Microstructures of NiCrAlY Coating Applied on CMSX-4 by Cathodic Arc Deposition
Bibliographic record
Abstract
NiCrAlY overlay coatings were applied on Ni-base single-crystal superalloy CMSX-4 substrates by cathodic arc deposition. The coated specimens were subjected to one- and two-step heat treatments performed under 870°C/20h/AC (AC stands for air cooling) and 1140°C/6h/AC+870°C/20h/AC conditions, respectively. The microstructure of the original NiCrAlY cathodes fabricated by spark plasma sintering and the as-deposited as well as heat-treated coatings were characterized using the scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction techniques. It was observed that the cathodes contained multiple phases uniformly distributed across the cathode volume. The as-deposited coatings exhibited a duplex microstructure consisting of splats and inter-splat regions with the latter showing internal porosity and a significantly lower Al concentration compared to that of the cathodes. The post-deposition heat treatments eliminated the porosity but further reduced the Al content, resulting in a coating microstructure dominated by the solid solution γ-Ni phase. The total thickness of the coating including the interdiffusion zone increased significantly during the two-step heat treatment. The oxide scale formed on the coating surface during heat treatment consisted primarily of α-Al2O3, with Y2O3 pegs underpinning the scale to the coating. The oxide scale was continuous on the smooth sections of the coating surface, but became fragmented at the protruding macroparticles present on the coating surface.
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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".