高压烧结对Bi-2223/Ag高温超导带材临界电流与力学性能的影响

Effects of Controlled Over-Pressure Sintering on the Critical Current and Mechanical Properties of Bi-2223/Ag Tape

摘要:

研究了高压烧结对Bi-2223/Ag高温超导带材临界电流以及力学性能的影响。结果表明：高压烧结使带材的临界电流提升了30%，抗拉强度提升到104 MPa，带材临界弯曲应变从0.54%提升到0.91%。采用XRD常规扫描、Omega扫描以及SEM等手段分析了带材电学性能和力学性能提升的原因。实验结果发现：高压烧结有利于Bi-2223相的形成，从而使Bi-2223的相含量增加，残余的Bi-2212相的含量减少；常压烧结和高压烧结后的带材中Bi-2223相晶粒的半高宽分别为6.5°和5.6°说明高压烧结的带材中的Bi-2223晶粒排列更加整齐；此外，通过观察带材的纵截面发现高压烧结使带材内部更加致密。正是三方面的共同作用大幅度提升了带材的临界电流以及力学性能

Abstract:

The influences of controlled over-pressure sintering on the critical current density and mechanical properties of the Bi-2223/Ag high-temperature superconducting tape have been investigated. XRD and SEM were used to analyze the reasons of the improvement of the tape’s properties. The results show that the critical current density of the tape is promoted by more than 30% while the tensile strength and critical bending strain are improved to 104 MPa and 0.91% respectively. The Bi-2223 content is increased and the FWMH value of the tape is lowered from 6.5° to 5.6° by the controlled over-pressure sintering process. Besides, the densities of the ceramic cores are improved. Due to the higher Bi-2223 content, better grain alignment and higher core density, the critical current density and mechanical property are improved