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Effect of Mo microstructure on the critical volume fraction for conduction in Mo-alumina cermets

Published online by Cambridge University Press:  31 January 2011

J. F. Kelso ,
R. R. Higgins  and
F. J. Krivda
J. F. Kelso
Affiliation:
Alcoa Technical Center, Alcoa Center, Pennsylvania 15069
R. R. Higgins
Affiliation:
Alcoa Technical Center, Alcoa Center, Pennsylvania 15069
F. J. Krivda
Affiliation:
Alcoa Technical Center, Alcoa Center, Pennsylvania 15069
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Abstract

The microstructure of Mo in an alumina/frit matrix was found to be dependent on the initial particle sizes of the alumina and Mo powders, the glass content in the matrix ceramic, and the amount of moisture in the firing atmosphere. The Mo microstructure had a significant influence on the critical volume fraction for conductivity in these cermets. Coarser alumina powder, finer Mo powder, and higher glass content promoted coalescence of Mo into conductive networks at lower metal contents. Drier firing atmospheres produced a more coarsened Mo microstructure with a slight decrease in the amount of network contiguity, causing an increase in the amount required for electrical percolation.

Type
Articles
Information
Journal of Materials Research , Volume 12 , Issue 3 , March 1997 , pp. 738 - 744
Copyright
Copyright © Materials Research Society 1997

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