Application of an external electric field has been shown to decrease the temperature needed for sintering and to increase the densification rate. The effect, called “flash sintering,” is striking: In yttria-stabilized zirconia, the application of a field of 120 V/cm decreases the sintering temperature from 1500^oC to below 900^oC and the densification, which takes hours without the applied field, occurs in seconds.

The objective of this research is to determine the processes that cause flash sintering. Recently, we showed that the density of point defects increases dramatically during flash sintering. We will investigate the coupling between charged point defects and the applied electric field using first principles density functional theory calculations and model Hamiltonians. The work will be performed in collaboration with experimental efforts on flash sintering.

 

Reference

Cologna M, Rashkova B, Raj R: "Flash Sintering of Nanograin Zirconia in < 5 s at 850^oC." Journal of the American Ceramic Society 93: 3556-3559, 2010

 

Keywords:

Density functional theory; Theoretical physics; Computational physics; Model Hamiltonians; Solid phase and solids; Condensed matter; Materials science; Atomistic simulations; Computer simulations; Electronic structure; Free Energy; First Principles;

Citizenship:  Open to U.S. citizens and permanent residents

Level:  Open to Postdoctoral applicants