Evaluation of Four High Velocity Thermal Spray Guns Using WC-10Co-4Cr Cermets
Bibliographic record
Abstract
Abstract Four high velocity thermal spray guns were evaluated in the production of 10%Co-4%Cr tungsten carbide cermets. Three HVOF guns (the JP-5000, JP-5000ST and DJ-2700) and one plasma gun, (the Mettech Axial III) were used to spray the same angular, agglomerated and crushed WC-10Co-4Cr powder. The DPV-2000 was used to monitor the in-flight velocity and temperature of the WC cermet sprayed particles. From those values, spray conditions were selected to produce coatings that were evaluated in terms of porosity, hardness and deposition efficiency. Results show that the plasma Axial III provides the highest particle temperature, between 2000°C and 2600°C, depending on the spray conditions. The JP-5000 imparts the highest velocity to the particles, between 550 m/s and 700 m/s, depending on the spray conditions. The ST version of the JP-5000 provides the same velocity as the standard version but with lower particle temperature. The DJ-2700 sprays particles with temperature and velocity between those of the JP5000 and the Mettech Axial III. Minimum porosity values of 2.1%, 3.7% and 5.3%) were obtained for the JP-5000, the DJ-2700 and the Axial III guns respectively. The porosity and carbide degradation are found to mostly depend on the particle velocity and temperature respectively. The values for the Vickers microhardness number (200g) ranged from 950 to 1250. Measurements of the deposition efficiency indicated a variation between 10 and 80%o, depending on the spray conditions and the gun used.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".