Preferential Corrosion in Cold Sprayed Cu Induced by Oxide Inclusions
Bibliographic record
Abstract
Cold spray (CS) deposition is a solid-state deposition technique that finds applications in additive manufacturing, coating, and repairing damaged components. During the cold spray deposition process, feedstock particles are accelerated by compressed gas and impinged onto the substrate at high velocity. Bonding between particles and the surface being coated is established by the high kinetic energy released during collision rather than by added thermal energy. As the particles remain in the solid state during spraying, oxidation is minimized. Despite the partial removal of the native air-formed oxides by the jetting effect, residual oxide debris often remains along the particle boundaries within the sprayed objects as inclusions [1]. The oxide inclusions have attracted attention concerning their influence on the inter-particle bonding strength in the deposit [2]. However, little is known about whether they affect the material’s corrosion behavior. In this work, we report a preferential corrosion phenomenon observed in a CS Cu-diluted HNO 3 system that is caused by the remaining oxide inclusions. A mechanism that integrates Cu-NO 3 – catalytic corrosion cycles with confined geometry resulting from the dissolution of the oxide inclusions is proposed. Furthermore, we find that this corrosion phenomenon may be mitigated through microstructure engineering. Annealing the CS Cu at 600 °C consolidated the oxide inclusions with their distribution changed from continuous thin films to isolated spherical particles [3]. The propagation of the preferential corrosion is hence interrupted by the lack of interconnected pathways. Counterintuitively, Cl – can function as an inhibitor for this preferential corrosion. Preferential corrosion did not initiate when 1 mM Cl – was initially present in the solution and slowed down when Cl – was added after the preferential corrosion occurred. Reference [1] S. Yin, X. Wang, W. Li, H. Liao, H. Jie, Deformation behavior of the oxide film on the surface of cold sprayed powder particle, Applied Surface Science, 259 (2012) 294-300. [2] Y. Ichikawa, R. Tokoro, M. Tanno, K. Ogawa, Elucidation of cold-spray deposition mechanism by auger electron spectroscopic evaluation of bonding interface oxide film, Acta Materialia, 164 (2019) 39-49. [3] J. Tam, B. Yu, W. Li, D. Poirier, J.-G. Legoux, J.D. Giallonardo, J. Howe, U. Erb, The effect of annealing on trapped copper oxides in particle-particle interfaces of cold-sprayed Cu coatings, Scripta Materialia, 208 (2022) 114333.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".