Size distribution and growth rate of crystal nuclei near critical undercooling in small volumes

27th Joint Seminar Development of Materials Science in Research and Education

材料科学;教育

Koíek, Z.^1 ; Demo, P.^1

Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Praha 6

162 00, Czech Republic^1

关键词: Critical nuclei;    Kinetic equations;    Nucleation models;    Reasonable value;    Simulation data;    Size dependence;    Station-ary values;    Supercritical clusters;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/266/1/012006/pdf
DOI  :  10.1088/1757-899X/266/1/012006

来源: IOP

【 摘 要 】

Kinetic equations are numerically solved within standard nucleation model to determine the size distribution of nuclei in small volumes near critical undercooling. Critical undercooling, when first nuclei are detected within the system, depends on the droplet volume. The size distribution of nuclei reaches the stationary value after some time delay and decreases with nucleus size. Only a certain maximum size of nuclei is reached in small volumes near critical undercooling. As a model system, we selected recently studied nucleation in Ni droplet [J. Bokeloh et al., Phys. Rev. Let. 107 (2011) 145701] due to available experimental and simulation data. However, using these data for sample masses from 23 μg up to 63 mg (corresponding to experiments) leads to the size distribution of nuclei, when no critical nuclei in Ni droplet are formed (the number of critical nuclei -9m3) nucleus size reaches some maximum extreme size, which quickly increases with undercooling. Supercritical clusters continue their growth only if the number of critical nuclei is sufficiently high.