CORROSION CHARACTERISTICS OF AMORPHOUS NICKEL-PHOSPHORUS ALLOYS PREPARED BY RAPID COOLING .3.

Electrochemical and corrosion behaviour of amorphous Ni81P19 alloys pr epared by rapid cooling from melts kept at different initial temperatu res have been investigated in 1 mol/dm(3) aqueous HCl solution by mass measurement combined with spectrophotometry as well as by the analysi s of polarization curves. It has been established that the electrochem ical behaviour is strongly related to the melt temperature (i.e., to t he structure existing and formed at that temperature) but in the corro sion process this relationship is screened by the formation of a phosp horus-rich surface layer. The possibility of producing alloys with hom ogeneous amorphous structure under strictly controlled conditions has been confirmed. The structural differences in the melts used for the p roduction of the alloy show up in the electrochemical properties of th e solid phase,