PdAgAu alloy with high resistance to corrosion by H2S
- Inst. de Investigaciones en Catalisis y Petroquimica, Santa Fe (Argentina)
- Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering; National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
- Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering
PdAgAu alloy films were prepared on porous stainless steel supports by sequential electroless deposition. Two specific compositions, Pd83Ag2Au15 and Pd74Ag14Au12, were studied for their sulfur tolerance. The alloys and a reference Pd foil were exposed to 1000 H2S /H2 at 623 K for periods of 3 and 30 hours. The microstructure, morphology and bulk composition of both nonexposed and H2S-exposed samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). XRD and SEM analysis revealed time-dependent growth of a bulk Pd{sub 4}S phase on the Pd foil during H2S exposure. In contrast, the PdAgAu ternary alloys displayed the same FCC structure before and after H2S exposure. In agreement with the XRD and SEM results, sulfur was not detected in the bulk of either ternary alloy samples by EDS, even after 30 hours of H2S exposure. X-ray photoelectron spectroscopy (XPS) depth profiles were acquired for both PdAgAu alloys after 3 and 30 hours of exposure to characterize sulfur contamination near their surfaces. Very low S 2p and S 2s XPS signals were observed at the top-surfaces of the PdAgAu alloys, and those signals disappeared before the etch depth reached ~ 10 nm, even for samples exposed to H2S for 30 hours. The depth profile analyses also revealed silver and gold segregation to the surface of the alloys; preferential location of Au on the alloys surface may be related to their resistance to bulk sulfide formation. In preliminary tests, a PdAgAu alloy membrane displayed higher initial H{sub 2} permeability than a similarly prepared pure Pd sample and, consistent with resistance to bulk sulfide formation, lower permeability loss in H2S than pure Pd.
- Research Organization:
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- DOE Contract Number:
- FE0004000
- OSTI ID:
- 1129477
- Report Number(s):
- A-UNIV-PUB--020
- Journal Information:
- International Journal of Hydrogen Energy, Journal Name: International Journal of Hydrogen Energy Journal Issue: 23 Vol. 37; ISSN 0360-3199
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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