SiC粉体作为一种高性能粉体，其高硬度、高强度、耐腐蚀、耐高温等被更多业内人士所认可；其中超细βSiC 粉体更具有优异、潜在的应用价值。然而由于超细βSiC 粉体易团聚，分散性、流动性、以及与其它介质的相容性差等缺陷，制约了其应用,因此本文就如何解决这些问题进行研究。 本文以粉体流动性综合指数为指标分别研究了不同表面改性剂及其添加量对超细β-SiC粉体表面改性效果的影响。实验结果表明：采用聚乙烯亚胺为改性剂、改性剂添加量为3wt%、反应时间5h时，改性粉体流动性较好，其休止角从54.56°减小到47.94，压缩度从49.19%减小到44.88%，综合流动指数从45提高到52，其素坯的密度从1.74 g/cm3提高到1.87g/cm3；采用聚乙烯亚胺改性并结合喷雾造粒工艺的方法，可以使粉体的休止角降低到到26.2°，压缩度降低到12.53%，综合性流动指数提高到92，流动性评价指数为最好。 本文先采用偶联剂对超细βSiC 粉体进行预处理，然后在其表面进行丙烯酰胺单体接枝聚合，确定了预处理的最佳工艺参数分别为：温度95℃、反应时间4h、偶联剂添加量10wt%；确定了接枝聚合改性的最佳工艺参数分别为：聚合温度85℃、聚合时间5h、单体添加量3wt%、引发剂添加量0.3g。通过对比润湿性、粒度分布、沉降性和休止角等讨论了改性βSiC 粉体的性能。并采用红外光谱、X-ray衍射等测试技术分析了改性前后βSiC 超细粉体表面物质的化学组成和结构特征，证实有机单体在β-SiC粉体表面形成接枝聚合包覆层。研究了改性前后超细βSiC 粉体的分散稳定性和沉降性，确定了改性β-SiC粉体在PH=10～12时可以获得较大的Zeta电位，由原来的42mv提高到52.5mv。并且沉降24h后，改性β-SiC粉体在液相介质中的沉降率由原来的93.2%降低到6%。改性β-SiC粉体的润湿性和分散稳定性均得到较大的改善。

SiC is a kind of high-performance powder, its high hardness, high strength, corrosion resistance, high temperature were recognized by more people in the industry; β-SiC ultra-fine powder which has more potential applications. However, β-SiC ultra-fine powder easily reunion, dispersion, mobility, and compatibility with other media, the poor, limiting the scope of its application. So this article to study how to resolve these issues. This article with powder flow index as an indicator studied the influence of different surface modifiers and its different amount on surface modification effect of β-SiC ultra-fine powder. The experimental results indicated that When the PEI is modifier 、the modifier amount is 3% weight of β-SiC ultra-fine power and the reaction time is 5h，the modified power has better flow characteristics. The Repose angle of β-SiC ultra-fine power is reduced to 47.94 from 54.56 °，the compression level decreases from 49.19% to 44.88%, integrated flow index increased from 45 to 52, the density of the green body increased from 1.74 g/cm3 to 1.87g/cm3. And the method combined PEI modification and pray granulation process modification make the powder repose angle reduced to 26.2 °, compression reduced to 12.53%, integrated flow index increased to 92. Evaluation of modified β-SiC powder flow index is the best! This article first adpot coupling agent pretreatment on β-SiC ultra fine powder, thenacrylamide monomer graft polymerization on its surface. Respectivly determine the optimal pretreatment parameters : temperature is 95 ℃, reaction time is 4h, coupling agent addition is 10wt%and determine the optimal graft modification parameters : reaction temperature is 85 ℃, reaction time is 5h, monomer content is 3wt%, the amount of initiator added is 0.3g. The performance of modified β-SiC ultra-fine powder were analyzed by comparing the wetting,particle size distribution, sedimentation and angle of repose etc…The chemicalcompositions and structure on the surface of β-SiC ultra-fine powder before and after modified were characterized through the Fourier Transformation Infrared and X-ray etc…And confirmed that the organic monomer formed graft polymerization coating on the surface of β-SiC powder. The dispersion stability and sedimentation ofβ-SiC ultra-fine powder before and after modification were researched. The modified power can acquire larger Zeta potential when PH=10~ 12,and the Zeta potential improved from the original 42mv to 52.5mv. And 24h after settlement, the sedimentation rate of the modified β-SiC powders in liquid media decreased from the origina 93.2% to 6%.The wetting and dispersion stability of modified β-SiC powder in liquid media were greatly improved.