GROWTH STABILITY IN SEMIOPEN PHYSICAL VAPOR TRANSPORT

An interface stability model is proposed for crystal growth by physica l vapour transport (PVT) in semiopen (SO) systems, which is based on t he constitutional supercooling criterium. The model, whose main featur e is the relaxation of the local eqilibrium assumption at the growing interface, proved suitable for explaining the remarkable growth stabil ity in SO systems when applied to urea growth. A semiempirical approac h for estimating the pressure inside a SO-system and the kinetic contr ibutions to stability is also proposed, which allows for quantitative comparison of model and experimental results.