The effect of high pressure on crystallisation kinetics with special reference to fused silica

PC 1966 5 119-122

A thermodynamic theory is developed for the effect of pressure on the kinetics of phase transformations. The results suggest that application of pressure may have a profound effect in increasing the rate of crystal nucleation, but that its effect on growth rate should generally be a smaller inhibitory one. Observations on SiO2 carried out in a Bridgman anvil high-pressure device have demonstrated the occurrence of crystallisation under conditions of temperature and pressure where none had been anticipated from the kinetic formalism. A number of hypotheses are suggested to account for the observations, the most satisfactory of which is based on the effect of water, and the possible existence of a water-rich region at the interface at high pressure, in enhancing the extent of crystallisation in a given time.

PC07 1966 V5_159-168