Structure and Size Distribution of Powders Produced from Melt-Spun Fe-Si-B Ribbons

2021 ◽  
Vol 876 ◽  
pp. 25-30
Author(s):  
Rosa M. Aranda Louvier ◽  
Raquel Astacio Lopez ◽  
Fátima Ternero Fernández ◽  
Petr Urban ◽  
Francisco G. Cuevas

This work studies the production of melt spun Fe78Si9B13 ribbons with amorphous or nanocrystalline structure. The main objective is the preservation of the amorphous structure after obtaining powders by mechanical milling of the ribbons, as well as the study of the influence of the milling conditions on the size distribution and structure of the obtained powders. In order to obtain high quality amorphous ribbons, the wheel rotation speed, crucible-wheel distance, melt homogenization time, ejection pressure and the ejection temperature were optimized in the melt spinning process. Different mills were used for powder production, studying the size distribution, efficiency, and preservation of the amorphous character as a function of the milling time. Ribbons and powders were characterized by X-ray diffraction (XRD) and electron microscopy (SEM and TEM); laser diffraction was used for powder granulometry.

2013 ◽  
Vol 58 (2) ◽  
pp. 419-423 ◽  
Author(s):  
A. Kukuła-Kurzyniec ◽  
J. Dutkiewicz ◽  
P. Ochin ◽  
L. Perrière ◽  
P. Dłuzewski ◽  
...  

In the present paper glass forming ability and structure of Al-Si-Ni based alloys were investigated. Three alloys starting from the ternary Al78Si12Ni10 [alloy 1], Al75Si12Ni8Zr5 [alloy 2] and Al73Si5Ni7Cu8Zr7 [alloy 3] were subjected to melt spinning process. The mean thickness of the obtained ribbons amounted between 25 and 40 μm. XRD and DSC studies showed predominantly amorphous structure of the ribbons. STEM and HRTEM methods confirmed participation of crystalline phase identified mainly as Al solid solution with the grain size near 10 nm. The mean microhardness [0.1N] of the ribbons was measured for alloys 1 - 3 respectively: 457 HV, 369 HV and 536 HV. The high value of hardness can be related to the presence of α-Al dispersoids in the amorphous matrix.


MRS Advances ◽  
2016 ◽  
Vol 1 (34) ◽  
pp. 2373-2378 ◽  
Author(s):  
Md A Mehedi ◽  
Yanfeng Jiang ◽  
Jian-Ping Wang

ABSTRACTWe are reporting an approach to prepare bulk foils of α″-Fe16N2that can be directly obtained from a melt spinning process. The diffraction peaks from α″-Fe16N2phase were found in X-ray diffraction spectrum of the foil, for which a nitrogen composition of 8.7at% was found by Auger electron spectroscopy. The microstructure of this melt spun foil was analyzed. We found 600 nm subgrains inside 8 μm grains for this foil. The coercivity of the α″-Fe16N2foil was found as 222 Oe with a saturation magnetization of 223 emu/g. We analyzed the coercivity based on the microstructure and proposed a model to explain how to further improve it in melt spun FeN foils.


2011 ◽  
Vol 399-401 ◽  
pp. 1419-1424
Author(s):  
Yang Huan Zhang ◽  
Guo Fang Zhang ◽  
Xia Li ◽  
Zhong Hui Hou ◽  
Yin Zhang ◽  
...  

The nanocrystalline and amorphous Mg2Ni1-xCox (x=0, 0.1, 0.2, 0.3, 0.4) alloys were prepared by melt-spinning technique. The structures of the alloys were studied by XRD, SEM and HRTEM. The hydrogen absorption and desorption kinetics and the high rate discharge ability (HRD) of the alloys were measured. The results show that the as-spun Co-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys containing Co display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The substitution of Co for Ni evidently improves the hydriding and dehydriding kinetics and the HRD of the alloys. With an increase in the amount of Co substitution from 0 to 0.4, the HRD value rises from 52.9% to 60.3% for the as-cast alloy, and from 65.9% to 76.0% for the as-spun (30 m/s) alloy.


2012 ◽  
Vol 457-458 ◽  
pp. 572-577
Author(s):  
Yang Huan Zhang ◽  
Bao Wei Li ◽  
Hui Ping Ren ◽  
Zai Guang Pang ◽  
Zhong Hui Hou ◽  
...  

Mg2Ni-type Mg20Ni10-xMx (M=Cu, Co; x=0, 1, 2, 3, 4) electrode alloys with nanocrystalline and amorphous structure were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by XRD, SEM and HRTEM. The electrochemical hydrogen storage properties of the experimental alloys were measured. The obtained results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Furthermore, such substitution results in the formation of secondary phases Mg2Cu and MgCo2 instead of changing the major phase of Mg2Ni. The substitution of M (M=Cu, Co) for Ni markedly improves the electrochemical performances of the alloys, involving the discharge capacity and the cycle stability as well as the high rate discharge ability.


