NUCLEATION BEHAVIOUR OF K2O-TiO2-3GeO2 UNDERCOOLED MELT

The nucleation of K2TiGe3O9 crystals in an under-cooled melt of stoichiometric composition was studied. Volume nucleatio n with spherical morphology of the growing crystals was dete rmined. The nucleation range was in the temperature interval 540-630 C. A maximum of the steady state nucleation rate of Imax = 1.4x10exp(15)/m3/s was determined at the temperature of maximum nucleation rate = 582 C. The temperature and tim e dependence of the nucleation rate was analyzed and it was shown that such nucleation behaviour was the result of a low thermodynamic and kinetic barrier. The temperature interval s of nucleation and crystal growth of this under-cooled melt partly overlapped. 27refs.