Vickers Microhardness Studies of Pure and Amino Acids Doped Potassium Dihydrogen Phosphate Crystals

2017 ◽  
Vol 6 (1) ◽  
pp. 96-101
Author(s):  
K. D. Parikh ◽  
D. J. Dave ◽  
B. B. Parekh ◽  
M. J. Joshi

Vickers microhardness study was carried out to understand the mechanical behaviour of pure and different amino acids (L-arginine, L-lysine, L-alanine) doped potassium dihydrogen phosphate (KDP) single crystals grown by slow solvent evaporation technique. Indentations were made on smooth {100} plane of pure and different amino acid doped crystals for loads varying from 0.298 N to 0.98 N. Vickers microhardness decreased as doping level of amino acid was increased. Indentation size effect (ISE), Kick's law, Hays and Kendall's law and Proportion specimen resistance (PSR) model were verified for pure and different amino acids doped crystals. The values of the load independent hardness and Newtonian pressure were higher in pure KDP crystals than the amino acids doped KDP crystals. It was found that as doping concentration of amino acids increased the load independent hardness and Newtonian pressure decreased. The results indicated that the doping of amino acids made KDP crystals softer.

2007 ◽  
Vol 1015 ◽  
Author(s):  
Selemani Seif ◽  
Ravindra Behari Lal

AbstractThis paper reports on preparation and characterization of Potassium Dihydrogen Phosphate (KDP) crystals doped with Potassium Dichromate (PD). The crystals were grown at room temperature by solution evaporation technique. The grown crystals were polished, sliced, and analyzed using UV-Spectrophotometer, which showed high concentration of PD impurities in KDP crystals at 200-280 nanometer. These concentrations were then verified using ICP measurements to determine specific amount in ppm of chromium ions in KDP crystals. In additional to that, the UV-transmittance data of these crystals were then converted to absorbance per thickness, and used to calculate absorption coefficients, extinction coefficients, and refractive index as a function of wavelength. The results showed that the presence of PD impurities in the crystal matrix of KDP has played a key reformative role in the UV sensing of Potassium Diphosphate crystals.


2013 ◽  
Vol 665 ◽  
pp. 172-178 ◽  
Author(s):  
Dipak J. Dave ◽  
Ketan D. Parikh ◽  
Mihir J. Joshi

Pure and various amino acids (L-histidine, L-threonine, DL-methionine) doped KDP crystals were grown by slow solvent evaporation technique. The doping of amino acids was confirmed by C, H, N analysis, FTIR spectroscopy and paper chromatography .Pure and doped KDP crystals were subjected to Vickers microhardness studies. Indentations were made on smooth (100) as grown faces of pure and doped crystals. The Vickers indenter loads were varied from 0.298 N to 0.981 N in order to study the effect of load on microhardness. A number of indents were made at each load and the mean diagonal length (d) was used in calculating the Vickers Hardness Number (HV). The Vickers micro-hardness decreased as amino acid doping level was increased indicating that the KDP crystals became softer after doping. The Indentation size effect (ISE) the Kicks law as well as PSR model was verified for all samples. The values of the load independent hardness and the Newtonian pressure (W) were higher in pure KDP crystals than the amino acids doped KDP crystals. It was found that as the doping concentration of amino acids increased the values of load independent hardness and Newtonian pressure decreased. Hays and Kendall law analysis was also applied to the hardness data.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma

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.


2020 ◽  
Vol 8 (4) ◽  
pp. 447-456
Author(s):  
Yong Zhang ◽  
Ning Hou ◽  
Liang-Chi Zhang ◽  
Qi Wang

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.


2007 ◽  
Vol 16 (02) ◽  
pp. 255-268 ◽  
Author(s):  
P. KUMARESAN ◽  
S. MOORTHY BABU ◽  
P. M. ANBARASAN

Amino acids (L-Glutamic acid, L-Histidine, L-Valine) doped potassium dihydrogen phosphate crystals were grown by the solution growth technique. Slow cooling as well as slow evaporation methods were employed to grow these crystals. The concentration of dopants in the mother solution was varied from 0.1 mole % to 10 mole %. The solubility data for all dopant concentrations were determined. The variation in pH and the corresponding habit modification of the grown crystals were characterized with UV - VIS, FT-IR and SHG trace elements, and dielectric studies reveal slight distortion of lattice parameter for the heavily doped KDP crystals. TGA-DTA studies reveal good thermal stability. The dopants increase the hardness value of the material, which also depends on the concentration of the dopants. Amino acids doping improved the NLO properties. The detailed results on the spectral parameters, habit modifications and constant values will be presented.


2012 ◽  
Vol 554-556 ◽  
pp. 31-34 ◽  
Author(s):  
Xu Zhang ◽  
De Xiang Jia

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.


2009 ◽  
Vol 626-627 ◽  
pp. 53-58 ◽  
Author(s):  
Shao Long Guo ◽  
Fei Hu Zhang ◽  
Yong Zhang ◽  
Dian Rong Luan

The characteristics and principle of deliquescent polishing technology for potassium dihydrogen phosphate (KDP) crystals are introduced, and the performance requirements of deliquescent polishing fluid for KDP crystals are proposed. The main components of the deliquescent polishing fluid for KDP crystals were selected according to these performance requirements. Through uniformity experiment, stability experiment and fluidity experiment, uniformity, stability and fluidity of deliquescent polishing fluid for KDP crystals prepared using the selected components were tested. Through deliquescent polishing experiment of KDP crystal, polishing performance of deliquescent polishing fluid compounded using the selected components was tested. The material removal rate of the KDP crystal in the deliquescent polishing experiment was 6.03μm/min, and the surface roughness of the KDP crystal after deliquescent polishing was 4.857nm. The experimental results show that the compounded deliquescent polishing fluid for KDP crystals has good polishing performance and can reach the requirements.


2009 ◽  
Vol 24 (7) ◽  
pp. 2316-2320 ◽  
Author(s):  
Jayesh R. Govani ◽  
William G. Durrer ◽  
Marian Manciu ◽  
Cristian Botez ◽  
Felicia S. Manciu

Inorganic potassium dihydrogen phosphate (KDP) is widely known for its value as a nonlinear optical material. In this study, pure and l-arginine–doped KDP single crystals were grown by the slow solvent evaporation technique and further subjected to infrared absorption and Raman studies for the confirmation of chemical group functionalization and possible bonding between the organic and inorganic materials. The appearance in the infrared absorption spectra of additional vibrational lines, which mostly originate from disturbed N–H, C–H, and C–N bonds of the l-arginine–doped salt, confirm the interaction between KDP and the organic material. This affirmation is supported by more evidence from Raman measurements, where the disappearance of NH vibrations of the amino group is observed. We are thus led to the possibility of hydrogen bonding primarily between the nucleophilic O− of the phosphate unit of KDP and the amino group of the l-arginine.


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