Molecular Dynamics Computer Simulations of Surface and Interface Phenomena in Vitreous Silica and Faceted Grain Boundaries of Alpha-alumina Containing Intergranular Films

Molecular Dynamics Computer Simulations of Surface and Interface Phenomena in Vitreous Silica and Faceted Grain Boundaries of Alpha-alumina Containing Intergranular Films
Title Molecular Dynamics Computer Simulations of Surface and Interface Phenomena in Vitreous Silica and Faceted Grain Boundaries of Alpha-alumina Containing Intergranular Films PDF eBook
Author David A. Litton
Publisher
Pages 260
Release 1998
Genre
ISBN

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American Doctoral Dissertations

American Doctoral Dissertations
Title American Doctoral Dissertations PDF eBook
Author
Publisher
Pages 784
Release 1998
Genre Dissertation abstracts
ISBN

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Dissertation Abstracts International

Dissertation Abstracts International
Title Dissertation Abstracts International PDF eBook
Author
Publisher
Pages 572
Release 1999
Genre Dissertations, Academic
ISBN

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Molecular Dynamic Simulations of the Intergranular Films Between Alumina and Silicon Nitride Crystal Grains

Molecular Dynamic Simulations of the Intergranular Films Between Alumina and Silicon Nitride Crystal Grains
Title Molecular Dynamic Simulations of the Intergranular Films Between Alumina and Silicon Nitride Crystal Grains PDF eBook
Author Shenghong Zhang
Publisher
Pages 130
Release 2007
Genre Aluminum oxide
ISBN

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The intergranular films (IGFs) between the ceramics grains have very important effects on the structure and mechanical properties on the whole ceramics and have been studied for many decades. In the thesis, molecular dynamic (MD) computer simulations were applied to study the IGFs between the alumina and silicon nitride ceramic grains. Preferential adsorption of specific ions from the IGFs to the contacting surfaces of the alumina crystals was observed in the study of calcium-alumino-silicate glassy (CAS) IGFs formed between the combined basal and prism orientations of [alpha]-Al2O3 crystals. This segregation of specific ions to the interface enables formation of localized, ordered structures between the IGF and the crystals. However, the segregation behavior of the ions is anisotropic, depending on the orientation of the [alpha]-Al2O3 crystals. Self-diffusion of calcium ions between these CAS IGFs was also carried out by MD simulations. The results show that the diffusion coefficients adjacent to the interfaces are smaller and the activation energies are much higher than those in the interior of the IGF and in bulk glasses. It was also suggested that Ca transport is mainly though the interior of the IGF and implies that diffusion would be significantly inhibited by sufficiently thin IGFs. The growth of the alumina ceramic grains was simulated in the contacting with IGFs containing high concentrations of aluminum ions. Five different compositions in the IGFs were studied. Results show preferential growth along the [1120] of the (1120) surface in comparison to growth along the [0001] direction on the (0001) surface for compositions near a Ca/Al ratio of 0.5. The simulations also show the mechanism by which Ca ions in the IGF inhibit growth on the basal surface. The simulations provide an atomistic view of attachment onto crystal surfaces, affecting grain growth in alumina. The dissolution of the alumina crystal grains in the silicate melts is another important issue in the application of alumina ceramics. The simulations results showed that alumina grains dissolved into the melts homogeneously at very high temperatures. The orientation of the crystals and the compositions of the melts only take effect at some intermediate temperatures, to make the alumina grains dissolution anisotropic. The fracture phenomena of the pure silica IGFs between the basal silicon nitride crystals were studied by applying the constant tensile strain on the simulated IGF system, as well as for the bulk silica glass for the comparison. The data indicated that the fracture was happened in the interior of the IGFs and the thickness of the IGFs has important effect on the fracture stress/strain relationships.

Molecular Dynamics (MD) Computer Simulations of Chemical Mechanical Polishing (CMP) Phenomena

Molecular Dynamics (MD) Computer Simulations of Chemical Mechanical Polishing (CMP) Phenomena
Title Molecular Dynamics (MD) Computer Simulations of Chemical Mechanical Polishing (CMP) Phenomena PDF eBook
Author Chien-Hsien Sam Lee
Publisher
Pages 242
Release 2006
Genre Molecular dynamics
ISBN

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Interfacial Phenomena

Interfacial Phenomena
Title Interfacial Phenomena PDF eBook
Author Clarence A. Miller
Publisher CRC Press
Pages 524
Release 2007-10-08
Genre Science
ISBN 1420044435

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Since the publication of the first edition of Interfacial Phenomena, the interest in interfaces and surfactants has multiplied, along with their applications. Experimental and theoretical advances have provided scientists with greater insight into the structure, properties, and behavior of surfactant and colloid systems. Emphasizing equil

Interfacial Phenomena

Interfacial Phenomena
Title Interfacial Phenomena PDF eBook
Author J.T. Davies
Publisher Elsevier
Pages 511
Release 2012-12-02
Genre Science
ISBN 0323161669

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Interfacial Phenomena explores the more primary properties of different liquid interfaces. This book is divided into eight chapters, where Chapter 1 establishes the basic concepts of the physics of surfaces, including the properties of matter in the surface layer. Chapters 2 and 3 further discuss the concepts of electrostatic and electrokinetic phenomena, respectively. Other areas discussed in the later chapters include adsorption at liquid interfaces; properties of monolayers; reactions at liquid interfaces; and mass transfer across interfaces. Chapter 8 discusses the more relevant aspects of disperse systems and adhesion as related to the interfacial properties discussed in the previous chapters. The text is a valuable source of information to students and researchers in the fields of chemistry, biology, and chemical engineering and can also be used for industrial and academic laboratories.