Microwave Heating and Control of Materials
- Alternatives to Conventional Flames

Microwaves are indispensable means of our daily life, the most typical
of which is a microwave oven. This device makes use of the heating of
dielectric materials by the microwave electric field, which include water
and carbon.

Recent studies showed that the magnetic field of microwaves also
selectively and efficiently heat and sinter magnetic materials, including iron,
nickel, cobalt, and their oxides. These magnetically sintered materials have
good properties as new generation materials.

The above mentioned things are only a few of microwave applications.
Academically, microwaves provide fundamental physics research regime
of electromagnetic wave-material interactions.

In Science and Technology of Microwave-Induced Themally
Non-Equilibrium Reaction Fields (MEXT Prime Area Research Project,
FY 2006 - 2010), we make both fundamental and applied researches,
including
(1) In-situ and real-time aquisition of microwave experiment data,
(2) Frontier materials science by theory approaches,
(3) Microwave-assisted industrial applications, such as industry scale
iron production, and chemical wastes disposition and rare-metal retrieval.

Generally speaking, electromagnetic waves are reflected at the surface
and do not penetrate into bulk metal due to the skin effect. Also, microwaves
are ultra-low energy photons unlike those of laser light. For these reasons,
it was believed that microwaves are hardly useful in processing of metal.
However, at the turn of the 21st century, pressed composite of metal
particles was shown by experiment to be heated and sintered in a very short
time by two orders of magnetude less than conventional heat furnaces (Roy
et al., Nature, 1999). Since then, microwaves have been paid new industrial
and academic attentions in the world.

This page intruduces to you our recent research results of these microwave
heating and possible material control (promotion of chemical reactions)
by means of thoery and molecular dynamics simulations.


Dielectric material:
Microwave heating of water, ice and salt solution (J.Chem.Phys, 2007)

Magnetic materials (metal oxides):
Microwave heating of magnetic metal oxides (Phys.Rev.B, 2009)

Metal (non-magnetic):
Absorption of microwave energy by compacted copper powder
irradiated at 2.45GHz (J.J.Appl.Phys., 2009)


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