Patent ID: 6043198
Filing Date: 2000-03-28
Classification: C04B,H01L,Y10S

Abstract:
A precursor or high temperature superconductor which has an average grain size of .ltoreq.3 .mu.m and a Fe content of less than 200 ppm prepared according to a process comprising:completely melting a mechanical mixture of metal oxides containing bismuth, strontium, calcium, and copper in a stoichiometric ratio corresponding to a superconductor in air at a temperature above 1000.degree. C.,pouring the melt out onto a base which is kept at room temperature to cool the melt,coarsely breaking up the cooled melt,tempering the melt at a temperature between 600 and 900.degree. C. at a defined oxygen partial pressure, anddisintegrating and grinding the cooled melt into a powder having a carbon content of less than 5000 ppm.