Effects of minor addition of reactive elements (Ce, Hf, La, Y, and Zr) on the structural and dynamical properties of liquid chromia were investigated by the ab initio molecular dynamics approach. The calculation results show that minor doping of reactive elements has a significant effect on the diffusivity of chromium and oxygen ions. It is observed that Hf and La are the most efficient elements in retarding the diffusion of chromium and oxygen, Ce and Y are secondarily efficient, while Zr is the least efficient. The relative bonding strength between doping elements and oxygen was found to be in descending order of Hf-O > Zr-O > (Ce,Y)-O > La-O, which could be estimated from the major peak intensities of pair correlation functions or the values of mean residence time. Our calculation results are in satisfactory agreement with those obtained from experimental measurement and thermodynamic database. The mechanism regarding the effects of reactive elements on diffusivity was further analyzed in view of possible factors: ionic size, bonding strength, and ionic weight. It turns out that no sole factor could be responsible for the relative efficiency of reactive elements, and a novel evaluation parameter combining these factors was proposed.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 30 2012|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics