采用KH-550硅烷偶联剂对SiC粉体进行表面改性,通过单因素实验及正交试验确定出改性过程最优化工艺参数：反应温度90℃,反应时间4h,KH-550硅烷偶联剂用量1.5g,并通过扫描电镜、X射线衍射仪、红外光谱仪、激光粒度分析仪对制备的改性粉体进行表征,分析改性对SiC料浆分散稳定性的影响。结果表明,SiC微粉经偶联剂处理后没有改变原始SiC微粉的物相结构,只是改变了其在水中的胶体性质;中位径d_0.5略有减小,粒度分度分布范围变窄,扫描电子显微镜(SEM)显示微粉团聚现象减少,分散性得到改善;改性SiC微粉与原始SiC微粉相比,表面特性发生了很大变化,在酸性条件下Zeta电位有显著的提高,pH值为3.78时,Zeta电位获得最高正电位为41mV,悬浮液的分散稳定性得到明显改善。

The surface modification of SiC powder with KH-550 aminoorganosilanes was carried out and the optimum process parameters of modification were pointed out by using single factor experiments and orthogonal experiments. The optimum reaction temperature is 90℃, the optimum reaction time is 4h, and the optimum KH-550 concentration is 1.5g. Modified powders are characterized by using scanning electron microscopy, X-ray diffraction, infrared spectroscopy, and laser particle size analyzer. The effect of surface modification on the dispersion stabilization of SiC slurry is also analyzed. The results show that the SiC powder treated by aminoorganosilanes does not change the phase structure of original SiC; it only changes the colloidal properties in water. d_0.5 decreases slightly and particle size distribution narrows down. SEM shows that powder agglomeration is reduced and dispersion property is improved for SiC powder. Comparing with the original SiC powder, the surface characteristics of modified SiC powder occur a great change and Zeta potential increases from 17.58mV to 41mV(with pH=3.78). The dispersion stabilization of SiC slurry is remarkably increased.