Fabrication of PZT

An alternative to firing in closed vessels is very rapid firing in which the material, carried on a moving belt, is exposed to a high peak temperature for a brief period in a special kiln. This procedure is applicable to thin sheets of material. 

Simple shapes are formed by die-pressing, long bodies of uniform section are formed by extrusion, thin plates are formed by band-casting or calendering, and large rings and more intricate shapes are formed by slip-casting. 

The sintered product usually has a density higher than 95% of theoretical and a crystallite size in the 5-30 /rm range. Both an excess and a deficiency of PbO result in inferior piezoelectric properties so that careful control of all aspects of the manufacturing process is essential. 

Electrodes are applied after any necessary machining to shape or finishing. For the majority of applications a suitably formulated silver-bearing paint is fired on at 600-800 °C. In the case of thin pieces, Ni-Cr or gold electrodes can be applied by sputtering or evaporation. 

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