Research On Fabricating YBCO Superconductor Films By Plasma Spraying

Owing to the good magnetic field dependence in liquid nitrogen temperature range and the perfect current conducting ability, the second generation(2G) high Tc superconducting tapes have a glories future in industrial application. Development of 2G high Tc superconductor wires is a challenge task. The 2G high Tc superconductor is brittle and has a intrinsic problem called"weak links", thus fabricating 2G wires should use coated technology. Recently, some feasible processes to fabricate 2G superconductor wires have been developed in Japanese and USA, realized the longest tape of several hundred meter's level. However in our country, exploring a appropriate processing is a problem that our confronted. Plasma spraying technique is used for fabricating coatings, no need for vacuum condition, high production rate, suitable for reel to reel processing,so I choose this technique to fabricate 2G superconductor films. Plasma spraying technique requires the use of powders with good rheological characteristics and good morphology. Producing 2G superconductor powders is one of the contents of my thesis. My thesis mainly consists of the following parts:First, introducing the research and development history and characters of superconductors, especially explain the processes of fabricating 2G high Tc superconductor wires. Summarizing progresses in 2G high Tc superconductor wires, so as to offering experience and guiding for fabricating 2G high Tc superconductor wires.Second, the 2G high Tc superconductor powders were produced by using the conventional solid-state reaction route, according to the requirement of the plasma spraying technique. Homogeneity significantly enhanced by milling and calcination several times.Third, designed and accomplished the plasma spraying experiments. 2G HTS films with different thickness had been sprayed, heat treatment followed. XRD and ESEM had been used to test the sprayed films and heat treatment films. The quality of the films had been estimated according to the test.