Ultrafine-grained LaB <sub>6</sub>–ZrB <sub>2</sub> composite ceramics with superior mechanical and thermionic emission properties prepared by high-pressure sintering
Bibliographic record
Abstract
In this study, ultrafine-grained LaB6–ZrB2 composite ceramics were successfully synthesized by sintering a mixture of self-produced LaB6 nanopowder and commercial ZrB2 nanopowder under high pressure. Compared with their coarse-grained counterparts, ultrafine-grained ceramics exhibit improved mechanical properties. Notably, the ultrafine-grained LaB6–ZrB2 composite ceramic sintered at 4 GPa and 1673 K, with an average grain size of 286 nm, shows optimal mechanical performance characterized by a Vickers hardness of 25.6 GPa, a fracture toughness of 4.1 MPa·m1/2, and an elastic modulus of 338 GPa. Furthermore, the ultrafine-grained LaB6–ZrB2 composite ceramics displayed strong thermal emission, reaching a maximum current density of 27.5 A∙cm−2 at 1773 K. The structural and functional advantages of ultrafine-grained LaB6–ZrB2 composite ceramics render them suitable for potential use in thermionic emission cathodes.
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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".