微米碳化硅晶须在水介质中的分散行为

Dispersion Behavior of SiC Micro Whiskers in Aqueous Medium

以去离子水为分散介质,六偏磷酸钠(SHP)和羧甲基纤维素钠(CMC)为分散剂,利用沉降法、ζ电位、傅里叶变换红外光谱(FTIR)、TEM等测试技术研究了微米碳化硅晶须在水介质中的分散稳定机制,探讨了pH值、分散剂种类及含量对SiC微米晶须分散行为的影响机制。结果表明:微米SiC晶须的分散机理为静电稳定机制,pH值、SHP和CMC对微米SiC晶须的分散性和稳定性有较大影响;pH值为11时,微米SiC晶须的分散性和稳定性较好;SHP和CMC含量均为4wt%时,SiC微米晶须悬浮液具有良好的分散性能,分别在沉降时间18.5 h和22 h时相对沉降高度仍达96.89%和98%。六偏磷酸钠的分散机制主要以提高颗粒间的静电斥力为主,而羧甲基纤维素钠则为增大晶须表面的亲水性和提高晶须表面的电位绝对值。

With deionized water as dispersion medium, as well as sodium hexametaphsphate （SHP） and sodium carboxymethyl cellulose （CMC） as dispersants, the dispersion and stabilization mechanisms of SiC micron whiskers aqueous suspension were studied by sedimentation test, （ potential, FTIR, SEM and TEM. The effect of pH value, the kinds and contents of dispersants was discussed. The results showed that the dispersion behavior ofSiC micron whiskers followed the mechanism of electrostatic stabilization to some extent. The dispersibility and stability of SiC micron whiskers were strongly influenced by pH value, SHP and CMC. The best dispersion was obtained when pH value was 1l. When the content of both SHP and CMC was 4wt%, SiC micro whiskers can be dispersed effectively, and the relative sedimentation heights of them were 96.89% and 98% at the time of 18.5 h and 22 h respectively. However, the dispersion mechanisms of SHP and CMC were different. The main mechanism of SHP is improving the static electricity among whiskers, whereas the dispersion modes of CMC are increasing the hydrophilicity and ~ potential of SiC micro whiskers.