Interphase boundary, grain boundary, and surface diffusion in Al2O3-GdAlO3 composites determined from bicrystal coble creep experiments

Coffman, D. Keith; Ma, Yonghui; Barr, Christopher M.; Ouyang, Jun; Hattar, Khalid Mikhiel; Dillon, Shen J.

doi:10.1016/j.jeurceramsoc.2022.02.052

Cited by 9 publications

(1 citation statement)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unfortunately, the ceramic community's understanding of these processes (and the associated activation energy values) is even more limited than that of grain boundary diffusion! A rare study that addressed the contribution of interphase boundary diffusion to the overall behavior of a composite system was carried out by Coffman et al 57 Based on TEM in situ bicrystal creep studies, these workers determined the activation energy for diffusion at an Al 2 O 3 -GdAlO 3 interface to be 559 ± 117 kJ/mol, and that the interphase boundary diffusivity was two orders of magnitude higher than that of the grain boundary diffusivities of the constituent phases. Clearly, more work is needed to understand the details of the reaction mechanism and the processes taking place at the boundary of the advancing CDT.…”

Section: Advancing Cdt Networkmentioning

confidence: 99%

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics

Zhang,

Anderson,

Rickman

et al. 2023

J Am Ceram Soc.

View full text Add to dashboard Cite

The solid‐state transformation behavior of cobalt dititanate (CoTi2O5) has been studied at different temperatures. The starting structure consisted of a duplex (1:1 molar) mixture of CoTiO3 and TiO2 grains. A seed layer of CoTi2O5 grains was incorporated at the upper surface of the green, precursor powder samples. Cobalt dititanate is a member of the pseudobrookite family (Cmcm, orthorhombic); it is an entropy‐stabilized compound, hence is stable only at elevated temperatures (T > 1140°C). It was observed that transformation initiated adjacent to the seed layer. First, a narrow layer of CoTi2O5 forms at the diphase boundaries, creating a 3‐D network that propagates at a constant velocity through the structure. The velocity of the reaction front follows an Arrhenius dependence on temperature. Both the rates of nucleation and growth increase with increasing temperature. At 1300°C, the velocity was estimated to be in excess of 10 mm/h. The progression of the reaction front was modelled based on a discontinuous template growth mechanism, with enhanced diffusion along the boundary between the product and reactant phases. The activation energy derived for boundary diffusion was 475 ± 69 kJ/mol. Behind the reaction front, the microstructure consists of a continuous matrix of CoTi2O5, with isolated remnant grains of CoTiO3 and TiO2. Further transformation occurs more slowly by solid‐state diffusion through the CoTi2O5 phase. Studies of the crystallographic orientation of the CoTi2O5 phase showed that it was pseudo‐ single crystal, with a preferred growth direction of [100]. The system exhibits novel features, which have not been reported previously for ceramic systems.

show abstract

Section: Advancing Cdt Networkmentioning

confidence: 99%

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics

Zhang,

Anderson,

Rickman

et al. 2023

J Am Ceram Soc.

View full text Add to dashboard Cite

show abstract

Interface nucleation rate limited densification during sintering

Dillon

Oyang

et al. 2023

Acta Materialia

View full text Add to dashboard Cite

Creep and failure at metal-oxide interfaces

Dillon,

Schoell,

Wright

et al. 2025

Acta Materialia

View full text Add to dashboard Cite

Interphase boundary, grain boundary, and surface diffusion in Al2O3-GdAlO3 composites determined from bicrystal coble creep experiments

Cited by 9 publications

References 54 publications

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics

Interface nucleation rate limited densification during sintering

Creep and failure at metal-oxide interfaces

Contact Info

Product

Resources

About

Interphase boundary, grain boundary, and surface diffusion in Al2O3-GdAlO3 composites determined from bicrystal coble creep experiments

Cited by 9 publications

References 54 publications

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi2O5: Microstructural evolution and kinetics

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi2O5: Microstructural evolution and kinetics

Interface nucleation rate limited densification during sintering

Creep and failure at metal-oxide interfaces

Contact Info

Product

Resources

About

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics

Pseudo‐single crystal growth of the entropy‐stabilized compound CoTi₂O₅: Microstructural evolution and kinetics