The Microstructure of Melt-Spun Iron Neodymium Permanent Magnet Materials

1985 ◽  
Vol 43 ◽  
pp. 210-211
Author(s):  
R. C. Dickenson
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Melt Spinning ◽  
Ion Milling ◽  
X Ray ◽  
Fine Grained ◽  
Cold Stage ◽  
Melt Spun ◽  
Fine Grained Structure ◽  
Permanent Magnet Materials

Rapidly-quenched iron rare-earth boron alloys, with appropriate heat treatment, exhibit commercially promising permanent magnetic properties. This paper will report the results of an AEM characterization undertaken to explain the origin of the magnetic properties of an iron-neodymium-boron alloy in terms of its microstructure. Ribbons of Fe76 Nd16 B8 were prepared by melt-spinning, and were subsequently annealed at 700°C for 6 minutes to promote growth of a fine-grained structure. Samples were prepared for AEM by ion-milling the ribbons on a cold stage and examined using a Philips 400T TEM/STEM equipped with an energy dispersive x-ray unit.Three different microstructures are commonly observed in these alloys, and several others have been found in isolated cases.

EFFECT OF NANOCRYSTALLIZATION ANNEALING ON MAGNETIC PROPERTIES AND MAGNETOIMPEDANCE OF CO-BASE RIBBONS

2012 ◽  
Vol 05 ◽  
pp. 841-846
Author(s):  
AMIR KEYVANARA ◽  
REZA GHOLAMIPOUR ◽  
SHAMSEDIN MIRDAMADI ◽  
FARZAD SHAHRI ◽  
HOSSEIN SEPEHRI AMIN
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Nanocrystalline Phases

Melt spun ribbons of Co 64 Fe 4 Ni 2 B 19 Si 8 Cr 3 alloy have been prepared and the nanocrystallization process was carried out by the heat treatment of the as spun ribbons above the crystallization temperature. Structural studies of the samples have been performed by transmission electron microscopy and X-ray diffraction. Magnetic properties of the samples and magnetoimpedance measurements were investigated and it was revealed that magnetic properties and magnetoimpedance of the samples deteriorate by the formation of nanocrystalline phases.

A Study on Nanocrystalline Nickel Parts Prepared by Jet Electrodeposition

2010 ◽  
Vol 37-38 ◽  
pp. 64-67
Author(s):  
Jin Song Chen ◽  
Yin Hui Huang ◽  
Bin Qiao ◽  
Jian Ming Yang ◽  
Yi Qiang He
Keyword(s):  
Dimensional Accuracy ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Scanning Microscope ◽  
Nanocrystalline Nickel ◽  
X Ray ◽  
Fine Grained ◽  
Average Grain Size ◽  
Jet Electrodeposition ◽  
Fine Grained Structure

The principles of jet electrodeposition orientated by rapid prototyping were introduced. The nanocrystalline nickel parts with simple shape were fabricated using jet electrodeposition. The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument. The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure (average grain size 25.6nm) with a smooth surface and high dimensional accuracy under the optimum processing parameters.

Microstructure in Rapidly Quenched Al-Ti,Al-B and Al-Ti-B Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
A. Majumdar ◽  
R. H. Mair ◽  
B. C. Muddle
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Melt Spinning ◽  
Analytical Electron Microscopy ◽  
Primary Phase ◽  
Nucleation Sites ◽  
Uniform Dispersion ◽  
Average Grain Size ◽  
Melt Spun ◽  
Chill Cast

AbstractRapidly quenched ribbons (˜50m thickness) of Al-5wt.%Ti, Al-lwt.%B and a range of Al-Ti-B alloys have been produced by melt spinning under He atmosphere and the microstructures of the ribbons, following solidification and post-solidification heat treatment, characterized using analytical electron microscopy. In the Al-5Ti alloy, the coarse equilibrium primary phase (b.c.t. Al3 Ti) that is observed following conventional casting is replaced by fine (0.1–0. 2μm), cuboidal particles of a metastable cubic (Ll2) Al3Ti in melt-spun ribbon. These metastable particles form directly from the melt and act as nucleation sites for the solid solution which subsequently forms. A refined microstructure with an average grain size of 1–2μm results. A supersaturation of Ti is retained in matrix solid solution following solidification and a variety of solid state precipitate forms, including fine dispersions of coherent, metastable Al3 Ti particles, is observed to emerge during post-solidification heat treatment. For the Al-1B alloy, the coarse distribution of primary AlB2 particles in a chill-cast ingot is replaced by a fine, uniform dispersion of the metastable boride, α-AlB12, in the melt-spun ribbon. Attempts to induce a refined boride dispersion in melt-spun Al-Ti-B alloys have proved largely unsuccessful.

