Experimental Research On The Crystal Growth Process Of KDP With Different Rotation Radii And Adding Methyl Violet As Additive

Potassium dihydrogen thophosphate(KH2PO4, KDP) is one of the important nonlinear optical crystal and has the excellent properties. Consequently, it is widely used in the fields of industry. At the same time, it is the only crystal which could be grown into large size and used in inertial confinement fusion(ICF) system, therefore how to obtain the fast growth of KDP growth becomes the focus of research of scholars home and abroad. At present, KDP crystal growth method is always concentric rotation. To some extent, it has the effect on improving flow of growth solution, but the effect is limited. Consequently, this paper conducted experiments of KDP crystal growth under different radii to explore the effect of rotation radius. Its effect on KDP growth rate and uniformity was analyzed. Based on this, the induction period of KDP growth solution doped with methyl violet was studied and then experiments of large size KDP crystal were conducted when methyl violet was added. The main contents are as follows:① Experiments under different rotation radii and different supersaturation were conducted. It was found that with the increase of rotation radius, growth rate of KDP crystal of every surface first increased and then decreased. This was related to the “Wall collision effect”. What’s more, under a same rotation radius, crystal growth rate was higher under a higher supersaturation.② Experiments of the same rotation velocity under different rotation radius were conducted. The results showed that at the same rotation velocity, crystal growth rate would be different under different rotation radii. It indicated that the mechanism of the effect of rotation radius on crystal growth rate change was not only the change of rotation velocity, more important was the change of stirring method on KDP crystal growth solution.③ It was found that the increase of growth rate was helpful to improve the growth rate difference of each surface and increase the uniformity. Then this was profitable to the cutting of crystal and its utilization rate. What’s more, the change trend of crystal surface uniformity was first improved and then worsened with the change of rotation radius.④ The solubility and induction period of KDP under different doping concentration were measured. The results of induction period of KDP solution showed that induction period could be increased by low concentration doping of methyl violet. The stability of rotation was improved. But a high concentration could decrease the stability and was negative to the growth of KDP crystal.⑤ KDP crystal experiments under different doping concentration and different rotation radii were developed. It was found that with the increase of rotation radius, growth rate also increased first and then decreased. The doping to some extent could increase the maximum growth rate of KDP crystal.