【摘要】 纳米镁粉通过高温高压法用于制备MgB2块材样品,得到了含有少量MgO杂相的密度为2.67g/cm3的理论密度MgB2超导样品.扣除MgO的影响。可以得到MgB2块材样品的密度是2.54g/cm3.样品SEM照片表明样品的晶粒间没有空隙.这是保证其密度能达到理论密度值的主要原因.M-T和R-T测量表明样品的超导转变温度Tc=39K,零场下4.2K的磁临界电流密度Jc=3×105A/cm2;下临界磁场Hc1=63662.4A/m,较普通颗粒镁粉和硼粉在各种条件下制得的MgB2样品的Hd值都要高.更多还原

【Abstract】 The theoretical density MgB2 sample was prepared by using nanometer Mg powder (the grain size is about 80 nm) and micrometer B powder (the grain size is 1μm) as the raw materials under 5.5 GPa at 850℃ for 1 hour. There were little amount MgO impurity phase in this sample. After taking off the influence of MgO on the sample density, it was obtained the density of pure MgB2 is 2.56 g/cm3. It is nearly the theoretical density value of MgB2. The SEM images indicated that there is not any hole or cave in the sample. R- T and M- T measurements shown that the Tc=39 K, and Jc =3×105 A/cm2 at zero field and 4 K.更多还原