Influence of Co-Doping on Magnetic Properties and Magnetocaloric Effect of Fe–Co–Zr–Cu–B Melt-Spun Ribbons

2021 ◽  
Vol 21 (4) ◽  
pp. 2552-2557
Author(s):  
Nguyen Hai Yen ◽  
Nguyen Hoang Ha ◽  
Pham Thi Thanh ◽  
Nguyen Huy Ngoc ◽  
Tran Dang Thanh ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetocaloric Effect ◽  
Melt Spinning ◽  
Room Temperature ◽  
Tangential Velocity ◽  
Magnetic Behavior ◽  
Entropy Change ◽  
Co Doping ◽  
Melt Spun ◽  
Melt Spun Ribbons

In this work, we investigated magnetic properties and magnetocaloric effect in Fe90−xCoxZr7Cu1B2 (x = 0, 1, 2, 3 and 4) melt-spun ribbons. The ribbons were prepared by using a melt-spinning method with a tangential velocity of a copper wheel of 40 m·s-1. The obtained ribbons are almost amorphous. The alloys exhibit typical soft magnetic behavior with low coercivity at room temperature. A minor replacement of Fe by Co gives an increment in Curie temperature (TC) of the alloys to higher temperatures. The TC of the alloys increases from 242 to 342 K with an increase of x from 0 to 4. Maximum magnetic entropy change, ΔSm max, of the alloys, was found to be larger than 0.7 J·kg-1·K-1 in a magnetic field change ΔH of 12 kOe for all the concentrations of Co. High refrigerant capacitys (RC >100 J ·kg-1 with ΔH = 12 kOe) at room temperature region have been obtained for the alloys. The large magnetocaloric effect near room temperature suggests that the alloys can be considered as magnetic refrigerants in the range of 250–350 K.

scholarly journals Phase Formation and Magnetic Properties of Melt Spun and Annealed Nd-Fe-B Based Alloys with Ga Additions

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 497
Author(s):  
Shchetinin ◽  
Aggrey ◽  
Bordyuzhin ◽  
Savchenko ◽  
Gorshenkov ◽  
...  
Keyword(s):  
Magnetic Property ◽  
Amorphous Phase ◽  
Melt Spinning ◽  
Fluorescence Analysis ◽  
Structural Transformations ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Melt Spun ◽  
Property Changes

The structural transformations and magnetic property changes of the Nd16.2FebalCo9.9Ga0.5B7.5 (SG1, SG2) and Nd15.0FebalGa2.0B7.3 (SG3) nanocomposite alloys obtained by melt spinning in the as-quenched state and after annealing at a temperature range of 560–650 °C for 30 min were studied. The methods used were X-ray diffraction analysis, magnetic property measurements, TEM studies, X-ray fluorescence analysis and Mössbauer spectroscopy. Amorphous phase and crystalline phase Nd2Fe14B (P42/mnm) were observed in the alloy after melt spinning. The content of the amorphous phase ranged from 20% to 50% and depended on the cooling rate. Annealing of the alloys resulted in amorphous phase crystallization into Nd2Fe14B and led to the increased coercivity of the alloys up to 1840 kA/m (23.1 kOe) at 600 °C annealing for 30 min. The alloy with the maximum coercivity had a grain size of the Nd2Fe14B phase ≈50–70 nm with an Nd-rich phase between grains.

scholarly journals Effect of Radial Forging on the Microstructure and Mechanical Properties of Ti-Based Alloys

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1488
Author(s):  
Lev B. Zuev ◽  
Galina V. Shlyakhova ◽  
Svetlana A. Barannikova
Keyword(s):  
Phase State ◽  
Metal Flow ◽  
Mechanical Processing ◽  
Radial Forging ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Fine Grained ◽  
Fine Grained Structure

Radial forging is a reliable way to produce Ti alloy rods without preliminary mechanical processing of their surface, which is in turn a mandatory procedure during almost each stage of the existing technology. In the present research, hot pressing and radial forging (RF) of the titanium-based Ti-3.3Al-5Mo-5V alloy were carried out to study the specifics of plasticized metal flow and microstructural evolution in different sections of the rods. The structural analysis of these rods was performed using metallography and X-ray diffraction techniques. The X-ray diffraction reveals the two-phase state of the alloy. The phase content in the alloy was shown to vary upon radial forging. Finally, radial forging was found to be a reliable method to achieve the uniform fine-grained structure and high quality of the rod surface.

