Hydrothermal Technology—Principles and Applications - Hydrothermal Technology - page 36

Hydrothermal Research
in Materials Science

(a)

Canada 2%

Others
10%

India 3%

USA
23%

Taiwan 3%

UK 4%

Germany
6%

France
6%

Japan
20%

CIS
9%

Based upon analysis of 2601
papers from CAS, SCI, and
INSPEC databases in 1989-1997

China
13%

4%

(b)

3% 2%

3%

Germ any 6%

USA
15%

Figure 1.14 (a) Number of papers on Hydrothermal Research in Materials Science country-
wise during 1989

1999. (b) Number of papers on Hydrothermal Research in Materials
Science country-wise during 2000 mid-2011.

greatly to understanding of the hydrothermal technique. One can now understand
the hydrothermal chemistry of solutions more or less precisely, which provides a
solid base for hydrothermal synthesis and processing at much lower pressure and
lower temperature conditions [12,35] . These developments are slowly removing the
concept of the black box for the hydrothermal system, and one can make use of
thick-walled silica autoclaves to carry out hydrothermal experiments up to a tem-
perature of 300 C and pressure up to several hundreds of bars, to facilitate direct
observation of the hydrothermal processes taking place in a given system. Already
some groups in Russia, Japan, and the United States have begun work in this direc-
tion and numerous publications have appeared. These developments have given
the hydrothermal technique an edge over other techniques for the preparation of
pure materials as it is a closed system providing a more controlled diffusion.