Development of Avrami´s kinetics to describe growth of Bi-2223 crystals

The Avrami´s kinetics was known to be the best theory to describe Bi-2223 crystals growth. Whereas, it cannot explain the fact that maximum product volume appearing at optimum sintering time during synthesis Bi-2223 crystal. Meanwhile, the Avrami´s equation can also be used to determine the activation energy of Bi-2223 crystal growth; unfortunately, the determined activation energy, E, had dispersion as much as hard to be accepted by researchers themselves. To solve those problems, we studied and developed Avrami´s kinetics and obtained a developed Avrami´s kinetics equation in this research. With the developed Avrami equation, the index of growth, n, and E of Bi-2223 crystals were determined, including the periods of Bi-2223 crystals growing and decomposing. The n and E for Bi-2223 crystals were changing during synthesis period, values of which can be positive, zero or negative for different reaction periods. And the negative E and n were no reports to be found before, which caused by the decomposition of the product. The developed kinetics can describe a phase transformation system that with metastable or stable product. The developed kinetics theory, as a universal theoretical tool, is expected to be widely applied in the science and engineering multidisciplines and their related interdisciplines.