SIZE DISTRIBUTION OF EMBRYOS PRODUCED BY CRYSTAL-ROD CONTACTS

We performed contact nucleation experiments on the (010) face of potassium hydrogen phthalate (KAP) crystals growing in a stagnant supersaturated aqueous solution and determined - after a given growth time t - (ex situ) the crystal size distribution (CSD) of the secondary nuclei (which at t = 0 are called "embryos") by using a scanning electron microscope (SEM). The origin of the secondary nuclei could clearly be revealed (damage to the crystal surface). The CSD can be fitted with a log-normal distribution which is typical for many powders obtained by grinding. Minimum size and mean size can be quantitatively understood by elementary fracture mechanics.

[1]  A. Chernov.  Modern Crystallography III , 1984 .

[2]  J. Garside,et al.  Growth rate dispersion among ADP crystals formed by primary nucleation , 1983 .

[3]  J. E. Helt,et al.  Effects of temperature on the crystallization of potassium nitrate by direct measurement of supersaturation , 1977 .

[4]  I. Saunders.  Crystal growth '78 , 1979 .

[5]  N. Kubota,et al.  The measurement of growth rate of K-alum contact nuclei , 1987 .

[6]  M. Hottenhuis,et al.  Fe3+ and Ce3+ acting as competitive impurities in the crystallization process of potassium hydrogen phthalate from solutions , 1988 .

[7]  Ralph A. Bradley,et al.  Introduction to Probability and Statistics. , 1960 .

[8]  H. Cummins,et al.  Origin of diffusional light scattering at the non-equilibrium crystal-melt interface , 1986 .

[9]  R. W. Rousseau,et al.  Contact nucleation of various crystal types , 1975 .

[10]  R. Ristic,et al.  Assessment of the strain in small sodium chlorate crystals and its relation to growth rate dispersion , 1988 .

[11]  J. Garside,et al.  Direct observation of secondary nuclei production , 1978 .

[12]  K. Puttick.  The mechanics of indentation fracture in poly(methyl methacrylate) , 1978 .

[13]  H. Güttinger,et al.  Fluctuations of the Ice-Water Interface during Solidification , 1978 .

[14]  C. B. Lucasius,et al.  The influence of impurities on crystal growth; In situ observation of the {010} face of potassium hydrogen phthalate , 1986 .

[15]  K. Puttick,et al.  The mechanical breakdown of sodium chloride crystals , 1987 .

[16]  R. Rosmalen,et al.  Evidence for spiral growth on the pyramidal faces of KDP and ADP single crystals , 1980 .

[17]  J. Garside,et al.  Origin and size distribution of secondary nuclei , 1979 .

[18]  M. Elwenspoek,et al.  Formation of new growth spirals due to impact with a rod on the (010) face of KAP , 1989 .

[19]  J. Mullin,et al.  CRYSTALLIZATION KINETICS OF POTASSIUM-SULFATE IN AN MSMPR AGITATED VESSEL , 1986 .

[20]  S. J. Jančić,et al.  Measurement and scale-up of secondary nucleation kinetics for the potash alum-water system , 1979 .

[21]  R. Howie,et al.  Crystal growth , 1982, Nature.

[22]  B. Degens,et al.  In situ observation of secondary nucleation , 1986 .