Comparison of nozzle gas shielding techniques for laser cladding of zirconium
Bibliographic record
Abstract
The use of zirconium is widespread in nuclear, chemical and biomedical industries considering its low thermal neutron cross-section, high corrosion resistance and good biocompatibility [1-3]. The present work studies the application of laser cladding using a powder spray laser deposition system. Commercially pure zirconium is deposited on a zirconium alloy substrate without the use of an enclosed atmosphere to limit oxygen and nitrogen contamination. The use of different powder nozzle designs and argon shielding gas flow rates are examined as the only mechanism for protecting the molten zirconium from the atmospheric contamination, in order to evaluate the feasibility of in-situ cladding and more convenient cladding systems. The powder nozzle geometry and gas flow rates are compared in terms of the cladding chemistry, microstructures, and microhardness. It is shown that the use of a powder delivery nozzle which only utilizes one stream of argon within the powder carrier gas is not sufficient to prevent atmospheric contamination. The addition of an auxiliary argon stream provides far greater protection to both the clad and substrate, which suggests it is possible to achieve acceptable zirconium claddings without the use of an enclosed shielded environment.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".