Processing of Ceramics and Glasses

There are perhaps a wider variety of techniques that can be used to form and shape ceramics and glasses than for any of the other materials classes. Much of the variation 

The powder-forming processes are similar in many ways to those nsed for powder metallurgy described in the previons section. For example, pressing is a common method for processing ceramics however, ceramic powders can be pressed in either dry or wet form. In wet form, they can also be extended, just like metals, and cast in a variety of process variations. The nominal forming pressures and shear rates associated with some of these processing methods are snmmarized in Table 7.3. Yon may want to refer back to this table when each of the varions processing techniques is described in more detail. 

Source J. S. Reed, Principles of Ceramics Processing, 2nd ed. Copyright 1995 by John Wiley Sons, Inc. 

The final volume, Vfl ai, is larger than the volume of the particulate material, VsoHds, when the product has residual porosity. We define a ratio of these two volumes. Dr, that gives a measure of the residual porosity  

When the densified component is pore-free, Vflnai = VsoUds and Dr = 1.0. Anything less than this value indicates the presence of porosity. Control of Dr requires control of both the microstructure of the as-formed part and the firing, because both affect the sintering shrinkage. 

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T. Abraham, Sol-Gel Processing of Ceramics and Glass, BCC Research, Norwalk, CT, 2006. 

The synthesis and propaties of metal alkoxides are been considered in detail by Bradley et al. (12), while several important synthesis reactions are described in a review article (13). Here we consider only a few of the main features relevant to the sol-gel processing of ceramics and glasses. 

Abraham, Th. (2006) Sol-gel processing of ceramics and glasses. BCC Research Report, AVM016E, June 2006. Available at www.bccresearch.com/report/index (accessed December 9, 2009). 

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