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Daniel Gajda - One of the best experts on this subject based on the ideXlab platform.
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the influence of high Isostatic Pressure on critical current density in c doped mgb 2 wires
Journal of Superconductivity and Novel Magnetism, 2019Co-Authors: D Majchrzak, A Morawski, A J Zaleski, Malgorzata A Malecka, M Rindfleisch, Daniel GajdaAbstract:This article reports the influence of Isostatic Pressure (from 0.1 MPa to 1.1 GPa), low annealing temperature of 570 ∘C, and annealing time for the formation of high-field pinning centers in 2% C-doped MgB2 wires. Measurements indicate that 1.1 GPa Pressure significantly increases the density of high-field pinning centers below 20 K. However, lower Pressure (0.6 GPa) slightly increases the density of high-field pinning centers. Increasing the annealing time from 120 to 210 min leads to a reduction of critical temperature (Tc), irreversibility field (Birr), critical current density (Jc), and upper critical field (Bc2), suggesting that a long annealing time leads to a reduction of high-field pinning center density and the number of connections between superconducting grains. The high Pressures and low annealing temperature lead to a high critical current density of 1000 A/mm2 in 7.2 T and 100 A/mm2 in 12.5 T at 4.2 K in MgB2 wires.
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influence of the lamella structure and high Isostatic Pressure on the critical current density in in situ mgb2 wires without a barrier
Journal of Alloys and Compounds, 2019Co-Authors: Z Mroczek, A Morawski, Tomasz Czujko, F Karaboga, Mustafa Akdogan, A J Zaleski, Malgorzata A Malecka, T Cetner, H Yetis, Daniel GajdaAbstract:Abstract In this article, the significant impact of a lamellar (layered) structure and a high Isostatic Pressure on the normal state resistance (Rn), critical temperature (Tc), irreversible magnetic field (Birr), upper magnetic field (Bc2) and critical current densities (Jc) at 4.2 K and 20 K was presented. Our research showed that annealing at temperatures in the range of 630 °C–680 °C (above the melting point of Mg) at atmospheric Pressure (0.1 MPa) did not create a lamellar (layered) structure. This led to low Tc, Jc and Birr and high Rn. The analysis, made by using scanning electron microscopy (SEM), showed that the annealing temperature increased up to 700 °C under a Pressure of 0.1 MPa, which created a lamellar structure. This led to significant growth of Tc, Jc and Birr and a slight increase of Rn. Moreover, the measurements showed that annealing at temperatures from 630 °C to 700 °C did not change the Bc2 value. In comparison to Pressureless heat treatment, annealing under the high Isostatic Pressure of 1.1 GPa obtained a lamellar structure with layers of lower thickness and higher density. This led to significant increases in Jc and Birr and a visible reduction of Rn. SEM analysis showed that the increase of Isostatic Pressure up to 0.3 GPa created a lamellar structure with thicker layers and lower density. This microstructure led to lower Jc and Birr and significantly higher Rn. On the other hand, the SEM analysis showed that annealing under 0.8 GPa did not cause the formation of a layered structure, and as a result, it led to significant reductions in Birr and Jc (4.2 K and 20 K) and higher Rn. The increase of the Isostatic Pressure from 0.1 MPa to 1.1 GPa did not affect Tc (B = 0 T) and Bc2. The results indicated that the layered structure obtained a high density of pinning centers, which were particularly effective at higher magnetic fields. Jc of 100 A/mm2 in 8 T at 4.2 K was obtained in in situ undoped MgB2 wires after annealing at 700 °C for 40 min under an Isostatic Pressure of 1.1 GPa.
