C and 3.7 to 5.6wt.%Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1200°C for 46 hours. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to not parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based homologues but worse than their nickel-based homologues, for the same conditions of oxidation test
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High Temperature Oxidation of HfC-Containing Chromium-Rich Iron-Based Alloys
'Springer Science and Business Media LLC', 2014Co-Authors: Berthod Patrice, Conrath ElodieAbstract:International audienceThree HfC-containing iron-based alloys were successfully prepared in the foundry. The alloys, all containing 25 wt% Cr, 0.25 or 0.50 wt% C and 3.7 to 5.6 wt% Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1,200 A degrees C for 46 h. Such exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to non-parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based counterparts, but worse than their nickel-based counterparts, for the same conditions of oxidation test
Berthod Patrice - One of the best experts on this subject based on the ideXlab platform.
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Oxidation behavior of chromium-rich Fe-based alloys containing HfC carbides at 1100 degrees C
'Wiley', 2015Co-Authors: Conrath Elodie, Berthod PatriceAbstract:International audienceThree HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 27wt% Cr, 0.25 or 0.50wt% C and 4 to 6wt% Hf, are composed of a dendritic matrix and of HfC carbides of two types: pre-eutectic blocky carbides and interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry tests in air at 1100 degrees C for 46 h. The presence of Hafnium led to oxidation kinetics globally parabolic and low mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia. Iron Oxides or (iron, chromium) Oxides were also present. Some particles of Hafnium Oxides were noticed in the subsurface and in the external scales. These particles obviously pegged the external oxide scale on the alloy surface. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. For the alloys in which they were present in the as-cast state, the eutectic chromium carbides played an important role. They dissolved and helped to supply chromium by enriching the interdendritic spaces which act as fast diffusion paths. In the alloy containing 0.50wt% Cr and 4wt% Hf, a parabolic constant of only 2.5 x 10(-10) g(2) x cm(-4) x s(-1) was thus obtained, which is a very low value for 1100 degrees C
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High Temperature Oxidation of HfC-Containing Chromium-Rich Iron-Based Alloys
'Springer Science and Business Media LLC', 2014Co-Authors: Berthod Patrice, Conrath ElodieAbstract:International audienceThree HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 25wt.%Cr, 0.25 or 0.50wt.%C and 3.7 to 5.6wt.%Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1200°C for 46 hours. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to not parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based homologues but worse than their nickel-based homologues, for the same conditions of oxidation test
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High Temperature Oxidation of HfC-Containing Chromium-Rich Iron-Based Alloys
'Springer Science and Business Media LLC', 2014Co-Authors: Berthod Patrice, Conrath ElodieAbstract:International audienceThree HfC-containing iron-based alloys were successfully prepared in the foundry. The alloys, all containing 25 wt% Cr, 0.25 or 0.50 wt% C and 3.7 to 5.6 wt% Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1,200 A degrees C for 46 h. Such exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to non-parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based counterparts, but worse than their nickel-based counterparts, for the same conditions of oxidation test
Elodie Conrath - One of the best experts on this subject based on the ideXlab platform.
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oxidation behavior of chromium rich fe based alloys containing hfc carbides at 1100 c
Materials and Corrosion-werkstoffe Und Korrosion, 2015Co-Authors: Elodie Conrath, Patrice BerthodAbstract:Three HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 27wt% Cr, 0.25 or 0.50wt% C and 4 to 6wt% Hf, are composed of a dendritic matrix and of HfC carbides of two types: pre-eutectic blocky carbides and interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry tests in air at 1100 degrees C for 46 h. The presence of Hafnium led to oxidation kinetics globally parabolic and low mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia. Iron Oxides or (iron, chromium) Oxides were also present. Some particles of Hafnium Oxides were noticed in the subsurface and in the external scales. These particles obviously pegged the external oxide scale on the alloy surface. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. For the alloys in which they were present in the as-cast state, the eutectic chromium carbides played an important role. They dissolved and helped to supply chromium by enriching the interdendritic spaces which act as fast diffusion paths. In the alloy containing 0.50wt% Cr and 4wt% Hf, a parabolic constant of only 2.5 x 10(-10) g(2) x cm(-4) x s(-1) was thus obtained, which is a very low value for 1100 degrees C.
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high temperature oxidation of hfc containing chromium rich iron based alloys
Oxidation of Metals, 2014Co-Authors: Patrice Berthod, Elodie ConrathAbstract:Three HfC-containing iron-based alloys were successfully prepared in the foundry. The alloys, all containing 25 wt% Cr, 0.25 or 0.50 wt% C and 3.7 to 5.6 wt% Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1,200 °C for 46 h. Such exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to non-parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples’ surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based counterparts, but worse than their nickel-based counterparts, for the same conditions of oxidation test.
