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Title: Oxidation behaviors of porous Haynes 214 alloy at high temperatures

The oxidation behaviors of porous Haynes 214 alloy at temperatures from 850 to 1000 °C were investigated. The porous alloys before and after the oxidation were examined by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) analyses, and X-ray photoelectron spectroscopy (XPS). The oxidation kinetics of the porous alloy approximately follows a parabolic rate law and exhibits two stages controlled by different oxidation courses. Complex oxide scales composed of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Al{sub 2}O{sub 3} are formed on the oxidized porous alloys, and the formation of Cr{sub 2}O{sub 3} on its outer layer is promoted with the oxidation proceeding. The rough surface as well as the micropores in the microstructures of the porous alloy caused by the manufacturing process provides fast diffusion paths for oxygen so as to affect the formation of the oxide layers. Both the maximum pore size and the permeability of the porous alloys decrease with the increase of oxidation temperature and exposure time, which may limit its applications. - Highlights: • Two-stage oxidation kinetics controlled by different oxidation courses is showed. • Oxide scale mainly consists of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Al{sub 2}O{submore » 3}. • Rough surface and micropores lead to the formation of uneven oxide structure. • Content of Cr{sub 2}O{sub 3} in the outer layer of the scale increases with time at 1000 °C. • Maximum pore size and permeability decrease with increasing temperature and time.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China)
  2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)
  3. State Key Laboratory of Porous Metals Materials, Northwest Institute for Nonferrous Metal Research, Xi'an 710016 (China)
  4. Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)
Publication Date:
OSTI Identifier:
22476172
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 107; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM OXIDES; CHROMATES; CHROMIUM OXIDES; DIFFUSION; HAYNES ALLOYS; LAYERS; MICROSTRUCTURE; OXIDATION; OXYGEN; PERMEABILITY; POROUS MATERIALS; SCANNING ELECTRON MICROSCOPY; SURFACES; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY