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1.
Guohui Li Youping He Genbo Su Zhengdong Li Xinxin Zhuang Jinbo Ma Xiangjin Huang 《Crystal Research and Technology》2005,40(3):217-221
Large size crystals of KH2PO4 (KDP) were grown by adopting rapid growth technique from point seeds in a 1500‐liter crystallizer which is used to grow KDP crystals by conventional method. The grown KDP crystal size can reach to 310 × 310 × 320 mm3 and the average growth rate was 8mm/day. The optic properties of the rapidly grown KDP crystals were characterized comparing with the KDP crystals grown by the traditional temperature reduction method. We found it that the optical quality of the KDP crystals we grown rapidly are not significantly different from those of KDP crystals grown by traditional method. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
A. P. Voronov V. I. Salo V. M. Puzikov V. F. Tkachenko Yu. T. Vydaĭ 《Crystallography Reports》2006,51(4):696-701
The conditions for the growth of potassium dihydrogen phosphate (KDP) and ammonium dihydrogen phosphate (ADP) crystals with concentrations of the thallium activator in the initial solution of 0.01, 0.1, and 1.0 wt % are investigated. It is shown that the character of incorporation and distribution of thallium in the KDP and ADP lattices is limited, apparently, by the difference in the ionic radii of K+, NH 4 + , and Tl+ cations and the charge state of prismatic {100} and pyramidal {101} growth planes. Doping of KDP and ADP with thallium (to 0.1 and 1.0 wt %, respectively) does not deteriorate the structural quality of these crystals. The dependence of the lattice parameters a and c on the thallium impurity concentration is investigated. The absorption bands of thallium in the KDP:Tl+ and ADP:Tl+ crystals peak at 218 and 215 nm, respectively, while the photoluminescence band peaks at 280 nm for both types of crystals. The relative light yield upon excitation of scintillations by α particles (Pu239) and β particles (Bi207) is measured. 相似文献
3.
V. Kannan R. Bairava Ganesh R. Sathyalakshmi N. P. Rajesh P. Ramasamy 《Crystal Research and Technology》2006,41(7):678-682
Single crystals of pure and Lanthanum added KDP crystals were grown from aqueous solution. The influence of La3+ ions in KDP crystals is studied. Isolated centers are formed by La3+ ions in KDP structure along (100) plane. La3+ ions incorporated into superficial crystal growth layer and slightly affect the growth process as they generate weak lattice stresses. The creation of these weak lattice stress is confirmed by Vickers's micro hardness test. The HRXRD analysis showed reduced structural defects in the La added KDP in the (100) plane than pure KDP. The incorporation of La in the crystal was confirmed by EDAX analysis. The Kurtz's powder SHG efficiency was found to be 1.5 times that of pure KDP. The UV‐Vis transmission spectra of La added KDP showed excellent transmittance from 1100 nm to 340 nm and did not show any change in lower cutoff wavelength with respect to pure KDP. Laser damage threshold value has been determined using Q‐switched Nd:YAG laser operating at 1064 nm and with 65 ns pulses in single shot mode. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
M. I. Kolybaeva V. I. Salo I. M. Pritula Yu. N. Velikhov A. P. Voronov V. F. Tkachenko V. M. Puzikov 《Crystallography Reports》2004,49(2):266-270
The influence of various technological parameters of crystallization (acidity of growth solutions, crystallization temperature, growth rate, degree of solution purification) on the optical absorption of large KDP single crystals has been studied in the UV range of the spectrum. It is shown that the method of solvent recirculation with the use of the starting material with the microimpurity content not exceeding 5 × 10?5 wt % and solution ultrafiltration under the optimum crystallization conditions (tcr = 80°C, Vcr ~ (0.8–1.6) × 10?6 cm/s, pH 4) enables one to grow KDP single crystals with cross sections up to 300 × 300 mm2 and the transmission in the vicinity of the fundamental absorption edge λ = 200 nm) equal to 86%. 相似文献
5.
