通过硅烷偶联剂处理以及丙烯酰胺单体在其颗粒表面上的接枝聚合对 Si C微粉进行表面改性 ,获得了在酸碱条件下均可水基稳定分散的有机包覆改性 Si C粉体 ,制备出固相体积分数≥ 5 0 %、表观粘度在 1Pa· s以下、稳定性好的Si C料浆。以 FTIR光谱、离子电导率、Zeta电位的测试结果来表征改性前后粉体表面物质的化学组成和 Si C颗粒的胶体行为 ,以料浆粘度和流动特性来表征改性对 Si C粉体分散性的影响 ,从而进一步分析有机包覆改性 Si C粉体水基分散的稳定机制。结果表明 :聚丙烯酰胺高分子链产生的空间位阻和 Si C颗粒表面的静电效应是料浆稳定分散的重要原因。

Study on Aqueous Dispersing and Stabilizing Mechanism of the Modified SiC Powder Prepared by Organics Coating LI Mei juan,WU Qi de,JI Xiao li,GUO Bing jian (Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education,WUT,Wuhan 430070,China)The surface modified silicon carbide (SiC) fine powder was prepared by organics coating through silane coupling agent linkage and organo monomer graft polymerization on its surface. In either acid or alkaline condition, the powder could be dispersed in aqueous media. Stable and concentrated SiC slurry with solids loading more than 50% volume fraction, apparent viscosity lower than 1 Pa·s could be prepared by the modified SiC powder. The chemical compositions and structure on SiC particle surface and the particle′s colloidal behaviors were characterized through the information of Fourier transformation infrared (FTIR) spectrum, ion conductivity and Zeta potential; and the effects of surface modification on the dispersity of SiC powders was characterized by viscosity and rheological properties of its suspensions. The result indicated that, steric effect brought by polymeric chains of poly acrylamide and electrostatic effect of SiC particles were the most important factors influencing the suspensions′ dispersion and stabilization.SiC; organic coating; aqueous dispersion; concentrated suspension