XXII.—The Effect of Thermal Treatment and the Effect of Longitudinal Strain in inducing a Sensitive State in certain Magnetic Materials

1914 ◽  
Vol 33 ◽  
pp. 243-256
Author(s):  
Margaret B. Moir
Keyword(s):  
Thermal Treatment ◽  
Magnetic Materials ◽  
Longitudinal Strain ◽  
Magnetic Condition

It has been pointed out by several experimenters, notably by Ewing, and Gray and Ross, that a specimen of steel freshly annealed is in a peculiar magnetic condition. Thus, if a specimen, thoroughly demagnetised, is annealed and then tested, a certain I–H curve is obtained. If it be then demagnetised, and tested again, a second I–H curve is obtained which lies definitely below the first; and any further tests after demagnetisation produce a repetition of the second curve, which is characteristic of the specimen. To obtain the first curve again, the specimen has to be annealed from the same temperature as before, and a test made before demagnetisation.

XIV.—On a Sensitive State induced in Magnetic Materials by Thermal Treatment.

1908 ◽  
Vol 28 ◽  
pp. 239-248 ◽  
Author(s):  
James G. Gray ◽  
Alexander D. Ross
Keyword(s):  
Magnetic Properties ◽  
Cast Iron ◽  
High Temperature ◽  
Thermal Treatment ◽  
Magnetic Materials ◽  
Mechanical Vibration ◽  
Saturation Point ◽  
Slight Degree ◽  
Maximum Value ◽  
Rate Of Cooling

SUMMARY1. Specimens of steel cooled from high temperatures are, as regards their magnetic properties, in a “sensitive state.”2. After magnetisation, reversal of the field reduces the susceptibility.3. Cyclic reversals of the field between definite limits bring the magnetic quality to a definite lower value for fields lying between these limits.4. So long as the field is not changed in sign, the “sensitive state” persists.5. Cyclic reversals of the field between narrow limits reduce the susceptibility for fields beyond these limits, but not to its lowest possible value.6. The rate of cooling from the high temperature—if not very rapid—has little influence on the magnitude of the effect.7. The “sensitive state” does not wear off with time.8. Mechanical vibration of the specimens considerably reduces the phenomenon.9. The “sensitive state” is most pronounced in hard steels.10. The effect is induced to a slight degree in some varieties of steel by temperatures as low as 100° C. It increases with increasing temperatures to about 700° C. Further increase in temperature has little influence.11. Similar effects are noticeable in cast iron and in cobalt. The “sensitive state” is absent, or is present to only a very slight extent, in soft iron.12. The effect has a maximum value for fields which give large values of μ, and tends to zero as the saturation point is approached.

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors

1991 ◽  
Vol 49 ◽  
pp. 954-955
Author(s):  
X. Qiu ◽  
A. K. Datye ◽  
T. T. Borek ◽  
R. T. Paine
Keyword(s):  
Thermal Treatment ◽  
Boron Nitride ◽  
Diffraction Pattern ◽  
Polymeric Precursors ◽  
Polymer Precursors ◽  
Diffuse Ring

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.

HIGH ENERGY SPECTROSCOPY OF MAGNETIC MATERIALS

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-25-C8-29 ◽  
Author(s):  
J. C. Fuggle ◽  
J. F. van Acker
Keyword(s):  
Magnetic Materials ◽  
High Energy

Effect of thermal treatment on Egyptian rice straw hardboard

1977 ◽  
Vol 27 (1) ◽  
pp. 93-98
Author(s):  
Naim A. Fadl ◽  
Magdi Z. Sefain ◽  
Mohomed Rakha
Keyword(s):  
Thermal Treatment ◽  
Rice Straw
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