分散剂用量对碳化硅浆料流变性能的影响

EFFECT OF DISPERSANT CONCENTRATION ON RHEOLOGICAL BEHAVIOR OF SiC AQUEOUS SUSPENSION

使用四甲基氢氧化铵(TMAH)作为分散剂,研究了分散剂用量对SiC浆料流变性能的影响,并分析了其原因。结果表明:TMAH能够显著提高SiC粉体的zeta电位,降低浆料粘度,从而显著优化浆料的流变性能。在pH为10左右,加入质量分数为0.3%和0.6%的TMAH后zeta电位分别提高了11.7mV和21mV。实验中,在不同体积分数SiC浆料中,加入0.6%TMAH时能够达到最优性能,浆料粘度都达到最低。过量的分散剂则会增加浆料中的离子浓度而导致双电层厚度减小,从而恶化浆料的流变性。

Using tetramethyl ammonium hydroxide (TMAH) as dispersant for SiC aqueous suspension, the effects of dispersant concentration and pH value on the rheological behavior of SiC aqueous suspension were studied. The results show that TMAH can improve dispersion by increasing the negative zeta potential of SiC particles and decrease the viscosity of SiC aqueous suspension. At pH value of 10, the absolute value of zeta potential with adding 0.3% and 0.6% (in mass fraction) dispersant increases to 11.7 mV and 22 mV, respectively. The suspension with 0.6% dispersant addition has the lowest viscosity at different solid loadings. The recommended amount of TMAH is 0.6% in order to obtain the minimum viscosity and the maximum negative zeta potential. Excessive dispersant will increase the ionic concentration in suspension and reduce the thickness of double electrical layer. The optimum dispersion occurs at the value of pH 10. The dispersion mechanism by TMAH is discussed.