Rare earth barium copper oxide (REBCO) coated conductor has emerged as one of the high T _c superconductors suitable for future ultrahigh field superconducting magnet applications. In the design and fabrication of such ultrahigh field REBCO magnets, it is essential to understand the behavior of REBCO coated conductor. The effect of heating on the properties of commercial REBCO coated conductors is very important for many practical reasons. Nevertheless, a comprehensive study on this effect have not yet been presented in the published literature. This work studies a commercial REBCO coated conductor heat-treated at temperatures between 175 C and 300 C for various durations. Critical current and lap joint resistivity were measured at 77 K and 4.2 K for the heat-treated samples. We found that critical current degrades with heat treatment time and temperature. This degradation can be described by a one-dimensional oxygen out-diffusion model with a diffusion coefficient of D = 2.5 10⁻⁶ exp (−1.17eV kT⁻¹) m² s⁻¹. The heat treatment also causes appreciable increase in joint resistivity. Comprehensive structural and chemical analyses were performed on Cu/Ag/RECBO interfaces by transmission electron microscopy. Our electron energy loss spectroscopy study provided direct evidence of oxygen deficiency in the heat treated REBCO samples. In addition, it is found that the oxygen diffused out of the REBCO layer forms mostly Cu₂O at both Ag/REBCO and Cu/Ag interfaces. Cu₂O is also observed at grain boundaries of the Ag layer. The oxygen out-diffusion model proposed in this work is used to predict REBCO thermal degradation in several engineering scenarios.

稀土钡铜氧化物（REBCO）涂布的导体已成为高的一个Ť _Ç适用于未来超高场超导磁体应用的超导体。在设计和制造这种超高场 REBCO 磁体时，必须了解 REBCO 涂层导体的行为。出于许多实际原因，加热对商用 REBCO 涂层导体性能的影响非常重要。然而，关于这种效应的综合研究尚未在已发表的文献中提出。这项工作研究了在 175 C 到 300 C 之间的温度下热处理不同时间的商用 REBCO 涂层导体。热处理样品的临界电流和搭接接头电阻率在 77 K 和 4.2 K 下测量。我们发现临界电流会随着热处理时间和温度而降低。D = 2.5 10 ^-6 exp (-1.17eV kT ^-1 ) m ² s ^-1。热处理还会导致接头电阻率显着增加。通过透射电子显微镜对 Cu/Ag/RECBO 界面进行了全面的结构和化学分析。我们的电子能量损失光谱研究提供了热处理 REBCO 样品缺氧的直接证据。此外，发现从 REBCO 层扩散出来的氧主要在 Ag/REBCO 和 Cu/Ag 界面形成 Cu ₂ O。铜₂在Ag层的晶界处也观察到O。这项工作中提出的氧外扩散模型用于预测几种工程场景中的 REBCO 热降解。