BaZrO3 insulation coatings for HTS coils

Single crystal growth of BaZrO3 from the melt at 2700 °C using optical floating zone technique and growth prospects from BaB2O4 flux at 1350 °C

“…Perovskites with general formula ABO 3 are an important family of multifunctional materials [1] and exhibit a broad variety of outstanding properties, which are widely used in various technological applications such as Solid Oxide Fuel Cells (SOFC) [2,3], steam electrolysis [4], substrates for multiferroic materials [5,6], piezoelectricity [7][8][9][10][11][12][13] or catalysis [14][15][16]. Among different perovskite compounds, barium zirconate BaZrO 3 (BZO) has attracted renewed interests as a high-temperature proton conductor [17], a dielectric material for wireless communication applications [18], a substrate for thin-film growth [19,20] and as an inert crucible for superconductors crystal growth [21]. Owing to its large lattice constant, high melting point, low thermal expansion coefficient, low dielectric loss, and low thermal conductivity [22][23][24], BaZrO 3 has become popular for both fundamental research and device applications.…”

Fabrication of La2Zr2O7 buffer layers on Ni tapes by reel-to-reel sol–gel technique

“…In that case, the texture depends greatly on processing, annealing conditions and vapor pressure [14]. Textures of oxide thin films on polycrystalline substrates appear to be mainly controlled by growth kinetics and not by the texture of the substrate material, although there are reports of buffer layers on the textured Ni tapes for YBCO coated conductor [9][10][11][12].…”

“…The gel films were dried at 300 • C for 1 min, and then dried samples were heat treated at 600 • C for 2 min in an in-line vertical 3-zone furnace. The technique of this production as successfully applied to buffer layers, YBCO and insulators described in detail elsewhere [8][9][10][11][15][16][17]. These procedures were repeated to achieve the desired film thickness.…”

“…Diffusion of Ni can be reduced the superconducting properties. In-plane aligned YBCO superconducting films are deposited on the buffer layers [11,12]. The various multilayer architectures of buffer layers have been deposited on the textured Ni tape for YBCO coated conductor [12,13].…”

Stress analysis of ceramic insulation coating on Cu/MgB2 wires for W&R MgB2 coils

“…The National High Magnetic Field Laboratory (NHMFL) developed this technique to provide turn-to-turn electrical insulation for high temperature superconductor (HTS) and low temperature superconductors (LTS) coil [7][8][9][10]. In literature, many studies concerning with the physical and mechanical properties of insulators are available, but very few are related with the residual stress, which suffer from failure due to flaking and cracking because of the thermal and elastic mismatch, the plastic flow stress of the metal, the relative substrate coating thickness, thickness of interlayers and fracture resistance of the interface.…”