Structural and phase composition modification of nanocrystalline Nd14Fe79B7 alloy during thermomagnetic measurements

Changes in the microstructure parameters, phase composition and magnetic properties of rapid quenched Nd-rich Nd14Fe79B7 alloy caused by thermomagnetic measurement (TM) were studied using XRD methods of phase analysis, crystallite size and lattice microstrain determination. The observed changes were analyzed between the optimized magnetic state of this alloy and state after TM up to 800oC. Measurement of magnetic properties was carried out on the SQUID magnetometer at ambient temperature. The obtained experimental results show that the investigated alloy in the optimized magnetic state has nearly monophase composition with predominant content of hard magnetic Nd2Fe14B phase (up to 95 mass %) with mean crystallite size below 60 nm. In the state after TM, it was found that the decreased amount of Nd2Fe14B phase (75 mass%), increased amount of soft magnetic phases, predominantly of Fe7Nd5, formation of Nd-rich oxide Nd2O3 phase, as well as grain growth have caused the observed quality loss of hard magnetic properties.

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Effects of phase composition and elemental partitioning on soft magnetic properties of AlFeCoCrMn high entropy alloys

Acta Materialia ◽

10.1016/j.actamat.2019.04.007 ◽

2019 ◽

Vol 171 ◽

pp. 31-39 ◽

Cited By ~ 9

Author(s):

Chanwon Jung ◽

Ku Kang ◽

Amalraj Marshal ◽

Konda Gokuldoss Pradeep ◽

Jae-Bok Seol ◽

...

Keyword(s):

Magnetic Properties ◽

Phase Composition ◽

High Entropy Alloys ◽

Soft Magnetic Properties ◽

Soft Magnetic ◽

High Entropy

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Nano-Crystalline Barium Hexaferrite Powders Prepared by Mechanical Alloying Using Acetate Precursor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.610 ◽

2008 ◽

Vol 368-372 ◽

pp. 610-612 ◽

Cited By ~ 3

Author(s):

M. Honarvar Nazari ◽

Abolghasem Ataie ◽

S.A. Seyyed Ebrahimi

Keyword(s):

Heat Treatment ◽

Magnetic Properties ◽

Phase Composition ◽

Mechanical Alloying ◽

Thermal Behavior ◽

Crystallite Size ◽

Barium Hexaferrite ◽

Subsequent Heat Treatment ◽

Molar Ratios ◽

Nano Crystalline

Nano-crystalline barium hexaferrite powders have been prepared by mechanical alloying of nFe2O3+Ba(CH3COO)2 with Fe/Ba molar ratios of 10-12 and subsequent heat treatment. Thermal behavior, phase composition, morphology and magnetic properties of samples were studied using DTA/TGA, XRD, SEM and VSM, respectively. Nano-crystalline Ba-hexaferrite with a mean crystallite size of 46 nm and magnetic properties as high as Ms = 73.9 A.m2/kg and Hci = 334.2 kA/m was formed for mixture of 5.5Fe2O3+Ba(CH3COO)2 which was milled for 48 h and then annealed at 1100 °C.

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A comparative thermomagnetic study of melt-spun Nd-Fe-B alloys with different Nd content

Science of Sintering ◽

10.2298/sos0903337g ◽

2009 ◽

Vol 41 (3) ◽

pp. 337-345 ◽

Cited By ~ 3

Author(s):

A. Grujic ◽

T. Zák ◽

N. Talijan ◽

J. Stajic-Trosic ◽

V. Cosovic

Keyword(s):

Magnetic Properties ◽

Phase Composition ◽

Magnetic State ◽

Hysteresis Loops ◽

Direct Influence ◽

X Ray ◽

Thermomagnetic Analysis ◽

Melt Spun ◽

Before And After ◽

Fe2b Phase

Changes in the phase composition and magnetic properties of three types of commercial Nd-Fe-B alloys with different Nd content - low (10-12 wt%), near stoichiometric (21-25 wt%) and rich (26-29 wt%) caused by thermomagnetic analysis (TM) were observed in regard to optimal magnetic state. Phase compositions of investigated alloys before and after TM measurement up to 800?C were compared using 57Fe M?ssbauer spectroscopy and X-Ray analysis. The TM measurements decompose all three materials and the main products of decomposition process ?-Fe and Fe2B phase. Observed changes in structure and phase composition had direct influence on magnetic properties. Loss of magnetic properties induced by thermal decomposition is clearly illustrated on corresponding SQUID hysteresis loops.

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MAGNETIC PROPERTIES AND MICROSTRUCTURE OF Co–Ni–Fe–Gd–Mn ELECTRODEPOSITED THIN FILM

Surface Review and Letters ◽

10.1142/s0218625x20500390 ◽

2020 ◽

pp. 2050039

Author(s):

R. SURESH ◽

P. SATHISHKUMAR ◽

S. KUMARAVELAN ◽

S. SESHADRI

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Copper Substrate ◽

Ion Concentration ◽

Recording Media ◽

Two Dimensional ◽

Soft Magnetic ◽

One Dimensional ◽

Mn Concentration ◽

Hard Magnetic Properties

The magnetic properties and microstructures of electrodeposited Co–Ni–Fe–Gd thin films have been investigated for various concentrations of Mn. Nanocrystalline Co–Ni–Fe–Gd alloy thin films were deposited by electrodeposition method on copper substrate with different concentrations of Mn. Microstructures of the deposited Co–Ni–Fe–Gd films were investigated with scanning electron microscope (SEM) and different morphologies such as one-dimensional flower-like crystallites and two-dimensional plate-like crystallites were observed. The Co–Ni–Fe–Gd alloy films exhibit both soft and hard magnetic properties as the Mn ion concentration is varied and the best soft magnetic character is obtained when Mn concentration is 0.1 M, which may be a good candidate for MEMS and recording media.

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Microstructure in soft magnetic E3 (S1, Al) (Sendust) alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105916 ◽

1988 ◽

Vol 46 ◽

pp. 770-771

Author(s):

June D. Kim

Keyword(s):

Electron Microscopy ◽

Magnetic Properties ◽

Ternary Phase Diagram ◽

Vertical Tube ◽

Vacuum Induction Melting ◽

Induction Melting ◽

Soft Magnetic ◽

Quenching Temperature ◽

Thin Foils ◽

Vertical Tube Furnace

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.

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