Sintering Sm2Fe17 Prior to Nitrogenation

2008 ◽  
Vol 591-593 ◽  
pp. 75-79 ◽  
Author(s):  
R. Bahr ◽  
R. Hesse ◽  
J.C. Boareto ◽  
Paulo A.P. Wendhausen
Keyword(s):  
Magnetic Properties ◽  
Casting Process ◽  
Mass Gain ◽  
Maximum Energy ◽  
X Ray Diffraction ◽  
Initial Composition ◽  
X Ray ◽  
Hard Magnets ◽  
Energy Products ◽  
Hard Magnetic Properties

The sintering of Sm2Fe17 compound prior to the nitrogenation process is studied as an alternative process to produce dense Sm2Fe17N3 hard magnets with higher maximum energy products (BH)max than conventional polymer bonded magnets. In order to optimize sintering and nitrogenation processes, powders made from alloys, with different compositions, in the as-cast as well in the as-homogenized state were used. It could be shown that the amount of α-Fe, formed in the casting process, was reduced during sintering and that Sm selective loss is restricted to the surface up to a depth of 100 +m. Moreover the density of the sintered samples was not much affected by the initial composition or by the prior homogenization of the alloys. Although the nitrogenation process was successful in producing the Sm2Fe17N3 as proved by the mass gain, magnetic properties measurements and X-Ray diffraction, the hard magnetic properties were much lower than expected, indicating that other variables, which are discussed in the text, must be considered.

Melt-Spun Permanent Magnet Alloy with Enhanced Isotropic Remanence

1986 ◽  
Vol 80 ◽  
Author(s):  
A. M. Kadin ◽  
R. W. McCallum ◽  
G. B. Clemente ◽  
J. E. Keem
Keyword(s):  
Permanent Magnet ◽  
High Performance ◽  
Melt Spinning ◽  
Maximum Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Performance ◽  
Magnet Alloy ◽  
Energy Products ◽  
Permanent Magnet Alloy

AbstractRapid solidification onto a copper quench surface (melt-spinning) has been used to fabricate a high-performance permanent magnet alloy (Ovonic Hi-Rem™) based on the Nd-Fe-B class of materials. Crucial idditions of alloying elements are combined with careful control over quench parameters to yield a random assembly of microcrystallites, with macrosconically isotropic magnetic properties including values of remanent induction that can exceed 10 kG and maximum energy products greater than 20 MGOe. These values exceed those expected from conventional randomly oriented magnets. The enhanced magnetic performance is related to results of x-ray diffraction and electron microscopy.

A study on the microstructural and magnetic properties of the Sr0.70-xBaxLa0.30Fe11.78Cu0.22O19 hexagonal ferrites

2014 ◽  
Vol 28 (21) ◽  
pp. 1450140 ◽  
Author(s):  
Yujie Yang ◽  
Xiansong Liu
Keyword(s):  
Magnetic Properties ◽  
Maximum Energy ◽  
Hexagonal Ferrites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Test Instrument ◽  
Intrinsic Coercivity ◽  
Ceramic Process

Hexagonal ferrite Sr 0.70-x Ba x La 0.30 Fe 11.78 Cu 0.22 O 19 (0 ≤ x ≤0.7) magnetic powders and magnets were synthesized by the ceramic process. The phase compositions of the magnetic powders were investigated by X-ray diffraction. There is a single magnetoplumbite phase in the magnetic powders with barium content (x) from 0 to 0.70. The micrographs of the magnets were observed by a field emission scanning electron microscopy. All magnets have formed hexagonal structures and the particles are distributed evenly. Magnetic properties of the magnets were measured by a magnetic properties test instrument. The remanence, intrinsic coercivity, magnetic induction coercivity and maximum energy product of the magnets continuously decrease with the increase of barium content (x).

The crystal morphology of 2:17 rare-earth cobalt permanent magnets

1983 ◽  
Vol 41 ◽  
pp. 256-257
Author(s):  
G. C. Hadjipanayis ◽  
K. R.
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Crystal Morphology ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Products ◽  
Hard Magnetic Properties

Precipitation hardened Sm2(Co,Fe,Cu,Zr)17 permanent magnets are of great technological importance because of their large coercive fields (Hc∽ 6-15 kOe) and energy products ((BH)m ∽ 25-30 MGOe). The hard magnetic properties of these magnets are usually achieved after a complex heat treatment. The samples are first sintered at 1200 C and then quenched to room temperature. The sintered magnets are aged at around 830 C, slowly cooled to 400 C and then quenched again to room temperature. Microstructure studies have been reported on several 2:17 magnets at their optimum state. The purpose of this study is to examine the changes in the microstructure that are produced by the described heat treatment and determine how they affect the hard magnetic properties of the magnets. Samples of a commercial TDK REC-26 magnet (Sm(Co,Fe,Cu,Zr)7.5) were prepared at different stages of the heat treatment. Electropolishing together with ion thinning were used to prepare the specimens for transmission electron microscopy. The microstructure observations were made with a Philips 400 TEM equipped with an energy dispersive x-ray analysis unit.