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The Impact of High Pressure, Doping and the Size of Crystalline Boron Grains on Creation of High-Field Pinning Centers in In Situ MgB2 Wires
Journal of Superconductivity and Novel Magnetism, 2018Co-Authors: D Majchrzak, A J Zaleski, Andrzej Morawski, Małgorzata A. Małecka, M A Rindfleisch, Daniel GajdaAbstract:In this work, we investigated the influence of Isostatic Pressure (of 0.1 MPa and 1.1 GPa) during heat treatment, doping, size and shape of crystalline boron grains, and annealing time at low annealing temperature (570 °C) on the formation of high-field pinning centers in MgB2 wires. The results indicate that high Isostatic Pressure (1.1 GPa) at low annealing temperature (570 ° C) and annealing time of 120 min significantly increases the density of high-field pinning centers in MgB2 wires with small and large boron grains. Transport measurements show that an increase of annealing time from 120 to 210 min at 1.1 GPa slightly decreases the critical current density (Jc) and irreversibility field (Birr) in MgB2 wires with large boron grains, suggesting that longer annealing time weakly affects the density of high-field pinning centers. On the other hand, for MgB2 wires with small boron grains, the annealing time of 210 min significantly reduces $J_{\mathrm {c}}$ and $B_{\text {irr}}$ . This indicates that the longer annealing time at 1.1 GPa significantly reduces the density of high-field pinning centers. Our studies indicate that dislocations created by the hot Isostatic Pressure process significantly increase $B_{\text {irr}}$ in the temperature range from 5 to 12 K. On the other hand, strains due to the shrinkage of MgB2 material increase $B_{\text {irr}}$ in the temperature range from 12 to 34 K. The results show that small grains of crystalline boron and high Isostatic Pressure lead to a high density of dislocations and strains during transformation to the MgB2 phase.
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enhancement of pinning centers density and structure by using hot Isostatic Pressure of 1 2 gpa in ba fe0 92 co0 08 2as2 superconducting material
Journal of Alloys and Compounds, 2017Co-Authors: Daniel Gajda, A Morawski, A J Zaleski, Malgorzata A Malecka, T Cetner, K RogackiAbstract:Abstract We report the influences of the high hot Isostatic Pressure (HHIP) on Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 superconducting bulks materials. Magnetic measurements showed that this material has a critical temperature ( T c ) of 26 K. The HHIP process increases the density of flux pinning centers without altering the dominant flux pinning mechanisms and without decreasing of T c . Structural studies have shown that the HHIP process increases the density of the material, reduces the size of voids, and thus allows to obtain homogeneous distribution of the components. Additionally, the HHIP process removes cracks in polycrystalline Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 , creates more superconducting phase and forms less amount of Ba precipitates.
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formation of high field pinning centers in superconducting mgb2 wires by using high hot Isostatic Pressure process
Journal of Superconductivity and Novel Magnetism, 2017Co-Authors: Daniel Gajda, A Morawski, F Karaboga, Mustafa Akdogan, A J Zaleski, T Cetner, H Yetis, I BelenliAbstract:This paper demonstrates the effects of hot Isostatic Pressure (HIP) on the structure and transport critical parameters of in situ MgB2 wires without a barrier. Our results show that only HIP and nano-boron allow the formation of more high-field pinning centers, which lead to the increase in critical current density (J c) at high applied magnetic fields. Nano-boron and annealing at a low Pressure increase the J c in the low magnetic field. This indicates that nano-particles create more high-field pinning centers. In addition, the results show that nano-boron improves the connection between the grains. Scanning electron microscope results show that HIP increases the reaction rate between Mg and B, density, and homogeneity of the MgB2 material. Additionally, HIP allows to create a structure with small grains and voids and eliminates the significance of the number of voids. High Isostatic Pressure allows to obtain high J c of 10 A/mm2 (at 4.2 K) in 10 T and increases irreversible magnetic field (B irr) and upper critical field (B c2). Measurements show that these wires have high critical temperature of 37 K.
T Cetner - One of the best experts on this subject based on the ideXlab platform.