Magnetic and Structural Properties of Ferrimagnetic Bioceramics

2005 ◽  
Vol 473-474 ◽  
pp. 117-122 ◽  
Author(s):  
A.C. Kis ◽  
Th. Leventouri ◽  
J.R. Thompson
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Calcium Phosphate ◽  
Powder Diffraction ◽  
Magnetic Measurements ◽  
Treatment Temperature ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Phase Development

Structure and magnetic properties of ferrimagnetic bioceramics in the system {0.45(CaO, P2O5) ySiO2 xFe2O3 0.03Na2O}, x=0.05, 0.10, 0.15, 0.20, were studied by x-ray powder diffraction and magnetic measurements. Magnetite and calcium phosphate, crystallizing in the hexagonal and monoclinic crystal systems, are the major phases in the compounds. Phase development, crystal structure, and magnetic properties of the composites are determined by the specific starting composition of oxides and the heat-treatment temperature.

Effect of Dysprosium Content on the Magnetic Properties of Nanocrystalline (Pr0.25Nd0.75)10-xDyxFe82Co2B6 Alloys

2014 ◽  
Vol 789 ◽  
pp. 28-31 ◽  
Author(s):  
He Wei Ding ◽  
Chun Xiang Cui ◽  
Ji Bing Sun
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Maximum Energy ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Intrinsic Coercivity ◽  
Electronic Microscope ◽  
Microstructure And Magnetic Properties

(Pr0.25Nd0.75)10-xDyxFe82Co2B6(x=0~0.3) ribbons were prepared by melt spinning at 25m/s and subsequent annealing. The effect of Dy content on the microstructure and magnetic properties of the ribbons has been investigated by X-ray diffractometer (XRD), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). The magnetic properties related to the Dy content were characterized. Intrinsic coercivity of 598kA/m, remanence of 0.58T, and the maximum energy product (BH)max of 43kJ/m3 were achieved in (Pr0.25Nd0.75)9.8Dy0.2Fe82Co2B6 after annealing at 700°C for 10 minutes.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND MAGNETOSTRICTIVE PROPERTY OF MELT-SPUN Fe85Ga15 RIBBONS

2013 ◽  
Vol 27 (30) ◽  
pp. 1350174 ◽  
Author(s):  
HAO LIU ◽  
HAIOU WANG ◽  
MENGXIONG CAO ◽  
WEISHI TAN ◽  
YANGGUANG SHI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
High Resolution ◽  
Nearest Neighbor ◽  
Annealed Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption Fine ◽  
Melt Spun ◽  
X Ray Absorption

In order to study the microstructure of Fe – Ga alloy, Fe 85 Ga 15 ribbons prepared with different wheel velocity were studied by high resolution X-ray diffraction (HRXRD) and extend X-ray absorption fine structure (EXAFS). HRXRD patterns showed that only disordered A 2 phase was observed in as-cast Fe 85 Ga 15 alloy. A modified- DO 3 phase was detected in all of the melt spun samples. The HRXRD associated with EXAFS results indicated that Ga atoms were located as second-nearest neighbor along [100] orientation. A little DO 3 phase was found in ribbons annealed at 1000°C under 0.06 MPa Ar atmosphere. The result of magnetostriction measurement revealed that in the ribbon prepared with higher wheel velocity, more modified- DO 3 phase will enhance the magnetostriction. DO 3 phase in the annealed sample will deteriorate the magnetostrictive properties of Fe – Ga ribbons.

Recrystallization of Amorphous or Nanocrystalline NdBa2Cu3O7−x and GdBa2Cu3O7−x

1992 ◽  
Vol 275 ◽  
Author(s):  
T. J. Folkerts ◽  
S. I. Yoo ◽  
Youwen Xu ◽  
M. J. Kramer ◽  
K. W. Dennis ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Xrd ◽  
Melt Spun ◽  
Temperature Heat ◽  
Higher Temperature ◽  
Xrd Studies ◽  
Melt Spinning Technique

ABSTRACTUsing a novel melt-spinning technique, we have produced highly disordered NdBa2Cu3O7−x and GdBa2Cu3Oy−x materials. Samples which were melt-spun in an O2 environment consist of nanocrystals with the tetragonal REBa2Cu3O7−x structure: samples which were processed in an N2 environment consist of an amorphous matrix with small amounts of crystalline BaCu2O2, as shown by x-ray diffraction and electron microscopy. High temperature XRD studies indicate that the BaCu2O2 is eliminated during heating to 500°C in O2 and that the REBa2Cu3O7−x Phase recrystallizes directly from the amorphous matrix at temperatures below 800°C. Preliminary magnetization measurements show that higher temperature heat treatments are needed to restore superconductivity.

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