GROWTH-PROMOTING EFFECT OF ORGANIC IMPURITIES ON GROWTH-KINETICS OF KAP AND KDP CRYSTALS

The experimental results of the influence of a variety of organic impu rities differing in their chemical behavior on the growth rates of dif ferent faces of KAP and KDP crystals are presented. It was observed th at, with increasing additive concentration in practically all experime nts, an impurity leads first to an increase and then a decrease in the growth rate, passing through a maximum. These features of the influen ce of an additive on crystal growth kinetics depend on the chemical na ture of both the impurity and the crystal face. The initial growth pro moting effect of additives is discussed in terms of the chemical natur e of the materials used in the experiments and changes in the thermody namic and kinetic parameters involved in the crystal growth models. Th e analysis suggests that the growth promoting effect is not connected with a decrease in the edge free energy in a simple manner. (C) 1998 E lsevier Science B.V. All rights reserved.