【摘要】 我们对用纳米镁粉 (平均颗粒度≤ 4 0nm)在常压下制备MgB2 超导样品 (以下简称纳米MgB2 超导样品 )进行了研究 .得到了一组与用普通颗粒镁粉分别在真空条件下和流动氩气下制备MgB2 超导样品时得到的原位 ρ T曲线不同的曲线 .实验结果表明纳米MgB2 超导样品的成相温区是 4 30℃到 4 90℃之间 ,低于用普通颗粒镁粉分别在真空条件下和流动氩气下制备MgB2 超导样品时的成相温度 :6 40℃～ 70 0℃和 5 30℃～ 6 30℃ .所得到的纳米MgB2 超导样品的密度是 1.4 6g/cm3.它高于用其他各种镁粉原料在常压下制备通过一次烧结制得的MgB2 超导样品 .更多还原

【Abstract】 MgB₂ superconducting sample,with nanometer magnesium powder and boron powder as raw materials （hereafter referee as to nano-MgB₂ superconducting sample）,was prepared at ambient pressure. A set of in-situ ρ-T curves were obtained It is different from those in-situ ρ-T curves obtained for the MgB₂ superconducting samples,with ordinary off-the-shelf powder and boron powder as the raw materials （hereafter referee as to ordinary-MgB₂ superconducting sample） prepared in the vacuum and flowing argon atmosphere respectively. The experimental results indicated that the temperature of formation MgB₂-phase of nano-MgB₂ superconducting sample is between 430℃ and 490℃. It is lower than the temperature of formation MgB₂-phase of ordinary-MgB₂ superconducting sample sintered in vacuum and argon atmosphere: 640℃～700℃ and 530℃～630℃ respectively. The density of nano-MgB₂ superconducting sample is 1.46g/cm 3,and is higher than the densities of other MgB₂ superconducting sample sintered for one time.更多还原