Surface phenomena during the early stage of liquid phase SPS of a mixture of coarse WC and Ni-alloy particles

2018 ◽  
Vol 50 (11) ◽  
pp. 1072-1076
Author(s):  
G. Maizza ◽  
R. Montanari ◽  
M. Richetta ◽  
A. Varone ◽  
S. Kaciulis ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Early Stage ◽  
Surface Phenomena ◽  
Alloy Particles ◽  
Ni Alloy

Synthesis and Magnetic Properties of Nanocrystalline Co-Ni Alloys: A Review

2012 ◽  
Vol 736 ◽  
pp. 229-240 ◽  
Author(s):  
Sudhakar Panday ◽  
P. Jeevanandam ◽  
B.S. Sunder Daniel
Keyword(s):  
Magnetic Properties ◽  
Binary Alloys ◽  
Synthesis Method ◽  
Surface Oxidation ◽  
Alloy Nanoparticles ◽  
Ni Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Co Concentration ◽  
Potential Applications

This review article deals with the synthesis, characterization and magnetic properties of Co-Ni nanoalloys. The various physical and chemical methods for the synthesis of Co-Ni alloy nanoparticles are discussed. Co-Ni alloy nanoparticles with different size and shape such as spherical, rods, wires chain-like assembly are found to depend on the synthesis method and experimental condition. The structure of Co-Ni alloys is eitherfcc,hcpor mixedfccandhcpphase and found to depends on size, shape and concentration of Co in the Co-Ni alloys. Sodium hydroxide (NaOH) concentration and Co to Ni ratio influence the shape of bimetallic Co-Ni nanoparticles. Pt nucleating agents produced smaller size of Co-Ni alloy particles compared to Ru and Ag. Higher Co concentration in the Co-Ni alloys also influences the size alloy particles. The magnetic properties of Co-Ni nanoalloys depend on the size, shape and composition of the binary alloys. Surface oxidation of Co-Ni alloy nanoparticles decrease the saturation magnetization and increases with Co concentration in the alloys. The shape of Co-Ni alloy nanoparticles has an influence on coercivity. The microwave absorption properties of the Co-Ni alloys found to depend on the shape, size and composition of the binary alloys. The absorbance peaks shifts to higher frequency with decrease in size of the alloy particles. Potential applications of Co-Ni alloys in various fields are highlighted.

scholarly journals A Novel Fabrication of Spherical Fe50ni50 Alloy Powders via in-Situ De-Wetting of Liquid Solid Interface

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 325
Author(s):  
Song ◽  
Lei ◽  
Zhong
Keyword(s):  
Spherical Shape ◽  
Soft Magnetic Property ◽  
Spherical Particles ◽  
Soft Magnetic ◽  
Sem Images ◽  
Cross Sectional ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Alumina Particles

: Spherical Fe50Ni50 alloy powders were fabricated via a novel route based on in-situ interface de-wetting between liquid Fe-Ni alloy and alumina. The obtained Fe50Ni50 alloy particles exhibit very good spherical shape according to SEM images. Furthermore, the cross-sectional SEM images show that there are no pores and bulk inclusions in the internal region of the spherical particles. The XRD results show a trace amount of the impurity alumina phase appearing in taenite phase. The size distribution agreed well with the SEM observation confirms that the alumina powders successfully segregated pre-alloy powders. As an incidental benefit, the surface alumina particles were treated as the electrical insulation coatings. The magnetic character shows that spherical Fe50Ni50 powders exhibit a good soft magnetic property even though with a slightly decreasing of saturation magnetization due to non-magnetic coatings. Our strategies provide a method to in-situ fabricate insulation coated Fe-Ni spherical alloy powders as magnetic powder core.

