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The purpose of this study is to investigate two basic modes of
oxidation behavior of the Mullite/ZrO2/SiC particle composite.
In Mode I, the diffusivity of oxygen in matrix is much less than
that of silica layer, but in Mode II, the diffusivity in matrix
is much larger than in silica. In the paper, one and two-
dimensional models were built to study the problem by assuming
only one SiC particle in different depth (sphereical model),
including matrix and SiC particle(Centreline model, Two-
dimensional model).The models were solved by finite difference
method. From the computational results, it can be found that
when the oxidation time increases or the depth decreases, the
concentration of oxygen increase and so does the thickness of
silica layer. In Centreline model, the slope of concentration
curve of oxygen in matrix is obviously different to that in SiC
particle. If the oxidation time is kept constant, the oxidation
depth of Mode I is smaller than that of Mode II,but the Mode I
has the larger gradient of silica layer versus depth. From the
Two-dimensional model results, can help to understand the oxygen
distribution in whole composite. The distribution of
concentration curve of oxygen is obviously different in this two
basic Modes and so does in complete oxidate particles and
incomplete oxidate particles. The trend of silica layer versus
depth is the same to that in the One-dimensional models.
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