The
dealloying mechanism of the duplex-
phase Cu-20Zr cast
alloy and sputtered Cu-20Zr film in hydrochloric acid solution was investigated using the electrochemical methods,chemical and surface analysis techniques.Results showed the duplex-phase in cast Cu-20Zr alloy is composed by two phases,one is the Zr-rich Cu_(51)Zr_(14) phase,the another is the eutectoid of the Cu and Cu_9Zr_2 phase.The rich-Zr Cu_(51)Zr_(14) phase selectively dissolves owing to its more reactivity at the low anodic potential,which illustrates the
dissolution mechanism of the Cu-20Zr alloy is decided by the stability of the microstructure.The study of the
corrosion rules of the sputtered Cu-20Zr film shows further that the dissolution process of each element is different at the different polarized potential.When the potential is lower than the redox of Cu/Cu~(2+),the dissolution of Zr
atoms is the main process;when the potential is higher than the redox of Cu/ Cu~(2+),Zr and Cu atoms in the film simultaneously
dissolve,and the dissolution rate of Cu atoms is higher than that of Zr atoms.Subsequently,Cu ions react with Cl ions in the electrolyte,and form the corrosion products of Cu(Ⅰ) and Cu(Ⅱ) complex compounds.These corrosion products covered the surface of the film,retarded the dissolution of Cu atoms.Zr atoms still dissolve continually with increasing the potential.
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