用PIT(powder in tube)法在不同条件下制备MgB2样品,通过X射线衍射、扫描电子显微镜(SEM)对不同参数下制备样品的成分和微观结构进行了表征;利用Campbell法检测样品的bac-λ′关系,求得样品的超导临界转变电流密度Jc;由样品的Jc结合形貌与相成分对比分析,结果表明:长时间烧结,晶粒较大,利于导电,但缺乏钉扎作用,在外磁场下超导电流减小。长时间烧结,晶界间氧化层增厚,超导电流密度减小。 MgB2 samples were prepared by PIT (powder in tube) method under different conditions. The composition and microstructure of samples prepared by different parameters were characterized by X-ray diffraction and scanning electron microscope (SEM). The bac- λc, the critical current density of supercritical transition Jc was obtained. The comparison of the Jc morphology and phase composition of the sample showed that: the long time sintering, the larger the crystal grain, which is conducive to conduction, but the lack of pinning, The superconducting current decreases under the external magnetic field. Prolonged sintering, the grain boundary oxide thickening, superconducting current density decreases.