Magnetic alignment improvement of Nd-Fe-B sintered magnets by a new axial pulse pressing method

A new axial pressing method using pulse magnetizing field was studied to improve the remanence of Nd-Fe-B sintered magnets. In pulsed axial die pressing(PADP) process , tapping density of powders, method of pulse supply and strength of pulse field were optimized to increase magnetic alignment and remanence. As a results, we could find that an axial pressing under pulse magnetizing field was very effective to increase the degree of magnetic alignment of powder, yielding remanences even higher than those obtained by the transverse die pressing. The remanence of 14.1 kG was easily obtained by PADP process from 31R-68TM-1B (in wt.%) sintered magnet

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High orientation Nd-Fe-B sintered magnets prepared by wet pressing method

Journal of Magnetism and Magnetic Materials ◽

10.1016/j.jmmm.2019.165826 ◽

2020 ◽

Vol 495 ◽

pp. 165826

Author(s):

Shuai Cao ◽

Xiaoqian Bao ◽

Jiheng Li ◽

Haijun Yu ◽

Kunyuan Zhu ◽

...

Keyword(s):

Pressing Method ◽

Sintered Magnets ◽

Wet Pressing ◽

High Orientation

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Axial Pressing Method Using Pulse Magnetizing Field for the Preparation of Nd-Ee-B Sintered Magnets

Journal of the Korean Magnetics Society ◽

10.4283/jkms.2003.13.4.182 ◽

2003 ◽

Vol 13 (4) ◽

pp. 182-186

Author(s):

Dong-Hwan Kim ◽

Byung-Kil Kang ◽

Dong-Youl Jang ◽

Andrew S. Kim ◽

Sang-Myun Kim ◽

...

Keyword(s):

Pressing Method ◽

Sintered Magnets ◽

Magnetizing Field

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Effects of Ca Excess Total Amount on the Magnetic and Physical Properties of Ca-La-Co Ferrite Sintered Magnets

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.136.503 ◽

2016 ◽

Vol 136 (8) ◽

pp. 503-508

Author(s):

Gaku Obara ◽

Yuta Kakimi

Keyword(s):

Physical Properties ◽

Sintered Magnets

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Tuning the Magnetic Alignment of Cellulose Nanocrystals from Perpendicular to Parallel Using Lepidocrocite Nanoparticles

10.26434/chemrxiv.8061839.v2 ◽

2019 ◽

Author(s):

Valentina Guccini ◽

Sugam Kumar ◽

Yulia Trushkina ◽

Gergely Nagy ◽

Christina Schütz ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Cellulose Nanocrystals ◽

Small Angle Neutron Scattering ◽

Lower Amount ◽

Magnetic Alignment ◽

Polarized Optical Microscopy ◽

Parallel Orientation ◽

Weak Magnetic Fields

The magnetic alignment of cellulose nanocrystals (CNC) and lepidocrocite nanorods (LpN), pristine and in hybrid suspensions has been investigated using contrast-matched small-angle neutron scattering (SANS) under in situ magnetic fields (0 – 6.8 T) and polarized optical microscopy. The pristine CNC (diamagnetic) and pristine LpN (paramagnetic) align perpendicular and parallel to the direction of field, respectively. The alignment of both the nanoparticles in their hybrid suspensions depends on the relative amount of the two components (CNC and LpN) and strength of the applied magnetic field. In the presence of 10 wt% LpN and fields < 1.0 T, the CNC align parallel to the field. In the hybrid containing lower amount of LpN (1 wt%), the ordering of CNC is partially frustrated in all range of magnetic field. At the same time, the LpN shows both perpendicular and parallel orientation, in the presence of CNC. This study highlights that the natural perpendicular ordering of CNC can be switched to parallel by weak magnetic fields and the incorporation of paramagnetic nanoparticle as LpN, as well it gives a method to influence the orientation of LpN.<br>

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Rare earth sintered magnets. Stability of the magnetic properties at elevated temperatures

10.3403/30164607 ◽

2009 ◽

Keyword(s):

Magnetic Properties ◽

Rare Earth ◽

Elevated Temperatures ◽

Sintered Magnets

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UV Inscription and Pressure Induced Long-Period Gratings through 3D Printed Amplitude Masks

Sensors ◽

10.3390/s21061977 ◽

2021 ◽

Vol 21 (6) ◽

pp. 1977

Author(s):

Ricardo Oliveira ◽

Liliana M. Sousa ◽

Ana M. Rocha ◽

Rogério Nogueira ◽

Lúcia Bilro

Keyword(s):

State Of The Art ◽

Low Cost ◽

Resonance Wavelength ◽

Complex Structures ◽

Pressing Method ◽

Long Period ◽

Long Period Gratings ◽

3D Printed ◽

Mechanical Pressing ◽

First Time

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).

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A study on using expanded perlite with hydroxyapatite: Reinforced bio-composites

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411921996565 ◽

2021 ◽

pp. 095441192199656

Author(s):

Erdoğan Karip ◽

Mehtap Muratoğlu

Keyword(s):

Body Fluid ◽

Xrd Analysis ◽

Cold Isostatic Pressing ◽

Expanded Perlite ◽

X Ray Diffraction ◽

Pressing Method ◽

X Ray ◽

Infra Red ◽

Ft Ir

People are exposed to different kinds of diseases or various accidents in life. Hydroxyapatite (HA) has been widely employed for bone treatment applications. In this study, HA was extracted from sheep bones. Bio-composites were doped with 1, 5, and 10 wt.% of expanded perlite and 5 wt.% of ZrO2–MgO-P2O5. The bio-composites were prepared by the cold isostatic pressing method (250 MPa) and sintered at 900°C for 1 h. In order to evaluate the characteristics of the bio-composites, microhardness, density, X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses were carried out on them. Additionally, the specimens whose characteristics were determined were kept in synthetic body fluid (SBF), and their in vitro behavior was examined. As a result, it was observed that microhardness increased as both the weight and the grain size of the expanded perlite were increased. Calcium silicate, tri-calcium phosphate, and hydroxyapatite were observed in the XRD analysis of all samples, and the formation of apatite structures was increased by addition of ZrO2–MgO–P2O5.

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