Regensburg 2002 – wissenschaftliches Programm

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M: Metallphysik

M 25: Wasserstoff in Metallen II

M 25.4: Fachvortrag

Donnerstag, 14. März 2002, 12:00–12:15, H4

The Electrochemical Hydrogen Sorption Behaviour of Zr-Cu-Al-Ni Metallic Glasses — •Nahla ismail, Margitta Uhlemann, Annett Gebert, Juergen Eckert, and Ludwig Schultz — IFW dresden, Institute for metallic Materials, P.O. Box 270016, D-01171 Dresden

Potentiodynamic polarisation tests were conducted to investigate the cathodic hydrogen reduction reactions on the surface of the melt-spun Zr₅₅Cu₃₀Al₁₀Ni₅ and Zr₆₅Cu_17.5Al_7.5Ni₁₀ ribbons. In the Tafel region, the electodic desorption reaction is the rate-determining step which competes with the hydrogen absorption reaction. The next potential region is under mass transfer-control. The ribbons are galvanostatically charged with hydrogen. The hydrogen absorption rate of the Zr₅₅Cu₃₀Al₁₀Ni₅ alloy is higher than that of the Zr₆₅Cu_17.5Al_7.5Ni₁₀ alloy, although the hydrogen discharge rate on the surface of the Zr₆₅Cu_17.5Al_7.5Ni₁₀ alloy is higher. Charging the samples at room temperature to H/M=1.3 using a low charging rate (-1 mA/cm²), the X-ray diffraction pattern showed the main peaks of a Zr-hydride and Cu rich phase(s) beside the amorphous phase. The reversibility of the absorbed hydrogen atoms has been studied by applying potential charge/discharge pulses. The Zr₅₅Cu₃₀Al₁₀Ni₅ alloy was found to absorb a higher fraction of reversible hydrogen than the Zr₆₅Cu_17.5Al_7.5Ni₁₀ alloy.