TY - JOUR
T1 - Intragranular glass/crystal conjugated particles in strip cast Nd-Fe-B flakes
AU - Chen, Hansheng
AU - Xu, Wanqiang
AU - Tang, Chunguang
AU - Chen, Zibin
AU - Liu, Hongwei
AU - Bian, Pengju
AU - Yao, Yin
AU - Qu, Jiangtao
AU - Yun, Fan
AU - Wong, Derek
AU - Ye, Zhixiao
AU - Zhang, Xingmo
AU - Yang, Tiebin
AU - Liao, Xiaozhou
AU - Ringer, Simon P.
AU - Zheng, Rongkun
N1 - Funding Information:
of Toronto for hospitality during the time this paper was written. The research of the second author is supported by NSERC Canada under grant A0579.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Intragranular rare earth-rich phases play a vital role in affecting the intrinsic coercivity of sintered Nd-Fe-B permanent magnets. To explore the origin of these intragranular rare-earth-rich phases, the starting material-strip cast Nd-Fe-B flakes were characterized by a variety of high-end microscopy techniques. It was surprisingly found that the intragranular rare-earth-rich phase is spherical in a diameter of ~150–300 nm and consists of amorphous regions rich in additive elements (e.g., Cu, Co, and Ga) and crystalline regions which are a combination of hexagonal light-rare-earth-rich phases and body centered cubic phases rich in light and heavy rare earth, and oxygen. Amorphous interfacial layers between the glass/crystal particles and the crystalline matrix were observed, probably due to insufficient time to reach a crystalline equilibrium state. Based on the microstructural observation, we proposed a formation mechanism of these intragranular glass/crystal conjugated particles in strip cast Nd-Fe-B flakes, which may facilitate to minimize the volume of these detrimental intragranular phases during the strip casting process.
AB - Intragranular rare earth-rich phases play a vital role in affecting the intrinsic coercivity of sintered Nd-Fe-B permanent magnets. To explore the origin of these intragranular rare-earth-rich phases, the starting material-strip cast Nd-Fe-B flakes were characterized by a variety of high-end microscopy techniques. It was surprisingly found that the intragranular rare-earth-rich phase is spherical in a diameter of ~150–300 nm and consists of amorphous regions rich in additive elements (e.g., Cu, Co, and Ga) and crystalline regions which are a combination of hexagonal light-rare-earth-rich phases and body centered cubic phases rich in light and heavy rare earth, and oxygen. Amorphous interfacial layers between the glass/crystal particles and the crystalline matrix were observed, probably due to insufficient time to reach a crystalline equilibrium state. Based on the microstructural observation, we proposed a formation mechanism of these intragranular glass/crystal conjugated particles in strip cast Nd-Fe-B flakes, which may facilitate to minimize the volume of these detrimental intragranular phases during the strip casting process.
KW - Atom probe microscopy
KW - Intragranular glass/crystal rare-earth-rich particle
KW - Magnetic force microscopy
KW - Nd-Fe-B
KW - Transmission electron microscopy
UR - http://www.scopus.com/inward/record.url?scp=85072624804&partnerID=8YFLogxK
U2 - 10.1016/j.jmmm.2019.165863
DO - 10.1016/j.jmmm.2019.165863
M3 - Journal article
AN - SCOPUS:85072624804
SN - 0304-8853
VL - 495
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
M1 - 165863
ER -