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Full-Text Articles in Engineering
Synthesis And Property Characterization Of Rare-Earth High-Entropy Oxides With Pyrochlore-Type Structures, Candice Kinsler-Fedon
Synthesis And Property Characterization Of Rare-Earth High-Entropy Oxides With Pyrochlore-Type Structures, Candice Kinsler-Fedon
Doctoral Dissertations
In the search for novel materials with advanced physical properties, the concept of adding configurational entropy onto a single atomic site is known to provide new avenues toward material discovery. In the case of high entropy oxides (HEOs), the ability to “tune” a material’s properties by having multiple cations on single or multiple sites allows for greater opportunity to design materials for specific applications. The work presented here explores the synthesis of new multicomponent (high entropy) oxides, followed by a detailed characterization using several techniques. We have successfully synthesized multiple single-phase polycrystalline rare-earth high entropy oxides and grown large, bulk …
Helium Diffusion And Accumulation In Gd2ti2o7 And Gd2zr2o7, Caitlin Anne Taylor
Helium Diffusion And Accumulation In Gd2ti2o7 And Gd2zr2o7, Caitlin Anne Taylor
Doctoral Dissertations
The effects of helium accumulation on bubble formation and mechanical properties, as well as the fundamentals of helium diffusion in pyrochlores, are experimentally investigated in Gd2Ti2O7 [gadolinium titanate] and Gd2Zr2O7 [gadolinium zirconate]. We find that helium accumulation results in bubble formation at concentrations of 6 at.% in pre-damaged Gd2Ti2O7 and 4.6 at.% in pre-damaged Gd2Zr2O7. Lattice parameter, residual stress, and hardness changes due to helium accumulation were investigated in Gd2Zr2O7, which remains crystalline …
Characterizing Local Order And Physical Properties Of Rare Earth Complex Oxides, Thomas Jacob Shamblin
Characterizing Local Order And Physical Properties Of Rare Earth Complex Oxides, Thomas Jacob Shamblin
Doctoral Dissertations
With more than 500 compositions, materials possessing the pyrochlore structure have a myriad of technological applications and physical phenomena. Three of the most noteworthy properties are the structure’s ability to resist amorphization making it a possible host matrix for spent nuclear fuel, its exotic magnetic properties arising from geometric frustration, and fast ionic conductivity for solid-oxide fuel cell applications. This work focuses on these three aspects of the pyrochlore’s many potential uses. Structural characterization revealed that pyrochlore-type oxides have a tendency to disorder from a high symmetry cubic structure to a lower symmetry orthorhombic arrangement in response to a variety …