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Oxidation of niobium particles embedded in a sintered ceramic matrix

✍ Scribed by M. A. G. Tommaselli; N. A. Mariano; E. M. J. A. Pallone; S. E. Kuri

Publisher
John Wiley and Sons
Year
2004
Tongue
German
Weight
219 KB
Volume
55
Category
Article
ISSN
0947-5117

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✦ Synopsis

The toughness of ceramic materials can be improved through the inclusion of metallic particles in the ceramic matrix. The plastic deformation of the particles limits the rupture of the ceramic matrix. Al 2 O 3 -Nb composites show the ability of niobium to form a strong bond with Al 2 O 3 , but the poor resistance to oxidation of niobium hinders the use of niobium for high temperature applications. The study of the oxidation mechanism was done using thermogravi-metric analysis under an oxygen atmosphere in order to obtain the oxidation reaction rate constants of the Al 2 O 3 -Nb composite. At the beginning the oxidation kinetics are linear, probably due to a great availability of oxygen. Later on, the oxidation mechanism showed to be parabolic, indicating that the process depends on the oxygen diffusion through the ceramic matrix.

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