Questions to be answered What's the crystallographic character at grain boundary? What's the chemical character at grain boundary? What's the magnetism at grain boundary? How to increase the magnetic property without using heavy rare-earth elements? 材料科学与工程学院 18 School of Materials Science and Engineering
材料科学与工程学院 School of Materials Science and Engineering Questions to be answered • What’s the crystallographic character at grain boundary? • What’s the chemical character at grain boundary? • What’s the magnetism at grain boundary? 18 How to increase the magnetic property without using heavy rare-earth elements?
③ The g.b.phase in Nd-Fe-B (a) 烧结态 () 回火态 (d) 回火态 520C 580C G.B.phase Nd-rich phase grains 10gm 10μm b 烧结态 e 回火态 5200 20 nm 10 nm 程学院 19 School of Materials Science and Engineering
材料科学与工程学院 School of Materials Science and Engineering 19 The g.b. phase in Nd-Fe-B 烧结态 烧结态 回火态 520oC 回火态 580oC 回火态 520oC Nd-rich phase grains G.B. phase
Crystal structure of Nd-rich phase in sintered Nd-Fe-B magnet Nd-rich phase (a (b) ⑤ 137131 Grain boundary 0223 1i03 Matrix Matrix phase phase 000 002 1120 0000 fcc hcp Matrix phase 1 um Matrix (a) (b) hcp [001]Nd2Fe14B//[011]Nd-rich dhcp hcp 70- (100)Nd2Fe14B//(111)Nd-rich fcc 40- 0 la3 dhcp 10- 0 Nd 10- ● 0 80 la3 20 4050 6070 90 100 Nd content (at.%) Scripta Materialia, Oxygen content (at.% 9 11-43 ~25 55-70 59(2008)179 Crystal structure dhcp fcc Ia3 hcp 材料科学与工程学院 20 School of Materials Science and Engineering
材料科学与工程学院 School of Materials Science and Engineering Crystal structure of Nd-rich phase in sintered Nd-Fe-B magnet 20 Matrix Nd-rich phase [001] Nd2Fe14B//[011] Nd-rich (100)Nd2Fe14B//(111)Nd-rich Scripta Materialia, 59(2008)179 fcc hcp