Bonding in Ceramics

All things are Atoms Earth and Water, Air and Fire, all Democritus foretold. Swiss Paracelsus, in alchemic lair Saw sulfur, salt and mercury unfold Amid Millennial hopes of faking Gold. Lavoisier dethroned Phlogiston then molecules analysis made bold Forays into the gases Hydrogen Stood naked in the dazzled sight of Learned Men. 

The properties of any solid and the way its atoms are arranged are determined primarily by the nature and directionality of the interatomic bonds holding the solid together. Consequently, to understand variations in properties, it is imperative to appreciate how and why a solid is glued together. 

This glue can be strong, which gives rise to primary bonds, which can be ionic, covalent, or metallic. Usually van der Waals and hydrogen bonds are referred to as. secondary bonds and are weaker. In all cases, however, it is the attractive electrostatic interaction between the positive charges of the nuclei and the negative charges of the electrons that is responsible for the cohesion of solids. 

Very broadly speaking, ceramics can be classified as being either ionically or covalently bonded and, for the sake of simplicity, this notion is maintained throughout this chapter. However, that this simple view needs some modification will become apparent in Chap. 4 bonding in ceramics is neither purely covalent nor purely ionic, but a mixture of both. 

Before the intricacies of bonding are described, a brief review of the shape of atomic orbitals is presented in Sec. 2.2. The concept of 

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Ceramics and metals are entirely held together by primary bonds - the ionic and covalent bond in ceramics, and the metallic and covalent bond in metals. These strong, stiff bonds give high moduli. 

Wygant, J. F. (1958). Cementitious bonding in ceramic fabrication. In Kingery, W. D. (ed.) Ceramic Fabrication Processes, pp. 171-88. New York John Wiley Sons. 

Contrast the bonding in ceramics with the bonding in metals. 

Hydraulic cements are excellent examples of accelerated chemical bonding. Hydrogen bonds are formed in these materials by chemical reaction when water is added to the powders. These bonds are distinct from the bonds in ceramics in which high temperature interparticle diffusion leads to consolidation of powders. 

In the following sections we summarize how these conclusions lead to our present view of the structure of the atom and, in particular, the nature and arrangement of the electrons in the atom. We are not attempting to summarize modem physics, but only the concepts that we use in this text. You need to understand the main aspects of the nature of the chemical bond in ceramic materials what is an ionic bond, what is a covalent bond, and why do most... 

In this chapter we will discuss techniques that can produce useful information about the structure, chemistry, and bonding in ceramics. There are so many characterization methods available that books are written on each one. Since we cannot cover all the details or even all the techniques, we will give examples and aim at making you aware of the key ones and their applications. 

Construct a chart summarizing the principal scattering techniques used to characterize the structure, chemistry, and bonding in ceramics emphasizing which of the three features is most directly addressed by each technique. 

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