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

Electrochemical and corrosion behaviour of amorphous Ni81P19 alloys prepared by rapid cooling from melts kept at different initial temperatures have been investigated in 1 mol/dm(3) aqueous HCl solution by mass measurement combined with spectrophotometry as well as by the analysis of polarization curves. It has been established that the electrochemical behaviour is strongly related to the melt temperature (i.e., to the structure existing and formed at that temperature) but in the corrosion process this relationship is screened by the formation of a phosphorus-rich surface layer. The possibility of producing alloys with homogeneous amorphous structure under strictly controlled conditions has been confirmed. The structural differences in the melts used for the production of the alloy show up in the electrochemical properties of the solid phase,