THE GROWTH OF KDP CRYSTALS AND ITS MECHANISM BY SPLICING MISORIENTED IN AQUEOUS-SOLUTION

The growing characteristics of splicing misoriented KDP seeds of both bulk and thin pieces were investigated. The chemical etching method was used to determine the prismatic and Z-plate surfaces of the crystals grown by splicing bulk KDP seeds. The X-ray Lang topography method was employed to measure original thin platy crystals grown by splicing thin pieces of KDP seeds. From the results it can be concluded that when the misorientation of two seeds on the Z-axis direction was about 1.5-degrees, the crystal was grown successfully if the secondary capping was controlled properly. In comparison with the growth of splicing "parallel" seeds, the misorientation of both seeds increases such that the secondary capping becomes difficult, the sub-grain boundary stretches longer, the stress field around the secondary cap enlarges and the crystals grown crack easily.