We show that the application of a modest dc electrical field, about 4 V/cm, can significantly reduce grain growth in yttria‐stabilized polycrystalline zirconia. These measurements were made by annealing samples, for 10 h at 1300°C, with and without an electrical field. The finding adds a new dimension to the role of applied electrical fields in sintering and superplasticity, phenomena that are critical to the net‐shape processing of ceramics. Grain‐growth retardation will considerably enhance the rates of sintering and superplasticity, leading to significant energy efficiencies in the processing of ceramics.

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Silica segregation at two grain junctions or in amorphous triple junction pockets can influence creep by altering the grain‐boundary diffusion coefficient. Although the addition of silica to superplastic yttria‐stabilized tetragonal zirconia enhances ductility, differences in reported creep parameters have limited critical identification of rate controlling mechanisms. The present study on a pure 3 mol% yttria‐stabilized tetragonal zirconia (3YTZ) and 3YTZ with 0.39 or 3.9 wt% silica involved a detailed characterization of creep over a wide range of experimental conditions and also tracer diffusion measurements. The data broadly show transitions in creep stress exponents from n∼1 to ∼2 to ∼3 with a decrease in the stress. The data at high stresses are consistent with Coble diffusion creep, and creep at lower stresses is attributed to interface‐controlled diffusion creep. Measurements indicated that silica does not have any significant influence on grain boundary or lattice diffusion, and this is consistent with the observation that 3YTZ and 3YTZ with 0.39% or 3.9% silica exhibit essentially identical creep behavior in the Coble creep regime. Silica influences the interface control process so that the transitions in stress exponents are pushed to lower stresses with an increase in silica content.

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