制备用于凝胶注模成形的SiC/炭黑浆料,采用旋转黏度计和Zeta电位测量仪表征浆料的黏度及稳定性,研究聚乙烯吡咯烷酮(PVP)和浆料制备工艺参数对炭黑浆料分散性的影响,分析影响SiC/炭黑凝胶注模浆料黏度的主要因素。结果表明：PVP在炭黑颗粒表面的吸附可增大炭黑在水中的Zeta电位绝对值,同时提高炭黑颗粒之间的空间位阻斥力,从而改善炭黑颗粒在水中的分散。PVP在炭黑浆料中的最佳添加量为2.25 mg/m2,浆料的最佳球磨时间为9 h。在SiC粗细颗粒级配为2∶1,炭黑质量分数为6%,单体质量分数为15%的优化工艺条件下,得到黏度适中的高固相含量浆料,适应于凝胶注模成形。
SiC/carbon black paste for gel casting was prepared, the viscosity and stability of the paste were measured by rotary viscometer and Zeta potential measuring instrument. The effects of polyvinylpyrrolidone (PVP) and processing parameters on the dispersion of carbon black were studied, and the main factors affecting the viscosity of SiC/carbon black suspension for gel casting were analyzed. The results show that the adsorption of PVP on the surface of carbon black particles can increase the absolute value of the Zeta potential of carbon black in water, and also can increase the steric repulsion between carbon black particles, thus the dispersion of carbon black particles in water is improved. The optimal amount of PVP addition to the carbon black slurry is 2.25 mg/m2, and the proposed ball milling time of the slurry is 9 h. Under the optimized process conditions that the grading of coarse and fine silicon carbide particles is 2∶1, the mass fraction of carbon black is 6%, and the mass fraction of monomer is 15%, the viscosity of the slurry is moderate, and it is suitable for gel casting of slurry with high solid content.
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