Guozong Zheng Jingkui Liang Zhengdong Li Genbo Su Xinxin Zhuang 《Crystal Research and Technology》2008,43(6):583-587
The combined effects of supersaturation and Ba2+ on potassium dihydrogen phosphate (KDP) were investigated in batch cooling suspension crystallization. Growth size, morphology, and impurity Ba2+ adsorbed in the KDP crystals were measured with changing Ba2+ concentration and supersaturation. Significant changes in shapes and volume of the grown crystals have been observed. The results further confirmed that the size and shape of crystals were greatly determined by supersaturation. Ba2+ ions significantly modified the growth habit of KDP crystals. The concentration of Ba2+ ions adsorbed in the crystals increases with the increasing Ba2+ ions in the solutions and supersaturation. The foggy phenomena caused by the addition of Ba to the KDP solution were also described. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
Guozong Zheng Genbo Su Xinxin Zhuang Xiuqin Lin Zhengdong Li 《Crystal Research and Technology》2008,43(8):811-816
KDP crystals were rapidly grown from solution doped with different Ba2+ concentrations. The effects of Ba2+ on the growth rate, morphology and quality of KDP crystals were discussed. Significant changes in shapes and volume of the grown crystals have been observed. During the growth process, defect region expands gradually with the increasing Ba2+ concentration. Samples were cut from different parts of the as‐grown crystals for investigating the optical quality, including transmission spectrum, scattering centers. Through comparison, it is found that the nonuniform distribution of Ba2+ ions causes remarkable difference in optical quality between prismatic and pyramidal sectors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
Jianxu Ding Yongqiang Lu Shenglai Wang Xiaoming Mu Qingtian Gu Zhengping Wang Yun Sun Xiaoling Liang Xinguang Xu Xun Sun Wenjie Liu Guangxia Liu Shengjun Zhu 《Crystal Research and Technology》2010,45(8):800-804
By altering the concentration of silicate (SiO32‐) impurity in the solution, a series of potassium dihydrogen phosphate (KDP) crystals was obtained by the conventional temperature cooling and the rapid growth methods, respectively. It was observed that the presence of SiO32‐ made KDP crystals tapering in conventional cooling method, while more SiO32‐ induced inclusions at prismatic sectors in the rapid growth method. Laser‐polarization‐interference results showed that SiO32‐ extended the dead zone and reduced the growth rate of (100) face of KDP crystals. The negative influence of SiO32‐on the growth was considered absolutely similar to the effect of cations. It was also suggested that the stability of solution doped with SiO32‐ was improved without seed crystals, while it was destructed with seed crystals. The inhibition mechanism was analyzed in terms of SiO32‐ absorption on (100) face. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
A. V. Kosinova M. I. Kolybaeva O. N. Bezkrovnaya V. F. Tkachenko E. V. Grishina A. N. Levchenko V. M. Puzikov I. M. Pritula 《Crystal Research and Technology》2014,49(12):965-974
Single crystals of KDP crystals with embedded Urea molecules and TiO2 nanoparticles have been grown from aqueous solution by the temperature lowering method. The effect of the organic molecules and nanoparticles on the structural and mechanical properties has been studied. It has been observed that addition of Urea molecules improves laser induced damage threshold and mechanical strength of the crystal, while TiO2 nanoparticles have the opposite effect. The structure and composition of KDP:Urea crystal are studied by three‐crystal X‐ray diffraction analysis, which reveals the existence of a correlation between the increase of the microhardness value and the change of the crystal lattice parameter. The surface features of KDP:TiO2 crystals are analyzed by scanning electron microscopy that reveals the presence of quasi‐equidistant growth bands caused by capture of the nanoparticles. It is shown that the rise of TiO2 nanoparticles concentration up to 10−4 wt.% and higher resulted in 3‐fold reduction of the laser damage threshold of KDP:TiO2 relative to pure KDP in [001] and [100] crystallographic directions. It is found that microhardness and fracture toughness decrease at the nanoparticles concentration of 10−3 wt.% due to crack formation at crystal lattice discontinuities. The grown crystals also have been subjected to dielectric studies. 相似文献
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10.
