RAPID FURNACE ANNEALING OF YBA2CU3OX THICK-FILMS ON NI/NIO AND INCONEL SUBSTRATES PREPARED BY SPRAY-PYROLYSIS OF YBA2CU3OX POWDER

A spray pyrolysis growth system has been employed for the formation of superconducting YBa2Cu3Ox (YBCO) thick films. YBCO films on polycrystalline Ni/NiO, Inconel 600, and Inconel X substrates ranging in-thickness from 80-100 mu m have been developed by a three-step process with observed T-c zero values up to 85 K. In the first step, the metallic substrates were examined with and without a preoxidation anneal to form a native oxide layer. Second, superconducting YBCO powder (0.2 mu m particle size) was mixed with ethanol and sprayed onto the substrates. Third, the films were sintered at high temperature and oxygenated to form the superconducting phase. The effect of a native oxide buffer layer upon superconducting properties was evaluated as a function of the duration of the preoxidation anneal and the sintering anneal. X-ray diffraction (XRD) theta/2 theta, variable temperature four-probe resistance, and Auger line scan characterization of these films will be discussed.