Absorption and desorption of H by NbMo alloys at high temperature

作者：Mazzolai Giovanni^*

来源：International Journal of Hydrogen Energy, 2013, 38(14): 5717-5723.

DOI：10.1016/j.ijhydene.2013.02.027

• H absorption/desorption
• H diffusion
• H permeation through oxides
• NbMo alloys

Absorption and desorption of hydrogen have been investigated in Nb95Mo5 and Nb80Mo20 alloys over wide temperature ranges. On continuous heating H desorption from Nb95Mo5 was found to take place between 800 and 1000 K and from Nb80Mo20 between 900 and 1100 K. The observed increase in the desorption temperature with increasing Mo content has been attributed to a higher stability of the Mo and NbMo oxides with respect to those of Nb. The solid-gas reaction during absorption was first order and the rate limiting process consisted in the penetration of H atoms through surface oxides. At high temperatures and in the presence of H the oxides are expected to become permeable to H due to the reduction of higher valence to lower valence oxides. The values of the activation energy for H diffusion within the oxide films were 0.82 +/- 0.04 eV for Nb95Mo5 and 1.1 +/- 0.1 eV for Nb80Mo20. The thicknesses of the oxide films estimated from the absorption data were of the order of 1 mu m.

• 出版日期2013-5-10