scholarly journals GROWTH MECHANISM OF KDP CRYSTALS FROM AQUEOUS SOLUTIONS

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Biljana Maksimović ◽  
Branislava Misailović ◽  
Mićo Mitrović ◽  
Andrijana Žekić
Keyword(s):  
Crystal Growth ◽  
Aqueous Solutions ◽  
Growth Mechanism ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Growth Mechanisms ◽  
Potassium Dihydrogen ◽  
Temperature Range ◽  
Growth History ◽  
Kdp Crystals

The results of the effect of the growth history on Potassium Dihydrogen Phosphate (KDP) crystals growth mechanism are presented in the paper. Crystals were grown in temperature range of from aqueous solutions, saturated at . Two types of the experiments were performed. In both types, after the nucleation at crystals were grown at the same temperature for about 1.5 hour and then dissolved at temperature for about 15 min. After refaceting, in the first type, the crystal growth started at , followed by the temperature increasing in steps of to . In the second type, after refaceting the crystal growth started at , followed by the temperature decreasing in steps of to . Obtained results indicate that KDP crystals growth mechanisms do not depend on growth history. They are discussed in accordance with the current theories.

scholarly journals Modeling the mass transfer processes in the growth of KDP crystals from solution

2019 ◽  
Vol 21 (1) ◽  
pp. 26-34
Author(s):  
N. A. Verezub ◽  
V. L. Manomenova ◽  
A. I. Prostomolotov
Keyword(s):  
Mathematical Model ◽  
Aqueous Solution ◽  
Mass Transfer ◽  
Crystal Growth ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Kdp Crystals

Finding the conditions of high-speed single crystal growth with an appropriate quality is a priority for the industrial production of crystalline materials. Crystals of potassium dihydrogen phosphate (KDP) are important optical materials, they are grown from an aqueous solution and an increase in the rate of growth and quality of a single crystal is of great practical importance.In this paper, mathematical simulation of hydrodynamic and mass transfer processes in growing KDP crystals is performed. The flow and mass transfer are modeled within the framework of continuous medium, which is considered as an aqueous solution of a special salt — potassium dihydrogen phosphate. This salt dissolves in water to a saturation level at a high temperature. Then, such supersaturated solution is used to grow crystals at lower temperatures in non-flowing and flowing crystallizers. The mathematical model is considered in a conjugate formulation with allowance for mass transfer in the«solution—crystal» system. Local features of hydrodynamics and mass transfer in a solution near the surface of a growing crystal are determined, which can affect on the local (for a particular place and direction) crystal growth rate and the formation of defects. The requirements to the crystallizers that provide the «necessary» hydrodynamics in the solution are discussed. Its validation is shown for the flow around a long horizontal plate simulating the growing facet of the crystal. The rate of precipitation of salt was evaluated by the proposed mathematical model, which matches the calculation of solution flow according to the Navier-Stokes equations for an incompressible fluid with a thermodynamic condition for the normal growth of a face under conditions of two-dimensional nucleation. The action of the flowing crystallizers was analyzed for various solution inflows (axial and ring) and its outflow through the axial bottom hole.

scholarly journals Effect of cyclohexane diamine tetraacetic acid on micro morphology of rapidly grown potassium dihydrogen phosphate crystals

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 23102-23108
Author(s):  
Weidong Li ◽  
Shenglai Wang ◽  
Guangwei Yu ◽  
Duanliang Wang ◽  
Pingping Huang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Rapid Growth ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Tetraacetic Acid ◽  
Growth Technique ◽  
Potassium Dihydrogen ◽  
Micro Morphology ◽  
Kdp Crystals ◽  
Point Seed

Potassium dihydrogen phosphate (KDP) crystals were grown from aqueous solutions with different concentrations of cyclohexane diamine tetraacetic acid (CDTA) by the “point seed” rapid growth technique.

scholarly journals The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Creep Deformation ◽  
Potassium Dihydrogen Phosphate ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Machining Process ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

scholarly journals Elastic-plastic-brittle transitions of potassium dihydrogen phosphate crystals: characterization by nanoindentation

2020 ◽  
Vol 8 (4) ◽  
pp. 447-456
Author(s):  
Yong Zhang ◽  
Ning Hou ◽  
Liang-Chi Zhang ◽  
Qi Wang
Keyword(s):  
Plastic Deformation ◽  
Brittle Fracture ◽  
Optical Switching ◽  
Potassium Dihydrogen Phosphate ◽  
Machining Process ◽  
Fracture Mechanisms ◽  
Dihydrogen Phosphate ◽  
Kdp Crystal ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

AbstractPotassium dihydrogen phosphate (KDP) crystals are widely used in laser ignition facilities as optical switching and frequency conversion components. These crystals are soft, brittle, and sensitive to external conditions (e.g., humidity, temperature, and applied stress). Hence, conventional characterization methods, such as transmission electron microscopy, cannot be used to study the mechanisms of material deformation. Nevertheless, understanding the mechanism of plastic-brittle transition in KDP crystals is important to prevent the fracture damage during the machining process. This study explores the plastic deformation and brittle fracture mechanisms of KDP crystals through nanoindentation experiments and theoretical calculations. The results show that dislocation nucleation and propagation are the main mechanisms of plastic deformation in KDP crystals, and dislocation pileup leads to brittle fracture during nanoindentation. Nanoindentation experiments using various indenters indicate that the external stress fields influence the plastic deformation of KDP crystals, and plastic deformation and brittle fracture are related to the material’s anisotropy. However, the effect of loading rate on the KDP crystal deformation is practically negligible. The results of this research provide important information on reducing machining-induced damage and further improving the optical performance of KDP crystal components.

Kinetics of Potassium Dihydrogen Phosphate Single-Crystal Growth Mapped by the Chemical Bond Simulation

2012 ◽  
Vol 554-556 ◽  
pp. 31-34 ◽  
Author(s):  
Xu Zhang ◽  
De Xiang Jia
Keyword(s):  
Chemical Bond ◽  
Crystal Morphology ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Chemical Bonds ◽  
Potassium Dihydrogen ◽  
Solution Interface ◽  
Shape Controlled ◽  
Kinetics Of ◽  
Kdp Crystals

A chemical bond simulation was proposed to quantitatively calculate the growth rate from the kinetic model of the crystal-solution interface. When this approach was applied to the cases of potassium dihydrogen phosphate (KDP) crystals grown from the solution with different surpersaturation, the growth behaviors of KDP crystals were predicted and the calculated results were consistent with the experimental data. These results demonstrate that regulating the distribution of the chemical bonds between the crystal and solution interfaces can effectively control the crystal morphology. Seeding experiments with the chemical bond simulation may have significant potential towards the development of shape-controlled growth with defined conditions.

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