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Patricia De Rango - One of the best experts on this subject based on the ideXlab platform.
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structural studies of Laves Phases zr cr1 xnix 2 with 0 x 0 4 and their hydrides
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Daniel Fruchart, Patricia De RangoAbstract:Abstract Hexagonal C14-type Laves Phases of the series Zr(Cr 1− x Ni x ) 2 with 0≤ x ≤0.4 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analyzed the structure of the alloys, and determined the sites for the Ni substitution. The positions of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of the Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Pressure-composition measurements and microstructural analysis of the Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Patricia De Rango, Daniel Fruchart, Jean-louis SoubeyrouxAbstract:The Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni have been synthesised in the hexagonal C14 type structure. Hydrogen absorption-desorption isotherms have been determined by pressure-composition isotherms (P-C-T) within the temperature range 298-423 K. We have observed that for more than 50% of chromium substitution, the compounds always have a relatively high capacity (H/M>1). Moreover, some isothermal curves reveal the existence of a sloping plateau. To understand the origin of this plateau, the phase composition and purity of polycrystalline alloys have been checked using SEM and EDX techniques.
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Structural studies of Laves Phases Zr(Cr1-xNix)2 with 0
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Patricia De Rango, Daniel FruchartAbstract:Hexagonal C14 Laves Phases of the series Zr(Cr1-xNix)2 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analysed the structure of the alloys and determined the sites for the Ni substitution. The position of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Phase stability and neutron diffraction studies of Laves Phases Zr(Cr(1-x)M(x))(2) with M=(Cu0.5Ni0.5) and 0
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Laves Phases of composition Zr(Cr(1-x)M(x))(2) with M = (Cu0.5Ni0.5) and 0 less than or equal to x less than or equal to 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H-M batteries.
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phase stability and neutron diffraction studies of Laves Phases zr cr1 xmx 2 with m cu0 5ni0 5 and 0 x 0 2 and their hydrides
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Abstract Laves Phases of composition Zr(Cr 1− x M x ) 2 with M = (Cu 0.5 Ni 0.5 ) and 0 ⩽ x ⩽ 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H M batteries.
Gerhard Sauthoff - One of the best experts on this subject based on the ideXlab platform.
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structure and stability of Laves Phases part ii structure type variations in binary and ternary systems
Intermetallics, 2005Co-Authors: Frank Stein, Martin Palm, Gerhard SauthoffAbstract:Abstract In Part I, various models for the prediction of the occurrence and stability of Laves Phases have been discussed. In the present Part II paper, an overview is given on the various types of manifestation of Laves Phases in intermetallic alloy systems with emphasis on transition metal systems. Temperature- and composition-dependent as well as stress-induced phase transformations between the cubic C15 and the hexagonal C14 and C36 structural polytypes of Laves Phases were observed in various binary and ternary systems. The phase fields of the different polytypes are generally separated by small two-phase fields. Some general rules for the occurrence of the different Laves phase polytypes are derived from a study of the results of experimental phase diagram investigations of various binary and ternary systems. The solubilities and site occupancies of ternary additions in the different Laves phase polytypes and the mutual miscibility of different binary Laves Phases are discussed. The need for careful experimental investigations of phase equilibria is demonstrated. Existing models discussed in the preceding Part I paper are shown to fail to predict the structure and stability of the presented Laves Phases in many cases.
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Structure and stability of Laves Phases part II—structure type variations in binary and ternary systems
Intermetallics, 2005Co-Authors: Frank Stein, Martin Palm, Gerhard SauthoffAbstract:Abstract In Part I, various models for the prediction of the occurrence and stability of Laves Phases have been discussed. In the present Part II paper, an overview is given on the various types of manifestation of Laves Phases in intermetallic alloy systems with emphasis on transition metal systems. Temperature- and composition-dependent as well as stress-induced phase transformations between the cubic C15 and the hexagonal C14 and C36 structural polytypes of Laves Phases were observed in various binary and ternary systems. The phase fields of the different polytypes are generally separated by small two-phase fields. Some general rules for the occurrence of the different Laves phase polytypes are derived from a study of the results of experimental phase diagram investigations of various binary and ternary systems. The solubilities and site occupancies of ternary additions in the different Laves phase polytypes and the mutual miscibility of different binary Laves Phases are discussed. The need for careful experimental investigations of phase equilibria is demonstrated. Existing models discussed in the preceding Part I paper are shown to fail to predict the structure and stability of the presented Laves Phases in many cases.
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structure and stability of Laves Phases part i critical assessment of factors controlling Laves phase stability
Intermetallics, 2004Co-Authors: Frank Stein, Martin Palm, Gerhard SauthoffAbstract:Laves Phases form the largest group of intermetallic Phases. Although they are well known since long, there are still unsolved problems concerning the stability of the respective crystal structures. The Laves Phases crystallize with a cubic MgCu2- or a hexagonal MgZn2 -o r MgNi2-type structure which differ only by the particular stacking of the same four-layered structural units. It is still not possible to predict which of the structure types is the stable one for a Laves phase compound AB2. Phase transformations from a cubic low-temperature structure to a hexagonal high-temperature structure were observed as well as stress-induced transformations from the hexagonal structure to the cubic one. In addition, deviations from the stoichiometric composition were reported to result in a change of the stable polytype in various systems. In this first of two consecutive papers dealing with fundamental aspects of the stability of Laves Phases, some factors which are known to affect the occurrence and structure type of Laves Phases are discussed and it is shown that, at least up to now, the existing models and calculations are not well suited to give a general description of the stability of Laves Phases. q 2004 Published by Elsevier Ltd.
