Kinetics of spontaneous crystallization of cubic boron nitride

Kinetic dependences of the number of crystallization centres, growth rate and transformation degree of cubic boron nitride are studied under the pressure of 4.8 GPa and at the temperature of 2000 K. Formation, growth and transformation rates are shown to be maximal at the initial stage of the synthesis (15-20) with a subsequent sharp fall (10-40). Kinetics of spontaneous crystallization of cubic boron nitride is described by the expression of the Kolmogorov type: α=1-exp(-3/4πJ(t) (t)sup(3)tsup(m)) where α is a degree of α-BN transformation into β-BN for time to J(t), ν(t) are β-BN formation and growth rates