Microwave sintering of the high- superconductor Y - Ba - Cu - O
Résumé
Use of microwave energy to produce high temperatures for sintering ceramics, especially superconductors, appears to be a technique of great interest. Here, new results are presented dealing with the sintering of high- superconducting Y - Ba - Cu - O samples in a TE102 microwave cavity. It is demonstrated that heating is mainly governed by magnetic induction. A good understanding of microwave - matter interactions allows us to optimize the sintering conditions of long bars. In spite of the very fast sintering rate, the samples exhibit a high density and the microstructure can be modulated depending on the sintering temperature. Furthermore, owing to the good connectivity between the grains of the samples, the superconducting properties are better than those obtained with conventional sintering. The critical current density can reach at 77 K, in the absence of an applied magnetic field. The process and the different results obtained are discussed in this paper.