Assessment of the strain in small sodium chlorate crystals and its relation to growth rate dispersion

• Published in: Journal of crystal growth 1988-08, Vol.91 (1), p.163-168
• Main Authors: Ristić, R.I., Sherwood, J.N., Wojciechowski, K.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(88)90382-X

The growth rates of small (5–150 μm) crystals of sodium chlorate grown in solution from secondary nuclei have been measured by optical microscopy. Significant growth rate dispersion((0–7.81)×10 -8 m s -1) was observed at constant supersaturation (0.35%). This dispersion was independent of crystal size and solution agitation. Zero growth rates were confined, however, to the smaller sized particles. Crystals removed from solution following growth were examined by Laue diffraction techniques using synchrotron X-radiation. The Laue patterns of separate crystals showed different degrees of radial asterism indicative of the presence of different degrees of lattice strain (mosaic spread) in the crystals. Analysis of these patterns confirmed that the growth rate of any crystal depended on the degree of lattice strain, the most strained crystals growing at the lowest rates. This correlation indicates that the strain concentrated in or at the surface of very small crystals during fracture or refacetting may well play a dominant role in growth rate dispersion.