| About this Abstract |
| Meeting |
MS&T23: Materials Science & Technology
|
| Symposium
|
Phase Transformations in Ceramics: Science and Applications
|
| Presentation Title |
Microstructural Evolution and Associated Kinetics of Seeded Solid State Single Crystal Growth of CoTi2O5 |
| Author(s) |
Junyan Zhang, Connor McNamara, Kevin P. Anderson, Animesh Kundu, Helen M. Chan, Jeffrey M. Rickman |
| On-Site Speaker (Planned) |
Junyan Zhang |
| Abstract Scope |
A duplex grain structure of CoTiO3 and TiO2 can react to form pseudo-single crystal CoTi2O5 during heat-treatment. CoTi2O5 is an entropy stabilized compound which is only stable above a critical temperature. For a sample seeded with an upper layer of polycrystalline CoTi2O5, CoTi2O5 nucleates at the seeded surface and grows inwards with a planar reaction front. The reaction initiates along the bi-phase boundaries and continues via bulk diffusion behind the reaction front. The CoTi2O5 morphology and degree of transformation was studied as a function of time for isothermal heat-treatment at temperatures from 1175 – 1300 oC. EBSD (electron backscattered diffraction) was used to characterize the preferred growth direction and the variation of orientation within the CoTi2O5. The kinetics of this complex and unusual transformation were studied using both dilatometry and microstructural observations. The results will be discussed in terms of the rate-determining transport mechanisms at and behind the reaction front. |