固体碳源在碳化硅浆料中的分散

Dispersion of solid carbon sources in the slurry of silicon carbide

碳化硅固相烧结必须添加C、B烧结助剂,才能促进碳化硅的致密。而烧结助剂在碳化硅粉体中间的分散是影响碳化硅陶瓷结构是否均匀以及能否提高其力学性能的关键。本文研究3种固体碳源材料石油焦、碳黑和石墨粉末在固含量为15%的碳化硅浆料中的分散行为。用沉降实验数据比较无分散剂、加入分散剂焦磷酸钠或Darven C3种不同分散条件下,固体碳源粉体的分散性。实验结果表明:分散剂的加入对SiC浆料分散效果有很大影响,3种碳源中碳黑分散最好;最佳分散组合为碳黑加入Darven.C。

Sintering aids C or B must be added in the process of solid phase sintering of silicon carbide in order to promote the densification of silicon carbide. And the dispersion of sintefing aid in the slurry of silicon carbide is the key to uniformize the structure of silicon carbide ceramics and enhance its mechanical property. Recent research is focused on the dispersion of three kinds of solid carbon sources, i.e. petrol coke, black carbon and powdered graphite, in the aqueous slurry of SiC. The solid content（mass fraction） of the slurry is 15 percent. The results of the sedimentation experiments is used to compare the dispersity of the solid carbon sources on three dispersion conditions. Those are： no dispersing agent added; sodium pyrophosphate aqueous solution; Darven C aqueous solution. The result shows that the presence of dispersing agent has great influence on the dispersing effect of the SiC slurry. Black carbon showed best effect in the three kinds of carbon sources. And the combination of black carbon and Darven C turns out to be the best.