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Phase diagram and electrical behavior of silicon-rich iridium silicide compoundsThe iridium-silicon phase diagram on the silicon-rich side was investigated by means of X-ray powder diffraction, density, differential thermal analysis, metalography, microprobe analysis, and electrical resistivity. Attempts were made to prepare eight previously reported silicon-rich iridium silicide compounds by arc melting and Bridgman-like growth. However, microprobe analysis identified only four distinct compositions: IrSi, Ir3Si4, Ir3Si5 and IrSi sub about 3. The existence of Ir4Si5 could not be confirmed in this study, even though the crystal structure has been previously reported. Differential thermal analysis (DTA) in conjunction with X-ray powder diffraction confirm polymorphism in IrSi sub about 3, determined to have orthorhombic and monoclinic unit cells in the high and low temperature forms. A eutectic composition alloy of 83 +/- 1 atomic percent silicon was observed between IrSi sub about 3 and silicon. Ir3Si4 exhibits distinct metallic behavior while Ir3Si5 is semiconducting. Both and IrSi and IrSi sub about 3 exhibit nearly temperature independent electrical resistivities on the order of 5-10 x 10 exp -6 ohms-m.
Document ID
19930042034
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Allevato, C. E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Vining, Cronin B.
(JPL Pasadena, CA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: IECEC '92; Proceedings of the 27th Intersociety Energy Conversion Engineering Conference, San Diego, CA, Aug. 3-7, 1992. Vol. 3 (A93-25851 09-44)
Publisher: Society of Automotive Engineers, Inc.
Subject Category
Solid-State Physics
Accession Number
93A26031
Distribution Limits
Public
Copyright
Other

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