Synthesis of Fe–Pt–B nanocomposite magnets with high coercivity by rapid solidification

2006 ◽  
Vol 99 (8) ◽  
pp. 08E914 ◽  
Author(s):  
Wei Zhang ◽  
Kunio Yubuta ◽  
Parmanand Sharma ◽  
Akihisa Inoue
Author(s):  
N. Qiu ◽  
J. E. Wittig

PtCo hard magnets have specialized applications owing to their relatively high coercivity combined with corrosion resistance and ductility. Increased intrinsic coercivity has been recently obtained by rapid solidification processing of PtCo alloys containing boron. After rapid solidification by double anvil splat quenching and subsequent annealing for 30 minutes at 650°C, an alloy with composition Pt42Co45B13 (at.%) exhibited intrinsic coercivity up to 14kOe. This represents a significant improvement compared to the average coercivities in conventional binary PtCo alloys of 5 to 8 kOe.Rapidly solidified specimens of Pt42Co45B13 (at.%) were annealed at 650°C and 800°C for 30 minutes. The magnetic behavior was characterized by measuring the coercive force (Hc). Samples for TEM analysis were mechanically thinned to 100 μm, dimpled to about 30 nm, and ion milled to electron transparency in a Gatan Duomill at 5 kV and 1 mA gun current. The incident ion beam angle was set at 15° and the samples were liquid nitrogen cooled during milling. These samples were analyzed with a Philips CM20T TEM/STEM operated at 200 kV.


2009 ◽  
Vol 404 (8-11) ◽  
pp. 1321-1325 ◽  
Author(s):  
Wang Zhanyong ◽  
Liu Wenqing ◽  
Zhou Bangxin ◽  
Ni Jiansen ◽  
Xu Hui ◽  
...  

1991 ◽  
Vol 133 ◽  
pp. 147-150 ◽  
Author(s):  
J. Wecker ◽  
M. Katter ◽  
L. Schultz

2004 ◽  
Vol 19 (9) ◽  
pp. 2730-2737 ◽  
Author(s):  
Tetsuji Saito ◽  
Tomonari Takeuchi ◽  
Hiroyuki Kageyama

We studied the effects of the sintering temperature and applied pressure on Nd–Fe–B bulk nanocomposite magnets produced by the spark plasma sintering (SPS) method. Amorphous Nd4Fe77.5B18.5 melt-spun ribbons were successfully consolidated into bulk form by the SPS method. When sintered at 873 K under applied pressures between 30 and 70 MPa, the bulk materials consisted of nanocomposite materials with a soft magnetic Fe3B phase and hard magnetic Nd2Fe14B phase. The density and magnetic properties of the bulk materials sintered at 873 K were strongly dependent on the applied pressure during sintering. Bulk Nd4Fe77.5B18.5 nanocomposite magnets sintered at 873 K under an applied pressure of 70 MPa showed a high remanence of 9.3 kG with a high coercivity of 2.5 kOe.


2018 ◽  
Vol 735 ◽  
pp. 81-87 ◽  
Author(s):  
Shan Tao ◽  
Zubair Ahmad ◽  
Pengyue Zhang ◽  
Xiaomei Zheng ◽  
Suyin Zhang ◽  
...  

2018 ◽  
Vol 735 ◽  
pp. 218-223 ◽  
Author(s):  
Tetsuji Saito ◽  
Daisuke Nishio-Hamane

2017 ◽  
Vol 5 (31) ◽  
pp. 7911-7918 ◽  
Author(s):  
K. T. Chan ◽  
J. R. Morales ◽  
Y. Kodera ◽  
J. E. Garay

Large iron-oxide based magnets with high magnetic coercivity.


2016 ◽  
Vol 400 ◽  
pp. 300-303 ◽  
Author(s):  
Rajasekhar Madugundo ◽  
Daniel Salazar-Jaramillo ◽  
Jose Manuel Barandiaran ◽  
George C. Hadjipanayis

Author(s):  
T. P. Nolan

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.


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