ICVI法制备Si3N4P/ Si3N4 复合材料致密化行为数值模拟

根据Si₃N₄ 颗粒增强体的结构特点及等温化学气相法( ICVI) 的工艺特点, 对Si₃N₄ 颗粒增强Si₃N₄ 复合材料的致密化过程进行了数值模拟。用球形孔隙模型表征Si₃N₄ 颗粒增强体的结构特征, 用传质连续方程表征先驱体在预制体中的浓度分布。为了检验模型的准确性和适用性, 进行了相应的实验验证。模拟结果与实验结果具有相似的致密化规律, 预测的渗透时间和孔隙率与实验结果均十分接近, 表明本文中建立的数学模型可以较好地表征Si₃N₄P / Si₃N₄ 复合材料的ICVI 过程。

Numerical simulation for ICVI process of Si3N4P/Si3N4 composites

A mathematical model according to structural feature of Si_3N_4 particle reinforcement and process characteristic of isothermal chemical vapor infiltration(ICVI) was proposed to numerically simulate the densification behaviors of Si_3N_4 particle reinforced Si_3N_(4)composites.The(ball-like) pore model is developed to depict the structure of Si_3N_4 particle reinforcement and the mass transfer equation of reagents is used to characterize the concentration profile in the preform.The corresponding experiment was done in order to testify the mathematical model.The calculated results represent the same densification regularity as the experimental data does,and the curves of calculated infiltration time and porosity are in agreement with the experimental ones,which indicates that the model developed here is reasonable to characterize the ICVI process of Si_3N_(4P)/Si_3N_(4)composites.