Title

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

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1996 Springer Verlag, All rights reserved.

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