"Formation of Structural Intermetallics by Reactive Metal Penetration o" by William Fahrenholtz, Kevin G. Ewsuk et al.
 

Formation of Structural Intermetallics by Reactive Metal Penetration of Ti and Ni Oxides and Aluminates

Abstract

Alumina-aluminum composites can be prepared by reactive metal penetration (RMP) of mullite by aluminum. The process is driven by a strong negative free energy for the reaction (8 +x)Al + 3Al6Si2013 → 13Al2O3 + 6Si + xAl. Thermodynamic calculations reveal that titanium oxide, aluminum titanate, nickel oxide, and nickel aluminate all have a negative free energy of reaction with aluminum from 298 to 1800 K, indicating that it may be possible to form alumina-intermetallic composites by reactions of the type (2 +x)Al + (3/y) MOy → Al2O3 + AlxM3/y. Experiments revealed that aluminum reacts with titanium oxide, nickel oxide, and nickel aluminate, but not aluminum titanate, at 1673 K. Reaction with the stoichiometric amount of aluminum (x = 0) leads to the formation of alumina and either titanium or nickel. In some cases, reactions with excess aluminum (x > 0) produce intermetallic compounds such as TiAl3 and NiAl.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Physical Chemistry; Materials Science; Structural Materials; Metallic Materials; Ceramics; Glass; Composites; Natural Methods

International Standard Serial Number (ISSN)

1073-5623

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1996 Springer Verlag, All rights reserved.

Publication Date

01 Aug 1996

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