DEVELOPMENT OF IN-SITU FABRICATION PROCESS OF COLUMNAR YBCO/Ag COMPOSITES

柱状YBCO/Ag复合材料原位制备工艺开发

• 批准号: 07555221
• 负责人: OGI Keisaku
• 金额: $ 3.97万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555221/
• 关键词: YBa2Cu3O7-x; superconductivity; silver; superconducting oxide; composite; interface resistivity; solidification; peritectic; YBa_2Cu_3O_<7-X>; 酸化物; YBCO; 接合; 酸化物高温超伝導体

Superconducting and mechanical properties of unidirectionally solidified YBCO are improved by Ag addition. However, many gas holes formed in YBCO/Ag composites melted/solidified in the atmosphere. In YBCO/Ag composites melted in a vacuum to reduce the gas holes and solidified in the atmosphere, Ag particle-rich zone formed near the central region of the sample. These Ag particles and gas holes changed thermal conductivity of composite and the effective temperature gradient in the sample. The distributions of Ag particles and gas holes were measured and the changes in thermal conductivity and the effective temperature gradient were estimated by applying the rule of mixtures. 123 columnar crystals in YBCO/Ag composites developed under the critical solidification condition of G>A・R,where A=6*10^5, G was temperature gradient (K/cm), and R was solidification rate (mu m/s). The above critical condition is a little harder than that (A=4*10^5) for YBCO without Ag, because of the diffusion barr … More ier effect of Ag particles at the 123 interface. Ag particles became larger at the 123 interface by the monotectic reaction and were trapped within 123 phase when they exceeded a critical size.. At the central region of the cell, Ag-free zones formed by pushing Ag particles from the interface. The crystallographic orientations of 123 cellular facet interfaces were measured, and the normal growth rate (Ri) of each interface was estimated from the trace of the cell tip, which was detected by the above Ag-free zones : Ri (001) =0.47R-0.61R,and Ri (100) =Ri (010) =0.62R-0.70R.From the measured critical radius (ro) of Ag particles trapped in the 123 phase, the relationship between ro and the growth rate (Ri) of faceted planes was given by the equation : Ri=b/ro, where b=1.05. Further, the interface resistivities (rho c) of YBCO/Ag joints fabricated by solid state processing and liquid state processing were measured, and the minimum rho c as low as about 10^<-12> OMEGA・m^2 was obtained in both cases, which satisfied the stability criteria for composite conductors. Less

添加Ag可提高单向凝固YBCO的超导和机械性能。然而，YBCO/Ag 复合材料中形成的许多气孔在大气中熔化/凝固。在真空中熔化以减少气孔并在大气中凝固的YBCO/Ag复合材料中，在样品的中心区域附近形成了富银颗粒区。这些银颗粒和气孔改变了复合材料的热导率和样品中的有效温度梯度。测量了银颗粒和气孔的分布，并应用混合物法则估计了热导率的变化和有效温度梯度。 YBCO/Ag复合材料在G>A·R临界凝固条件下发育了123种柱状晶，其中A=6*10^5，G为温度梯度（K/cm），R为凝固速率（μ m/s）。由于 123 界面处 Ag 颗粒的扩散阻挡效应，上述临界条件比不含 Ag 的 YBCO 的临界条件 (A=4*10^5) 稍微困难一些。通过偏晶反应，Ag 颗粒在 123 界面处变得更大，当它们超过临界尺寸时，它们被捕获在 123 相内。在电池的中心区域，通过将 Ag 颗粒从界面推出而形成无银区。测量了123个细胞小面界面的晶体取向，并根据上述无银区检测到的细胞尖端的痕迹估计了每个界面的正常生长速率（Ri）：Ri（001）=0.47R-0.61R，Ri（100）=Ri（010）=0.62R-0.70R。根据测量的Ag颗粒的临界半径（ro） 困在 123 相中，ro 与刻面生长速率 (Ri) 之间的关系由以下方程给出：Ri=b/ro，其中 b=1.05。此外，测量了固态加工和液态加工制备的YBCO/Ag接头的界面电阻率(rho c)，两种情况下都获得了低至约10^<-12> OMEGA·m^2的最小rho c，满足复合导体的稳定性标准。较少的

项目成果

Nobuyuki Mori and Keisaku Ogi: "Peritectic Solidification Mechanism of YBCO Facet Crysuals from 211+Liquid+Ag Phases" Solidification Science and Processing : Proc.of the Int.Symposia on Advanced Materials and Technology for the 21th Century,Edited by I.Oh

Nobuyuki Mori 和 Keisaku Ogi：“来自 211 个液态银相的 YBCO 晶面晶体的包晶凝固机制”凝固科学与加工：21 世纪先进材料与技术国际研讨会论文集，由 I.Oh 编辑

N.Mori, H.Nishi and K.Ogi: "Peritectic Solidification Mechanism of YBCO Facet Crystals from 211+Liquid+Ag Phases" Solidification Science and Processing : Proc. of the Int. Symposia on Advanced Materials and Technology for the 21th Century in the 117th Mee

N.Mori、H.Nishi 和 K.Ogi：“211 个液态 Ag 相的 YBCO 晶面晶体的包晶凝固机制”凝固科学与加工：Proc。

Nobuyuki Mori and Keisaku Ogi: "Peritectic Solidification Mechanism of YBCO Facet Crystals from 211+Liquid+Ag Phases" Proc.of″Solidification Science and Processing″in JIM Conference,Hawaii,December 1995. 275-282 (1996)

Nobuyuki Mori 和 Keisaku Ogi：“211+Liquid+Ag Phases 的 YBCO Facet Crystals Peritectic Solidification Mechanism of YBCO Facet Crystals from 211+Liquid+Ag Phases”Proc. of “Solidification Science and Processing”，夏威夷 JIM 会议，1995 年 12 月。275-282 (1996)

森 信幸: "一方向凝固した超伝導YBCO酸化物と銀の接合体作製と界面特性" 溶接学会論文集. 14. 162-167 (1996)

Nobuyuki Mori：“单向凝固超导 YBCO 氧化物和银接头的制造和界面特性”日本焊接学会会议记录 14. 162-167 (1996)。