Speaker
Description
Flash sintering, in which densification occurs almost instantaneously above a threshold electric field strength and furnace temperature, has been widely demonstrated in various oxide ceramics. In addition, bulk ceramics show superplastic flow, accelerated sinter forging, good joining performance and crack healing under flash events, suggesting that flash events significantly promote diffusion of constitutive ions. It has been widely accepted that the onset of a flash event is triggered by thermal runaway through Joule heating and increased electrical conductivity. However, several studies suggested that the effect of flash events may involve athermal processes to accelerate diffusional mass transport.
In the present study, the diffusivity of Er3+ cations in Y2O3 was determined by interdiffusion experiments using Er2O3/Y2O3 diffusion couples under alternating current (AC) flash events. In the diffusion couple, Er3+ cations act as tracers of Y3+ in Y2O3, and vice versa. The increase in specimen temperature via Joule heating, which represents the important aspect of flash events, were carefully evaluated by coupling the experimental and numerical approaches. The interdiffusion experiments eventually revealed the athermal acceleration of both lattice and grain boundary diffusion coefficients under AC electric fields.
| Professional Status of the Speaker | Senior Scientist |
|---|---|
| Invitation letter for visa | No |
| Interest in submitting a paper in a special issue of | No interest |
