In this paper, we studied the effects of precursor powder particle size on Ag-sheathed powder-in-tube Ba_1−xK_xFe₂As₂ (Ba-122) superconducting tapes. Precursor powders with different particle sizes were prepared by changing the grinding time of calcined bulks. We systematically investigated the relationship between particle size of precursor powder, microstructure and superconducting properties of tapes. For short grinding time, the uneven particle size distribution damages the interface between Ba-122 core and Ag sheath, resulting in distinct sausage effect and decline of mass density of the Ba-122 core, causing severe fluctuation for the transport current density (J _c). Then with the extension of grinding time, the transport J _c becomes more uniform due to the improved homogeneity but lower with the reduction of average particle size from 21.5 to 9.5 μm. The J _c of samples made with precursor powders by grinding 20 min reaches 5 × 10⁴ A cm⁻² at 4.2 K and 10 T. It has been shown that the coarse grains are easier to align along the rolling direction of tapes and lead to a higher degree of c-axis texture. Our results demonstrated the importance of controlling the homogeneity and particle size of precursor powders in achieving superior J _c for iron-based superconducting tapes.

中文翻译：

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前驱体粉末粒径对管内粉末 Ba1−xKxFe2As2 超导带的影响

在本文中，我们研究了前驱体粉末粒径对管内包银粉末 Ba _1−x K _x Fe ₂ As ₂ (Ba-122) 超导带的影响。通过改变煅烧块体的研磨时间来制备具有不同粒度的前体粉末。我们系统地研究了前驱体粉末的粒径、带材的微观结构和超导性能之间的关系。对于较短的研磨时间，不均匀的粒度分布破坏了 Ba-122 核和 Ag 鞘之间的界面，导致明显的香肠效应和 Ba-122 核的质量密度下降，导致传输电流密度剧烈波动（杰 _三）。然后随着研磨时间的延长，运杰 _{由于均匀性提高， c}变得更均匀，但随着平均粒径从 21.5 减小到 9.5 而降低μ米。这杰 在 4.2 K 和 10 T 下，用前体粉末研磨 20 分钟制成的样品的_{c达到 5 × 10} ⁴ A cm ^-2。已经表明，粗晶粒更容易沿带的滚动方向排列并导致更高的程度C轴纹理。我们的结果证明了控制前体粉末的均匀性和粒度对于实现卓越的重要性杰 _c用于铁基超导带。