Microstructure, phase evolution and magnetic properties of melt-spun SmCo 6.8− x Sn x Zr 0.2 ( x = 0, 0.1 and 0.3) ribbons (original) (raw)
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Y1-XSmXCo5 ribbons obtained by Melt Spinning
Recibido el de de ; aceptado el de de YCo 5 and Y 0.5 Sm 0.5 Co 5 ribbons were synthesized by melt-spinning with a copper wheel velocity of 29 m/s. X-ray diffraction patterns showed that the samples were essentially single phase with a hexagonal CaCu 5 -type crystal structure. A grain size of a few micrometers was observed for both composition, with equiaxed grains and dendritic-like grains for YCo 5 and Y 0.5 Sm 0.5 Co 5 respectively. The Y 0.5 Sm 0.5 Co 5 sample have a σr/σmax ratio of 0.63 and it developed a coercivity iHC =4.4 kOe higher than that of the YCo5 sample. From zero field cooling and field cooling curves as a function of temperature an irreversibility temperature of approximately 300K was determined.
Journal of Applied Physics, 2014
We have investigated effects of metal substitutions on the magnetic properties and microstructure of melt-spun Sm-Co-Cu-Fe-M (M ¼ Zr, V, Nb, Mo, Ta) magnets. We prepared melt-spun ribbons with compositions of Sm(Co 1Àx Cu x) 5 Fe 0.54Ày M y (x ¼ 0.1-0.5, y ¼ 0-0.43, M ¼ Zr, V, Nb, Mo, Ta). For compositions of Sm(Co 1Àx Cu x) 5 Fe 0.54 (x ¼ 0.1-0.5), coercivity increased with increasing of annealing temperature, and a high coercivity of 17.6 kOe was obtained at a Cu content of x ¼ 0.3. The coercivity was found to increase with increasing melting point of the substitution element. A high coercivity of 24.5 kOe was obtained for a composition of Sm(Co 0.7 Cu 0.3) 5 Fe 0.34 Ta 0.2. V
High performance isotropic Sm–(Co,Fe)–C and Sm–(Co,Fe,Mn)–C magnets by melt spinning
Journal of Applied Physics, 2008
The magnetic properties and microstructure of melt-spun ribbons with a composition Sm x ͑Co 1−y M y ͒ 100−x−z C z for M = Fe or Fe+ Mn and x = 10-15, y = 0-0.375, and z =0-6 have been studied systematically. The results indicate a strong dependence of the microstructure on the addition of C. The grain size decreases from few 100 nm to below 20 nm with addition of C. On the other hand, addition of Fe and Mn modifies both the saturation magnetization and the magnetocrystalline anisotropy. The Mn addition results in a coercivity of 11.7 kOe for Sm 12 ͑Co 0.75 Fe 0.185 Mn 0.065 ͒ 86.5 C 1.5 ribbons spun at 40 m / s. The highest remanence of 102 emu/ g was obtained in Sm 12 ͑Co 0.75 Fe 0.25 ͒ 83.5 C 4.5 ribbons spun at 50 m / s. A ͑BH͒ max of 14.7 MGOe with a coercivity of 5.6 kOe was obtained in as spun Sm 13 ͑Co 0.75 Fe 0.25 ͒ 82.5 C 4.5 ribbons.
Journal of Magnetism and Magnetic Materials, 2013
The structural, magnetic, magnetocaloric and magnetotransport properties of Ni 46 Co 4 Mn 38 Sb 12 melt spun ribbons have been systematically investigated. The partially ordered B2 phase of the as-spun ribbon transforms to fully ordered L2 1 phase upon annealing, which signifies a considerable change of the atomic ordering in the system. The presence of atomic disorder in the as-spun ribbon gives rise to a higher martensitic transition temperature and a lower magnetization as compared to the bulk sample. However, annealing the ribbons helps in regaining the bulk properties to a large extent. Significant changes in magnetocaloric effect, exchange bias and magnetoresistance have been observed between the as-spun and the annealed ribbons, indicating the role of atomic ordering on the functional as well as fundamental properties in the Heusler system. Importantly, the study shows that one can reduce the hysteresis loss by preparing melt spun alloys and subjecting them to appropriate annealing conditions, which enable them to become practical magnetic refrigerants.
