TY - JOUR
T1 - Effects of Intergranular Phase and Structure Defect on the Coercivity for the HDDR Nd-Fe-B Bonded Magnet
AU - Liu , Min
AU - Jin , Xiao-Chen
AU - Gao , Ru-Wei
JO - Journal of Atomic and Molecular Sciences
VL - 3
SP - 218
EP - 226
PY - 2012
DA - 2012/03
SN - 3
DO - http://doi.org/10.4208/jams.053111.071211a
UR - https://global-sci.org/intro/article_detail/jams/8195.html
KW - bonded magnet, bivariate model, microstructure, coercivity.
AB - <p style="text-align: justify;">Based on the specific microstructure of HDDR (hydrogenation, disproportionation, 
desorption, recombination) grains, that the bivariate model concerning the anisotropy 
constant $K&#39;_1$ and exchange integral $A&#39;_1$ in defect region, which was put forward. 
Subsequently, the dependence of magnet coercivity on the intergranular phase thickness $d$ and structure defect thickness $r_0$ was studied. The results showed that the coercivity, $H_c,$ increases with increasing $d,$ for the $r_0,$ the anisotropy constant $K_1(0)$ and exchange 
integral constant $A_1(0)$ at the grain surface taking different values. While $K_1(0)$ and $A_1(0)$ are fixed, $H_c$ enhances with increasing $r_0$ for the same $d.$ On the contrary, 
for the fixed $r_0$ and $d,$ $H_c$ decreases with increasing $K_1(0)$ or $A_1(0).$ The calculated 
coercivity is in good agreement with experimental results given by others when $d$ takes 1 nm, $r_0$ is in the rang of 2-5 nm, $A_1(0)$ and $K_1(0)$ change in the range of (0.6-0.7) of $A_1$ and $K_1,$ respectively.</p>