Dresden 2003 – wissenschaftliches Programm

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M: Metallphysik

M 25: Flüssige und amorphe Metalle II

M 25.3: Vortrag

Dienstag, 25. März 2003, 12:15–12:30, IFW D

Structural Homogeneity and Chemical Degradation of Zr-based Amorphous Alloys — •Kamachi Mudali^1,2, Annett Gebert¹, Juergen Eckert¹, and Ludwig Schultz¹ — ¹IFW Dresden, P.O. 270016, D-01171 Dresden, Germany — ²IGCAR, Kalpakkam, India

The macroscopic corrosion resistance of amorphous structures is affected by the presence of concentrated cluster zones of heterogeneous natured elements and crystalline defects. An attempt is made to characterise the properties of amorphous Zr59Ti3Cu20Al10Ni8 ribbons in acidic as well as chloride solution, under neutral and acidic pH conditions. Potentiodynamic anodic polarisation was carried out in different concentrations of acidic as well as acidic chloride solutions for this purpose. The tested specimens were examined by SEM/EDAX, AFM, and AES. The main results of the present investigation indicated that the alloy undergoes localised corrosion in chloride solutions, and the attack was specifically at sites where clusters of alloying elements were concentrated, with least noble element being more at such sites. Structural heterogeneity associated with such compositional fluctuations assist in the initiation of the corrosion processes by damaging the passive films developed. However, in pure acidic solution the alloy possessed good resistance against any chemical degradation indicating the superiority of the amorphous structure.