Processing Sm-Fe(Ta)-N hard magnetic materials

1999 ◽  
Vol 577 ◽  
Author(s):  
K Žužek ◽  
PJ Mcguiness ◽  
S Kobe
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Processing Parameters ◽  
High Energy ◽  
Small Particle Size ◽  
Optimum Conditions ◽  
Hard Magnetic Materials ◽  
Negative Effect ◽  
Cast Alloys

ABSTRACTSmFe based alloys interstitially modified with nitrogen are potential candidates for high energy permanent magnets. In order to obtain the optimum properties a thorough understanding of the starting material and processing parameters is required. The microstructures of two cast alloys of composition Sm13.8Fe82.2 Ta4.0 and Sm13.7 Fe86.3 were carefully examined with a SEM equipped with EDX and the exact stoichiometries of the phases were determined. The SmFeTa material was found to contain significant amounts of TaFe2as well as the Sm2Fe17, SmFe2, SmFe3 phases observed in the SmFe material but without the a-iron dendrites which are characteristic of the latter material. The optimum conditions necessary to provide the highest coercivities using the conventional HDDR process, and for the HDDR process combined with pre-milling were investigated. The coercivities obtained after using the HDDR process and subsequent nitriding were 680 kA/m for the SmFeTaN and 360 kA/m for the SmFeN samples. Significantly higher coercivites of 1000 kA/m for SmFeN and 1275 kA/m for SmFeTaN were achieved by reducing the particle size with milling prior to the HDDR process.The better coercivities obtained with the Ta containing sample were found to be due to the presence of a much smaller amount of a. The milling prior to the HDDR treatment improves the magnetic properties because of the small particle size which prevents the grains growing too large, with their consequent very negative effect on the coercivity.

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

Regulation of Nanomaterials under present and future Chemicals legislation Analysis and regulative options

elni Review ◽  
2009 ◽  
pp. 31-38
Author(s):  
Stefanie Merenyi ◽  
Martin Führ ◽  
Kathleen Ordnung
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Automobile Industry ◽  
Small Particle ◽  
Chemical Properties ◽  
Active Surface ◽  
High Energy ◽  
Small Particle Size ◽  
White Pigment ◽  
Negative Results

Nanotechnology has already entered our everyday life. It finds application in a large number of industrial areas, for instance in the automobile industry, in energy and environmental technology, mechanical engineering, the chemicals and pharmaceuticals industry, in medicine, cosmetics and the food industry. Nanoscale titanium dioxide in sunscreen products, for example, provides UV protection, car tyres contain – not only recently – nanoscale carbon black, and many scratchproof, antireflection, non-stick and de-misting surfaces are manufactured with the help of nanomaterials. What distinguishes nanomaterials from previously used substances and processes is, above all, their large and active surface in proportion to their volume. The small particle size can result in modified chemical properties and functionalities compared to conventional substance in a non-nanoscale form, which can range from varied melting and boiling points to greater hardness, magnetism and catalytic effects. Nanotechnology is regarded as a key technology of the 21st century. Considerable economic expectations are attached to its further development. Due to its low consumption of resources and high energy efficiency, nanotechnology also offers potential ecological relief that should be exploited. At the same time, little is presently known about risks to human health and the environment associated with nanotechnology. The modified properties of nanoscale substances can lead to different risk assessment compared to conventional materials. Early knowledge in this respect has been available for some time. As far as titanium dioxide is concerned, the suspicion has been confirmed: This material, which has been manufactured and used as white pigment for many years, was regarded as unproblematic before its appearance in this small particle size, since tests carried out with non-nanoscale particles were negative. Results of tests on titanium dioxide in the nanoscale form showed, however, that these particles could have ecotoxic effects. In view of this conflict between expected benefits and potential risks, the question arises as to which legal requirements nanotechnology is subject to. In the spring of 2006 the Federal Environmental Agency commissioned a legal appraisal of the present framework of environmental legislation with regard to nanotechnologies and the drawing up of proposals for initial action should regulatory gaps be identified. The main focus of this analysis was chemicals law, and its findings are presented in this article.

