Morphologies of solid-liquid interface and surface steps during rapid growth of BaB2O4 single crystals

Pan, Xiuhong; Ai, Fei; Jin, Weiqing; Liu, Yan; Zhang, Ying

doi:10.1007/s11433-007-0051-9

Cited by 7 publications

(6 citation statements)

References 17 publications

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“…It hints that the present glass matrix can in some sense be treated as a high-temperature solution since layer-like growth usually occurs in solution system [11]. As for the problem how BBO step propagates in high-temperature solution, much thorough work has been done in our previous papers [12,13].…”

Section: Resultsmentioning

confidence: 99%

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

Pan

Jin

Liu

et al. 2009

Cryst. Res. Technol.

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The morphological evolution and growth mechanism of β-BaB 2 O 4 microcrystal in Li 2 B 4 O 7 -BaB 2 O 4 glass (Li 2 O-B 2 O 3 -BaO) matrix were investigated by optical in situ observation method. And the crystallization temperature T c has been examined by differential thermal analysis (DTA). It demonstrates that homogeneous distribution of hexagonal shaped BBO microcrystals with size up to several tens of microns is typical when temperature is much higher than T c , however, heterogeneous nucleation occurs when annealing temperature is close to T c . For the latter case, crystal clusters that consist of several microcrystal grains are obvious. When the crystals in one specific cluster grows larger, crystal motion occurs in glass matrix while their orientation and symmetrical shape keep nearly no changes. Additionally, the BBO microcrystal has been determined to grow nearly in linear with time, which suggests a mechanism of interface-controlled growth. Furthermore, the activation energy of BBO crystal growth in glass matrix is calculated which is around 2.4 eV.

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Section: Resultsmentioning

confidence: 99%

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

Pan

Jin

Liu

et al. 2009

Cryst. Res. Technol.

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“…Our previous works [5,6] have shown that, for oxide melt morphological instability will occur and skeletal or dendritic shape will be obtained during rapid growth. In this work, using an in situ observation system, we distinguished diffusive and convective effects on crystal morphological stability in case of high cooling rate.…”

Section: Introductionmentioning

confidence: 99%

Solute distribution in KNbO ₃ melt-solution and its effect on dendrite growth during rapid solidification

et al. 2009

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This paper reports that the rapid solidification of mixed Li 2 B 4 O 7 and KNbO 3 melted in a Pt loop heater has been performed experimentally by the method of quenching, and various morphologies of KNbO 3 crystals have been observed in different regions of the quenched melt-solution. Dendrites were formed in the central region where mass transfer is performed by diffusion, whereas polygonal crystals with smooth surface grew in the marginal region where convection dominates mass transport. Based on measurement of KNbO 3 concentration along crystal interface by electronic probe analysis, it finds the variety of crystal morphologies, which is the result of different solute distributions: in the central region the inhomogeneity of solute concentration is much sharper and morphological instability is easier to take place; nevertheless in the marginal region the concentration homogeneity has been greatly enhanced by convection which prevents the occurrence of morphological instability. Additional solute distribution in the melt along the primary dendrite trunk axis as well as that in mushy zones has also been determined. Results show that the solute concentration in the liquid increases linearly with distance from the trunk tip and more solutes were found to be concentrated in mushy zones. The closer the mushy zone is to trunk tip, the lower the solute concentration will be there.

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“…As a kind of multifunctional crystal, crystal growth of ADP was extensively studied. In recent years, much progress was achieved on crystal growth [2−5], especially at the aspect of increasing the crystal growth rate and improving crystal quality [6,7]. As for ADP crystal, the research works mainly focused on ADP rapid growth technique, the effect of doping on the properties of ADP crystals and KADP (NH 4 H 2 PO 4 -KH 2 PO 4 ) crystal growth [8−10].…”

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confidence: 99%

Optical homogeneity of ADP crystals from rapid growth

et al. 2010

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ADP (NH 4 H 2 PO 4 ) crystals were grown through the traditional method and rapid growth technology. The optical homogeneity of rapid grown ADP crystals was analyzed by laser interferometry and X-ray topography. Laser interferometry revealed sector boundaries at which optical homogeneity decreased dramatically. The main defects that seriously reduced the optical homogeneity of the rapid grown ADP crystal were sector boundaries, growth bands and inclusions. The concentration of Fe and Cr impurities was tested by a plasma emission spectrometer. It was found that the preferential incorporation of metallic impurities into the prismatic faces resulted in high density of growth bands and inclusions, thus reducing optical homogeneity of the prismatic sector. ADP crystal, optical homogeneity, X-ray topography, laser interferometryCitation: Zhong D G, Teng B, Rupp A R, et al. Optical homogeneity of ADP crystals from rapid growth. ADP crystal is a kind of multifunctional crystal, widely used in frequency converters of coherent radiation of high-power picosecond lasers, clectro-optics, monochromators for X-ray fluorescence analysis, etc. [1]. As a kind of multifunctional crystal, crystal growth of ADP was extensively studied. In recent years, much progress was achieved on crystal growth [2−5], especially at the aspect of increasing the crystal growth rate and improving crystal quality [6,7]. As for ADP crystal, the research works mainly focused on ADP rapid growth technique, the effect of doping on the properties of ADP crystals and KADP (NH 4 H 2 PO 4 -KH 2 PO 4 ) crystal growth [8−10]. The defects directly influence the properties of ADP crystal. In 2007, first principal calculations on supercomputers revealed that the positions of ammonium ions as well as the presence of stresses or defects determined whether ADP crystals behaved ferroelectric or anti-ferroelectric [11]. The fact that hydrogen bonds can form between NH 4 + and H 2 O makes it hard for NH 4 + to get rid of the solvent. As a consequence, the growth of ADP crystal is very unstable [12], and especially for the rapid growth, defects are easy to appear. For that reason ADP crystals are usually grown by the slow temperature reduction method, which unfortunately is time consuming and expensive. In this work, the homogeneity of rapidly grown ADP crystals is characterized by laser interferometry and synchrotron radiation white-beam X-ray topography, respectively. Growth defects of ADP crystals that are suspected to greatly reduce the optical homogeneity were vividly revealed. The growth parameters that are closely related to the optical homogeneity were analyzed.

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Morphologies of solid-liquid interface and surface steps during rapid growth of BaB2O4 single crystals

Cited by 7 publications

References 17 publications

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

Solute distribution in KNbO ₃ melt-solution and its effect on dendrite growth during rapid solidification

Optical homogeneity of ADP crystals from rapid growth

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Morphologies of solid-liquid interface and surface steps during rapid growth of BaB2O4 single crystals

Cited by 7 publications

References 17 publications

In situ observation of β‐BaB2O4 microcrystal growth in glass matrix

In situ observation of β‐BaB2O4 microcrystal growth in glass matrix

Solute distribution in KNbO 3 melt-solution and its effect on dendrite growth during rapid solidification

Optical homogeneity of ADP crystals from rapid growth

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Product

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About

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

In situ observation of β‐BaB₂O₄ microcrystal growth in glass matrix

Solute distribution in KNbO ₃ melt-solution and its effect on dendrite growth during rapid solidification