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influence of the lamella structure and high Isostatic Pressure on the critical current density in in situ mgb2 wires without a barrier
Journal of Alloys and Compounds, 2019Co-Authors: Z Mroczek, A Morawski, Tomasz Czujko, F Karaboga, Mustafa Akdogan, A J Zaleski, Malgorzata A Malecka, T Cetner, H Yetis, Daniel GajdaAbstract:Abstract In this article, the significant impact of a lamellar (layered) structure and a high Isostatic Pressure on the normal state resistance (Rn), critical temperature (Tc), irreversible magnetic field (Birr), upper magnetic field (Bc2) and critical current densities (Jc) at 4.2 K and 20 K was presented. Our research showed that annealing at temperatures in the range of 630 °C–680 °C (above the melting point of Mg) at atmospheric Pressure (0.1 MPa) did not create a lamellar (layered) structure. This led to low Tc, Jc and Birr and high Rn. The analysis, made by using scanning electron microscopy (SEM), showed that the annealing temperature increased up to 700 °C under a Pressure of 0.1 MPa, which created a lamellar structure. This led to significant growth of Tc, Jc and Birr and a slight increase of Rn. Moreover, the measurements showed that annealing at temperatures from 630 °C to 700 °C did not change the Bc2 value. In comparison to Pressureless heat treatment, annealing under the high Isostatic Pressure of 1.1 GPa obtained a lamellar structure with layers of lower thickness and higher density. This led to significant increases in Jc and Birr and a visible reduction of Rn. SEM analysis showed that the increase of Isostatic Pressure up to 0.3 GPa created a lamellar structure with thicker layers and lower density. This microstructure led to lower Jc and Birr and significantly higher Rn. On the other hand, the SEM analysis showed that annealing under 0.8 GPa did not cause the formation of a layered structure, and as a result, it led to significant reductions in Birr and Jc (4.2 K and 20 K) and higher Rn. The increase of the Isostatic Pressure from 0.1 MPa to 1.1 GPa did not affect Tc (B = 0 T) and Bc2. The results indicated that the layered structure obtained a high density of pinning centers, which were particularly effective at higher magnetic fields. Jc of 100 A/mm2 in 8 T at 4.2 K was obtained in in situ undoped MgB2 wires after annealing at 700 °C for 40 min under an Isostatic Pressure of 1.1 GPa.
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enhancement of pinning centers density and structure by using hot Isostatic Pressure of 1 2 gpa in ba fe0 92 co0 08 2as2 superconducting material
Journal of Alloys and Compounds, 2017Co-Authors: Daniel Gajda, A Morawski, A J Zaleski, Malgorzata A Malecka, T Cetner, K RogackiAbstract:Abstract We report the influences of the high hot Isostatic Pressure (HHIP) on Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 superconducting bulks materials. Magnetic measurements showed that this material has a critical temperature ( T c ) of 26 K. The HHIP process increases the density of flux pinning centers without altering the dominant flux pinning mechanisms and without decreasing of T c . Structural studies have shown that the HHIP process increases the density of the material, reduces the size of voids, and thus allows to obtain homogeneous distribution of the components. Additionally, the HHIP process removes cracks in polycrystalline Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 , creates more superconducting phase and forms less amount of Ba precipitates.
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formation of high field pinning centers in superconducting mgb2 wires by using high hot Isostatic Pressure process
Journal of Superconductivity and Novel Magnetism, 2017Co-Authors: Daniel Gajda, A Morawski, F Karaboga, Mustafa Akdogan, A J Zaleski, T Cetner, H Yetis, I BelenliAbstract:This paper demonstrates the effects of hot Isostatic Pressure (HIP) on the structure and transport critical parameters of in situ MgB2 wires without a barrier. Our results show that only HIP and nano-boron allow the formation of more high-field pinning centers, which lead to the increase in critical current density (J c) at high applied magnetic fields. Nano-boron and annealing at a low Pressure increase the J c in the low magnetic field. This indicates that nano-particles create more high-field pinning centers. In addition, the results show that nano-boron improves the connection between the grains. Scanning electron microscope results show that HIP increases the reaction rate between Mg and B, density, and homogeneity of the MgB2 material. Additionally, HIP allows to create a structure with small grains and voids and eliminates the significance of the number of voids. High Isostatic Pressure allows to obtain high J c of 10 A/mm2 (at 4.2 K) in 10 T and increases irreversible magnetic field (B irr) and upper critical field (B c2). Measurements show that these wires have high critical temperature of 37 K.
