Microstructural aspects of joining superconductive components using solder

Schmitz, Georg J.; Tigges, A; Schmidt, Jens

doi:10.1088/0953-2048/11/1/015

Cited by 17 publications

(12 citation statements)

References 8 publications

(9 reference statements)

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“…Mechanically robust joints with a highly aligned structure and low residual porosity have been produced using this technique. However to-date no superconducting properties have been reported for this type of joint [19,20].…”

Section: Introductionmentioning

confidence: 96%

“…This uses the same principle as the IG technique for growing large single grains. A variety of ytterbium, yttrium and erbium-based powder compositions have been trialled for this purpose [19]. The RE-211 powder has a lower decomposition temperature than YBCO, so the bulk superconductor sections both remain solid throughout the joining process and facilitate epitaxial nucleation.…”

Section: Introductionmentioning

confidence: 99%

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A reliable technique to fabricate superconducting joints between single grain, Y–Ba–Cu–O bulk superconductors

Congreve

Dennis

Shi

et al. 2021

Supercond. Sci. Technol.

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The production of large (RE)Ba-Cu-O single grains ((RE) BCO), where RE = Y, Gd or Sm, of complex geometries is presently limited by the intrinsic slowness of the grain growth process. Additionally, the shapes achievable using established melt processing are constrained by the small number of post-processing techniques available. These materials are brittle and hard, which makes machining a difficult task and largely eliminates the possibility of producing highly intricate shapes. An alternative to this slow and inflexible growth process would be to join many small single grains to form one large composite grain, connected by high-performance superconducting joints. A reliable joining technique would also overcome the need for the careful and time-consuming post-growth machining processes. In this work we report on the use of single grain YBCO-Ag as an interface medium to achieve superconducting joints between (RE)BCO bulks. This joining technique is relatively quick and does not require tight process parameter control as there is no need to re-grow the interface joining material. We report on six joints produced from samples cut and joined in a variety of orientations. In addition, a joint was produced using bulk YBCO from two independent single grains. The trapped field properties of the resulting joined sample were measured and the microstructure at the joint was examined. We show that this simple but effective joining technique makes it possible to produce multiple composite grains with comparable superconducting properties to those of a single grain of the same size.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

A reliable technique to fabricate superconducting joints between single grain, Y–Ba–Cu–O bulk superconductors

Congreve

Dennis

Shi

et al. 2021

Supercond. Sci. Technol.

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“…Techniques used to form joints between bulk superconductors can be grouped into four categories. These are solid-state diffusion, infiltration joining, welding using an intermediate material with a lower peritectic temperature and joining using a non-superconducting intermediary to locally lower the peritectic temperature of the interface between the (RE)BCO bulks [11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of high-quality joints between Gd–Ba–Cu–O bulk superconductors

Tutt,

Congreve,

Shi

et al. 2023

Supercond. Sci. Technol.

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This work reports a technique for fabricating superconducting joints between GdBCO-Ag bulk superconductors, using YBCO-Ag as an intermediate joining material. The ability to provide reliable joints between multiple bulk superconductors overcomes many of the challenges of fabricating large superconductors or machining hard and brittle bulk superconductors into practical shapes. We report on nine single grains of GdBCO-Ag which have been joined with a YBCO-Ag intermediate. Samples were cut and joined in a variety of c-plane orientations to refine and understand the effect this had on the superconducting properties of jointed samples. The trapped field of pre-jointed and jointed bulk superconductors were compared; the maximum trapped field achieved was 59% of the pre-jointed sample. Further analysis showed that the critical temperature and critical current of the samples were degraded by the jointing process. Microstructural and chemical analysis showed that the jointing process facilitated diffusion of silver towards the joint and in some cases large pores were formed at the joint interface. These factors consequently inhibited current flow across the joint and thus reduced the maximum trapped field achievable when compared to the original unjointed sample.

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“…Using low melt temperature REBCO as a superconducting solder has also been used in joining Y123 single domain bulks [14][15][16][17][18]. In all these researches, appropriate oxygen annealing is essential to achieve high supercurrent capability [19].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ErBa2Cu3O7−δ Superconductor Solder for the Fabrication of Superconducting Joint between Gdba2cu3o7−δ Coated Conductor

et al. 2019

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ErBa2Cu3O7−δ (Er123) superconductor is one of the best candidates of superconductor solder for the fabrication of superconducting joint between GdBa2Cu3O7−δ (Gd123) coated conductor, due to its high Tc value (93 K) and highest optimized oxygen annealing temperature among RE123 compounds. In this paper, we systematically research the effect of sintering parameters on the phase formation, microstructure and superconducting properties of Er123 powder. The optimized synthesis route to acquire high purity Er123 powder with as good superconducting properties as Gd123 has been uncovered. The melt temperature of Er123 with different dopant compared to Gd123 is also investigated, and the feasible operating temperature range of Er123 superconductor solder is discussed. This work reveals a very important starting point on fabrication high-quality superconducting joint between the commercial Gd123 coated conductor, which can further improve the development of the persistent operating mode on ultra-high field nuclear magnetic resonance and magnetic resonance imaging.

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Microstructural aspects of joining superconductive components using solder

Cited by 17 publications

References 8 publications

A reliable technique to fabricate superconducting joints between single grain, Y–Ba–Cu–O bulk superconductors

A reliable technique to fabricate superconducting joints between single grain, Y–Ba–Cu–O bulk superconductors

Fabrication of high-quality joints between Gd–Ba–Cu–O bulk superconductors

Synthesis of ErBa2Cu3O7−δ Superconductor Solder for the Fabrication of Superconducting Joint between Gdba2cu3o7−δ Coated Conductor

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