Influence of Cladless Hot Isostatic Pressing on Magnetic Properties and Corrosion Resistance of Sintered NdFeB Magnets

2013 ◽  
Vol 538 ◽  
pp. 211-214
Author(s):  
Zhi Qin Liao ◽  
Feng Xu ◽  
Wei Jin Yan ◽  
Qi Jun Huang ◽  
Guang Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Magnetic Energy ◽  
Hot Isostatic Pressing ◽  
X Ray Diffraction ◽  
Ndfeb Magnets ◽  
X Ray ◽  
Isostatic Pressing ◽  
Energy Products

In this work, the cladless hot isostatic pressing (HIP) is performed on sintered NdFeB magnets. After the processings, the density of the magnets is slightly increased. The statistics of microstructure shows the growth of grains. The evaluation by X-ray diffraction shows that the alignment degree of grains decreases. These effects slightly improve the magnetic energy products, meanwhile bring about the deterioration of coercivity. Corresponding to the increase of density, the corrosion resistance checked by electrochemistry method becomes better after HIP processings.

scholarly journals Green synthesis and characterization of hexaferrite strontium-perovskite strontium photocatalyst nanocomposites

2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Magnetic Properties ◽  
Green Synthesis ◽  
Sol Gel ◽  
Synthesis Method ◽  
Combustion Method ◽  
Lemon Juice ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.

scholarly journals Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Low Frequency ◽  
Solid State Reaction Method ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Frequency Regime ◽  
Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

Effect of Nitridation Magnetic Properties of Nanocrystalline Fe-Co Alloy Powders

2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron ◽  
Nitridation Temperature ◽  
Microstructure And Magnetic Properties

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.

Magnetic Properties of Bulk Zn0.95-XMnXFe0.05O2 Prepared by Sol-Gel Method and Subsequent Hot Pressing

2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He
Keyword(s):  
Magnetic Properties ◽  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Sol Gel ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.

High temperature corrosion behaviour of aluminised FC 25 cast iron using pack cementation

2019 ◽  
Vol 66 (2) ◽  
pp. 236-241 ◽  
Author(s):  
Somrerk Chandra-Ambhorn ◽  
Neramit Krasaelom ◽  
Tummaporn Thublaor ◽  
Sirichai Leelachao
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
Corrosion Behaviour ◽  
Mass Gain ◽  
High Temperature Corrosion ◽  
Pack Cementation ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Seat Insert

Purpose This study aims to apply the pack cementation to develop the Fe-Al layers on the surface of FC 25 cast iron in order to increase the high-temperature corrosion resistance of the alloy. Design/methodology/approach Pack cementation was applied on the surface of FC 25 cast iron at 1,050°C. The bare and aluminised alloys were subjected to the oxidation test in 20 per cent O2-N2 at 850 °C. Scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD) were used for characterisation. Findings The layers of pack cementation consisted of Fe2Al5, FeAl2 and FeAl, and solid solution alloyed with Al. The oxidation kinetics of the bare cast iron was parabolic. Mass gain of the aluminised cast iron was significantly decreased compared with that of the bare cast iron. This was because of the protective alumina formation on the aluminised alloy surface. Al in the Fe–Al layer also tended to be homogenised during oxidation. Originality/value Even though the aluminising of alloys was extensively studied, the application of that process to the FC 25 cast iron grade was originally developed in this work. The significantly reduced mass gain of the aluminised FC 25 cast iron makes the studied alloy be promising for the use as a valve seat insert in an agricultural single-cylinder four-stroke engine, which might be run by using a relatively cheaper fuel, i.e. LPG, but as a consequence requires the higher oxidation resistance of the engine parts.

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

2007 ◽  
Vol 130 ◽  
pp. 171-174 ◽  
Author(s):  
Z. Stokłosa ◽  
G. Badura ◽  
P. Kwapuliński ◽  
Józef Rasek ◽  
G. Haneczok ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Second Stage ◽  
Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

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