A powder metallurgy review on synthesis and densification processing of REBCO superconductors

Abstract REBa 2 Cu 3 O 7− δ (REBCO) high-temperature superconductors exhibit considerable promise for high-power applications. Bulk materials fabricated via powder metallurgy, in particular, are frequently employed as targets for coated conductor deposition and in energy storage applications. This review outlines recent progress in REBCO powder synthesis and densification technologies. In powder synthesis, recent advances in solid-state reaction methods are reviewed, focusing on the effects of raw materials and grinding processes on the final material properties. Meanwhile, chemical synthesis routes including sol–gel, citrate pyrolysis, co-precipitation, PVP-assisted pyrolysis, microwave synthesis, and electrospinning-sol–gel hybrids stand out due to their proven capacity to improve compositional homogeneity, reduce particle size, and minimize agglomeration. The discussion on densification technologies outlines their historical and ongoing evolution. It covers established compaction approaches like die pressing, hot pressing, and isostatic pressing, while also highlighting the field’s transition toward advanced methods including spark plasma sintering and three-dimensional printing. Through a comparative analysis of their technical features and consequent effects on microstructures and superconducting properties, the advantages and limitations of different processing routes are clarified. This review also presents a methodological framework for REBCO characterization, evaluating solid experimental standards while examining prevalent issues. It systematically details the essential techniques and critical parameters involved in each processing stage, from powder analysis to sintered body evaluation, in order to ensure reliability and reproducibility in both fundamental research and application development.