Long-Range Diffusion of Hydrogen in Solid-Solution PdCe Alloys as Deduced from Absorption Experiments

Abstract:

The diffusion of H and the thermal decomposition of hydrides have been investigated at high temperatures in two PdCe alloys of composition 5% and 9% Ce. It has been found that the H diffusion coefficient obeys an Arrhenius-type of law with the following values of the activation energy W and diffusion constant D0, ( )     = ± × = ± − s m D W eV 2 7 0 2 2 10 0.20 0.02 (Pd95Ce5 alloy) ( )     = ± × = ± − s m D W eV 2 7 0 2 1 10 0.24 0.01 (Pd91Ce9 alloy) The high-temperature absorption data match the low-temperature ones deduced from internal friction measurements, indicating that Ce atoms do not act as strong trapping centres for H. Thermal decomposition of hydrides in the Pd95Ce5H0.008 alloy occurs in a single stage showing a homogeneous solid solution state of the H-Me system.

• Periodical: Defect and Diffusion Forum (Volumes 273-276)
• Pages: 381-387
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.273-276.381
• Online since: February 2008
• Authors: Giovanni Mazzolai
• Keywords: H Absorption, H Desorption, Hydrogen Diffusion, Pd-Ce Alloys

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