Growth Kinetics of Potassium‐Dihydrogen Phosphate Crystals in Solution

Abstract

Growth rate data of (101) faces of KDP crystals as a function of the relative supersaturation of the solution are analyzed on the basis of BURTON, CABRERA and FBANE surface-diffusion model applied t o the growth from solution. The characteristic constants in the BCF function are determined for 50 "C. Approximate values of the free activation energies for dehydration, desorption, surface diffusion and entering the kinks from the surface are calculated. The experimental data previously obtained by MULLIN and AMATAVIVADHANA and by BELOUET are also discussed.Messungen der Wachstumsgeschwindigkeit von (101) Fliichen von KDP-Kristallen als Funktion der relativen tfbersattigung der Losung werden mit Hilfe des Oberfliichendiffusionsmodells von BURTON, CABRERA und FRANK, angewandt auf Losungswachstum, analysiert. Fur 60 "C werden die charakteristischen Konstanten der BCF-Funktion bestimmt. Aproximierte Werte fiir die freien Aktivierungsenergien der Entwasserung, der Desorption, der Oberflachendiffusion und der Anlagerung an den ,,kinks" an der Oberflikhe werden berechnet. Die friiher gewonnenen experimentellen Daten von MULLIN und AMATAVIVADHANA und von BELOUET werden ebenfalls diskutiert.

Investigation of Temperature Dependence and Impurity Content on the Growth Rate of KDP Crystals

“…The growth mechanism incorporates the correlation of thermodynamics, kinetics, and transportation factors to explain the behavior and the morphology of the grown crystal in supersaturated solutions. 3 Nicolau et al 4 have determined the solubility by reducing the temperature from 53 to 50 °C after adding cold deionized water to dissolve the polycrystals lying on the bottom of the KDP solution. The solution became saturated after 72 h; twelve seeds were mounted on the axle-tree and introduced to the crystallizer to accomplish an ordinary charge of single-crystal growth.…”