Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/15757

TitleVacuum infiltration of copper aluminate by liquid aluminium
Author(s)Guedes, M.
Ferreira, J. M. F.
Rocha, L. A.
Ferro, A. C.
KeywordsComposites
Microstructure-final
Spinels
Reactive aluminium infiltration
B. Composites
B. Microstructure-final
D. Spinels
Issue date2011
PublisherElsevier Sci Ltd
JournalCeramics International
CitationGuedes, M., Ferreira, J. M. F., Rocha, L. A., & Ferro, A. C. (2011). Vacuum infiltration of copper aluminate by liquid aluminium. Ceramics International, 37(8), 3631-3635. doi: http://dx.doi.org/10.1016/j.ceramint.2011.06.022
Abstract(s)This paper studies attained microstructures and reactive mechanisms involved in vacuum infiltration of copper aluminate preforms with liquid aluminium. At high temperatures, under vacuum, the inherent alumina film enveloping the metal is overcome, and aluminium is expected to reduce copper aluminate, rendering alumina and copper. Under this approach, copper aluminate toils as a controlled infiltration path for aluminium, resulting in reactive wetting and infiltration of the preforms. Ceramic preforms containing a mixture of Al2O3 and CuAl2O4 were infiltrated with aluminium under distinct vacuum levels and temperatures, and the resulting reaction and infiltration behaviour is discussed. Copper aluminates stability ranges depend on vacuum level and oxygen partial pressure, which determine both CuAl2O4 and CuAlO2 ability for liquid aluminium infiltration. At 1100 °C and 0.76 atm vacuum level CuAl2O4 is stable, indicating pO2 above 0.11 atm. Reactive infiltration is achieved via reaction between aluminium and CuAl2O4; however, fast formation of an alumina film blocking liquid aluminium wicking results in incipient infiltration. At 1000 °C and 3.8 × 10−7 atm vacuum level, CuAlO2 decomposes to Cu and Al2O3 indicating a pO2 below 6.0 × 10−7 atm; infiltration of the ceramic is hindered by the non-wetting behaviour of the resulting metal alloy. At 1000 °C and 1.9 × 10−6 atm vacuum level CuAlO2 is stable, indicating pO2 above 6.0 × 10−7 atm. Extensive infiltration is achieved via redox reaction between aluminium and CuAlO2, rendering a microstructure characterised by uniform distribution of alumina particles amid an aluminium matrix. This work evidences that liquid aluminium infiltration upon copper aluminate-rich preforms is a feasible route to produce Al–matrix alumina-reinforced composites. The associated reduction reaction renders alumina, as fine particulate composite reinforcements, and copper, which dissolves in liquid aluminium contributing as a matrix strengthener.
TypeArticle
URIhttp://hdl.handle.net/1822/15757
DOI10.1016/j.ceramint.2011.06.022
ISSN0272-8842
Other identifiers0272-8842
AccessOpen access
Appears in Collections:CT2M - Artigos em revistas nacionais com arbitragem científica

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