Cross-sectional Area Dependency of Shrinkages and Grain Sizes of Flash-sintered 3 mol%Y₂O₃–ZrO₂ Polycrystals with a Circular Truncated Cone-shape at High Frequency Alternating Electric Current Fields

Abstract

The uniformity of shrinkages and the distribution of grain sizes were investigated for flash-sintered 3 mol%Y₂O₃-ZrO₂ compacts in direct current and alternating current (AC) electric fields using rectangular-shaped and circular truncated cone-shaped green compacts. The use of a high-frequency AC electric field enough to suppress electrode overvoltage was confirmed to be advantageous for uniform shrinkages, regardless of the shapes of the green compacts. However, the grain size distribution became larger in cone-shaped green compacts, the cross-sectional areas of which varied along the compact. The grain sizes in flashed cone-shaped green compacts were found to exhibit a near linear relation to current density, which provides a means for determining the grain size distribution upon the flash sintering of green compacts with different cross-sectional areas along an electric field.