粒度分布对碳化硅挤压成型流变性和坯体密度的影响

THE EFFECT OF PARTICLE DISTRIBUTION ON SILICON CARBIDE EXTRUSION PASTE'S RHEOLOGICAL PROPERTY AND GREEN BODY DENSITY

通过改变物料组分中碳化硅粉料颗粒度分布范围以及改变粒度的含量,研究了其对物料挤压成型流变性能以及挤出坯体密度的影响。研究结果表明:用粒度相近的粗颗粒碳化硅粉料在挤压成型时易发生液体的析出现象,物料表现出较高的模壁间滑移膜初始剪切应力和低的屈服强度,并且挤出坯体的密度相对较低。粒度分布较宽的含有细碳化硅的挤压物料具有高的屈服值和低的滑移膜初始剪切应力,使物料在模段内容易挤出,且挤出坯体的密度有较大幅度提高。另外,对导致挤压成型流变参数以及坯体密度变化的因素进行了讨论和分析。

The effect of silicon carbide particle distribution on extrusion paste＇s rheological property and green bodies＂ density were investigated by changing the volume fraction of different particles. The results indicate that drainage phenomenon easily occurred in silicon carbide paste forming with particles of near sizes, the paste had higher dieland wall shear stress and lower yield stress, and the density of green body was relatively lower. Otherwise, the pastes with wide particle distribution have higher yield stress, lower dieland wall shear stress, and higher green body density. In the end, the factors that caused the change of extrusion paste＇s rheological property and green bodies＂ density were analyzed.