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The influence of HIP process on critical parameters of MgB2/Fe wires with big boron grains and without barriers
Journal of Alloys and Compounds, 2016Co-Authors: Daniel Gajda, F Karaboga, Mustafa Akdogan, A J Zaleski, T Cetner, H Yetis, Andrzej Morawski, Ibrahim BelenliAbstract:Abstract We show transport results of the critical temperature (Tc), irreversible magnetic field (Birr), upper critical field (Bc2), critical current density (Jc) and the pinning force (Fp) for undoped MgB2 wires without barriers. The results of SEM show that the hot Isostatic Pressure process increases the density and uniformity of MgB2 materials. Hot Isostatic Pressure allows for obtaining small grains and increasing the number of connections between the grains, accelerated reaction rate and limits the diffusion of Fe atoms into MgB2 material from the adjacent sheath. The Pressure of 1.1 GPa increases Tc quite significantly in high magnetic field range of 6–12 T, improves the Birr and Bc2 and increase the Jc at 4.2 K and 20 K of about three times. Our results may be important for this field since many MgB2 wires are made from big grains of boron greater than 1 μm. Moreover, our research can be important for the production of MgB2 wires for the International Thermonuclear Experimental Reactor with boron 11B.
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Point pinning centers in SiC doped MgB2 wires after HIP
Superconductor Science and Technology, 2016Co-Authors: D. Gajda, A J Zaleski, T Cetner, Andrzej Morawski, C J Thong, M A RindfleischAbstract:In this study we show that dominant point pinning mechanisms in SiC doped MgB2 wires can be obtained by annealing in high Isostatic Pressure. The results indicate that the point pinning centers increase the critical current density in medium and high magnetic fields, but not at low magnetic fields. In addition, our study shows that dominant pinning mechanism changes from point to surface type with increase of magnetic fields. An MgB2 wire heat treated in a high Pressure of 1.4 GPa shows a high critical current density of 100 A mm−2 in 13 T at 4.2 K. Scanning electron microscope studies show that high Isostatic Pressure increases the density of the MgB2 material, eliminates voids, allows for small Si precipitates and homogeneous distribution of Si precipitates. Transport measurements E - B and E - I show that the MgB2 wires manufactured by Hyper Tech Research did not heat up after transition into a normal state. This is important for applications in coils.
A J Zaleski - One of the best experts on this subject based on the ideXlab platform.
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the influence of high Isostatic Pressure on critical current density in c doped mgb 2 wires
Journal of Superconductivity and Novel Magnetism, 2019Co-Authors: D Majchrzak, A Morawski, A J Zaleski, Malgorzata A Malecka, M Rindfleisch, Daniel GajdaAbstract:This article reports the influence of Isostatic Pressure (from 0.1 MPa to 1.1 GPa), low annealing temperature of 570 ∘C, and annealing time for the formation of high-field pinning centers in 2% C-doped MgB2 wires. Measurements indicate that 1.1 GPa Pressure significantly increases the density of high-field pinning centers below 20 K. However, lower Pressure (0.6 GPa) slightly increases the density of high-field pinning centers. Increasing the annealing time from 120 to 210 min leads to a reduction of critical temperature (Tc), irreversibility field (Birr), critical current density (Jc), and upper critical field (Bc2), suggesting that a long annealing time leads to a reduction of high-field pinning center density and the number of connections between superconducting grains. The high Pressures and low annealing temperature lead to a high critical current density of 1000 A/mm2 in 7.2 T and 100 A/mm2 in 12.5 T at 4.2 K in MgB2 wires.
