晶粒间界相及结构缺陷对HDDR 粘结磁体矫顽力的影响

本文根据氢化／歧化／脱氢／重组（HDDR）Nd-Fe-B 磁粉晶粒边界微结构的特点，建立了缺陷区内的磁晶各向异性常数K1´及交换积分常数A1´的双变量连续变化模型，研究了晶粒间界相厚度d及晶粒表面结构缺陷厚度r0对磁体矫顽力的影响。结果表明：晶粒表面各向异性常数K1(0)、交换积分常数A1(0)及r0取不同值时，磁体的矫顽力Hc均随d增加而增大。K1(0)和A1(0)取确定值时，相同的d值对应的Hc随r0的增大而上升。r0和d取确定值时，Hc随K1(0)或A1(0)的减小而增大。当d 为1nm，r0 在 (2~5) nm范围内，A1(0)和K1(0)的值分别在A1和K1值的(0.6~0.7)范围内变动时，计算的矫顽力与实验值符合得很好。

Dependence of coercivity on the intergranular phase and structure defect for HDDR bonded magnet

According to the microstructure of HDDR (hydrogenation, disproportionation, desorption and recombination) Nd-Fe-B magnetic powders grains, the model of double continuous variations was proposed for the anisotropy constant K1´ and the exchange integral A1´ in defect region. The dependence of coericivity of magnet on the intergranular phase thickness d and the structure defect thickness r0 was studied. The results showed that the coercivity, Hc, increases as d increases when the thickness r0, the anisotropy constant K1(0) at the grain surface and the exchange integral constant A1(0) take different values. When K1(0) and A1(0) are fixed, Hc enhances as r0 increases for the same d. On the contrary, for the fixed r0 and d, Hc decreases with increasing K1(0) or A1(0). The calculated coercivity is in good agreement with experimental results given by others when d takes 1nm, r0 is in the rang of (2~5) nm, A1(0) and K1(0) change in the range of (0.6~0.7) of A1 and K1, respectively.