POSSIBILITY OF PRODUCING A SUPERCONDUCTIVE LAYER OF LARGE AREA ON THE BULK PREPARED BY PRESS FORMING OF BI SYSTEM SUPERCONDUCTIVE POWDER BY LASER SURFACE MELTING METHOD

摘要

A bulk prepared by press forming of Bi system superconductive powder never shows superconductive characteristics. To yield superconductive characteristics on the bulk, heat treatment of the bulk in an electric furnace is an essential process. This process, however, has such problems as that the size of the bulk is limited by the size of the furnace and that the process requires time as long as several ten hours. To overcome the problems, a method using laser technique has been applied. This method melts the surface of the bulk by a laser, without strict control of irradiation conditions, to yield a superconductive layer underneath the melted layer. This paper deals with the possibility of producing a superconductive layer of large area on the bulk by CO{sub}2 laser surface treatment.