Grain Size Control of Tetragonal Zirconia Polycrystals Using the Space Charge Concept

Grain growth kinetics and grain-boundary segregation of 12Ce-TZP and 2Y-TZg containing divalent to pentavalent cationic dopants, were studied. In all cases, normal grain growth following the parabolic growth relation was observed at higher temperatures. The mobility of grain boundaries was suppressed by the addition of divalent and trivalent cations, unchanged or enhanced by the addition of tetravalent and pentavalent cations. Larger cations have a stronger effect in suppressing grain growth. From ESCA, AES, and STEM analysis of the near grain-boundary regions, it is further concluded that only divalent and trivalent cations segregate. These observations can be satisfactorily rationalized using the space charge concept and the model of impurity drag. [Key words: grain growth, tetragonal zircoda polycrystals, segregation, grain boundaries, dopants.]

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