Accurate control of fH₂ in cold-seal pressure vessels with the Shaw membrane technique

authored by

Burkhard C. Schmidt, Bruno Scaillet, Francois Holtz

Abstract

An experimental setup is described to use the Shaw membrane technique in cold-seal pressure vessels (CSPV), allowing constant partial pressures of hydrogen (PH₂) and hence hydrogen and oxygen fugacities (fH₂, fO₂) to be maintained in experimental charges for long durations (up to several weeks). The experimental setup permits the accurate determination of fH₂ prevailing in gas pressurized vessels. In contrast to previous designs, osmotic equilibrium with this setup can be attained by diffusion of H₂ from the membrane toward the pressure vessel (without adding H₂ to the pressure medium before the heating up). Osmotic equilibrium is reached within less than 2 or less than 20 hours, with membranes made of Ag₂₃Pd₇₇ and Ag₇₀Pd₃₀ alloys, respectively. The technique described here has been successfully used to calibrate the fO₂ imposed by the Co-CoO solid buffer assemblage at 735°C and 780°C at 1 kbar. -from Authors

External Organisation(s)

Centre national de la recherche scientifique (CNRS)

Type

Article

Journal

European Journal of Mineralogy

Volume

7

Pages

893-903

No. of pages

11

ISSN

0935-1221

Publication date

26.07.1995

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Geochemistry and Petrology

Electronic version(s)

https://doi.org/10.1127/ejm/7/4/0893 (Access: Unknown)