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Influence of the Field and the Current Limit on Flash Sintering at Isothermal Furnace Temperatures
Author(s) -
Francis John S. C.,
Raj Rishi
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12472
Subject(s) - sintering , materials science , flash (photography) , isothermal process , cubic zirconia , nucleation , yttria stabilized zirconia , metallurgy , current (fluid) , composite material , thermodynamics , ceramic , optics , physics
We report, for the first time, the observation of an incubation time for the onset of flash sintering in experiments carried out at isothermal furnace temperatures. The incubation time varies highly nonlinearly with the strength of the DC field, akin to a nucleation‐like phenomenon. The setting of the maximum current at the power supply has a significant influence on the extent of densification. The hold time at these current settings has an influence on the grain size increasing it with time and the magnitude of the current setting. The experiments were carried out on 3 mol% yttria‐stabilized zirconia. In all instances the specimen temperatures during flash sintering, estimated from a previously validated blackbody radiation model remain well below the temperatures that would be required for conventional sintering of yttria‐stabilized zirconia. Taken together these observations imply a nucleation of defect avalanche as a possible mechanism for flash sintering.