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Title: Smart oxygen diffusion barrier based on IrAl alloy

Abstract

Ir should be used as an effective oxygen diffusion barrier (ODB) for ultrahigh temperature structural materials since Ir exhibits extremely low oxygen diffusivity. Oxidation resistance of Ir is, however, not good due to formation of gaseous oxide, IrO{sub 3}, over 1,390K. In this study, the improvement of oxidation resistance was aimed through alloy design of alloying with Al. IrAl is expected to form a self-healing multifunctional layered structure composed of Ir layer as ODB and Al{sub 2}O{sub 2} layer as a protective oxide (PO) on the Ir layer. Ar arc-melted IrAl alloy was crushed into powder, followed by hot pressing and heat treatment to remove Ir formed by eutectic reaction. Oxidation behavior was measured using thermogravimetry (TG) and differential thermal analysis (DTA) under the conditions of (1) dynamic heating of 0.167K/s and (2) isotherms at 1,273K to 1,673K in O{sub 2} environment. It was found that oxidation resistance is much improved by alloying with Al and that the designed structure (PO/ODB) is formed on the IrAl substrate. Compressive mechanical properties were investigated from RT to 1873K: both the strength as a function of normalized temperature and specific strength are higher than those of pure Ir, NiAl, TiAl and Ni{sub 3}Al.more » IrAl is promising as an advanced smart coating material equipping good oxidation resistance as well as high temperature strength.« less

Authors:
; ;
Publication Date:
Research Org.:
Tohoku Univ., Sendai (JP)
OSTI Identifier:
20001662
Report Number(s):
CONF-981104-
ISBN 1-55899-458-0; ISSN 1067-9995; TRN: IM0001%%99
Resource Type:
Conference
Resource Relation:
Conference: High-Temperature Ordered Intermetallic Alloys VIII, Materials Research Society Symposium Proceedings, Boston, MA (US), 11/30/1998--12/03/1998; Other Information: PBD: 1999; Related Information: In: High-temperature ordered intermetallic alloys VIII. Materials Research Society symposium proceedings: Volume 552, by George, E.P.; Mills, M.J.; Yamaguchi, Masaharu [eds.], [600] pages.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPRESSION STRENGTH; OXIDATION; IRIDIUM ALLOYS; ALUMINIUM ALLOYS; INTERMETALLIC COMPOUNDS; THERMAL ANALYSIS; OXYGEN; TEMPERATURE DEPENDENCE; EXPERIMENTAL DATA

Citation Formats

Hosoda, Hideki, Watanabe, Sadao, and Hanada, Shuji. Smart oxygen diffusion barrier based on IrAl alloy. United States: N. p., 1999. Web.
Hosoda, Hideki, Watanabe, Sadao, & Hanada, Shuji. Smart oxygen diffusion barrier based on IrAl alloy. United States.
Hosoda, Hideki, Watanabe, Sadao, and Hanada, Shuji. 1999. "Smart oxygen diffusion barrier based on IrAl alloy". United States.
@article{osti_20001662,
title = {Smart oxygen diffusion barrier based on IrAl alloy},
author = {Hosoda, Hideki and Watanabe, Sadao and Hanada, Shuji},
abstractNote = {Ir should be used as an effective oxygen diffusion barrier (ODB) for ultrahigh temperature structural materials since Ir exhibits extremely low oxygen diffusivity. Oxidation resistance of Ir is, however, not good due to formation of gaseous oxide, IrO{sub 3}, over 1,390K. In this study, the improvement of oxidation resistance was aimed through alloy design of alloying with Al. IrAl is expected to form a self-healing multifunctional layered structure composed of Ir layer as ODB and Al{sub 2}O{sub 2} layer as a protective oxide (PO) on the Ir layer. Ar arc-melted IrAl alloy was crushed into powder, followed by hot pressing and heat treatment to remove Ir formed by eutectic reaction. Oxidation behavior was measured using thermogravimetry (TG) and differential thermal analysis (DTA) under the conditions of (1) dynamic heating of 0.167K/s and (2) isotherms at 1,273K to 1,673K in O{sub 2} environment. It was found that oxidation resistance is much improved by alloying with Al and that the designed structure (PO/ODB) is formed on the IrAl substrate. Compressive mechanical properties were investigated from RT to 1873K: both the strength as a function of normalized temperature and specific strength are higher than those of pure Ir, NiAl, TiAl and Ni{sub 3}Al. IrAl is promising as an advanced smart coating material equipping good oxidation resistance as well as high temperature strength.},
doi = {},
url = {https://www.osti.gov/biblio/20001662}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 01 00:00:00 EDT 1999},
month = {Thu Jul 01 00:00:00 EDT 1999}
}

Conference:
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