Iron nitride based magnetic powder synthesized by mechanical alloying of Fe-based glassy powders and solid nitrogen compounds

2021 ◽  
pp. 168329
Author(s):  
Jinyoung Kim ◽  
Jiyong Hwang ◽  
Seonghoon Yi
Keyword(s):  
Mechanical Alloying ◽  
Iron Nitride ◽  
Nitrogen Compounds ◽  
Magnetic Powder ◽  
Solid Nitrogen

Effect of Hydrogen on Formation of Fe-Al Nanoparticles by Mechanical Milling

2014 ◽  
Vol 29 ◽  
pp. 23-28 ◽  
Author(s):  
František Lukáč ◽  
Jakub Čížek ◽  
Yvonna Jirásková ◽  
Ivan Procházka ◽  
Marian Vlček ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Hydrogen Atmosphere ◽  
Nanocrystalline Powders ◽  
Iron Nitride ◽  
Nominal Composition ◽  
Al Nanoparticles ◽  
Air Atmosphere ◽  
Iron Aluminum ◽  
High Concentrations

Nanocrystalline powders of iron aluminum alloy of the Fe82Al18 nominal composition were prepared under air, hydrogen and nitrogen atmospheres from the Fe and Al elemental powders by mechanical alloying and also from the conventionally cast Fe82Al18 alloy by the high-energy ball milling. The intensive plastic deformation during high-energy mechanical treatment has introduced high concentrations of open volume defects and contributed to a rapid decrease in the crystallite size down to a nanoscopic range.The hydrogen atmosphere was found to be the most efficient for the Fe-Al mechanical alloying since it has resulted into the fully alloyed Fe82Al18 after 30 h of milling. On the other hand, the nitrogen and air atmosphere have slightly prevented mechanical alloying and after the same milling time the pure iron particles were still detected in the powder mixtures. This partial suppression of the mechanical alloying process is explained by a formation of thin iron nitride and/or oxide layers on the surface of Fe particles preventing mutual inter-diffusion of Fe and Al atoms.

Characterization of iron nitride powders formed by mechanical alloying and atmospheric heat treatment techniques

2001 ◽  
Vol 24 (6) ◽  
pp. 753-760 ◽  
Author(s):  
Chung‐Kwei Lin ◽  
Giin‐Shan Chen ◽  
Jium‐Shyong Chen ◽  
Tsung‐Shune Chin ◽  
Pee‐Yew Lee
Keyword(s):  
Heat Treatment ◽  
Mechanical Alloying ◽  
Iron Nitride ◽  
Treatment Techniques ◽  
Atmospheric Heat

Preparation of iron nitride powders through mechanical alloying and atmospheric heat treatment

1999 ◽  
Author(s):  
Pee-Yew Lee ◽  
Chung-Kwei Lin ◽  
Chieh-Lung Chang ◽  
Yeukuang Hwu ◽  
Tsung-Shune Chin
Keyword(s):  
Heat Treatment ◽  
Mechanical Alloying ◽  
Iron Nitride ◽  
Atmospheric Heat

Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

Microstructure of mechanically alloyed and hot-pressed Al5CuZr2

1990 ◽  
Vol 48 (4) ◽  
pp. 970-971
Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz
Keyword(s):  
Mechanical Alloying ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Rapid Quenching ◽  
Hardened Steel ◽  
Alloyed Powder ◽  
Ion Milling ◽  
Mechanical Grinding ◽  
Mechanically Alloyed ◽  
Steel Container

Al3Zr has the highest melting temperature (1580°C) among the tri-aluminide intermetal1ics. When prepared by casting, Al3Zr forms in the tetragonal DO23 structure but by rapid quenching or by mechanical alloying (MA) it can also be prepared in the metastable cubic L12 structure. The L12 structure can be stabilized to at least 1300°C by the addition of copper and other elements. We report a TEM study of the microstructure of bulk Al5CuZr2 prepared by hot pressing mechanically alloyed powder.MA was performed in a Spex 800 mixer using a hardened steel container and balls and adding hexane as a surfactant. Between 1.4 and 2.4 wt.% of the hexane decomposed during MA and was incorporated into the alloy. The mechanically alloyed powders were degassed in vacuum at 900°C. They were compacted in a ram press at 900°C into fully dense samples having Vickers hardness of 1025. TEM specimens were prepared by mechanical grinding followed by ion milling at 120 K. TEM was performed on a Philips CM30 at 300kV.

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