Electron microscopy of iron oxides and implications for the origin of magnetizations and rock magnetic properties of Banded Series rocks of the Stillwater Complex, Montana

1997 ◽  
Vol 102 (B6) ◽  
pp. 12139-12157 ◽  
Author(s):  
Weixin Xu ◽  
John W. Geissman ◽  
Rob Van der Voo ◽  
Donald R. Peacor
Author(s):  
June D. Kim

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Naberezhnov ◽  
Nadezda Porechnaya ◽  
Viktor Nizhankovskii ◽  
Alexey Filimonov ◽  
Bernard Nacke

This contribution is devoted to the study of morphology and magnetic properties of sodium borosilicate glasses with different concentrations (15, 20, and 25 wt.%) ofα-Fe2O3in an initial furnace charge. These glasses were prepared by a melt-quenching method. For all glasses a coexistence of drop-like and two-phase interpenetrative structures is observed. The most part of a drop structure is formed by self-assembling iron oxides particles. All types of glasses demonstrate the magnetic properties and can be used for preparation of porous magnetic matrices with nanometer through dendrite channel structure.


2009 ◽  
Vol 152-153 ◽  
pp. 66-69 ◽  
Author(s):  
V.V. Gubernatorov ◽  
T.S. Sycheva ◽  
Irina I. Kositsyna

A new concept is suggested that serves to explain the effects of thermomagnetic treatment. Its validity is proved via measurements of magnetic properties and electron microscopy examination of structure of soft magnetic materials after different treatments. This concept allows one to consciously choose the treatment mode aiming on improvement of magnetic properties of alloys.


2005 ◽  
Vol 70 (10) ◽  
pp. 1213-1217 ◽  
Author(s):  
Nebojsa Nikolic

Nickel deposits obtained from a Watt solution both without and with a perpendicularly oriented magnetic field were examined by scanning electron microscopy (SEM). The nickel deposit obtained without an imposed magnetic field was very rough, with a clearly visible clustered structure. The nickel deposit obtained under a perpendicularly oriented magnetic field has a very developed dendritic structure, which can be denoted as arboreous ? bead dendritic structure. The ob- served difference is essentially ascribed to the effect of a magnetic field on the magnetic properties of nickel.


2010 ◽  
Vol 663-665 ◽  
pp. 1142-1145
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Ming Meng

During the chemical synthesis nanometer-sized particles of ferrous iron oxide were in situ infiltrated into the mesopores in a porous silicon film. The microstructures of porous silicon and the magnetic properties of the nanometer-sized particles of the ferrous iron oxide were characterized with scanning electron microscopy, X-ray diffractometry, and the hysteresis loop measurement, respectively. Our results have demonstrated that the magnetic properties of the nanometer-sized Fe3O4 particles can be dramatically modified when they are confined into the mesopores of the porous silicon film.


Clay Minerals ◽  
1985 ◽  
Vol 20 (2) ◽  
pp. 255-262 ◽  
Author(s):  
S. Mann ◽  
R. M. Cornell ◽  
U. Schwertmann

Aluminium-substituted goethites are found in many soils and can also be synthesised readily in the laboratory. In recent years, synthetic substituted goethites have been examined by various techniques including XRD, IR, TEM and dissolution kinetics (Thiel, 1963; Jonas & Solymar, 1970; Fey & Dixon, 1981; Fysh & Fredericks, 1983; Schulze & Schwertmann, 1984; Schwertmann, 1984). Transmission electron microscopy (TEM) studies have shown that as Al substitution rises above 10%, the goethite needles become shorter and also thicker in the a direction. Furthermore, crystals which at zero substitution consist of domains parallel to the c axis become less domainic with increasing Al substitution (Schulze & Schwertmann, 1984).


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