Abstract: The effects of annealing on superconducting transition and the thermostability of MgB₂ have been investigated. MgB₂ is fabricated on boron flakes by annealing in the magnesium atmosphere at different temperatures and period of times. The temperature range from 700 to 1000℃ is appropriate to prepare MgB₂ in the experiments. At higher temperature shorter time is needed to get relatively high T_c. The thermostability experiments show that after the heat treatment in the atmosphere without Mg, MgB₂ is stable below 700℃ and begins to decompose from 800℃ until the complete loss of superconductivity. The lower temperature is needed to form MgB₂ phase when using Mg-B film precursor instead of boron flakes.

Key words: MgB₂ phase, thermostability, superconducting film

摘要： 报道了关于 MgB₂ 超导体制备过程中的退火效应和热稳定性的实验研究。把硼片在不同的温度 Mg 气氛中退火不同时间得到 MgB₂，制备样品的测量结果显示制备 MgB₂ 的合适温度范围是 700～1000℃，并且较高的制备温度下只需要相对短的退火时间内就能得到较高转变温度的样品。热稳定性实验的结果显示在没有 Mg 的气氛中 MgB₂ 在 700℃ 下是稳定的，从 800℃ 开始分解，直到完全失去超导电性。实验还观测到利用 MgB₂ 混合物薄膜前驱代替硼片制备 MgB₂ 时，在 600℃ 退火时样品就显示超导电性。

关键词: MgB₂相, 热稳定性, 超导薄膜