Thermodynamics of Ceramics and Glasses

As you can see, the process by which the iron-carbon alloy is processed and solidified is jnst as important as the overall stoichiometry. Although a discussion regarding phase transformations is more the realm of kinetic processes, it is nonetheless pertinent to snmmarize here the types of important ferrous alloys, particularly those in the cast iron categories. This is done in Fignre 2.13. 

Three-component systems, or ternary systems, are fundamentally no different from two-component systems in terms of their thermodynamics. Phases in eqnilibrium must still meet the equilibrium criteria [Eqs. (2.14)-(2.16)], except that there may now be as many as five coexisting phases in eqnilibrinm with each other. The phase rule still 

Just as with the lever rnle in binary phase diagrams, segments can be measnred in any consistent units of length. 

Person 1 Lightly sketch in grid lines on the diagram and use them to determine the composition at the indicated point. 

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Sintering of Ceramics. The thermodynamics of the sintering process were presented in Section 2.2.2.4. We describe here some of the more practical aspects of sintering as they relate to the firing of ceramics and glasses. 

In the uniaxial tension test (Fig. 2.8), there is usually a transverse strain, i.e., a strain perpendicular to the applied stress. This can be used to define a second elastic constant, Poisson s ratio (v), as the negative ratio of the transverse strain (e.j.) to the longitudinal strain (s ), i.e., v= -Sj/cl- For isotropic materials, it can be shown from thermodynamic arguments, that -1< u <0.5. For many ceramics and glasses, v is usually in the range 0.18-0.30. 

Silicon exists in nature only in the most thermodynamically stable form in a oxygen-containing atmosphere. Each silicon atom is surrounded by four oxygen atoms in tetrahedral symmetry. Mankind has used the special stability of such compounds to prepare glass, chinaware, ceramics, and building materials like concrete, etc. Silicates today are still one of the most important materials. 

Aimed at master s degree or PhD students as well as researchers and specialist engineers, this work focuses on electrochemical systems using electrolytes in solid phases (ionic crystals, ceramics, different types of glass and polymers). The fundamental concepts of electrochemistry are laid out (the thermodynamics of point defects and amorphous phases, transport mechanisms, mixed conduction, and gas electrode reactions) alongside the specific research methods used. Several applications are also described. 

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