浮力对流对KH2PO4晶体薄表面层生长的影响

Effects of Buoyancy Convection on the Growth of KH_2PO_4 Crystal Thin Surface Layer

通过对Z切片等多种非完整形态下KH_2PO_4晶体生长薄表面层的实时观察,发现薄表面层的生长与浮力对流导致的溶液过饱和度梯度之间存在密切联系。晶体棱边处的过饱和度往往高于晶面内部,使得处于该条件下的非完整形态晶体的棱边可在后续生长过程中产生薄表面层,进而恢复晶体的完整形态。棱边处拥有的"过饱和度优势"是其产生薄表面层的先决条件,若棱边处于"过饱和度劣势",则薄表面层生长必然受到抑制。合理利用浮力对流,可使用非完整的Z切片籽晶生长KDP晶体,以节约晶体材料。

The regeneration of Z-cut plates and other KDP crystals with incomplete shapes were investigated,and found that the growth of thin surface layer is closely related to the solution supersaturation caused by buoyancy convection.Supersaturation near the crystal edges is always higher than that at the center of crystal plane,which is also a prerequisite for the growth of thin surface layer from edge,resulting in restoring the crystal＇s intact shape.Otherwise,the growth of thin surface layer will definitely be suppressed.By rationally controlling the buoyancy convection,thin surface layer incomplete Z-cut plates can be used as seeds to grow KDP crystals which will save crystal material.