PREPARATION OF NICKEL-BASED AMORPHOUS-ALLOYS WITH FINELY DISPERSED LEAD AND LEAD BISMUTH PARTICLES AND THEIR SUPERCONDUCTING PROPERTIES

The aim of this paper is to examine the microstructure and superconducting properties of melt-quenched Ni-S(or P)-B-Pb and Ni-Si(or P)-B-Pb-Bi alloys and to investigate the usefulness of the addition of small amounts of immiscible elements into the nickel-based amorphous alloys. Melt quenching of amorphous phase-forming alloys containing an immiscible element has been demonstrated, enabling us to produce amorphous composite materials exhibiting unique and useful characteristics which cannot be obtained in homogeneous amorphous alloys. These duplex alloys were found to exhibit superconductivity by the proximity effect of finely dispersed lead or lead-bismuth particles at temperatures higher than 4. 2 K.