Ultrasonic Irradiation Effect in Supercooled Liquids of Naphthalene

Hiroshi ABE, Issei HORI, Takaharu YATOMI, Makoto KIKUCHI, Hitoshi MATSUMOTO and Haruyo YOSHIZAKI

Department of Materials Science and Engineering, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan

Jpn. J. Appl. Phys. 42, 3552 (2003).

Abstract
Solidification of the supercooled liquids of naphthalene was influenced by ultrasonic irradiation. The solidification temperatures, T_s, of the supercooled liquids of naphthalene were independent of applied ultrasonic transducer power, though T_sunder no ultrasonic irradiation decreased. By isothermal holding above T_s, incubation time was greater than zero only under ultrasonic irradiation until the supercooled liquids of naphthalene solidified. Moreover, incubation time increased at fixed temperature with increasing holding temperature or applied transducer power. In optical microscopy observation, the fractal distribution of microstructures was observed in the sample, which solidified under ultrasonic irradiation without isothermal holding. These results are due to the anomalous nucleation caused by the local pressure induced by ultrasonic waves.

KEYWORDS: ultrasonic irradiation, incubation time, kinetics, local pressure field, nucleation and growth process, fractal

	Figure 1 Melting points depend on purities. Each purity is determined by DSC measurement.
	Figure 2 Applied power to an ultrasonic transducer (PZT) is proportional to the burst values, t_bur. Burst sine waves are repeated a fixed time interval, t_rpt. In the experiments, t_rpt is fixed at 900 ms.
	Figure 3 Solidification temperature remains almost constant above irradiated ultrasonic power. Under no ultrasonic irradiation, the solidification temperature decreases.
	Figure 4 Time dependence of ultrasonic transducer power at fixed temperature. Apparently, the incubation time appears above solidification temperature.
	Figure 5 Incubation time depends on both ultrasonic transducer power and holding temperature. The solid lines show the calculated incubation time (See text).
	Figure 6 Microstructures of solid naphthalene revealed using an optical microscope. (a) The sample is obtained by quenching under ultrasonic irradiation. Fractal dimension is 1.76. (b) The sample is obtained by isothermal holding above Ts under ultrasonic irradiation.
	Figure 7 Fractal dimension, D, for the surface pattern shown in Fig. 6(a) is found to be 1.76 +- 0.04 by the scaling method.

References

1) D. W. J. Cruickshank: Acta Crystallogr. 10 (1957) 504.
2) G. S. Pawley and E. A. Yeats: Acta Crystallogr. Sec. B 25 (1969) 2009.
3) C. P. Brock and J. D. Dunits: Acta Crystallogr. Sec. B 38 (1982) 2218.
4) H. G. Kjaerggard and B. R. Henry: J. Phys. Chem. 100 (1996) 4749.
5) K. Ishii, H. Nakayama, M. Kawahara, K. Koyama, K. Ando and J. Yokoyama: Chem. Phys. 199 (1995) 245.
6) K. Ishii, H. Nakayama, T. Yoshida, H. Usui and K. Koyama: Bull. Chem. Soc. Jpn. 69 (1996) 2831.
7) K. Ishii, H. Nakayama, Y. Yagasaki, K. Ando and M. Kawahara: Chem. Phys. Lett. 222 (1994) 117.
8) A. Yethiraj and A. van Blaaderen: Nature 421 (2003) 513.
9) X. Chavanne, S. Balibar and F. Caupin: Phys. Rev. Lett. 86 (2001) 5506.
10) L. E. Kinsler and A. R. Frey: Fundamentals of Acoustics (John Wiley & Sons, New York, 1962).
11) T. Kakeshita, K. Kuroiwa, K. Shimizu, T. Ikeda, A. Yamagishi and M. Date: Mater. Trans. JIM 34 (1993) 415.
12) H. Abe, K. Ohshima and T. Suzuki: Mater. Trans. JIM 36 (1995) 1200.

Back to Publications List

ab@nda.ac.jp

Department of Materials Science and Engineering
National Defense Academy

Last Modified: April 1, 2009