Structure and magnetic properties of Sm(Co0.74Fe0.1Cu0.12Zr0.04)8 melt-spun nanostructured alloys
Materials Science and Engineering: B, 2008
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In this work, the (Zr-Ti)(Fe-Cr) 2 based compounds have been synthesized while charging-discharging hydrogen ability has been examined. Relatively low hydrogen pressure has been used for the hydrogenation of the samples. After following the discharging procedure, a high desorbed amount of hydrogen ~180 (ml of H 2 )/(gr of the alloy) has been measured on the first 15 min by using a volumetric device. The crystal structure has been analyzed by means of x-ray diffraction (XRD) while a Rietveld analysis has been performed on the x-ray diffraction patterns and the characteristic MgZn 2 type of structure has found to be the dominant phase in both compounds. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) have been used for microstructural studies and quantitative analysis, respectively. Magnetic measurements have been performed on the samples and a paramagnetic behaviour has found to be at room temperature.
Sm(Co, Fe, Cu, Zr, C)8.2 ribbons for high-temperature magnets
Journal of Magnetism and Magnetic Materials, 2004
The effect of carbon substitution for cobalt on the structure and magnetic properties at room and high temperature of melt spun ribbons with composition Sm(Co 0.86Àx Fe 0.1 Zr 0.04 C x ) 8.2 and Sm(Co 0.74Àx Fe 0.1 Cu 0.12 Zr 0.04 C x ) 8.2 (x ¼ 0 À 0:015) has been studied. Arc-melted bulk samples have Th 2 Ni 17 -type structure while ribbons have TbCu 7type structure. Average grain size for Cu-free sample with x ¼ 0:005 is 23 nm while for Cu-doped samples it varies from 53 to 22 nm when x varies from 0.005 to 0.015, respectively. Coercive as-spun samples have H c B2:227:8 kOe and reduced remanence m r ¼ M r =M s up to 0.74. Ribbons of the Cu-free composition with x ¼ 0 and 0.005 and annealed at 750 C for 1 h have TbCu 7 -type structure with coercivity values 4.9 and 3.0 kOe respectively, while for x ¼ 0:01 and 0.015, FCC-Co is the dominant phase. Cu-doped ribbons with x ¼ 0:005; after annealing at 750 C for 2 h, are characterized at room temperature by square hysteresis loop with H c ¼ 8:3 kOe, reduced remanence m r ¼ 0:75 and (BH) max =6.3 MGOe. Loops at higher temperatures are also square with high m r ; for x ¼ 0:01 the magnetization is 89 emu/g and the coercive field is 1.8 kOe at 400 C. r 2004 Elsevier B.V. All rights reserved.
Journal of Applied Physics, 2002
In this work we examine the effect of small boron substitution (xϭ0, 0.005, 0.010, 0.015) on the structural and magnetic properties of Sm(Co 0.86Ϫx Fe 0.1 Zr 0.04 B x ) 7.5 and Sm͑Co 0.74Ϫx Fe 0.1 Cu 0.12 Zr 0.04 B x ) 7.5 melt-spun samples, as a function of wheel speed and annealing conditions. Boron substituted as-spun ribbons are found to have increased coercivity, HcϾ5 kOe, and small grain size of 60-100 nm. For copper containing samples, the highest coercivity (Hc ϭ16.3 kOe) was obtained in as-spun ribbons with xϭ0.015. In samples without copper the coercivity increased after short annealing ͑Hcϭ12 kOe for xϭ0.015͒. The large coercivities are attributed to a fine microstructure consisting mainly of hexagonal TbCu 7 -type phase and a small amount of soft-phase grains.
Mn\(_{55-x}\)Co\(_x\)Bi\(_{45}\) Melt Spun Ribbons: Microstructures and Magnetic Properties
Communications in Physics, 2022
In this paper, we present the effect of Cobalt (Co) addition on the crystallization, microstructures and magnetic properties of Mn55-xCoxBi45 (x = 0, 5, 10, 20) melt – spun ribbons. The ribbons were prepared by the melt-spinning techique and subsequent anneal at 280 oC for 5 h. The investigations by using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) traces as well the Vibration Sample Magnetometer (VSM) measurements result in the optimal content of Co added to the MnBi system is arounf 5 %at. The larger Co content causes the eutectic Mn-Co formation which restricts the reaction between Mn and Bi to form MnBi ferromagnetic phase responsible for ribbons’ performance the saturation magnetization Ms. The maximum saturation magnetization Ms of 65emu/g and the coercivity iHc of 4.7 kOe was achived for the ribbon of Mn50Co5Bi45. The effect of Co content on the microstructures and magnetic properties of Mn55-xCoxBi45 melt – spun ribbons will be discussed in detail.