Tape processing of HBCCO, BSCCO, and YBCO thick films on metallic substrates with high J_C by the spray/compress technique

A simple spray/compress technique has been developed for the fabrication of thick film tapes of HBCCO, BSCCO, and YBCO on metallic substrates with high J_C. The technique has successfully incorporated crucial processing factors to achieve composition uniformity, phase purity, preferred microstructure, grain alignment, and high density for high temperature superconducting tapes of high performance. We have obtained a J_C of 8.8×10⁴ A/cm² in YBa₂Cu₃O_6+δ thick films on Ag/Pd substrates at 77K and self-field; 7×10⁴ A/cm² in HgBa₂Ca₂Cu₃O_8+δ thick films on Ni substrates with a buffer layer at 77K and self-field; and 5×10⁵ A/cm² and 3×10⁵ A/cm² in Bi₂Sr₂CaCu₂O_x thick films on Ni substrates with a buffer layer at 4.2K in self-field and 8T, respectively.