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Oxidation of niobium particles embedded in a sintered ceramic matrix – a proposed model
Author(s) -
Tommaselli M. A. G.,
Mariano N. A.,
Kuri S. E.
Publication year - 2005
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200403807
Subject(s) - niobium , materials science , ceramic , thermogravimetric analysis , brittleness , kinetics , ceramic matrix composite , composite material , toughness , deformation (meteorology) , composite number , matrix (chemical analysis) , phase (matter) , metallurgy , chemical engineering , chemistry , physics , organic chemistry , quantum mechanics , engineering
Ceramics display superior properties of hardness, chemical stability and refractoriness. However, their brittleness often limits their application as engineering components. The addition of second‐phase 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.