Enhanced Densification of Cerium (IV) Oxide during Spark Plasma Sintering under a Carbon Dioxide Atmosphere
Bibliographic record
Abstract
Abstract Cerium dioxide (CeO2) finds extensive utility in electro ceramics applications, including solid oxide fuel cells, oxygen sensors, and catalysts. However, Spark Plasma Sintering (SPS) of CeO2 presents challenges due to the heightened mobility of O2− ions in the presence of an electric field, as well as its reactivity with graphite tooling. Traditionally, CeO2 is sintered in an oxidative environment to prevent it from reducing to CeO2−δ or Ce2O3. Nevertheless, oxidative atmospheres are detrimental to the graphite and steel tooling used in SPS processing. In this study, we investigated CeO2 SPS in a CO2 atmosphere and observed substantial enhancement in the relative density (RD) of the as-sintered samples in comparison to those sintered in an Ar atmosphere. The improved densification is attributed to reduced formation of oxygen vacancies in the CO2 atmosphere. Furthermore, the reaction between CeO2 and graphite generates COx gases, and that reaction can be reversed in a CO2 atmosphere. In summary, CeO2 SPS in a CO2 environment demonstrates superior densification, effectively mitigating the challenges associated with ionic mobility and graphite reactivity.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".