【作者】 梁志梅；

【导师】 崔春翔；

【作者基本信息】 河北工业大学 ， 材料学， 2005， 硕士

【摘要】 Sm₃（Fe,Co,Ti）₂₉N_x是一种具有新的结构、高性能的铁基稀土金属间化合物。但是这种化合物的形成需要稳定化元素的加入,制备工艺十分复杂。本课题通过合金元素的复合添加,并采用先进的HD（Hydrogenation Decrepitation）和HDDR（Hydrogenation-Disproportionation-Desorption-Recombination）法对合金进行破碎处理,制备了Sm₃（Fe,Co,Ti）₂₉N_x、Sm₃（Fe,Co,Ti）₂₉N_x/α磁粉。试验采用X射线衍射仪、扫描电子显微镜、透射电子显微镜及振动样品磁强计等分析手段对合金的制备工艺和磁粉的微结构以及磁性能等进行了检测分析,着重研究了HD和HDDR处理方法的工艺参数及其对合金制备过程和磁性能的影响。 试验按照四种理论成份配比Sm_3.75Fe_21.5Co₆Ti₁、Sm₃Fe_21.5Co₆Ti_1.5、Sm_3.75Fe_18.5Co₉Ti_1.5和Sm₃Fe_18.5Co₉Ti_1.5进行了母合金的制备,得到了由3:29相为主相近乎单相组织,试样中只存在少量的2:17相。 经HD处理的合金基本保持了母合金的相组成,对合金具有很好的破碎效果,同时其工艺过程比较容易实现,最佳HD温度为350℃。试验发现在HD处理过程中应严格控制合金中含铁量,合金中α-Fe的产生会导致合金剩磁和矫顽力的降低。 通过对HDDR处理的深入研究分析,发现合金在800℃反应1小时后歧化反应已进行彻底,反应的中间产物是α-（Fe,Co,Ti）和Sm的氢化物。在脱氢重组过程中氢压是反应的关键因素,降低氢压可有效促进反应的发生。经过HDDR处理后的合金性能好于未经过HDDR处理的合金,经过HDDR处理后产生了软硬磁间的交换耦合作用。 研究了不同破碎工艺及合金成份对氮化工艺的影响,给出了最佳氮化时间。试验获得的磁粉具有高的居里点513.56℃,这可能与合金Co元素的加入有关。同时指出合金粒径分布不均匀、在未产生耦合效应的3:29相合金中,过量非纳米相α-Fe是造成材料磁性能不高的主要原因。更多还原

【Abstract】 Sm3(Fe,Co,Ti)29Nx with a structure of monoclinic Nd3(Fe,Ti)29 and Excellent intrinsic magnetic properties is a kind of iron-base rare earth intermetallic compound. The processing of such compound is very complex and as a metastable phase during the preparation some stabilizing element is needed. In this work the magnetic powder of Sm3(Fe,Co,Ti)29Nx and Sm3(Fe,Co,Ti)29Nx/α were prepared with more than one elements added as alloying agents and pulverized by HD (Hydrogenation Decrepitation) or HDDR (Hydrogenation -Disproportionation - Desorption - Recombination) treatment. X-ray diffraction, scanning electronic microscope, transmission electron microscope and vibrating-sample magnetometer were used to analysis the processing parameters, microstructure and magnetic properties. In this work the HD and HDDR treatment were systematically studies and the effect of such treatment on other processes and magnetic properties were analyzed.The master alloys were prepared according to four stoichiometric compositions of Sm3.75Fe21.5Co6Ti1.5, Sm3Fe21.5Co6Ti1.5, Sm3.75Fe18.5Co9Ti1.5 and Sm3Fe18.5Co9Ti1.5 The master alloy formed in the 3:29 phase with an addition of some 2:17 phase.All the four kinds of alloys retained the composition of the master alloy after HD treatment. HD treatment had an excellent pulverizing effect and the process is easy to carry out. The optimal temperature for HD was determined to be 350℃. It is found that during HD treatment the mount of a-Fe should be strictly controlled for the increase of a-Fe will lead to the decrease of Ms and Hc.The Hydrogenation-Disproportionation process will have completed after 1 hour hydrogen treatment at 800℃ with the products of a-(Fe,Co,Ti) and the hydride of Sm. Thedecrease of the pressure of hydrogen can stimulate the reaction during Desorption -Recombination. Alloys after HDDR treatment showed better magnetic properties because the exchange coupling effect between the soft and hard magnetic phase was induced by HDDR.The effect of different pulverizing processes on nitrogenation were analysed and the optimal time for nitrogenation was given. The compounds after nitrogenation had a high Curie tempterature due to the addition of Co. The non-uniform of the size of the magnetic powder particles and the a-Fe contained in the uncoupling 3:29 phase were the main cause that leads to low magnetic properties.更多还原