Dimensionality of the crystal growth, exponents of the power laws and activation energy for nucleation and growth processes in glass-crystal transformations under non-isothermal regime. Application to the crystallization of the Sb 0.13 As 0.35 Se 0.52 glassy semiconductor

Cr-substituted mesoporous aluminophosphate molecular sieve (Cr-MAP) was synthesized and characterized. Crystallization kinetics curves measured as an index to the relative degree of crystallinity, according to the Arrhenius equation to calculate the apparent nucleation activation energy and crystal growth activation energy of Cr-MAP, which was 63.7 and 14.7 kJ• mol-1, respectively. Cr-MAP had highly catalytic activity for fabricating acetophenone by selectively oxizing ethylbenzene. Using tert-butylhydroperoxide as oxidant and chlorobenzene as solvent at 100 °C for 8 h, acetophenone selectivity, acetophenone yield and ethylbenzene conversion reaches 85.4, 62.2 and 72.8 %, respectively.

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Evolution of cluster size distribution in nucleation and growth processes

Journal of Non-Crystalline Solids ◽

10.1016/0022-3093(91)90489-s ◽

1991 ◽

Vol 136 (3) ◽

pp. 181-197 ◽

Cited By ~ 43

Author(s):

J. Bartels ◽

U. Lembke ◽

R. Pascova ◽

J. Schmelzer ◽

I. Gutzow

Keyword(s):

Size Distribution ◽

Cluster Size ◽

Nucleation And Growth ◽

Cluster Size Distribution ◽

Growth Processes

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Phase separation in undercooled molten Pd80Si20: Part I

Journal of Materials Research ◽

10.1557/jmr.1999.0493 ◽

1999 ◽

Vol 14 (9) ◽

pp. 3653-3662 ◽

Cited By ~ 31

Author(s):

K. L. Lee ◽

H. W. Kui

Keyword(s):

Growth Rate ◽

Phase Separation ◽

Crystal Growth ◽

Grain Refinement ◽

Crystallization Temperature ◽

Sharp Decrease ◽

Nucleation And Growth ◽

Crystal Growth Rate ◽

Large Undercooling ◽

Kinetic Crystallization

Three different kinds of morphology are found in undercooled Pd80Si20, and they dominate at different undercooling regimens ΔT, defined as ΔT = T1 – Tk, where T1 is the liquidus of Pd80Si20 and Tk is the kinetic crystallization temperature. In the small undercooling regimen, i.e., for ΔT ≤ 190 K, the microstructures are typically dendritic precipitation with a eutecticlike background. In the intermediate undercooling regimen, i.e., for 190 ≤ ΔT ≤ 220 K, spherical morphologies, which arise from nucleation and growth, are identified. In addition, Pd particles are found throughout an entire undercooled specimen. In the large undercooling regimen, i.e., for ΔT ≥ 220 K, a connected structure composed of two subnetworks is found. A sharp decrease in the dimension of the microstructures occurs from the intermediate to the large undercooling regimen. Although the crystalline phases in the intermediate and the large undercooling regimens are the same, the crystal growth rate is too slow to bring about the occurrence of grain refinement. Combining the morphologies observed in the three undercooling regimens and their crystallization behaviors, we conclude that phase separation takes place in undercooled molten Pd80Si20.

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