MAGNETIC PROPERTIES OF SINTERED Nd-Fe-B TYPE MAGNETS CONTAINING CALCIUM, CHLORINE AND CARBON

The microstructure and magnetic properties of Nd 16-x X x Fe 70.5 Co 5 AlB 7.5 and Nd 14-x Dy 2 X x Fe 71 Co 5 B 8 ( X = Ca , Cl and C ) magnets with various x were examined. In magnets after sintering and heat treatment carbon-rich areas were produced within the non-magnets Nd -rich phase. However chlorine-rich and calcium-rich areas were present in both non-magnetic Nd -rich and B -rich phases. The contribution of C ≤0.35 at%, Cl ≤0.013 at% and Ca ≤0.09 at% had no influence on the magnetic properties (B r and i H c ), but higher concentration of these elements caused decrease in these properties. Abnormal grain growth was found in magnets containing Cl .

Download Full-text

Influence of Heating Rate and Decarburization Temperature on the Microstructure and Magnetic Properties of Grain Oriented Electrical Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.2622 ◽

2012 ◽

Vol 706-709 ◽

pp. 2622-2627 ◽

Cited By ~ 1

Author(s):

Chun Kan Hou ◽

Jian Ming Tzeng

Keyword(s):

Magnetic Properties ◽

Heating Rate ◽

Grain Growth ◽

Electrical Steel ◽

Rapid Heating ◽

Abnormal Grain Growth ◽

Heating Rates ◽

Abnormal Growth ◽

Steel Sheets ◽

Microstructure And Magnetic Properties

Effects of three heating rates, 5, 20/min., and 300°C/sec and decarburization temperature, 700-850°C in primary annealing on the microstructure and magnetic properties of a grain oriented electrical steel were investigated. It was found that the oxide layer thickness and grain size increased with increasing decarburization temperature. However, they decreased with increasing heating rate. On the other hand, injection nitrogen content into steel sheets decreased with increasing decarburization temperature. The percentage of abnormal grain growth obtained a peak value at 800°C in the specimens treated with heating rate less than 20°C per minute. But specimens with rapid heating rate, percentage of abnormal grain growth increased with increasing decarburization temperature. As percentage of abnormal growth increased, magnetic properties got better.

Download Full-text

Effect Of The Desorption-Recombination Temperature On The Microstructure And Magnetic Properties Of HDDR Processed Nd-Fe-B Powders

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0160 ◽

2015 ◽

Vol 60 (2) ◽

pp. 1499-1501

Author(s):

J.-G. Lee ◽

H.-R. Cha ◽

S. Liu ◽

J.-H. Yu ◽

Y.-K. Baek ◽

...

Keyword(s):

Magnetic Properties ◽

Grain Boundaries ◽

Grain Growth ◽

Rich Phase ◽

Homogenizing Annealing ◽

Casting Alloys ◽

Microstructure And Magnetic Properties

Abstract The effect of the desorption-recombination temperature on the microstructure and magnetic properties of hydrogenation-disproportionation-desorption-recombination (HDDR) processed Nd-Fe-B powders was studied. The NdxB6.4Ga0.3Nb0.2Febal (x=12.5-13.5, at.%) casting alloys were pulverized after homogenizing annealing, and then subjected to HDDR treatment. During the HDDR process, desorption-recombination (DR) reaction was induced at two different temperature, 810°C and 820°C. The higher Nd content resulted in enhanced coercivity of the HDDR powder, and which was attributed to the thicker and more uniform Nd-rich phase along grain boundaries. But this uniform Nd-rich phase induced faster grain growth. The remanence of the powder DR-treated at 820°C is higher than that DR-treated at 810°C. In addition, it was also confirmed that higher DR temperature is much more effective to improve squareness.

Download Full-text

Grain growth kinetics, microstructure and magnetic properties of mechanically activated Nd1−xCaxMnO3±δ manganites

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.158816 ◽

2021 ◽

Vol 864 ◽

pp. 158816

Author(s):

Galina Kozhina ◽

Valentin Mitrofanov ◽

Olga Fedorova ◽

Andrey Fetisov ◽

Aidar Murzakaev ◽

...

