Effect of Silver Addition on the Mechanical and Field Trapping Properties of Gd-Ba-Cu-O Bulk Superconductors
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Open Access
- 1 January 2002
- journal article
- Published by Japan Institute of Metals in Journal of the Japan Institute of Metals and Materials
- Vol. 66 (4) , 309-314
Abstract
The effect of Ag addition on the microstructure and the mechanical and field trapping properties of Gd Ba Cu O bulk superconductor has been investigated. The single grain Gd Ba Cu O bulk superconductors 32 mm in diameter were fabricated with 0 30 massAg 2 O additions by the melt growth method under controlled oxygen partial pressure of 1.0. From microscopic observations, it was found that the macro cracks in the a b plane decreased with Ag addition. The three point bending test showed that the average strength of Ag free bulk was 69 MPa at room temperature, while the strength was dramatically improved to 110 115 MPa with 10 30 massAg 2 O additions. The trapped magnetic field of Ag free bulk sample was 1.3 T at 77 K. The trapped field of bulk Gd Ba Cu O samples with 10 20 massAg 2 O exhibited high values of 1.8 2.0 T at 77 K. However, the trapped field of the sample with 30 massAg 2 O addition was lowered to 1.1 T with decreasing the critical current density. The trapped field of Ag added sample did not deteriorate with thermal cycles. The trapped fields at lower temperatures were also measured for the Ag free and 20 massAg 2 O added bulk samples without reinforcement by the metal ring or resin. The Ag free bulk exhibited the trapped field of 3.0 T at 65 K, however, the bulk was fractured at lower temperature due to an electromagnetic force. On the other hand, the Ag added bulk could trap the higher field of 6.7 T at 55 K, thanks to the improvement in mechanical strength.Keywords
This publication has 1 reference indexed in Scilit:
- Erratum to “Perfect fits of Jc–B dependencies in NEG-123 bulk samples with 30% Gd-211 fine particles” [Physica C 357–360 (2001) 489–493]Physica C: Superconductivity and its Applications, 2001