RESEARCH STUDIES ON SOLID HYDROGEN PURIFICATION MEMBRANES.
Abstract
The permeation rate of hydrogen through tantalum was measured over the temperature range of 400-700C and at pressures up to 160 psig. Tantalum membranes coated with a thin palladium layer, approximately 1000A thick, are stable between 400 and 525C and show rates which are limited by bulk, solid-state diffusion of hydrogen. The diffusion rate through these membranes is substantially greater than that through palladium of the same thickness under the same temperature and pressure. At lower temperatures the tantalum membranes are mechanically unstable because of the lattice expansion caused by the solution of large quantities of hydrogen. At temperatures above 525C, the surface coat degrades with time. The susceptibility to poisoning of tantalum membranes coated by palladium is essentially that of pure palladium. The membranes are stable in air at room temperature and at elevated temperatures. Carbon dioxide and carbon monoxide decrease the permeation rate of hydrogen, but the effect is small and is easily reversible. Hydrogen sulfide decreases the rate of permeation substantially, and its effect is only partially eversed by replacing the gas with pure hydrogen. Preliminary measurements with Ta - 5 at % Pd membranes show that this alloy also has a substantial rate for permeation by hydrogen. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 15, 1966
- Accession Number
- AD0634547
Entities
People
- A. C. Makrides
- D. Jewett
- Micah Wright