Materials Processing by Use of a High Intensity Magnetic Field

Abstract

Non-magnetic substances such as water, plastic, wood, etc. can be levitated when a magnetic field over 20 T is imposed [1]. This phenomenon is based on the established fact that a magnetization force, which is a well-known force attracting an iron to a magnet, is significantly intensified by a high magnetic field. Thus, in recent times, much attention has been paid to this force. As an example, a super-conducting magnet with a cryostat, which does not require liquid helium as a coolant, has been developed so that a highly intensified magnetic field, as much as 10 T, has become easily available in ordinary laboratories in universities. Effects of a high magnetic field have been examined in a large number of natural science fields such as physics, chemistry and biology and have found many new and interesting phenomena that can not be observed under the ordinary intensity of a magnetic field provided by electric or permanent magnets. For example, Fig. 5.1 shows a water surface depressed by imposition of a high magnetic field. This phenomenon is called the Moses effect for the escape from Egypt story written in the Old Testament [2]. As the second example, Fig. 5.2 shows a living frog being levitated in the bore of a super-conducting magnet, where a gravity force is balanced with a magnetization force [3]. Furthermore, Fig. 5.3 shows that the flame of a candle is deformed by a magnetic field with a gradient. In fact, this phenomenon was first found by Faraday in the nineteenth century and has been understood as an effect of the magnetization force. In addition, various interesting phenomena, such as that the vaporizing rate of water is accelerated and the absorption rate of oxygen gas into water is increased by the imposition of a high magnetic field, have been reported [4, 5]. These circumstances have in recent years given further development of the concept of “Magneto-Science”, a subject of research that impacts a variety of science in which high magnetic fields are significant. Reported phenomena relating to “Materials Science” have provided useful information on the creation of new materials, leading finally to the combined identification of “Electromagnetic Processing of Materials” [6]. Of course the Materials Science relating to a high magnetic field is obviously based on a number of principles of physics such as the magnetization force, the Lorentz force, the Zeeman effect, etc., and these principles are combined in complex ways in both physical and chemical phenomena.

Appendix [47]

The orientation index of (${h_i},\,{k_i},{l_i}$) plane ${N_{{{h_i},{k_i},{l_i}}}}$ defined as Eq. 5.62, is evaluated from the X-ray diffraction patterns.

$$ {N_{{{h_i},\,{k_i},{l_i}}}} = {F_{{{h_i},{k_i},{l_i}}}}/F_{{{h_i},{k_i},{l_i}}}^0, $$

(5.62)

where ${F_{{{h_i},{k_i},{l_i}}}}$ is an intensity fraction of a (${h_i},\,{k_i},\,{l_i}$) plane and defined by Eq. 5.63 and $F_{{{h_i},{k_i},{l_i}}}^0$ is obtained from the standard data of JCPDS cards.

$$ {F_{{{h_i},{k_i},{l_i}}}} = {I_{{{h_i},{k_i},{l_i}}}}/({I_{{{h_5},{k_5},{l_5}}}} + {I_{{{h_2},{k_2},{l_2}}}} + {I_{{{h_3},{k_3},{l_3}}}} + \ldots \ldots + {I_{{{h_n},{k_n},{l_n}}}}), $$

(5.63)

where ${I_{{{h_i},{k_i},{l_i}}}}$ is intensity for the diffraction line of (${h_i},\,{k_i},\,{l_i}$).

Moreover, in order to comprehensively evaluate the over-all degree of crystalline texture, the definition of a relative facial angle ${\theta_F}$ is obtained by Eq. 5.64.

$$ {\theta_F} = \sum {({I_{{{h_i},{k_i},{l_i}}}}\, \times \,{\theta_{{{h_i},{k_i},{l_i}}}})} /\sum {{I_{{{h_i},{k_i},{l_i}}}}} $$

(5.64)

${\theta_{{{h_i},{k_i},{l_i}}}}$ is the facial angle between $({h_i},{k_i},{l_i})$ and (0, 0, n) planes. The relative facial angle ${\theta_F}$ is reduced to 0° when all crystals are oriented to the (0, 0, n) plane and to 90° when oriented to the plane perpendicular to (0, 0, n).