Crystal growth and nucleation in two large diabase dikes

1970 ◽  
Vol 7 (2) ◽  
pp. 366-375 ◽  
Author(s):  
N. H. Gray
Keyword(s):  
Crystal Growth ◽  
Nucleation Rate ◽  
Unit Volume ◽  
Single Phase ◽  
Bulk Composition ◽  
Numerical Constant ◽  
N Value ◽  
Olivine Tholeiite

The total number of nuclei, Z, of a single phase formed in a unit volume of a crystallizing magma at the distance y from the contact of a semi-infinite intrusion is[Formula: see text]where n is a numerical constant determined by growth controlling process during the nucleation period and the value of m in the expression assumed for the nucleation rate, J[Formula: see text]The observed variation of Z for clinopyroxene and plagioclase from the contact towards the center of two large dikes appears to follow this relation. In the 106 m wide Kigaviarluk olivine tholeiite dike the value of n is significantly greater for the clinopyroxene (−2.2) than the plagioclase (−0.84). In the 60 m Grenville dike, a quartz tholeiite, the n value (−1.5) is the same for both minerals. The growth-controlling mechanisms of plagioclase and clinopyroxene appears to be sensitive to the bulk composition of the magma from which it is crystallizing.

Crystallization kinetics for the system CuSO4-ZnSO4-H2O forming solid solutions

1986 ◽  
Vol 51 (11) ◽  
pp. 2473-2480 ◽  
Author(s):  
Jaroslav Nývlt ◽  
Věra Šnoblová ◽  
Miloslav Karel
Keyword(s):  
Solid Solution ◽  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Solid Solutions ◽  
Nucleation Rate ◽  
Diffusion Mechanism ◽  
Crystal Growth Rate ◽  
Component System ◽  
Metastable Zone

The three-component system CuSO4-ZnSO4-H2O forms three types of solid solution. Metastable zone widths measured for selected solution compositions at two cooling rates were used to calculate the kinetic parameters of nucleation. The rate of crystal growth was measured by the fluidized bed method. The results show that the addition of Zn2+ to a solution of CuSO4 increases both the nucleation and crystal growth rates, whereas Cu2+ added to a solution of ZnSO4 retards the nucleation rate and slightly increases the rate of crystal growth. The nucleation rate (the metastable zone width) is substantially more sensitive to the addition of a second component than is the rate of crystal growth. The crystal growth rate is controlled by a diffusion mechanism.

Studies on nucleation and crystal growth kinetics of plutonium(IV) oxalatex

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chuanbo Li ◽  
Bo Wang ◽  
Xiang Li ◽  
Taihong Yan ◽  
Weifang Zheng
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Nucleation Rate ◽  
Crystal Growth Rate ◽  
Acid Solutions ◽  
Dilution Ratio ◽  
Secondary Nucleation ◽  
Supersaturation Ratio ◽  
Crystal Growth Kinetics ◽  
Kinetics Of

Abstract A new method is developed to calculate the dilution ratio N of the two reactant solutions during nucleation rate determination. When the initial apparent supersaturation ratio S N  = f(N) in the dilution tank is controlled between 1.66 and 1.67, the counted nuclei is the most, both nuclei dissolving and secondary nucleation avoided satisfactorily. Based on this methoed, Plutonium(IV) oxalate is precipitated by mixing equal volumes of tetravalent plutonium nitrate and oxalic acid solutions. Experiments are carried out by varying the supersaturation ratio from 8.37 to 22.47 and temperature from 25 to 50 °C. The experimental results show that the nucleation rate of plutonium(IV) oxalate in the supersaturation range cited above can be expressed by the equation R N  = A N exp(−E a /RT)exp[−B/(ln S)2], where A N  = 4.8 × 1023 m−3 s−1 , and E a  = 36.2 kJ mol−1, and B = 20.2. The crystal growth rate of plutonium(IV) oxalate is determined by adding seed crystals into a batch crystallizer. The crystal growth rate can be expressed by equation G(t) = k g exp(−E’ a /RT) (c − c eq) g , where k g  = 7.3 × 10−7 (mol/L)−1.1(m/s), E’ a  = 25.7 kJ mol−1, and g = 1.1.

