Growth mechanisms of NaClO3 and KBr from aqueous solutions under relatively high supersaturation ranges.

Abstract

Normal growth rates of (100) faces of NaClO3 and KBr crystals in aqueous solutions have been measured under relatively high supersaturation, using a specially designed cell for in situ observation. The growth rates vs supersaturation relations were examined in order to investigate the growth mechanisms, based on BCF and two dimensional nucleation growth theories. The birth and spread model in two dimensional nucleation growth theory is suggested for both crystals in the supersaturation ranges investigated. The growth mechanism of NaClO3 and KBr in aqueous solutions from low to high supersaturation ranges is also discussed, using the present results and previously published data. It is concluded that the BCF mechanism is applicable in the lower supersaturation region, whereas two dimensional nucleation growth will predominate up to the supersaturation range where dendritic growth occurs. -T.Y.