Pattern formation from boundary reaction

2002 ◽  
pp. 13-18 ◽  
Author(s):  
José Arrieta ◽  
Neus Cónsul ◽  
Aníbal Rodríguez-Bernal
Keyword(s):  
Pattern Formation ◽  
Boundary Reaction

The measurement of thin-film reaction layers with high-resolution FESEM

1995 ◽  
Vol 53 ◽  
pp. 330-331
Author(s):  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Reaction Layer ◽  
Product Layer ◽  
Buffer Layers ◽  
Oxide Superconductors ◽  
Rate Limiting Step ◽  
Ceramic Thin Film ◽  
Backscattered Electron ◽  
Boundary Reaction

Thin-film reactions in ceramic systems are of increasing importance as materials such as oxide superconductors and ferroelectrics are applied in thin-film form. In fact, reactions have been found to occur during the growth of YBa2Cu3O6+x on ZrO2. Additionally, thin-film reactions have also been intentionally initiated for the production of buffer layers for the subsequent growth of high-Tc superconductor thin films. The problem is that the kinetics of ceramic thin-film reactions are not well understood when the reaction layer is very thin; that is, when the rate-limiting step is a phase-boundary reaction as opposed to diffusion of the reactants through the product layer. In this case, the reaction layer is likely to be laterally non-uniform. In the present study, the measurement of thin reaction-product layers is accomplished by first digitally acquiring backscattered-electron images in a high-resolution field-emission scanning electron microscope (FESEM) followed by image analysis. Furthermore, the problem of measuring such small thicknesses (e.g., 20-500nm) over lengths of interfaces longer than 3mm is addressed.

Domain coarsening by grain boundary migration in ordered Ni4Mo

1986 ◽  
Vol 44 ◽  
pp. 560-561
Author(s):  
K. Vasudevan ◽  
H. P. Kao ◽  
C. R. Brooks ◽  
E. E. Stansbury
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Short Range ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Rapid Cooling ◽  
Temperature Range ◽  
Fee Structure ◽  
Domain Coarsening ◽  
Boundary Reaction

The Ni4Mo alloy has a short-range ordered fee structure (α) above 868°C, but transforms below this temperature to an ordered bet structure (β) by rearrangement of atoms on the fee lattice. The disordered α, retained by rapid cooling, can be ordered by appropriate aging below 868°C. Initially, very fine β domains in six different but crystallographically related variants form and grow in size on further aging. However, in the temperature range 600-775°C, a coarsening reaction begins at the former α grain boundaries and the alloy also coarsens by this mechanism. The purpose of this paper is to report on TEM observations showing the characteristics of this grain boundary reaction.

Pattern formation in the splay Freedericks transition of a nematic side-group polysiloxane

1993 ◽  
Vol 3 (6) ◽  
pp. 865-889 ◽  
Author(s):  
Norbert Schwenk ◽  
Hans Wolfgang Spiess
Keyword(s):  
Pattern Formation ◽  
Side Group

Pattern Formation in Thin Polymer Films: A New Morphology

2000 ◽  
Vol 629 ◽  
Author(s):  
Jean-Loup Masson ◽  
Peter F. Green
Keyword(s):  
Growth Rate ◽  
Pattern Formation ◽  
Early Stage ◽  
Structural Evolution ◽  
Distinct Form ◽  
Thin Polymer Films ◽  
Intermediate Morphology ◽  
Thin Polymer ◽  
Nonwetting Liquid ◽  
Cylindrical Holes

ABSTRACTResearchers have shown that thin, nonwetting, liquid homopolymer films dewet substrates, forming patterns that reflect fluctuations in the local film thickness. These patterns have been shown to be either discrete cylindrical holes or bicontinuous “spinodal-like” patterns. In this paper we show the existence of a new morphology. During the early stage of dewetting, discrete highly asymmetric holes appear spontaneously throughout the film. The nucleation rate of these holes is faster than their growth rate. The morphology of the late stage of evolution, after 18 days, is characterized by a bicontinuous pattern, distinct form conventional spinodal dewetting patterns. This morphology has been observed for a range of film thicknesses between 7.5 and 21nm. The structural evolution of this intermediate morphology is discussed.

Pattern Formation Survey on Non Uniformly Forced Swift-Hohenberg Equation

2019 ◽  
Author(s):  
Daniel Coelho ◽  
José da Rocha Miranda Pontes ◽  
Norberto Mangiavacchi
Keyword(s):  
Pattern Formation
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