Swelling liquid-phase sintering

FIGURE 1 49 Schematic of the effects cl solubility on densification or swelling during liquid phase sintering. Taken from German [116, p. 69]. 

Another key parameter is the solubility of the solid in the liquid. The common requirement is for the solid to be soluble in the liquid but for the liquid to have a low solubility in the solid. This requirement leads to a liquid that persists during sintering. A high liquid solubility in the solid leads to a transient liquid phase and swelling of the compact during heating. 

In a solid-liquid two phase system, the solid can be dissolved in the liquid and the liquid can also be dissolved in the solid. A high solubility of the solid in the liquid will facilitate potentially a high mass transport rate through the liquid layer, which is the basic requirement of liquid-phase sintering. However, the dissolving of the liquid in the solid is totally prevented, otherwise the compact would be severely swelling due to the formation of transient liquid phases. The effect of solubUily on densification and swelling of the compact is demonstrated schematically in Fig. 5.33 [73]. 

Briefly discuss whether each of the following factors is likely to promote shrinkage or swelling during the initial stage of liquid-phase sintering ... 

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