采用熔融共混法制备了聚酰胺66/铷铁硼(PA66/Nd Fe B)复合材料,并对其熔体流变行为进行了系统研究。结果表明:PA66/Nd Fe B复合材料的表观黏度(ηa)随着剪切速率的增加而降低,为假塑性流体;ηa随着温度的升高而降低,随着Nd Fe B用量的...采用熔融共混法制备了聚酰胺66/铷铁硼(PA66/Nd Fe B)复合材料,并对其熔体流变行为进行了系统研究。结果表明:PA66/Nd Fe B复合材料的表观黏度(ηa)随着剪切速率的增加而降低,为假塑性流体;ηa随着温度的升高而降低,随着Nd Fe B用量的增加而提高;非牛顿指数(n)随着温度的升高而增大,随着Nd Fe B用量的增加而降低;熔体的黏流活化能(ΔEη)随着剪切速率的提高而增大,并逐渐趋于平缓;另外,ΔEη随着Nd Fe B用量的增加而减小,即复合材料的温敏性随着Nd Fe B用量的增加而下降。展开更多
MM_（33）Fe_（66）B（MM=La, Ce, Pr, Nd） alloys（mass ratio） were prepared by induction melting and heat-treated at 1353 K for 24 h to produce homogeneous MM_2Fe_（14） B phase. The phase structure and element distri...MM_（33）Fe_（66）B（MM=La, Ce, Pr, Nd） alloys（mass ratio） were prepared by induction melting and heat-treated at 1353 K for 24 h to produce homogeneous MM_2Fe_（14） B phase. The phase structure and element distribution of the alloys were analyzed by X-ray diffraction（XRD） and scanning electron microscope（SEM）. The alloys were applied ball milling to obtain powders with good size distribution and then magnetic aligned in a static magnetic field of 2 T for 4 h, in order to achieve the intrinsic magnetic properties by vibrating sample magnetometer（VSM）. XRD results showed that the alloys were composed of the single 2：14：1 main phase and RE-rich phase, which was similar to Nd_2Fe_（14）B structure. Magnetic measurements showed that the saturation magnetization（Ms） and anisotropy field（HA） of the MM_（33）Fe_（66）B alloy were 11.3 k Gs and 48.4 k Oe, respectively, demonstrating its good potential as permanent magnets. The Curie temperature of the MM_（33）Fe_（66）B alloy was determined as 502.9 K by magnetization-temperature curves. Microstructure observation showed that Nd and Pr were mainly in the 2：14：1 ferromagnetic phase, while La and Ce prefered to aggregate in the RE-rich grain boundary phase, which is beneficial to fabricating（Pr, Nd, MM）_2Fe_（14）B magnets with good magnetic properties.展开更多
文摘采用熔融共混法制备了聚酰胺66/铷铁硼(PA66/Nd Fe B)复合材料,并对其熔体流变行为进行了系统研究。结果表明:PA66/Nd Fe B复合材料的表观黏度(ηa)随着剪切速率的增加而降低,为假塑性流体;ηa随着温度的升高而降低,随着Nd Fe B用量的增加而提高;非牛顿指数(n)随着温度的升高而增大,随着Nd Fe B用量的增加而降低;熔体的黏流活化能(ΔEη)随着剪切速率的提高而增大,并逐渐趋于平缓;另外,ΔEη随着Nd Fe B用量的增加而减小,即复合材料的温敏性随着Nd Fe B用量的增加而下降。
基金Project supported by the National High Technology Research and Development Program of China(2012AA063201)National Natural Science Foundation of China(51371002+2 种基金51331003)International S&T Cooperation Program of China(2015DFG52020)the 2011 Cooperative Innovation Center of Beijing University of Technology
文摘MM_（33）Fe_（66）B（MM=La, Ce, Pr, Nd） alloys（mass ratio） were prepared by induction melting and heat-treated at 1353 K for 24 h to produce homogeneous MM_2Fe_（14） B phase. The phase structure and element distribution of the alloys were analyzed by X-ray diffraction（XRD） and scanning electron microscope（SEM）. The alloys were applied ball milling to obtain powders with good size distribution and then magnetic aligned in a static magnetic field of 2 T for 4 h, in order to achieve the intrinsic magnetic properties by vibrating sample magnetometer（VSM）. XRD results showed that the alloys were composed of the single 2：14：1 main phase and RE-rich phase, which was similar to Nd_2Fe_（14）B structure. Magnetic measurements showed that the saturation magnetization（Ms） and anisotropy field（HA） of the MM_（33）Fe_（66）B alloy were 11.3 k Gs and 48.4 k Oe, respectively, demonstrating its good potential as permanent magnets. The Curie temperature of the MM_（33）Fe_（66）B alloy was determined as 502.9 K by magnetization-temperature curves. Microstructure observation showed that Nd and Pr were mainly in the 2：14：1 ferromagnetic phase, while La and Ce prefered to aggregate in the RE-rich grain boundary phase, which is beneficial to fabricating（Pr, Nd, MM）_2Fe_（14）B magnets with good magnetic properties.