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influence of the lamella structure and high Isostatic Pressure on the critical current density in in situ mgb2 wires without a barrier
Journal of Alloys and Compounds, 2019Co-Authors: Z Mroczek, A Morawski, Tomasz Czujko, F Karaboga, Mustafa Akdogan, A J Zaleski, Malgorzata A Malecka, T Cetner, H Yetis, Daniel GajdaAbstract:Abstract In this article, the significant impact of a lamellar (layered) structure and a high Isostatic Pressure on the normal state resistance (Rn), critical temperature (Tc), irreversible magnetic field (Birr), upper magnetic field (Bc2) and critical current densities (Jc) at 4.2 K and 20 K was presented. Our research showed that annealing at temperatures in the range of 630 °C–680 °C (above the melting point of Mg) at atmospheric Pressure (0.1 MPa) did not create a lamellar (layered) structure. This led to low Tc, Jc and Birr and high Rn. The analysis, made by using scanning electron microscopy (SEM), showed that the annealing temperature increased up to 700 °C under a Pressure of 0.1 MPa, which created a lamellar structure. This led to significant growth of Tc, Jc and Birr and a slight increase of Rn. Moreover, the measurements showed that annealing at temperatures from 630 °C to 700 °C did not change the Bc2 value. In comparison to Pressureless heat treatment, annealing under the high Isostatic Pressure of 1.1 GPa obtained a lamellar structure with layers of lower thickness and higher density. This led to significant increases in Jc and Birr and a visible reduction of Rn. SEM analysis showed that the increase of Isostatic Pressure up to 0.3 GPa created a lamellar structure with thicker layers and lower density. This microstructure led to lower Jc and Birr and significantly higher Rn. On the other hand, the SEM analysis showed that annealing under 0.8 GPa did not cause the formation of a layered structure, and as a result, it led to significant reductions in Birr and Jc (4.2 K and 20 K) and higher Rn. The increase of the Isostatic Pressure from 0.1 MPa to 1.1 GPa did not affect Tc (B = 0 T) and Bc2. The results indicated that the layered structure obtained a high density of pinning centers, which were particularly effective at higher magnetic fields. Jc of 100 A/mm2 in 8 T at 4.2 K was obtained in in situ undoped MgB2 wires after annealing at 700 °C for 40 min under an Isostatic Pressure of 1.1 GPa.
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The Impact of High Pressure, Doping and the Size of Crystalline Boron Grains on Creation of High-Field Pinning Centers in In Situ MgB2 Wires
Journal of Superconductivity and Novel Magnetism, 2018Co-Authors: D Majchrzak, A J Zaleski, Andrzej Morawski, Małgorzata A. Małecka, M A Rindfleisch, Daniel GajdaAbstract:In this work, we investigated the influence of Isostatic Pressure (of 0.1 MPa and 1.1 GPa) during heat treatment, doping, size and shape of crystalline boron grains, and annealing time at low annealing temperature (570 °C) on the formation of high-field pinning centers in MgB2 wires. The results indicate that high Isostatic Pressure (1.1 GPa) at low annealing temperature (570 ° C) and annealing time of 120 min significantly increases the density of high-field pinning centers in MgB2 wires with small and large boron grains. Transport measurements show that an increase of annealing time from 120 to 210 min at 1.1 GPa slightly decreases the critical current density (Jc) and irreversibility field (Birr) in MgB2 wires with large boron grains, suggesting that longer annealing time weakly affects the density of high-field pinning centers. On the other hand, for MgB2 wires with small boron grains, the annealing time of 210 min significantly reduces $J_{\mathrm {c}}$ and $B_{\text {irr}}$ . This indicates that the longer annealing time at 1.1 GPa significantly reduces the density of high-field pinning centers. Our studies indicate that dislocations created by the hot Isostatic Pressure process significantly increase $B_{\text {irr}}$ in the temperature range from 5 to 12 K. On the other hand, strains due to the shrinkage of MgB2 material increase $B_{\text {irr}}$ in the temperature range from 12 to 34 K. The results show that small grains of crystalline boron and high Isostatic Pressure lead to a high density of dislocations and strains during transformation to the MgB2 phase.