Patrice Berthod - One of the best experts on this subject based on the ideXlab platform.
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oxidation behavior of chromium rich fe based alloys containing hfc carbides at 1100 c
Materials and Corrosion-werkstoffe Und Korrosion, 2015Co-Authors: Elodie Conrath, Patrice BerthodAbstract:Three HfC-containing iron-based alloys were successfully elaborated by foundry. The alloys, all containing 27wt% Cr, 0.25 or 0.50wt% C and 4 to 6wt% Hf, are composed of a dendritic matrix and of HfC carbides of two types: pre-eutectic blocky carbides and interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry tests in air at 1100 degrees C for 46 h. The presence of Hafnium led to oxidation kinetics globally parabolic and low mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples' surfaces were never composed exclusively of chromia. Iron Oxides or (iron, chromium) Oxides were also present. Some particles of Hafnium Oxides were noticed in the subsurface and in the external scales. These particles obviously pegged the external oxide scale on the alloy surface. The long exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. For the alloys in which they were present in the as-cast state, the eutectic chromium carbides played an important role. They dissolved and helped to supply chromium by enriching the interdendritic spaces which act as fast diffusion paths. In the alloy containing 0.50wt% Cr and 4wt% Hf, a parabolic constant of only 2.5 x 10(-10) g(2) x cm(-4) x s(-1) was thus obtained, which is a very low value for 1100 degrees C.
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high temperature oxidation of hfc containing chromium rich iron based alloys
Oxidation of Metals, 2014Co-Authors: Patrice Berthod, Elodie ConrathAbstract:Three HfC-containing iron-based alloys were successfully prepared in the foundry. The alloys, all containing 25 wt% Cr, 0.25 or 0.50 wt% C and 3.7 to 5.6 wt% Hf, are characterized by a dendritic matrix and the presence of interdendritic script-like HfC carbides. These alloys were subjected to thermogravimetry test in air at 1,200 °C for 46 h. Such exposure at this high temperature did not significantly modify the characteristics of the bulk HfC carbides. In contrast the presence of Hafnium led to non-parabolic oxidation kinetics and fast mass gain rates, by comparison with similar Hf-free ternary alloys. The scales formed all over the samples’ surfaces were never composed exclusively of chromia and iron Oxides or (iron, chromium) Oxides were present in significant quantities. Some particles of Hafnium Oxides were also present in the external scales. A subsurface zone in which the HfC carbides were in situ replaced by Hafnium Oxides developed from the oxidation front. Catastrophic oxidation started in several locations and threatened to expand all around the samples beyond the stage duration. The high temperature oxidation behavior of these HfC-containing iron-based alloys appeared better than their cobalt-based counterparts, but worse than their nickel-based counterparts, for the same conditions of oxidation test.
Josep Fontcuberta - One of the best experts on this subject based on the ideXlab platform.
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Polarization and Resistive Switching in Epitaxial 2 nm Hf0.5Zr0.5O2 Tunnel Junctions
'American Chemical Society (ACS)', 2021Co-Authors: Milena Cervo Sulzbach, Huan Tan, Saúl Estandía, Jaume Gàzquez, Florencio Sánchez, Ignasi Fina, Josep FontcubertaAbstract:In the quest for reliable and power-efficient memristive devices, ferroelectric tunnel junctions are being investigated as potential candidates. Complementary metal oxide semiconductor-compatible ferroelectric Hafnium Oxides are at the forefront. However, in epitaxial tunnel devices with thicknesses around ≈4–6 nm, the relatively high tunnel energy barrier produces a large resistance that challenges their implementation. Here, we show that ferroelectric and electroresistive switching can be observed in ultrathin 2 nm epitaxial Hf0.5Zr0.5O2 (HZO) tunnel junctions in large area capacitors (≈300 μm2). We observe that the resistance area product is reduced to about 160 and 65 Ω·cm2 for OFF and ON resistance states, respectively. These values are 2 orders of magnitude smaller than those obtained in equivalent 5 nm HZO tunnel devices while preserving a similar OFF/ON resistance ratio (210%). The devices show memristive and spike-timing-dependent plasticity behavior and good retention. Electroresistance and ferroelectric loops closely coincide, signaling ferroelectric switching as a driving mechanism for resistance change
