Microstructure and microanalysis of sintered Fe-Nd-B permanent magnets

1990 ◽  
Vol 48 (4) ◽  
pp. 990-991
Author(s):  
Mahesh Chandramouli
Keyword(s):  
Electron Microscope ◽  
Liquid Phase ◽  
Permanent Magnets ◽  
Phase Distribution ◽  
Energy Dispersive Spectrometer ◽  
Nucleation And Growth ◽  
Liquid Phase Sintering ◽  
Domain Wall Energy ◽  
Oxide Phases ◽  
Scanning Electron

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.

Thermodynamic Analysis of Copper Melt Deoxidation with Lanthanum

2017 ◽  
Vol 265 ◽  
pp. 900-905
Author(s):  
O.V. Samoilova ◽  
G.G. Mikhailov ◽  
L.A. Makrovets
Keyword(s):  
Electron Microscope ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Energy Dispersive Spectrometer ◽  
Rare Earth Metals ◽  
Inclusion Type ◽  
Experimental Part ◽  
Copper Melt ◽  
Oxide Phases ◽  
Scanning Electron

Using rare earth metals as deoxidizers is an efficient way of getting highly deoxidized copper melt required for certain bronzes production. Thermodynamic modeling of phase equilibria in the Cu–La–O system in the temperature range of 1100–1300 °С was performed to assess a possible depth of copper melt deoxidation with lanthanum, and also to determine the resulting oxide phases. During the experimental part of the work, Cu–La–O system metal samples were melted and then studied with the JEOL JSM 6460-LV scanning electron microscope equipped with the energy-dispersive spectrometer providing electron microprobe analysis to specify formed nonmetallic inclusion type.

Studying on High Temperature Thermoplastic of High Carbon Steel

2014 ◽  
Vol 809-810 ◽  
pp. 384-389
Author(s):  
Lang He ◽  
Yu Tang
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Melting Point ◽  
Liquid Phase ◽  
Energy Dispersive Spectrometer ◽  
High Carbon Steel ◽  
Optical Microscope ◽  
High Carbon ◽  
Solid Liquid ◽  
Scanning Electron

High temperature thermoplastic of 50Mn2V casting slab was tested by Gleeble-1500 thermal simulator machine. The morphology, microstructure and composition of fracture surfacewere observed and analyzed by optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).The results show that, there are two brittle temperature zones of 50Mn2V casting slab at the temperature of 600~950°C and 1300~1465°C, respectively, The section shrinkaging rate is less than 60%. The fracture mode changes from mixed one dominated by intergranular to toughness transgranular one with the increase of temperature at the range of 600~1250°C. However, the fracture is along with the solid-liquid phase at the range of 1300°C~ melting point.

Study on the Formation of Nanometer Silver Sol by Micro Arc Discharge

2014 ◽  
Vol 490-491 ◽  
pp. 8-13
Author(s):  
Jing Yang ◽  
Zhi Yu Yan ◽  
Bing Sun ◽  
Qiao Min Wang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electrolyte Solution ◽  
Sodium Citrate ◽  
Preparation Method ◽  
Arc Discharge ◽  
Energy Dispersive Spectrometer ◽  
Original Size ◽  
Stabilizer Type ◽  
Scanning Electron

A preparation of nanometer silver sol by micro arc discharge has been study here through the reduction of Ag3PO4. Sodium citrate and polyvinylpyrrolidone were added respectively into the electrolyte as stabilizer. The results show that, the Ag3PO4 concentration, stabilizer type and concentration have great impacts on the formation of the nanometer silver sol. By means of UV-VIS extinction spectrophotometer, scanning electron microscope and energy dispersive spectrometer, it is found that the solid powder extracted from the electrolyte solution after discharge is the aggregation of the silver formed in the solution and their original size maybe less than 20nm. Nanometer silver with smaller size and narrower size distribution can be obtained with sodium citrate as stabilizer than with polyvinylpyrrolidone. But the latter has higher conversion rate. From this experiment, we found that micro arc discharge can be a rapid, stable preparation method of nanometer silver sol.

Photoelectrochemical Properties of Anatase TiO2 Films Prepared by Improved Liquid Phase Deposition

2015 ◽  
Vol 1120-1121 ◽  
pp. 419-423
Author(s):  
Cai Xia Lei ◽  
X.L. Jiang ◽  
Y. Liu ◽  
X. Liu ◽  
Y.T. Ma ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Liquid Phase ◽  
Scanning Electron Microscope ◽  
Reaction Temperature ◽  
White Light ◽  
Photoelectrochemical Properties ◽  
Liquid Phase Deposition ◽  
X Ray ◽  
Good Crystallinity ◽  
Scanning Electron

In this paper, the hydrothermal-assisted liquid phase deposition (HT-LPD) method has been developed to prepare TiO2 films. The crystalline structures and morphologies of as-prepared TiO2 films were analyzed using an X-ray diffractometer (XRD) and scanning electron microscope (SEM). It was found that the HT-LPD TiO2 film showed good crystallinity with preferrred orientation along c-axis. Moreover, the as-prepared TiO2 films consisted of two layers, with the tiny nanoparticles as the underlying layer and the flower-like clusters as the upper layer. The photoelectrochemical measurements revealed that, when illuminated by the white light, the HT-LPD TiO2 films exhibited a more negative photopotential value and an increased photocurrent value with elevated reaction temperature, excepting for the sample prerared at 150 °C. In summary, the TiO2 films prepared by the improved LPD method could be served as the promising photoanode for the photoelectrochemical applications.