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enhancement of pinning centers density and structure by using hot Isostatic Pressure of 1 2 gpa in ba fe0 92 co0 08 2as2 superconducting material
Journal of Alloys and Compounds, 2017Co-Authors: Daniel Gajda, A Morawski, A J Zaleski, Malgorzata A Malecka, T Cetner, K RogackiAbstract:Abstract We report the influences of the high hot Isostatic Pressure (HHIP) on Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 superconducting bulks materials. Magnetic measurements showed that this material has a critical temperature ( T c ) of 26 K. The HHIP process increases the density of flux pinning centers without altering the dominant flux pinning mechanisms and without decreasing of T c . Structural studies have shown that the HHIP process increases the density of the material, reduces the size of voids, and thus allows to obtain homogeneous distribution of the components. Additionally, the HHIP process removes cracks in polycrystalline Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 , creates more superconducting phase and forms less amount of Ba precipitates.
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formation of high field pinning centers in superconducting mgb2 wires by using high hot Isostatic Pressure process
Journal of Superconductivity and Novel Magnetism, 2017Co-Authors: Daniel Gajda, A Morawski, F Karaboga, Mustafa Akdogan, A J Zaleski, T Cetner, H Yetis, I BelenliAbstract:This paper demonstrates the effects of hot Isostatic Pressure (HIP) on the structure and transport critical parameters of in situ MgB2 wires without a barrier. Our results show that only HIP and nano-boron allow the formation of more high-field pinning centers, which lead to the increase in critical current density (J c) at high applied magnetic fields. Nano-boron and annealing at a low Pressure increase the J c in the low magnetic field. This indicates that nano-particles create more high-field pinning centers. In addition, the results show that nano-boron improves the connection between the grains. Scanning electron microscope results show that HIP increases the reaction rate between Mg and B, density, and homogeneity of the MgB2 material. Additionally, HIP allows to create a structure with small grains and voids and eliminates the significance of the number of voids. High Isostatic Pressure allows to obtain high J c of 10 A/mm2 (at 4.2 K) in 10 T and increases irreversible magnetic field (B irr) and upper critical field (B c2). Measurements show that these wires have high critical temperature of 37 K.
A Morawski - One of the best experts on this subject based on the ideXlab platform.
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the influence of high Isostatic Pressure on critical current density in c doped mgb 2 wires
Journal of Superconductivity and Novel Magnetism, 2019Co-Authors: D Majchrzak, A Morawski, A J Zaleski, Malgorzata A Malecka, M Rindfleisch, Daniel GajdaAbstract:This article reports the influence of Isostatic Pressure (from 0.1 MPa to 1.1 GPa), low annealing temperature of 570 ∘C, and annealing time for the formation of high-field pinning centers in 2% C-doped MgB2 wires. Measurements indicate that 1.1 GPa Pressure significantly increases the density of high-field pinning centers below 20 K. However, lower Pressure (0.6 GPa) slightly increases the density of high-field pinning centers. Increasing the annealing time from 120 to 210 min leads to a reduction of critical temperature (Tc), irreversibility field (Birr), critical current density (Jc), and upper critical field (Bc2), suggesting that a long annealing time leads to a reduction of high-field pinning center density and the number of connections between superconducting grains. The high Pressures and low annealing temperature lead to a high critical current density of 1000 A/mm2 in 7.2 T and 100 A/mm2 in 12.5 T at 4.2 K in MgB2 wires.