2012 ◽  
Vol 586 ◽  
pp. 50-57
Author(s):  
Yang Huan Zhang ◽  
Tai Yang ◽  
Hong Wei Shang ◽  
Guo Fang Zhang ◽  
Xia Li ◽  
...  

In order to obtain a nanocrystalline and amorphous structure, the Mg20Ni8M2 (M=Cu, Co) hydrogen storage alloys were fabricated by the melt spinning technology. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the hydriding and dehydriding kinetics of the alloys were investigated. The results indicate that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if the limited spinning rate is applied, while the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as the spinning rate grows to 30 m/s, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably improves the gaseous hydriding and dehydriding kinetics of the alloys. As the spinning rate grows from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) is enhanced from 56.72% to 92.74% for the (M=Cu) alloy and from 80.43% to 94.38% for the (M=Co) alloy. The hydrogen desorption ratio ( ) is raised from14.89% to 40.37% for the (M=Cu) alloy and from 24.52% to 51.67% for the (M=Co) alloy.


1996 ◽  
Vol 460 ◽  
Author(s):  
Jinmin Chen ◽  
W. E. Frazier ◽  
E. V. Barrera

ABSTRACTIn an effort to expand the composition range over which Al3Ti is stable, various amounts of niobium were substituted for titanium and processed by melt-spinning. Several samples were annealed both at 600°C and 1000°C for 24 hours. The effects of processing parameters such as wheel speed, the amount of niobium, and annealing temperatures on the structure were investigated by XRD and EXAFS. XRD showed that for all the samples the only structure present was DO22-The DO22 structure was stable even after the high temperature heat treatments. By means of EXAFS, niobium atoms were observed to occupy titanium sites in the DO22 structure. Furthermore, in the unannealed samples, increasing wheel speed of the melt spinning process or the niobium concentration tended to distort the crystal structure. It was observed that Ti EXAFS had different results from the Nb EXAFS beyond their occupying similar sites, which suggested there may exist some composition zones, i.e. rich Nb zone or rich Ti zones, although the structures present were still DO22. The samples were found to experience different distortions as a function of annealing temperatures.


2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.


Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 497
Author(s):  
Shchetinin ◽  
Aggrey ◽  
Bordyuzhin ◽  
Savchenko ◽  
Gorshenkov ◽  
...  

The structural transformations and magnetic property changes of the Nd16.2FebalCo9.9Ga0.5B7.5 (SG1, SG2) and Nd15.0FebalGa2.0B7.3 (SG3) nanocomposite alloys obtained by melt spinning in the as-quenched state and after annealing at a temperature range of 560–650 °C for 30 min were studied. The methods used were X-ray diffraction analysis, magnetic property measurements, TEM studies, X-ray fluorescence analysis and Mössbauer spectroscopy. Amorphous phase and crystalline phase Nd2Fe14B (P42/mnm) were observed in the alloy after melt spinning. The content of the amorphous phase ranged from 20% to 50% and depended on the cooling rate. Annealing of the alloys resulted in amorphous phase crystallization into Nd2Fe14B and led to the increased coercivity of the alloys up to 1840 kA/m (23.1 kOe) at 600 °C annealing for 30 min. The alloy with the maximum coercivity had a grain size of the Nd2Fe14B phase ≈50–70 nm with an Nd-rich phase between grains.


2011 ◽  
Vol 415-417 ◽  
pp. 1565-1571
Author(s):  
Zhi Hong Ma ◽  
Bo Li ◽  
Dong Liang Zhao ◽  
Hui Ping Ren ◽  
Guo Fang Zhang ◽  
...  

In this paper, melt-spinning technology was used for preparing Mg20Ni10-xCox (x = 0, 1, 2, 3, 4) hydrogen storage alloys. The influences of both the Co substitution and the melt spinning on the the physical and electrochemical hydrogen storage kinetics of the alloys were investigated. The XRD, SEM and TEM characterization exhibits that the as-spun Co-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys substituted by Co display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The Co substitution gives rise to forming secondary phase MgCo2 without altering the Mg2Ni major phase of the alloys. The measurement of the physical and electrochemical hydrogen storage kinetics of the alloys shows that both the melt spinning and the substitution of Co for Ni markedly improve the physical hydriding and dehydriding kinetics and the electrochmeical kinetics (HRD) of the alloys.


2014 ◽  
Vol 556-562 ◽  
pp. 4264-4267
Author(s):  
Shu Wen Wang ◽  
Te Li Su

In melt spinning process, evenness of polypropylene melt spun yarns affects the appearance, hairiness, strength and productivity of yarns, as well as product production and profits, causing rejection due to nonconformity. The research is to find optimal manufacturing parameters of melt spun yarns. Firstly, to proceed the parameter design by Taguchi method, then to select a manufacturing parameter which will affect the quality of melt spun yarns as controllable factors. Also to choose a suitable orthogonal arrays. Meanwhile, according to variation of analysis, to decide optimal manufacturing parameters of melt spun yarns and its remarkable factor. Finally, using 95% confidence interval to proof the experiment’s reliability and repeatability.


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