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Laves Phases for high temperatures part ii stability and mechanical properties
Intermetallics, 2002Co-Authors: A. Von Keitz, Gerhard SauthoffAbstract:Abstract The hardness and indentation cracking at room temperature as well as the yield and creep at high temperatures in the range 800 – 1400 °C have been studied for various Laves Phases AB2 with the transition metals A=Zr, Nb, Ta and B=Cr, Fe, Co with partial substitution of the B elements Fe and Co by Al, which effects a transition from cubic C15 structure to hexagonal C14 structure in the case of Nb(Co,Al)2. These Phases are brittle with a thermally activated brittle-to-ductile transition at about 2/3 of the melting temperature. Above the brittle-to-ductile transition temperature deformability is still restricted with possible deformation twinning and in addition with possible microcracking at higher strains. A close positive correlation of the yield stress, hardness and apparent activation energy of creep with the sublimation enthalpy is observed which is analogous to Gruneisen's first rule for the elastic bulk modulus.
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Laves Phases for high temperatures : Structure, stability and constitution
Zeitschrift Fur Metallkunde, 1998Co-Authors: A. Von Keitz, Gerhard Sauthoff, P. NeumannAbstract:The effect of alloying with Al on phase stability and crystal structure of the Laves Phases NbCo 2 and TaFe 2 was studied as part of extended work on Laves Phases of transition metals. The ternary Phases can be described as Nb(Co 1-x Al x ) 2 and Ta(Fe 1-x Al x ) 2 in view of the respective ternary phase diagrams. Melting temperatures and lattice constants have been measured. The phase equilibria between Ta(Fe 1-x Al x ) 2 and bcc Fe-Al. Fe 3 Al with DO 3 structure and FeAl with B2 structure have been studied. The cubic C15 structure of NbCo 2 transforms to the hexagonal C14 structure in the temperature range 1050 to 1350 C and is unstable for Al contents above 5 at.% Al. The stability of Laves Phases with C15 structure is favoured by a high valence electron concentration.
Daniel Fruchart - One of the best experts on this subject based on the ideXlab platform.
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structural studies of Laves Phases zr cr1 xnix 2 with 0 x 0 4 and their hydrides
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Daniel Fruchart, Patricia De RangoAbstract:Abstract Hexagonal C14-type Laves Phases of the series Zr(Cr 1− x Ni x ) 2 with 0≤ x ≤0.4 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analyzed the structure of the alloys, and determined the sites for the Ni substitution. The positions of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of the Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Pressure-composition measurements and microstructural analysis of the Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Patricia De Rango, Daniel Fruchart, Jean-louis SoubeyrouxAbstract:The Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni have been synthesised in the hexagonal C14 type structure. Hydrogen absorption-desorption isotherms have been determined by pressure-composition isotherms (P-C-T) within the temperature range 298-423 K. We have observed that for more than 50% of chromium substitution, the compounds always have a relatively high capacity (H/M>1). Moreover, some isothermal curves reveal the existence of a sloping plateau. To understand the origin of this plateau, the phase composition and purity of polycrystalline alloys have been checked using SEM and EDX techniques.
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Structural studies of Laves Phases Zr(Cr1-xNix)2 with 0
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Patricia De Rango, Daniel FruchartAbstract:Hexagonal C14 Laves Phases of the series Zr(Cr1-xNix)2 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analysed the structure of the alloys and determined the sites for the Ni substitution. The position of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Phase stability and neutron diffraction studies of Laves Phases Zr(Cr(1-x)M(x))(2) with M=(Cu0.5Ni0.5) and 0
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Laves Phases of composition Zr(Cr(1-x)M(x))(2) with M = (Cu0.5Ni0.5) and 0 less than or equal to x less than or equal to 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H-M batteries.
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phase stability and neutron diffraction studies of Laves Phases zr cr1 xmx 2 with m cu0 5ni0 5 and 0 x 0 2 and their hydrides
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Abstract Laves Phases of composition Zr(Cr 1− x M x ) 2 with M = (Cu 0.5 Ni 0.5 ) and 0 ⩽ x ⩽ 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H M batteries.
Mohamed Bououdina - One of the best experts on this subject based on the ideXlab platform.
