Table 3.
Normalized deposition rate (DR), estimated DE, eimulated velocity associated to d50 (Vd50), simulated average velocity (Vavg), calculated critical velocity (Vcr) and coating quality of as-received and heat-treated powders
| ID | HT atm. | HT CR (°C/h) |
d50 (µm) |
Normalized DR (µm/pass)1 | Estimated DE (%) | Vd50 (m/s) |
Vavg (m/s) |
Vcr (m/s) | Coating quality |
|---|---|---|---|---|---|---|---|---|---|
| C-AR | NA | NA | 36.9 | 02 | 0 | 666 | 680 | >850 | Almost no deposition |
| C-HT 875 °C | N2 | 22 | 36.5 | 42 | 23 | 669 | 680 | 698 | Cracked coating |
| F-AR | NA | NA | 7 | 33 | 18 | 944 | 881 | 950 | Cracked coating |
| F-HT 875 °C-1a | N2 | 22 | 19.8 | 78 | 43 | 783 | 790 | 800 | Sound coating |
| F-HT 875 °C-1b | N2 | 22 | 17.2 | 74 | 41 | 811 | 823 | 830 | Sound coating |
| F-HT 875 °C-2 | N2 | 70 | 17 | 49 | 27 | 813 | 819 | 865 | Sound coating |
| F-HT 875 °C-3 | N2 | 350 | 14.8 | 54 | 30 | 836 | 839 | 880 | Sound coating |
| F-HT 875 °C-4 | HP Ar | 350 | 15.4 | 127 | 703 | 830 | 828 | 785 | Sound coating |
Velocities of the agglomerated powders are underestimated and can not be compared with the values for non-agglomerated powders.
1normalized for a feed rate of 20 g/min and traverse speed of 300 mm/s.
2particles could not be deposited beyond the first monolayer after multiple passes.
3calculated from the ratio of the weight of the coating to the weight of the powder sprayed on the substrate as described in section Cold Spray Process.