Development of textured Au layer on Ni substrate for YBCO coated conductors

Much effort has been made to develop new metallic buffers to explore the possibility of designing YBCO coated conductors (CC's) with a simple architecture. We selected Au because of its small lattice mismatch to Ni and chemical novelty, and plated it on a biaxially textured Ni substrate by the electroless-plating method. The texture of Au/Ni template was evaluated by X-ray pole-figure and orientation distribution function (ODF) analysis. The surface roughness and grain boundary morphology were characterized by atomic force microscopy (AFM). We fabricated the cube textured Au/Ni template for the CC and evaluated its texture formation and microstructural evolution. Texture analysis indicated that the Au layer was epitaxially deposited on the Ni substrate and formed a strong cube texture when the processing variables were optimized. The full-width at half-maximum (FWHM) was 8.4° for out-of-plane and 9.98° for in-plane texture when the plating time was 30 min. In addition, the root-mean-square (RMS) and the depth of the grain boundary for the Au layer were 14.6 nm and 160 Å, respectively, which are significantly smaller than the corresponding values for the Ni substrate (27.0 nm and 800 Å), indicating that the electroless-plated Au layer had a relatively smooth surface and effectively mollified grain grooves.