INFLUENCE OF UNIT CLUSTER-SIZE ON NUCLEATION RATE OF LI2B4O7 MELT

The effects of the cluster size on the physical properties of a L2B4O7 Melt have been studied via measuring the transition temperatures from liquid to crystal and from quenched glass to crystal by using differential thermal analysis (DTA). Theoretical modeling of the cluster-size dependent entropy of the melt has been developed, based on the classical homogeneous nucleation theory, and simulation of the homogeneous nucleation rate has been carried out for the melts soaked at different temperatures to match the experimental data. The calculation results show that a decrease of the soaking temperature from 1050 to 950-degrees-C yields 3% radial growth of the unit cluster leading to a 40-degrees-C increase of the crystallization temperature from the melt while leading to a 30-degrees-C decrease of the crystallization temperature from the quenched glass and an 8-degrees-C increase of the equilibrium melting temperature, provided that the melt retains the structure at the soaking temperature.