scholarly journals Calorimetric study on Bi-Cu-Sn alloys

2019 ◽  
Vol 38 (2019) ◽  
pp. 541-546
Author(s):  
Jolanta Romanowska
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Temperature Interval ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Calorimetric Study ◽  
Calorimetric Investigation ◽  
Scanning Calorimetry ◽  
Scanning Electron

AbstractThe paper presents results of calorimetric investigation of the Bi-Cu-Sn system by means of differential scanning calorimetry (DSC) at the temperature interval 25-1250∘C, Values of liquidus, solidus and invariant reactions temperatures, as well as melting enthalpies of the selected alloys were determined. Microstructure investigation of the alloys were performed by the use of a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS).

scholarly journals Effect of Cerium on the Microstructure and Inclusion Evolution of C-Mn Cryogenic Vessel Steels

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5262
Author(s):  
Liping Wu ◽  
Jianguo Zhi ◽  
Jiangshan Zhang ◽  
Bo Zhao ◽  
Qing Liu
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Heterogeneous Nucleation ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Vessel Steel ◽  
Cryogenic Vessel ◽  
Central Segregation ◽  
Scanning Electron

The effects of Cerium (Ce) were studied on the casting slab quality, microstructure, and inclusion evolution of cryogenic vessel steel. An optical metallographic microscope, scanning electron microscope, energy dispersive spectrometer, and Thermo-calc thermodynamic software were used for characterization and analysis. The results indicated that the central segregation was significantly improved after adding Ce and reached the lowest level when the content of Ce was 0.0009 wt.%. Meanwhile, the presence of Ce reduces the size of ferrite and improves pearlite morphology. Ce also enables the modification of Al2O3 and MnS + Ti4C2S2 inclusions into ellipsoid CeAlO3 and spherical Ce2O2S + Ti4C2S2 composite inclusions, respectively, which are easier to remove. The formed Ce2O2S inclusions are fine and can work as heterogeneous nucleation points to refine the microstructure of steel.

Effect of Nano CaO and MgO Addition on the Inclusions Composition in the Cast Microstructure of X80 Pipeline Steel

2013 ◽  
Vol 395-396 ◽  
pp. 289-292
Author(s):  
Yan Liu ◽  
Chun Lin He ◽  
Qian He Ma ◽  
Yang Liu
Keyword(s):  
Electron Microscope ◽  
Molten Steel ◽  
Pipeline Steel ◽  
Energy Dispersive Spectrometer ◽  
X80 Pipeline Steel ◽  
Composite Oxides ◽  
Segregation Phenomenon ◽  
Calcium And Magnesium ◽  
Scanning Electron ◽  
Cast Microstructure

Nanometer calcium and magnesium oxides were added into molten steel by the carrier method in the experiment. The experiment takes the X80 pipeline steel as the research object and analyses the effect of nanometer calcium and magnesium oxides addition on the inclusions in the cast microstructure of the X80 pipeline steel. The scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were used to analyze the composition of the inclusions in the cast microstructure of the X80 pipeline steel. The result reveals that when no addition of nanooxides, the inclusions in the cast microstructure are the C-Fe-Si-Al-Mn-based inclusions. When adding nanoMgO, the inclusions are mainly the composite oxides of Fe-Mg-Si-O, Fe-Mg-Si-Mn-O and Mg-Si-Mn-Al-O. When adding nanoCaO, the inclusions are mainly the composite oxides of Fe-Ca-Al-O, Fe-Ca-Si-O, Fe-Ca-Si-Mn-O and the composite oxides or sulfides of Fe-Ca-Si-Mn-O-S. There is more Fe in some inclusions and Fe is not uniformly dispersed in the molten steel. As the result, some certain segregation phenomenon takes place.

scholarly journals Enhancing the Mechanical Properties of Hot Roll Bonded Al/Ti Laminated Metal Composites (LMCs) by Pre-Rolling Diffusion Process

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 795 ◽  
Author(s):  
Cheng Zhang ◽  
Shouxin Wang ◽  
Hanxue Qiao ◽  
Zejun Chen ◽  
Taiqian Mo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Diffusion Process ◽  
Energy Dispersive Spectrometer ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Interfacial Structure ◽  
Metal Composites ◽  
Diffusion Temperature ◽  
Scanning Electron

In this study, the traditional hot rolling to fabricate Al/Ti laminated metal composites (LMCs) was improved by using a pre-rolling diffusion process. The effect of the pre-rolling diffusion on microstructure and mechanical properties of Al/Ti LMCs were investigated by various methods, such as optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and tensile tests. The results show that, with increasing diffusion temperature, the thickness in diffusion layer was increased and the mechanical properties of LMCs were improved obviously, which was attributed to the optimized interfacial structure after diffusion process. In addition, the formation of TiAl3 intermetallic compounds (IMCs) was detected in the bonding interface, which played an important role in improving the mechanical properties for Al/Ti LMCs. The predicted results of stress-strain curves from rule of mixture (ROM) indicated that, there existed an extra interfacial strengthening in Al/Ti LMCs beside the mechanical properties provided by the contribution of constituent layers. The pre-rolling diffusion process is effective for the optimization of interfacial structure and improvement of mechanical properties in Al/Ti LMCs.

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