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influence of the lamella structure and high Isostatic Pressure on the critical current density in in situ mgb2 wires without a barrier
Journal of Alloys and Compounds, 2019Co-Authors: Z Mroczek, A Morawski, Tomasz Czujko, F Karaboga, Mustafa Akdogan, A J Zaleski, Malgorzata A Malecka, T Cetner, H Yetis, Daniel GajdaAbstract:Abstract In this article, the significant impact of a lamellar (layered) structure and a high Isostatic Pressure on the normal state resistance (Rn), critical temperature (Tc), irreversible magnetic field (Birr), upper magnetic field (Bc2) and critical current densities (Jc) at 4.2 K and 20 K was presented. Our research showed that annealing at temperatures in the range of 630 °C–680 °C (above the melting point of Mg) at atmospheric Pressure (0.1 MPa) did not create a lamellar (layered) structure. This led to low Tc, Jc and Birr and high Rn. The analysis, made by using scanning electron microscopy (SEM), showed that the annealing temperature increased up to 700 °C under a Pressure of 0.1 MPa, which created a lamellar structure. This led to significant growth of Tc, Jc and Birr and a slight increase of Rn. Moreover, the measurements showed that annealing at temperatures from 630 °C to 700 °C did not change the Bc2 value. In comparison to Pressureless heat treatment, annealing under the high Isostatic Pressure of 1.1 GPa obtained a lamellar structure with layers of lower thickness and higher density. This led to significant increases in Jc and Birr and a visible reduction of Rn. SEM analysis showed that the increase of Isostatic Pressure up to 0.3 GPa created a lamellar structure with thicker layers and lower density. This microstructure led to lower Jc and Birr and significantly higher Rn. On the other hand, the SEM analysis showed that annealing under 0.8 GPa did not cause the formation of a layered structure, and as a result, it led to significant reductions in Birr and Jc (4.2 K and 20 K) and higher Rn. The increase of the Isostatic Pressure from 0.1 MPa to 1.1 GPa did not affect Tc (B = 0 T) and Bc2. The results indicated that the layered structure obtained a high density of pinning centers, which were particularly effective at higher magnetic fields. Jc of 100 A/mm2 in 8 T at 4.2 K was obtained in in situ undoped MgB2 wires after annealing at 700 °C for 40 min under an Isostatic Pressure of 1.1 GPa.
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enhancement of pinning centers density and structure by using hot Isostatic Pressure of 1 2 gpa in ba fe0 92 co0 08 2as2 superconducting material
Journal of Alloys and Compounds, 2017Co-Authors: Daniel Gajda, A Morawski, A J Zaleski, Malgorzata A Malecka, T Cetner, K RogackiAbstract:Abstract We report the influences of the high hot Isostatic Pressure (HHIP) on Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 superconducting bulks materials. Magnetic measurements showed that this material has a critical temperature ( T c ) of 26 K. The HHIP process increases the density of flux pinning centers without altering the dominant flux pinning mechanisms and without decreasing of T c . Structural studies have shown that the HHIP process increases the density of the material, reduces the size of voids, and thus allows to obtain homogeneous distribution of the components. Additionally, the HHIP process removes cracks in polycrystalline Ba(Fe 0.92 ,Co 0.08 ) 2 As 2 , creates more superconducting phase and forms less amount of Ba precipitates.
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formation of high field pinning centers in superconducting mgb2 wires by using high hot Isostatic Pressure process
Journal of Superconductivity and Novel Magnetism, 2017Co-Authors: Daniel Gajda, A Morawski, F Karaboga, Mustafa Akdogan, A J Zaleski, T Cetner, H Yetis, I BelenliAbstract:This paper demonstrates the effects of hot Isostatic Pressure (HIP) on the structure and transport critical parameters of in situ MgB2 wires without a barrier. Our results show that only HIP and nano-boron allow the formation of more high-field pinning centers, which lead to the increase in critical current density (J c) at high applied magnetic fields. Nano-boron and annealing at a low Pressure increase the J c in the low magnetic field. This indicates that nano-particles create more high-field pinning centers. In addition, the results show that nano-boron improves the connection between the grains. Scanning electron microscope results show that HIP increases the reaction rate between Mg and B, density, and homogeneity of the MgB2 material. Additionally, HIP allows to create a structure with small grains and voids and eliminates the significance of the number of voids. High Isostatic Pressure allows to obtain high J c of 10 A/mm2 (at 4.2 K) in 10 T and increases irreversible magnetic field (B irr) and upper critical field (B c2). Measurements show that these wires have high critical temperature of 37 K.
