Study of the dissolution and growth of salt single crystals in inhomogeneous acoustic fields: II. A focused acoustic field

The growth and dissolution of the isolated (100) face of a KDP crystal at exposure of the phase boundary to focused acoustic fields have been investigated. Visualization tools have been developed and the scale and dynamics of the arising acoustic flows have been established. A quadratic dependence of the dissolution rate on the sound pressure has been obtained; such a dependence is in agreement with the theoretical concepts about the dependence of the mass exchange rate in the acoustic boundary layer on the field parameters. A significant growth response of the face under study, normally exposed to ultrasound along the acoustic axis in the prefocal and postfocal planes of a spherical concentrator (f = 1.4 MHz), has been revealed. It is shown that the mechanisms of mass exchange enhancement in these acoustic modes are radically different. The results obtained show a possibility of controlling growth and dissolution of crystals by varying the parameters of an inhomogeneous acoustic field.