STRUCTURAL STUDY OF A PHASE-TRANSITION IN A NIP METALLIC-GLASS

The structure of NiP amorphous alloys has been the subject of several controversies, especially concerning the nature of the short- and medi um-range orders. It has already been reported that these metallic glas ses can exhibit polymorphism, i.e., different types of local order, de pending upon the production technique. In this study, amorphous ribbon s of Ni81P19 produced by two different techniques, melt spinning and e lectrodeposition, have been investigated. The results obtained from va rious types of structural analysis have been correlated: differential scanning calorimetry (DSC) and neutron diffraction during heating at d ifferent rates until complete crystallization. A hilly region in the D SC curve as well as some significant changes in the diffraction patter n could be observed prior to crystallization in both the melt-spun and the electrodeposited samples. The results are interpreted and discuss ed in terms of a phase transition in the material. (C) 1997 Elsevier S cience S.A.