Structural and Magnetic Properties of New Type CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3 Magnets

2014 ◽  
Vol 1058 ◽  
pp. 107-112
Author(s):  
Xian Song Liu ◽  
Ji Liang Yang ◽  
Hui Yang
Keyword(s):  
Magnetic Properties ◽  
Permanent Magnets ◽  
Charge Compensation ◽  
High Energy ◽  
Hysteresis Curve ◽  
X Ray Diffraction ◽  
M Phase ◽  
New Type ◽  
Process Structure ◽  
Material Preparation

Considering that Ca2+ has the similar ion radius and the substituted ability as Sr2+ and Ba2+ but the same family, CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3 ferrites have been synthesized by the conventional ceramic process. Structure and magnetic properties of CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3 compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) and B-H hysteresis curve measurements. Several compositions are selected to investigate the formation of M phase with the joint replacement of Ca-La-Co. It is found that the formation mechanism is based on the replacement of Sr2+ by La3+ plus Ca2+ and the charge compensation by Co2+. In futher results, the unexpectedly intrinsic coercivity of 436 kA/m and residual flux density of 0.445 T were obtained. In terms of material preparation, we believe that CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3 is effective in the production of future high energy permanent magnets.

scholarly journals Instantaneous preparation of high lithium-ion conducting sulfide solid electrolyte Li7P3S11 by a liquid phase process

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 46499-46504 ◽  
Author(s):  
Marcela Calpa ◽  
Nataly Carolina Rosero-Navarro ◽  
Akira Miura ◽  
Kiyoharu Tadanaga
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Solid Electrolyte ◽  
Lithium Ion ◽  
High Energy ◽  
Small Particle Size ◽  
Solid State Battery ◽  
Ion Conducting ◽  
Energy And Power Density ◽  
Phase Process

A solid electrolyte with a small particle size, good mechanical properties and high ionic conductivity is required to achieve high energy and power density in the all-solid-state battery.

Sinthesis and Characterization of Nd2Fe14B Powder from Nd-Fe-B Flakes by Wet Mechanical Milling and Heat Treatment

2016 ◽  
Vol 864 ◽  
pp. 70-74 ◽  
Author(s):  
Priyo Sardjono ◽  
Muljadi ◽  
Suprapedi ◽  
Nenen Rusnaeni Djauhari
Keyword(s):  
Particle Size ◽  
Mechanical Milling ◽  
Permanent Magnets ◽  
Magnetic Phase ◽  
Fine Powder ◽  
Xrd Analysis ◽  
High Energy ◽  
Milling Process ◽  
Raw Material ◽  
Milling Method

The Nyodimium-Iron-Boron (Nd-Fe-B) based materials are known as the best type of magnetic materials and it contains a magnetic phase Nd2Fe14B. The Nd-Fe-B alloy Flakes is one of the main raw material for producing of NdFeB-based permanent magnets and the size of Nd-Fe-B flakes are still coarse. Synthesis of Nd2Fe14B powder has been done by a wet mechanical milling method using the High Energy Milling (HEM) for 10 hrs and continued by heating at 600°C in vacuum condition (10-4 Pa). This process is used to produce a fine powder Nd2Fe14B for making of permanent magnets. The milling medium was used a toluene (pa-Emerck)) to protect of particle from oxidation during the milling process. After milling processes, the samples were measured distribution particle size by using Particle Size Analyzer (PSA). Microstructure analysis has been conducted by using X-ray diffractometer (XRD) and Scanning Electron Microscope (SEM/EDX) for samples before milling and sample after heating. The characterization results show that after milling 10 hours, it was obtained fine powder with average size about 1.35 μm. According to SEM/EDX and XRD analysis show that the crystal structure of the sample before milling was different compared to the sample after heating. It is found new magnetic phase with formula Nd2Fe14B.

Structure and Magnetic Properties of NdFeB Powder Prepared by Hydrogen Decrepitation and High-Energy Ball Milling

2014 ◽  
Vol 604 ◽  
pp. 262-266 ◽  
Author(s):  
Zoryana Mural ◽  
Lauri Kollo ◽  
Rainer Traksmaa ◽  
Kaspar Kallip ◽  
Joosep Link ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Ball Milling ◽  
Magnetic Moments ◽  
Weight Ratio ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Final Particle ◽  
Energy Ball ◽  
Hydrogen Decrepitation

An ingot of NdFeB alloy was disintegrated by hydrogen decrepitation (HD). High-energy ball milling technique with hard metal milling elements and balls was employed to refine HD powders down to particle size optimum for magnet processing. The experiments were performed according to experimental plan to optimize the milling parameters regarding particle size, contamination and magnetic properties of the powder. The effect of milling time, speed of rotation, ball-powder weight ratio (BPR) and amount of wet agent was investigated. The highest influence was shown to be from attritor speed of rotation, ball-to powder ratio and combined effect of milling wet agent and rotating speed. Unified parameter of estimated number of total ball impacts was calculated, which allows predicting the final particle size of the powder at different milling speeds. Magnetic moments of powders were measured.

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