Powder processing method

Glass-ceramic articles can be fabricated by means of either bulk or powder processing methods. Both methods begin with melting a glass of the desired composition. 

Figure 24. Electrode array prepared by the powder processing method shown in Figure 23. The electrode array structure is intact, although the individual rods contain defects.

PZT ceramics can be made by normal powder processing methods. The main difficulty is the high volatility of PbO. To retain as much PbO as possible sintering may be performed with the component surrounded by a lead-rich powder such as PZ and enclosed in a lidded crucible. Even with these precautions there is usually some (typically 2-3%) loss of PbO, which is compensated for by adding additional PbO to the starting batch. A note about safety lead is toxic and exposure to lead compounds has a cumulative effect. It is therefore necessary that evaporation is controlled. 

Sigmund WM, Bell NS, Bergstrom L (2000) Novel powder-processing methods for advanced ceramics. J Am Ceram Soc 83 1557-1574... 

PLS allows near net shaping of ceramic components with complex geometries using standard powder-processing methods, which results in reduction of the process cost. It will be of special interest for the sintering of the UHTC complex shapes and/or porous architectures in combination with wet forming techniques that are the main object of this chapter. 

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