Particle size effects in flash sintering

Abstract

The study of 3mol% yttria stabilized zirconia (3YSZ) with different particle sizes provides new insights into flash sintering. Four powders, all with the same crystallite size but various particle size were investigated: described as nominally 1μm (D80=0.51μm, meaning 80vol% has a size less than 0.51μm), 2μm (D80=0.90μm), 5μm (D80=2.11μm) and 10μm (D80=3.09μm). While the furnace temperature for flash sintering, at a field of 100Vcm -1, increased from 920°C to 1040°C with particle size, the specimen temperature in all instances remained at ∼1200°C. The quantum increase in density decreased with larger particles. The grain size distribution of conventionally and flash sintered specimens remained similar, with some evidence of a preponderance of nanograins in the flash sintered specimens. Joule heating was well below the temperatures that would have been required for sintering in a few seconds. An explanation based upon the nucleation of Frenkel pairs is proposed. © 2012 Elsevier Ltd.