Enhanced hydrogen sorption capacities and kinetics of Mg2Ni alloys by ball-milling with carbon and Pd coating

2003 ◽  
Vol 18 (8) ◽  
pp. 1749-1752 ◽  
Author(s):  
R. Janot ◽  
L. Aymard ◽  
A. Rougier ◽  
G. A. Nazri ◽  
J. M. Tarascon
Keyword(s):  
Ball Milling ◽  
Surface Composition ◽  
Chemical Deposition ◽  
Practical Method ◽  
Hydrogen Desorption ◽  
Hydrogen Storage Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Kinetics Of ◽  
Determinant Factor

Solid-state hydrogen storage alloys are becoming a practical method to transport and utilize hydrogen as fuel for various technologies. In this paper, the kinetics and capacity of hydrogen desorption from Mg-based alloys have markedly been enhanced by tuning the surface composition of alloy particles. Mg2Ni–Ct, x composites (where t refers to the pregrinding time and x to the Brunauer–Emmet–Teller specific surface area) were prepared by ball-milling the alloy in the presence of preground graphite, and Pd-coated Mg2Ni alloy powders were obtained by controlled chemical deposition of Pd on the alloy surface. We have found that the optimization of the pregrinding step of carbon is a determinant factor in enhancing the hydrogen desorption capacity of the Mg2Ni–10 wt.% C10,320 composites to 2.6 wt.% at 150 °C, the maximum performance so far reported on desorption for Mg-based alloys. Such value can even be raised to 2.8 wt.% by applying Pd deposition on the composite.

Microstructural anomalies in a W-Ni alloy liquid phase sintered under microgravity conditions

1995 ◽  
Vol 26 (9) ◽  
pp. 2484-2486 ◽  
Author(s):  
Yixiong Liu ◽  
Ronald G. Iacocca ◽  
John L. Johnson ◽  
Randall M. German ◽  
Shiro Kohara
Keyword(s):  
Liquid Phase ◽  
Ni Alloy ◽  
Microgravity Conditions

Transient lunar phenomena, deep moonquakes, and high-frequency teleseismic events: possible connections

1977 ◽  
Vol 285 (1327) ◽  
pp. 485-487 ◽  
Keyword(s):  
High Frequency ◽  
Early Stage ◽  
The Moon ◽  
Surface Phenomena ◽  
Transient Phenomena ◽  
Teleseismic Events

The positions of the epicentres of the recently discovered, high-frequency teleseismic (h.f.t.), shallow moonquakes have been compared with those of the surface phenomena known as lunar transient phenomena (l.t.p.). About 300 sites for the latter and about 17 shallow moonquake epicentres have been recorded. Most of the epicentres are within 5° of at least one l.t.p. site and the depths are given by Nakamura et al. (1974) as up to 265 km. The present paper considers some of the implications of the correlations between the two classes of sites and between the l.t.p. and the epicentres of the deep moonquakes at levels of about 800-1000 km below the surface. It appears likely that channels produced by the outrush of gases from the interior of the Moon are associated with the sites of the h.f.t. and of the l.t.p. that are almost vertically above them, and that release of gases through poorly consolidated soils at an early stage of the Moon’s history may have led to the formation of at least some of the craters on the Moon.

Additive Sintering Process in Aluminum Nitride Ceramics

1991 ◽  
Vol 249 ◽  
Author(s):  
H. Makihara ◽  
N. Kamehara
Keyword(s):  
Thermal Conductivity ◽  
Phase Diagram ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Early Stage ◽  
Sintering Process ◽  
Residual Oxygen ◽  
Nitride Ceramics ◽  
Calcium Compounds ◽  
Oxygen Impurities

ABSTRACTCalcium compounds and yttrium compounds are frequently used as additives to densify AlN ceramics[l,2]. They react with oxygen impurities, such as A1203 in the raw AlN powder and in aluminate forms. A phase diagram is helpful in deciding the amount of additives to add, but the AlN sintering process doesn't come to equilibrium. We investigated the differences between sintering AlN with CaCO3 and with Y2O3.With CaCO3 added, the calcium-aluminate liquid phase evaporates from the sintered AlN body at high sintering temperatures. The AlN thermal conductivity doesn't increase above a sintering temperature of 1700°C because residual oxygen substitutes into the AlN grains. With Y2O3 added, AlN sinters below 1850°C, as predicted by a phase diagram. With a large amount of Y2O3 added, 5 wt%, thermal conductivity doesn't depend on residual oxygen. This is because yttrium doesn't evaporate from the sintered AlN body and residual oxygen substitutes into AlN grains at an early stage of the AlN sintering.

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