Ceramic powder processing green bodies

Ceramic processing typically consists of three main steps (i) synthesis or preparation of precursor powders, (ii) consolidation or packing of the powders into green bodies, and (iii) sintering [44]. Every step has a significant effect on the microstructure and optical performance of the final transparent ceramics. There are a number of parameters relevant to the quality of the powders, facility, and way of consolidation and techniques of sintering, which can be used to optimize the fabrication process as a whole. 

In this chapter, we have described the colloid chemistiy of ceramic powders in suspension. Colloid stability is manipulated by electrostatic and steric means. The ramifications on processing have been discussed with emphasis on single-phase ceramic suspensions with a distribution of particle sizes and composites and their problems of component segregation due to density and particle size and shape. The next chapter will discuss the rheology of Uie ceramic suspensions and the mechanical behavior of dry ceramic powders to prepare the ground for ceramic green body formation. The rheology of ceramic suspensions depends on their colloidal properties. 

These mechanical properties are important in designing the equipment necessary to process the ceramic suspensions, pastes, and dry powders into ceramic green bodies. Each of the different raw materials... 

Because of their strong chemical bonds, bulk ceramics are most efficiently fabricated by means of densification of powders. The fabrication process involves two main stages (1) consolidation of the powder to form a porous, shaped article (the green body), also referred to as forming, and (2) heating of the shaped powder form to produce a dense article, referred to as firing or sintering. The final product commonly consists of a relatively dense polycrystal with some residual porosity (Fig. 1). The microstructure, which... 

A ceramic support is formed by shaping a powder and then consolidation of the green body by sintering. The fabrication process consists of four main stages the choice of inorganic material, paste preparation, shaping, and firing (Fig. 5.2). 

The density of the compact as a function of the applied pressure is usually used to characterize the compaction behavior of a ceramic powder, which can be used for process optimization and quality control of the green bodies. If the density is plotted... 

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