CVI treatment of short carbon fibers and their dispersion in CFRC

The carbon fibers were treated by chemical vapor infiltration (CVI) technology and they were pre-dispersed with the aid of ultrasonic vibration. Both a new dispersant hydroxyethyl cellulose (HEC) and silicon fume were adopted to disperse the carbon fibers in the cement matrix. The fracture surface of CFRC was observed by using SEM to show the dispersion of carbon fibers. The variation coefficient of the mass of separate carbon fibers was applied to evaluate the dispersion of carbon fibers in CFRC. The results show that prior to the adding of dispersants, both CVI surface treatment and pre-dispersion of carbon fibers were helpful for improving the dispersion of carbon fibers. Different mass fractions of HEC and silicon fume in the cement improve the dispersion apparently, which increases with the increasing amount of HEC. The variation coefficient is a minimum when the contents of HEC and silicon fume are 0.6% and 10% in the mixture respectively, at which the dispersion of the carbon fibers is most ideal.