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structural studies of Laves Phases zr cr1 xnix 2 with 0 x 0 4 and their hydrides
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Daniel Fruchart, Patricia De RangoAbstract:Abstract Hexagonal C14-type Laves Phases of the series Zr(Cr 1− x Ni x ) 2 with 0≤ x ≤0.4 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analyzed the structure of the alloys, and determined the sites for the Ni substitution. The positions of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of the Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Pressure-composition measurements and microstructural analysis of the Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Patricia De Rango, Daniel Fruchart, Jean-louis SoubeyrouxAbstract:The Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni have been synthesised in the hexagonal C14 type structure. Hydrogen absorption-desorption isotherms have been determined by pressure-composition isotherms (P-C-T) within the temperature range 298-423 K. We have observed that for more than 50% of chromium substitution, the compounds always have a relatively high capacity (H/M>1). Moreover, some isothermal curves reveal the existence of a sloping plateau. To understand the origin of this plateau, the phase composition and purity of polycrystalline alloys have been checked using SEM and EDX techniques.
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Structural studies of Laves Phases Zr(Cr1-xNix)2 with 0
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Patricia De Rango, Daniel FruchartAbstract:Hexagonal C14 Laves Phases of the series Zr(Cr1-xNix)2 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analysed the structure of the alloys and determined the sites for the Ni substitution. The position of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Phase stability and neutron diffraction studies of Laves Phases Zr(Cr(1-x)M(x))(2) with M=(Cu0.5Ni0.5) and 0
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Laves Phases of composition Zr(Cr(1-x)M(x))(2) with M = (Cu0.5Ni0.5) and 0 less than or equal to x less than or equal to 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H-M batteries.
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phase stability and neutron diffraction studies of Laves Phases zr cr1 xmx 2 with m cu0 5ni0 5 and 0 x 0 2 and their hydrides
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Abstract Laves Phases of composition Zr(Cr 1− x M x ) 2 with M = (Cu 0.5 Ni 0.5 ) and 0 ⩽ x ⩽ 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H M batteries.
Jean-louis Soubeyroux - One of the best experts on this subject based on the ideXlab platform.
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structural studies of Laves Phases zr cr1 xnix 2 with 0 x 0 4 and their hydrides
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Daniel Fruchart, Patricia De RangoAbstract:Abstract Hexagonal C14-type Laves Phases of the series Zr(Cr 1− x Ni x ) 2 with 0≤ x ≤0.4 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analyzed the structure of the alloys, and determined the sites for the Ni substitution. The positions of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of the Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Pressure-composition measurements and microstructural analysis of the Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Patricia De Rango, Daniel Fruchart, Jean-louis SoubeyrouxAbstract:The Laves Phases Zr(Cr0.5Mo0.2M0.3)(2) with M=Fe, Co, Ni have been synthesised in the hexagonal C14 type structure. Hydrogen absorption-desorption isotherms have been determined by pressure-composition isotherms (P-C-T) within the temperature range 298-423 K. We have observed that for more than 50% of chromium substitution, the compounds always have a relatively high capacity (H/M>1). Moreover, some isothermal curves reveal the existence of a sloping plateau. To understand the origin of this plateau, the phase composition and purity of polycrystalline alloys have been checked using SEM and EDX techniques.
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Structural studies of Laves Phases Zr(Cr1-xNix)2 with 0
Journal of Alloys and Compounds, 1997Co-Authors: Mohamed Bououdina, Jean-louis Soubeyroux, Patricia De Rango, Daniel FruchartAbstract:Hexagonal C14 Laves Phases of the series Zr(Cr1-xNix)2 have been synthesised. Purity and quality of polycrystalline alloys have been checked using SEM and EDX techniques. By X-ray and neutron diffraction we have analysed the structure of the alloys and determined the sites for the Ni substitution. The position of hydrogen atoms in the structure and the occupation of the different interstitial sites of the hydrides have been determined. The effects of Ni/Cr substitution have been studied with regard to the phase stability, the maximum hydrogen content and the hydrogen site stability.
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Phase stability and neutron diffraction studies of Laves Phases Zr(Cr(1-x)M(x))(2) with M=(Cu0.5Ni0.5) and 0
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Laves Phases of composition Zr(Cr(1-x)M(x))(2) with M = (Cu0.5Ni0.5) and 0 less than or equal to x less than or equal to 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H-M batteries.
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phase stability and neutron diffraction studies of Laves Phases zr cr1 xmx 2 with m cu0 5ni0 5 and 0 x 0 2 and their hydrides
Journal of Alloys and Compounds, 1995Co-Authors: Jean-louis Soubeyroux, Mohamed Bououdina, Daniel Fruchart, Patricia De RangoAbstract:Abstract Laves Phases of composition Zr(Cr 1− x M x ) 2 with M = (Cu 0.5 Ni 0.5 ) and 0 ⩽ x ⩽ 0.2 have been synthesised with the hexagonal C14- and/or cubic C15-type structures. By X-ray and neutron diffraction we have determined the structures of the alloys, and in particular the sites for the 3d metal substitution. The position of the hydrogen atoms in the structures and the occupation of the different sites of the hydrides have been determined. Purity and quality of polycrystalline alloys have been checked by using scanning electron microscopy and energy dispersive X-ray analysis techniques. The effects of the M/Cr substitution have been studied for phase stability, maximum hydrogen content and hydrogen site stability and analyzed in view of applications as electrodes in H M batteries.