Mn_4N固相合成反钙钛矿型Mn_3MN(M∶Cu,Ge)的机理研究

Study on Synthesis Mechanism of Antiperviskite Type Mn_3MN(M∶Cu,Ge) Prepared by Solid State Reaction from Mn_4N

以Mn4N、Cu和Ge粉末为原料,在N2气氛下固相烧结合成了反钙钛矿结构的锰基氮化物Mn3MN(M∶Cu,Ge)。利用热重-差热分析(TG-DSC),X射线衍射(XRD),扫描电镜(SEM)等技术研究了合成Mn3MN(M∶Cu,Ge)的固相反应机理及制备的工艺条件。固相反应的主要机理是Cu(或Ge)原子通过固溶扩散置换出Mn4N立方结构中顶点的Mn原子形成反钙钛矿结构;置换出来的Mn与多余的Cu反应形成Mn3Cu固溶相,在N2气氛中氮化再次生成反钙钛矿Mn3CuN相。以Mn4N制备纯的反钙钛矿结构的Mn3MN需要严格控制原料的配比,且需要在高真空高纯N2保护气氛中进行烧结。

Antiperovskite-type structure manganese nitrides Mn3MN（M∶Cu,Ge） were successfully synthesized by solid-state reaction in a pure nitrogen atmosphere using Mn4N,Cu,and Ge powders as raw materials.The synthetical process and condition of Mn3MN（M ∶Cu,Ge） were studied by thermogravimetry and differential scanning calorimetry analysis,X-ray diffraction analysis,and scanning electron microscope.The main mechanism of forming antiperovskite-type structure in solid-state reaction is that Mn atoms in the corner site of cubic strucrure Mn4N could be substituted by Cu（or Ge） atoms in the solid diffuse process;The substituted Mn atoms could react with the excessive Cu atoms to form Mn3Cu solid solution phase,then be nitrogenated in a nitrogen atmosphere also to form antiperovskite Mn3CuN phase.To get pure-form antiperovskite-types mangances nitrides Mn3MN（M∶Cu,Ge） from Mn4N,it needs to control the stoichiometric amounts of the starting materials strictly and sinter in a high vacuum and high-pure nitrogen atmosphere.