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the critical parameters in in situ mgb2 wires and tapes with ex situ mgb2 barrier after hot Isostatic Pressure cold drawing cold rolling and doping
Journal of Applied Physics, 2015Co-Authors: Daniel Gajda, A Morawski, Tomasz Czujko, A J Zaleski, W Hasler, K Nenkov, M Rindfleisch, E żuchowska, G Gajda, T CetnerAbstract:MgB2 precursor wires were prepared using powder in tube technique by Institute of High Pressure PAS in Warsaw. All samples were annealed under Isostatic Pressure generated by liquid Argon in the range from 0.3 GPa to 1 GPa. In this paper, we show the effects of different processing routes, namely, cold drawing (CD), cold rolling (CR), hot Isostatic Pressure (HIP) and doping on critical current density (Jc), pinning force (Fp), irreversible magnetic-field (Birr), critical temperature (Tc), n value, and dominant pinning mechanism in MgB2/Fe wires with ex situ MgB2 barrier. The results show that medium Pressures (∼0.35 GPa) lead to high Jc in low and medium magnetic fields (0 T – 9 T). On the other hand, higher Pressures (∼1 GPa) lead to enhanced Jc in high magnetic fields (above 9 T). Transport measurements show that CD, CR, and HIP have small effects on Birr and Tc, but CD, CR, HIP, and doping enhance Jc and Fp in in situ MgB2 wires with ex situ MgB2 barrier. Transport measurements on in situ undoped MgB2 ...
One Young Oh - One of the best experts on this subject based on the ideXlab platform.
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effect of high Pressure on the solid liquid phase change of a nickel base superalloy during hot Isostatic pressing
Journal of Alloys and Compounds, 2009Co-Authors: One Young OhAbstract:Abstract Effects of high Pressure during a hot Isostatic pressing (HIPing) on the solid–liquid phase change and the microstructure of a directionally solidified (DS) nickel base superalloy were studied. This alloy was treated under various HIP cycles at temperatures of 1330 or 1340 °C, higher than the liquidus of the alloy. The evolution of the microstructure, composition, crystallographic orientation of the texture and the hardness of the alloy was analyzed for the evaluation of the high Isostatic Pressure effect. The microstructural analysis revealed that high Pressure around 120 MPa has a great influence not only on the metallography but also on the crystallography of the alloy at the processing temperature. The DS grain structure was preserved for some HIPed specimens, suggesting an increase in the melting temperature of the alloy at least by 10 K at 120 MPa. All the findings of this work were elucidated in terms of the change in the Gibbs free energy due to volume changes upon solid–solid and liquid–solid phase transformation and of the migration of constituent elements to mitigate the Gibbs free energy under a high Isostatic Pressure condition.
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Effect of high Pressure on the solid–liquid phase change of a nickel base superalloy during hot Isostatic pressing
Journal of Alloys and Compounds, 2009Co-Authors: One Young OhAbstract:Abstract Effects of high Pressure during a hot Isostatic pressing (HIPing) on the solid–liquid phase change and the microstructure of a directionally solidified (DS) nickel base superalloy were studied. This alloy was treated under various HIP cycles at temperatures of 1330 or 1340 °C, higher than the liquidus of the alloy. The evolution of the microstructure, composition, crystallographic orientation of the texture and the hardness of the alloy was analyzed for the evaluation of the high Isostatic Pressure effect. The microstructural analysis revealed that high Pressure around 120 MPa has a great influence not only on the metallography but also on the crystallography of the alloy at the processing temperature. The DS grain structure was preserved for some HIPed specimens, suggesting an increase in the melting temperature of the alloy at least by 10 K at 120 MPa. All the findings of this work were elucidated in terms of the change in the Gibbs free energy due to volume changes upon solid–solid and liquid–solid phase transformation and of the migration of constituent elements to mitigate the Gibbs free energy under a high Isostatic Pressure condition.