MICROWAVE SINTERING OF THE HIGH-T-C SUPERCONDUCTOR Y-BA-CU-O

Use of microwave energy to produce high temperatures for sintering cer amics, especially superconductors, appears to be a technique of great interest. Here, new results are presented dealing with the sintering o f high-T-c superconducting Y-Ba-Cu-O samples in a TE102 microwave cavi ty. It is demonstrated that heating is mainly governed by magnetic ind uction. A good understanding of microwave-matter interactions allows u s to optimize the sintering conditions of long bars. In spite of the v ery fast sintering rate, the samples exhibit a high density and the mi crostructure 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 2 000 A cm(-2) at 77 K, in the absence of an applied magnetic field. The process and the different results obtained are discussed in this pape r.