Kouji Maeda Akira Sonoda Hideo Miki Yusuke Asakuma Keisuke Fukui 《Crystal Research and Technology》2004,39(11):1006-1013
Single potassium dihydrogen phosphate (KDP) crystals were grown in a supersaturated solution containing an organic dye (sunset yellow FCF, brilliant blue FCF, and sky blue). The growth rate, morphology, and impurity dye distribution of faces, (100) and (101) in a KDP crystal were measured as dye concentration and the supersatutation of KDP were changed. Complete expressions for the effect of dye on all aspects of the growth of KDP crystals were discussed. The growth rates of (100) and (101) faces were well correlated by the empirical equation, and resulted in good estimation of the morphology. The distribution of dye in a KDP crystal was represented by the distribution model containing the minimum growth rate for coloring. The growth rate equation and distribution equation were expressed by functions of the supersaturation and dye concentration, and they could effectively provide the operational conditions with coloring the KDP crystal. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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12.
V. A. Brailovskaya V. V. Zilberberg L. V. Feoktistova 《Journal of Crystal Growth》2000,210(4):767-771
Numerical simulation of the solution dynamics (natural and forced convection) above the surface of growing aqueous-soluble KDP crystals is carried out. A flow of supersaturated solution falling on the crystal surface through the multi-nozzle feeder is considered. An effective method based on time-dependent Navier–Stokes and energy equations in Boussinesq approximation has been developed for numerical investigation. Parametrical calculations of different regimes of hydrodynamics and mass transfer in a crystallization chamber are performed. Some important quantitative characteristics for high-rate growth technology development are obtained. 相似文献
13.
The dielectric properties of rapidly grown potassium dihydrogen phosphate KH2PO4 (KDP) crystals have been studied over a wide temperature range and compared with the properties of traditionally grown KDP crystals. It was found that the contribution of domains to permittivity in rapidly grown crystals is considerably less than in conventionally grown ones. The dielectric properties in various growth sectors of KDP crystals are determined. 相似文献
14.
Guozong Zheng Genbo Su Xinxin Zhuang Guohui Li Jiancheng Wang Zhengdong Li 《Crystal Research and Technology》2010,45(2):145-148
KDP crystals were rapidly grown from solutions doped with different Nd3+ concentrations. During the growth process, “foggy” inclusions were selectively captured in the pyramidal sector of KDP crystal and hourglass shaped crystals were obtained. It is found that the nonuniform distribution of Nd3+ ions causes remarkable differences in optical quality between prismatic and pyramidal sectors. With increasing Nd3+ concentration, the optical quality is greatly decreased for pyramidal sectors, while the change is not so obvious for prismatic sectors. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
15.
点籽晶法快速生长中等口径KDP单晶及其性能表征 总被引:2,自引:2,他引:0
本文使用德国MERCK公司生产的KDP原料和自行研制的晶体快速生长装置,采用"点籽晶"快速生长法成功生长出了150 mm级中等口径的KDP单晶,晶体生长速度达到20 mm/d.晶体生长过程中,生长溶液稳定,没有杂晶出现,生长的晶体完好且透明.X射线粉末衍射和摇摆曲线分析表明晶体有着较好的结构完整性;同时,测试了晶体的透过光谱和光损伤阈值,发现快速生长的晶体有着较好的光学性能. 相似文献
16.
The influence of significant dissolution and refaceting of KDP and Rochelle salt crystals on their further growth is studied. It is shown that the crystal growth rate ‐ initial crystal size dependence is better defined for growth after refaceting. Initial conditions for growth of individual crystals after refaceting are better defined, than in the case of classical seed nucleation. By dissolution and refaceting, it is easy to provide the same initial conditions for crystal growth in each of several experiments, preformed under the same macroscopic external conditions. 相似文献
17.
Conductivity of potassium dihydrophosphate (KDP) crystals grown from solutions with different pH has been studied with due regard for the sectorial structure and the impurity composition of the crystals grown. The dependence of the conductivity parameters on these two factors is established. The data obtained lead to a conclusion on the formation of the real structure important for various electro-optical applications of KDP crystals and provide the optimization of growth conditions. 相似文献
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The space group theoretical analyses and assignment of the lattice modes of the KDP crystal have been made, and the Raman spectra of their growth solution have been observed in different growth regions. The attention is focused on the analysis of the 912 cm‐1 band arising from the H2PO4‐ anions in the interface between the KDP crystals and their growth solution. This has been assigned to the asymmetrical stretching mode of the deformation P(OH)2 . From these results, the growth units of KDP crystal has been concluded to be the dimers of H2PO4‐ anions. We consider that the result presented here is an important step towards the development of more complete crystal growth theories. 相似文献