Corrosion Properties Of Amorphous Alloys
The knowledge of electrochemistry necessary for an understanding of metallic corrosion will be described before characterization of corrosion behavior of amorphous alloys. If the high corrosion resistance of amorphous alloys is mainly attributed to the alloy homogeneity, the alloys would be quite resistant against initiation of localized corrosion attack. The chemical heterogeneity seems to form a high density of weak points in the passive film with respect to corrosion as well as localized corrosion attack. One of differences between passive films and ordinary corrosion product films is that the beneficial cations in improving the protective quality of the films are highly concentrated in the passive films. Consequently, phosphorus contained in amorphous metal-metalloid alloys accelerates active dissolution of alloys prior to the passive film formation, and accordingly leads to the rapid enrichment of beneficial species at the alloy solution interface and to the rapid formation of passive film.