Oxidation Behavior of the Mullite/ZrO2/SiC Particle Composite

• Main Authors: Shen, Jyh-bin, 沈志濱
• Other Authors: Chao Long-Sun
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/75305514512638069173

碩士 === 國立成功大學 === 工程科學系 === 86 === 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.