Nowadays it is a widely interest to composites containing nanoparticles. But as it appears from our study nanoparticles can not only play the role as filler agent but affect directly on morphology during solidification. Thus it opens the possibility to make material with structure that impossible to get using conventional methods.

In present research impact of nanoparticles of  I₂O₃ (d=20 nm) on the growth of salol crystals under different supercoolings ∆Т  (2, 5, 10, 32 ⁰C) was studied. If was found difference as in morphology of crystal growth as in tendency of gas bubbles release from the melt. Fig. 1 shows growth of pure salol Figs. 1а-1d and salol with 10 wt.% nanoparticles Figs. 1e-1h. 

 As it can be seen, for pure salol increasing of supercooling resulted in direct transition from faceted  Figs. 1a, 1b, 1c to spherulite morphology Fig. 1d. For sample with nanoparticles intermediate (between faceted  Fig. 1e and spherulite morphology Fig.  1h) dendrite stage took place Figs. 1f and 1g.

 Relatively gas bubble release it must be noted that for pure salol intensive emission took place, followed by “classical” capturing – repulsion, Fig. 1c and 1d. For salol with nanoparticles another situation was observed. Gas bubbles appears occasionally, for ΔT < 22 ⁰C its interaction with interface is the same as for pure salol (see captured bubbles, Fig. 1g). For greater supercoolings gas bubble ahead the front “attract” sharp protuberance, Fig. 2a.

Fig. 2. Salol with nanoparticles, ΔT =22 ⁰C. Stages of growth, (a) t=o s, ( b) t=15 s, (c) t=25 s, (d) t=40 s. Bubble is marked by arrow.

    Than with the rate,   essentially greater than rate of main crystal interface, this protuberance with bubble at the end  propagates in the melt by rather arbitrary trajectory, Fig. 2b – 2d. It must be noted, that such behavior was not accidental and observed in all experiments with  ΔT >20 ⁰C (Fig. 1h is the stage of growth before  meeting with bubble).

    For pure salol such behavior was not observed in all interval of studied supercoolings. 

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/29050 must be provided.