Nd_2Fe_(14.5)Cr_(2.5)化合物的结构和相变

Structure and Phase Transition of Nd_2Fe_(14.5)Cr_(2.5) Compound

通过X射线衍射、差热分析及磁测量等手段对电弧炉熔炼的Nd2Fe14.5Cr2.5化合物的结构和相变进行了研究,研究结果表明,950℃下退火的样品具有Th2Zn17型结构,其居里温度为375 K。1100℃下退火的样品具有Nd3(Fe,Ti)29型结构,其居里温度为445 K。Nd2Fe14.5Cr2.5化合物在1100℃左右发生结构相变,由菱方相的Th2Zn17型结构转变成单斜相的Nd3(Fe,Ti)29型结构。具有Th2Zn17型相结构的Nd2Fe14.5Cr2.5化合物在约300℃左右可以发生有效的吸氮反应。

Structure and its phase transitions of the arc-melted Nd/Fe14,5 Cr2.5 were investigated by using differential thermal analyzer, X-ray diffractions, and magnetization measurements. The result showed that the sample annealed at 950 ℃ had a Th2Zn17-type structure, its Curie temperature was about 375 K. The sample annealed at 1100℃ had a Nd3（Fe,Ti）29 structure, its Curie temperature was about 445 K. At about 1100℃, the structure phase transition was oc- curred, and the rhombohedral Th2ZnlT-type structure translated into monoclinic Nd3 （ Fe, Ti） 29-type struc- ture. The nitrogenized reaction of the compound with Th2Zn17-type structure was more sufficient at about 300℃. The detailed discussion was presented.