Keyword(s):

Magnetic Properties ◽

Grain Growth ◽

Growth Kinetics ◽

Grain Growth Kinetics ◽

Microstructure And Magnetic Properties

Download Full-text

Magnetic Properties, Nanostructure, and Ordering Kinetics of Nb Additive FePtCu Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.1743 ◽

2010 ◽

Vol 638-642 ◽

pp. 1743-1748

Author(s):

G.J. Chen ◽

Y.H. Shih ◽

Jason S.C. Jang ◽

S.R. Jian ◽

P.H. Tsai ◽

...

Keyword(s):

Heat Treatment ◽

Activation Energy ◽

Magnetic Properties ◽

Heating Rates ◽

Fept Alloy ◽

Ordering Kinetics ◽

Nb Content ◽

Kinetics Of ◽

Nb Addition ◽

Microstructure And Magnetic Properties

In this study,the (FePt)94-xCu6Nbx (x=0, 2.87, 4.52, 5.67) alloy films were prepared by co-sputtering. The effects of Nb addition content and heat treatment on the microstructure and magnetic properties of the polycrystalline FePtCu films are reported. Our previous experiments showed that the ordering temperature of the (FePt)94Cu6 films reduced to 320 °C, which is much lower than that of the FePt alloy. However, the grain growth after heat treatment limited the practical application in recording media. By adding the Nb content in the (FePt)94Cu6 film, the grain sizes of the films can be adjusted from 50 to 18nm, even for the films annealed at temperature as high as 600°C. DSC traces of as-deposited disorder films at different heating rates, to evaluate the crystallization of the order phase, revealed that the addition of Nb enhanced the activation energy of ordering from 87 kJ/mol to 288 kJ/mol for the (FePt)94-xCu6Nbx (x=0 and 2.87, respectively) films. The reduction of the grain size and the corresponding increase in the activation energy of the Fe-Pt-Cu-Nb films might result from the precipitation of the Nb atoms around the ordering FePt phase. The (FePt)94-xCu6Nbx (x=2.87) film showed a coercive force of 13.4 kOe and the magnetization of 687 emu/cc.

Download Full-text

Influence of Heat Treatment on the Microstructure and Magnetic Properties of Mn–Sn–Co–N Alloys

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.maw201312 ◽

2013 ◽

Vol 54 (10) ◽

pp. 2007-2010 ◽

Cited By ~ 3

Author(s):

Keita Shinaji ◽

Tsuyoshi Mase ◽

Keita Isogai ◽

Masashi Matsuura ◽

Nobuki Tezuka ◽

...

Keyword(s):

Heat Treatment ◽

Magnetic Properties ◽

Microstructure And Magnetic Properties

Download Full-text

Friction Stir Welding Parameters: Impact of Abnormal Grain Growth during Post-Weld Heat Treatment on Mechanical Properties of Al–Mg–Si Welded Joints

Metals ◽

10.3390/met10121607 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1607

Author(s):

Amir Hossein Baghdadi ◽

Zainuddin Sajuri ◽

Mohd Zaidi Omar ◽

Armin Rajabi

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Friction Stir Welding ◽

Grain Growth ◽

Precipitation Hardening ◽

Al Alloys ◽

Abnormal Grain Growth ◽

Post Weld Heat Treatment ◽

Welding Parameters ◽

Friction Stir

Friction stir welding (FSW) is an alternative method to join aluminum (Al) alloys in a solid-state condition. However, the coarsening or dissolution of precipitation hardening phases in the welding zone causes strength reduction or softening behavior in the welded area of age-hardened Al alloys. Therefore, this research aimed to improve the mechanical properties of an FSW Al–Mg–Si alloy via post-weld heat treatment (PWHT) and the possibility of controlling the abnormal grain growth (AGG) using different welding parameters. FSW was performed with different rotational and travel speeds, and T6 heat treatment was carried out on the FSW samples as the PWHT. The results showed a decrease in the strength of the FSW samples compared with that of the base material (BM) due to the dissolution of precipitation hardening particles in the heat-affected zone. However, the emergence of AGG in the microstructure after the T6-PWHT was identified as the potential event in the microstructure of the PWHT samples. It is found that the AGG of the microstructure in similar joints of Al6061(T6) was governed by the welding parameters. The results proved that PWHT was able to increase the tensile properties of the welded samples to values comparable to that of Al6061(T6)-BM. The increased mechanical properties of the FSW joints were attributed to a proper PWHT that resulted in a homogeneous distribution of the precipitation hardening phases in the welding zones.

Download Full-text