Characterization of thin films of the palladium-hydrogen system

doi:10.1016/0022-5088(80)90077-6

Journal of the Less Common Metals

Volume 74, Issue 1, 1 October 1980, Pages 89-96

https://doi.org/10.1016/0022-5088(80)90077-6 Get rights and content

Abstract

In this paper we present a study of the pressure-concentration (P−C) isotherms and the resistance properties of evaporated palladium films to which hydrogen has been added in situ at 27 °C. Hydrogen was introduced into the samples via the gas phase and the equilibrium $H Pd$ ratio was determined using a quartz-crystal mass monitor. We find that the P−C function is highly dependent on film thickness, with the slope of the α + β coexistence region increasing and the limiting β-phase concentration decreasing with decreasing film thickness. However, the P−C function does approach bulk behavior for thick films ( $t > 1000 A ̊$ ).

Film resistance was measured as hydrogen was cycled in and out of annealed and unannealed films. The annealed films show reversible electrical behavior with respect to hydrogen cycling; unannealed films are also electrically reversible in the α phase but show a monotonie decrease in resistance with cycling of hydrogen concentration through the β phase. For the unannealed films the ratio of the film resistance after maximum hydrogen uptake (β phase at a hydrogen pressure of 60 Torr) to the vacuum film resistance increases with cycling. This ratio never exceeds that for the annealed films.

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^☆: Paper presented at the International Symposium on the Properties and Applications of Metal Hydrides, Colorado Springs, Colorado, U.S.A., April 7–11, 1980.

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Characterization of thin films of the palladium-hydrogen system☆

Abstract

Surf. Sci.

J. Catal.

J. Catal.

J. Catal.

J. Phys. Chem.

The Palladium-Hydrogen System

J. Phys. C

J. Phys. D