【摘要】 本文在国产六面顶高温高压设备上成功制备出具有超高硬度和良好导电特性的二硼化镁(MgB2)聚晶体材料。样品制备的压力和温度条件分别为5.5GPa和700~1000℃。光学显微镜观测表明,合成样品具有褐色金属光泽。通过X射线衍射对合成样品进行了晶体结构的表征。X射线衍射谱表明,二硼化镁晶体具有典型的六角结构,空间群为P6/mmm(191)。晶格常数为,a=0.308nm,c=0.352nm。常态下,合成样品的显微硬度、体密度和电阻率分别被测量。其显微硬度为4109.5 kgf/mm2,常态下电导率为2.42×10-6Ωm。这些特性决定着硼化镁聚晶有着潜在的应用价值。更多还原

【Abstract】 Superhard MgB₂ polycrystalline compact with good electrical conductivity was synthesized in a cubic anvil high-pressure apparatus.The synthesis conditions of HPHT are 5.5 GPa and 700 1000 ℃.Observed by an optical microscope（OM）,the sample has brown metallic shine.X-ray diffraction（XRD） data were collected to study the crystal structure.X-ray diffraction spectra show that MgB₂ has typical hexagonal structure,and the space group is P6/mmm（191）,the cell parameter is a=0.308 nm,c=0.352 nm.At ambient state,the Vickers hardness,bulk density,and electrical resistance of the synthesized sample were measured.The results show that the Vicker’s Hardness(H_v) of the sample is 4109.5 kgf / mm²,and the electronic conductivity is 2.42×10^-6Ωm.更多还原