Abstract
The study of 3 mol% 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 1 mu m (D80=0.51 mu m, meaning 80 vol% has a size less than 0.51 mu m), 2 mu m (D80=0.90 mu m), 5 mu m (D80=2.11 mu m) and 10 mu m (D80=3.09 mu m). While the furnace temperature for flash sintering, at a field of 100 V cm(-1), increased from 920 degrees C to 1040 degrees C with particle size, the specimen temperature in all instances remained at similar to 1200 degrees 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. (c) 2012 Elsevier Ltd. All rights reserved.