Microstructures of Directionally Solidified Nb15Ti55Fe30 Alloy and Its Hydrogen Permeation Properties in the Presence of H2S
Bibliographic record
Abstract
Currently, the main limitations of Pd-coated Nb-TiFe dual-phase alloys include insufficient hydrogen permeability, susceptibility to hydrogen embrittlement (HE), and poor tolerance of H2S poisoning. To address these issues, this study proposes a series of improvements. First, a novel Nb15Ti55Fe30 alloy composed of a well-aligned Nb-TiFe eutectic was successfully prepared using directional solidification (DS) technology. After deposition with a Pd catalytic layer, this alloy exhibits high hydrogen permeability of 3.71 × 10−8 mol H2 m−1 s−1 Pa−1/2 at 673 K, which is 1.4 times greater than that of the as-cast counterpart. Second, to improve the H2S corrosion resistance, a new Pd88Au12 catalytic layer was deposited on the surface using a multi-target magnetic control sputtering system. Upon testing in a 100 ppm H2/H2S mixture, this membrane exhibited better resistance to bulk sulfidation and a higher permeance recovery (ca. 58%) compared to pure Pd-coated membrane. This improvement is primarily due to the lower adsorption energies of the former with H2S, which hinders the formation of bulk Pd4S. Finally, the composition region of the Pd-Au catalytic membrane with high comprehensive performance was determined for the first time, revealing that optimal performance occurs at around 12–18 at.% Au. This finding explains how this composition maintains a balance between high H2 permeability and excellent sulfur resistance. The significance of this study lies in its practical solutions for simultaneously improving hydrogen permeability and resistance to H2S poisoning in Nb-based composite membranes.
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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 | 0.000 |
| 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) | 0.000 | 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".