Materials Sciences and Applications

Volume 8, Issue 8 (August 2017)

ISSN Print: 2153-117X   ISSN Online: 2153-1188

Google-based Impact Factor: 0.97  Citations  

CVD Treatment of Carbon Fibers and Evaluation of Their Dispersion in CFRC

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DOI: 10.4236/msa.2017.88046    1,034 Downloads   2,183 Views  Citations

ABSTRACT

Carbon-fiber-reinforced cement-based (CFRC) composites is a promising functional material which can be used both in the military and civil fields against electromagnetic interference. However, it is essential to make carbon fibers dispersed uniformly during the preparation of CFRC. In this work, short carbon fibers were treated through Chemical Vapor Deposition (CVD) process at high temperature between 900°C and 1200°C under the protection of diluted nitrogen gas N2 to modify the surface of carbon fibers to further strengthen the bonding between carbon fibers and cement matrix. Natural gas (98% CH4) was used as a precursor. It was decomposed to produce an uneven layer of pyrocarbon that was deposited on the surface of carbon fibers. CVD-treated carbon fibers were pre-dispersed by using ultrasonic wave. Both hydroxyethyl cellulose (HEC) and silicon fume were used as dispersants and as admixtures. They helped CVD-treated carbon fibers distribute uniformly. The mass fraction of HEC was around 1.78% in the aqueous solution. Four methods, namely, the simulation experiment (SE) method, the scanning electron microscopy (SEM) method, the fresh mixture (FM) method, and the electrical resistivity measurement (ERM) method were, respectively, applied to evaluate fiber dispersion degree. Each method indicated its own advantages and disadvantages and it therefore catered for different conditions. Of the four evaluation methods, the SE method was the most convenient way to determine the pre-dispersion state prior to the preparation of CFRC composites. This method was helpful for predicting the subsequent dispersion state of carbon fibers in the cement matrix because it economized a large quantity of raw materials and time.

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Wang, C. , Li, B. , Peng, L. , He, W. , Zhao, L. and Li, K. (2017) CVD Treatment of Carbon Fibers and Evaluation of Their Dispersion in CFRC. Materials Sciences and Applications, 8, 649-661. doi: 10.4236/msa.2017.88046.

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