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Oxidation of niobium particles embedded in a sintered ceramic matrix – a proposed model

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

Publisher
John Wiley and Sons
Year
2005
Tongue
German
Weight
172 KB
Volume
56
Category
Article
ISSN
0947-5117

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✦ Synopsis

Ceramics display superior properties of hardness, chemical stability and refractoriness. However, their brittleness often limits their application as engineering components. The addition of secondphase inclusions that influence crack propagation has been exhaustively studied. One of the main toughness enhancement theories proposes it is caused by the plastic deformation of ductile inclusions during crack propagation. This article proposes a model to explain the oxidation mechanisms of niobium particles embedded in an Al 2 O 3 matrix, based on a thermogravimetric analysis. Two types of oxidation kinetics are identified here: linear and parabolic kinetics, with activation energies of 12.4 kJ/mol and 24.9 kJ/mol, respectively. Based on our results, a kinetic model is proposed to describe the oxidation of niobium particles embedded in alumina ceramic composite matrix.

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