Multi-Step Sintering Method Study of HP Y-SiAlON Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 908-909
Author(s):  
Jiu Jun Xu ◽  
Ying Chun Shan ◽  
Jiang Tao Li ◽  
Qin Ji Song
Keyword(s):  
Crystal Growth ◽  
Low Temperature ◽  
Hot Pressing ◽  
Single Phase ◽  
Nitrogen Atmosphere ◽  
One Step ◽  
Hot Pressing Sintering ◽  
Kinetics Of ◽  
Sintering Method ◽  
Kinetics Of Crystal Growth

Multi-step hot pressing sintering was adopted to prepare Y-SiAlON (Y0.4Si9.6Al2.4O1.2N14.8) at 1950°C for 60 min under 25 Mpa in nitrogen atmosphere, and the microstructure was studied. The phase assemblages, microstructures and densification of the sintered samples were discussed in detail. In order to contrast to multi-step sintering, one step sintering also was adopted. The results reveal that single-phase α-SiAlON with elongated grain pattern is formed in the multi-step sintering specimens, because of holding at low temperature in multi-step sintering is helpful to reduce the kinetics of crystal growth, the mount of elongated grain in multi-step sintering samples is more than that of in one step sintering ones.

Growth and Facet Orientations in Single-Phase TiAl Single Crystals

1994 ◽  
Vol 364 ◽  
Author(s):  
R. Mahapatra ◽  
H. Lin ◽  
D. P. Pope ◽  
Y. T. Chou
Keyword(s):  
Crystal Growth ◽  
Single Crystals ◽  
Single Phase ◽  
Tial Alloy ◽  
Solidification Rate ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscattering

AbstractSingle crystals of single-phase TiAl alloy (Ti-56 at. % Al) have been grown at lOmm/h solidification rate in an ASGAL FZ-SS35W Optical Floating Zone Furnace. The orientations of the resulting single crystals have been determined using the Laue X-ray diffraction, and Electron Backscattering Pattern (EBSP) methods. A correlation between orientations of the crystal growth and grown-in facets has been established.

A new surfactant-introduction strategy for separating the pure single-phase of metal–organic frameworks

2015 ◽  
Vol 51 (46) ◽  
pp. 9479-9482 ◽  
Author(s):  
Jun Zhao ◽  
Yenan Wang ◽  
Wenwen Dong ◽  
Yapan Wu ◽  
Dongsheng Li ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Phase ◽  
Metal Organic Frameworks ◽  
Mixed Phase ◽  
Metal Organic

Surfactant-directed crystal growth can effectively separate mixed-phase crystals. By introducing different surfactants, two previous mixed-phase Ni(ii)–MOFs constructed from an undeveloped pyridyl-tetracarboxylate and Ni(ii) salts were successfully isolated to obtain two pure products.

Growth of CuInSe2 monograin powders with different compositions

2005 ◽  
Vol 865 ◽  
Author(s):  
Marit Kauk ◽  
Mare Altosaar ◽  
Jaan Raudoja ◽  
Kristi Timmo ◽  
Maarja Grossberg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Concentration Ratio ◽  
Single Phase ◽  
Bulk Composition ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dominant Peak ◽  
Scanning Electron

AbstractCuInSe2 monograin powders (MGP) were synthesized from Cu-In alloys of different Cu/In concentration ratios and elemental Se in liquid phase of flux material in evacuated quartz ampoules. The surface morphology, phase structure, and composition of the powder crystals were analyzed by scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis respectively. Bulk composition was analyzed polarographically. Photoluminescence spectra were measured at 9 K. It was found that the composition of MGP material (Cu/In concentration ratio) can be controlled by the concentration ratio of precursor Cu-In alloys. Single phase CuInSe2 growth is realisable between 0.7<Cu/In<1 at the growth temperature of 1000 K. Photoluminescence spectra of near-stoichiometric materials had one dominant peak at 0.93 eV, which is typical to In-rich CuInSe2. Samples with high In content exhibited two broad bands with peak positions at 0.86 and 0.93 eV.

Designed single-phase ZrO2 nanocrystals obtained by solvothermal syntheses

CrystEngComm ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1802-1811
Author(s):  
Mayara S. Santos ◽  
Jair C. C. Freitas ◽  
Cleocir J. Dalmaschio
Keyword(s):  
Crystal Growth ◽  
Single Phase ◽  
Capping Agent ◽  
Crystalline Phases ◽  
Solvothermal Syntheses

Crystal growth pathways controlled by the acidity, type and concentration of the capping agent lead to different nanostructures and crystalline phases.

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