FAST GROWTH AND EVALUATION OF POTASSIUM DIHYDROGEN PHOSPHATE SINGLE-CRYSTALS BY ELECTRODIALYSIS WITH PH CONTROL

A novel technique of pH control is proposed in the electrodialysis method of a three-chamber structure. This technique allows using small-sized equipment for the growth of large potassium dihydrogen phosphate (KDP) single crystals. High-quality KDP crystals can be grown at a growth rate of 3 mm/day. Larger growth rates cause spontaneous nucleation, which can be suppressed using a solution doped with 0.3 ppm Cr3+ and 1.5 ppm Al3+. As a result of doping, good optical quality single crystals could be grown at a growth rate of 6.6 mm/day, and the unwanted spontaneous nucleation was suppressed.