| Autor: |
Bolokang, A. S., Phasha, M. J., Motaung, D. E., Bhero, S. |
| Předmět: |
|
| Zdroj: |
Journal of Metallurgy; 2012, p1-7, 7p, 1 Black and White Photograph, 1 Chart, 7 Graphs |
| Abstrakt: |
Cold pressing (CP) of the amorphous-like Co powder suppressed most of the XRD peaks, in particular the peak along (100) plane. The DSC curve of unmilled CP Co powder has shown a distinct sharp exothermic peak at 615°C. Upon annealing at 700°C, only the FCC phase with lattice parameter of 3.51 Å was detected by XRD. Our results implied that the exotherm at 615°C corresponds to compaction-pressure-assisted HCP to FCC first-order phase transition. The XRD analysis of 30 hmilled powder revealed for the first time the FCC phase with a = 3.80 Å . However, due to presence of (100) and (210) peaks, this phase is thought to be FCT with lattice parameters a = b = 3.80 and c = 3.07 Å . Consequently, the high-energy milling carried out in the current work induced for the first time HCP to FCT transition in Co. Upon CP of milled powder, the lattice parameter a shrunk from 3.80 to 3.75 Å . However, during annealing of the CP milled Co powder at 750°C, the FCT to FCC transition occurred, yielding the FCC phase with a = 3.51 Å. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text