Abstract
The optimum route to fabricate nano-sized Fe-50 wt% Co and hydrogen-reduction behavior of calcined Fe-/Co
nitrate was investigated. The powder mixture of metal oxides was prepared by solution mixing and calcination of Fe-/Co-nitrate.
A DTA-TG and microstructural analysis revealed that the nitrates mixture by the calcination at 300oC for 2 h was changed to
Fe-oxide/Co3O4 composite powders with an average particle size of 100 nm. The reduction behavior of the calcined powders
was analyzed by DTA-TG in a hydrogen atmosphere. The composite powders of Fe-oxide and Co3O4 changed to a Fe-Co
phase with an average particle size of 40 nm in the temperature range of 260-420oC. In the TG analysis, a two-step reduction
process relating to the presence of Fe3O4 and a CoO phase as the intermediate phase was observed. The hydrogen-reduction
kinetics of the Fe-oxide/Co3O4 composite powders was evaluated by the amount of peak shift with heating rates in TG. The
activation energies for the reduction, estimated by the slope of the Kissinger plot, were 96 kJ/mol in the peak temperature range
of 231-297oC and 83 kJ/mol of 290-390oC, respectively. The reported activation energy of 70.4-94.4 kJ/mol for the reduction
of Fe- and Co-oxides is in reasonable agreement with the measured value in this study
nitrate was investigated. The powder mixture of metal oxides was prepared by solution mixing and calcination of Fe-/Co-nitrate.
A DTA-TG and microstructural analysis revealed that the nitrates mixture by the calcination at 300oC for 2 h was changed to
Fe-oxide/Co3O4 composite powders with an average particle size of 100 nm. The reduction behavior of the calcined powders
was analyzed by DTA-TG in a hydrogen atmosphere. The composite powders of Fe-oxide and Co3O4 changed to a Fe-Co
phase with an average particle size of 40 nm in the temperature range of 260-420oC. In the TG analysis, a two-step reduction
process relating to the presence of Fe3O4 and a CoO phase as the intermediate phase was observed. The hydrogen-reduction
kinetics of the Fe-oxide/Co3O4 composite powders was evaluated by the amount of peak shift with heating rates in TG. The
activation energies for the reduction, estimated by the slope of the Kissinger plot, were 96 kJ/mol in the peak temperature range
of 231-297oC and 83 kJ/mol of 290-390oC, respectively. The reported activation energy of 70.4-94.4 kJ/mol for the reduction
of Fe- and Co-oxides is in reasonable agreement with the measured value in this study
| Translated title of the contribution | Fabrication and Characterization of Nano-sized Fe-50 wt% Co Powder from Fe- and Co-nitrate |
|---|---|
| Original language | Korean |
| Journal | 한국재료학회지 |
| Volume | 20 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2010 |