Abstract
The microstructural evolution of Nd-rich grain boundary phases (GBP) in connection with triple junction phases (TJP) during post-sintering annealing (PSA) was investigated. The Cu-rich TJP in the as-sintered sample was mostly a fcc-NdO phase but the GBP were a mixture of h-Nd2O3 and Nd phases. The fcc-NdO of the TJP in the as-sintered state gradually transformed to h-Nd2O3 during the first and the second PSA steps. However, it transformed to a C-Nd2O3 phase as both a massive form such as TJP and a thin GBP after the modified second PSA step. This suggests that the mechanism for the formation of metastable C-Nd 2O3 may not be solely the interface energy. In contrast, the mixture of h-Nd2O3 and Nd of the GBP in the as-sintered state gradually transformed to C-Nd2O3 which is embedded in the amorphous matrix as the PSA goes from the first to second or modified second PSA step. The formation of the C-Nd2O3 GBP with an amorphous phase is the main factor for increasing the coercivity (from 21.8 to 30.4 kOe) after the second or modified second PSA step.
| Original language | English |
|---|---|
| Article number | 07A703 |
| Journal | Journal of Applied Physics |
| Volume | 109 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2011 Apr 1 |
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Microstructural evolution of triple junction and grain boundary phases of a Nd-Fe-B sintered magnet by post-sintering annealing. / Kim, Tae Hoon; Lee, Seong Rae; Kim, Dong Hwan; Nam-Kung, Seok; Jang, Tae Suk.
In: Journal of Applied Physics, Vol. 109, No. 7, 07A703, 01.04.2011.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Microstructural evolution of triple junction and grain boundary phases of a Nd-Fe-B sintered magnet by post-sintering annealing
AU - Kim, Tae Hoon
AU - Lee, Seong Rae
AU - Kim, Dong Hwan
AU - Nam-Kung, Seok
AU - Jang, Tae Suk
PY - 2011/4/1
Y1 - 2011/4/1
N2 - The microstructural evolution of Nd-rich grain boundary phases (GBP) in connection with triple junction phases (TJP) during post-sintering annealing (PSA) was investigated. The Cu-rich TJP in the as-sintered sample was mostly a fcc-NdO phase but the GBP were a mixture of h-Nd2O3 and Nd phases. The fcc-NdO of the TJP in the as-sintered state gradually transformed to h-Nd2O3 during the first and the second PSA steps. However, it transformed to a C-Nd2O3 phase as both a massive form such as TJP and a thin GBP after the modified second PSA step. This suggests that the mechanism for the formation of metastable C-Nd 2O3 may not be solely the interface energy. In contrast, the mixture of h-Nd2O3 and Nd of the GBP in the as-sintered state gradually transformed to C-Nd2O3 which is embedded in the amorphous matrix as the PSA goes from the first to second or modified second PSA step. The formation of the C-Nd2O3 GBP with an amorphous phase is the main factor for increasing the coercivity (from 21.8 to 30.4 kOe) after the second or modified second PSA step.
AB - The microstructural evolution of Nd-rich grain boundary phases (GBP) in connection with triple junction phases (TJP) during post-sintering annealing (PSA) was investigated. The Cu-rich TJP in the as-sintered sample was mostly a fcc-NdO phase but the GBP were a mixture of h-Nd2O3 and Nd phases. The fcc-NdO of the TJP in the as-sintered state gradually transformed to h-Nd2O3 during the first and the second PSA steps. However, it transformed to a C-Nd2O3 phase as both a massive form such as TJP and a thin GBP after the modified second PSA step. This suggests that the mechanism for the formation of metastable C-Nd 2O3 may not be solely the interface energy. In contrast, the mixture of h-Nd2O3 and Nd of the GBP in the as-sintered state gradually transformed to C-Nd2O3 which is embedded in the amorphous matrix as the PSA goes from the first to second or modified second PSA step. The formation of the C-Nd2O3 GBP with an amorphous phase is the main factor for increasing the coercivity (from 21.8 to 30.4 kOe) after the second or modified second PSA step.
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UR - http://www.scopus.com/inward/citedby.url?scp=79955421201&partnerID=8YFLogxK
U2 - 10.1063/1.3561805
DO - 10.1063/1.3561805
M3 - Article
AN - SCOPUS:79955421201
VL - 109
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 7
M1 - 07A703
ER -