Tailored Resistance Carbon Fiber

The addition of 0.53 1.1 % v/v short (5 mm) isotropic pitch carbon fiber in mortar applied to steel reinforced concrete decreased the contact resistivity and volume resistivity of the new mortar, enabling a satisfactory electrical contact material to be made for the cathodic protection of steel reinforced old mortar or concrete [44]. 

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SiC whiskers. The particulates or whiskers were uniformly distributed among the carbon fibers and preforms prepared from the treated fibers were directly infiltrated by molten A1 under applied stress. It was found that the longitudinal tensile strengths of hybrid composites were greatly improved, although their fiber volume fractions were quite low compared to those of conventional composites. With this hybridization method, it is also practical to tailor the fiber volume fraction of composites from 60 to 25 vol%, which is not possible in direct infiltration of fiber preforms by pressure easting. The results obtained lead to the conclusion that particulate or whisker additions do not act directly as reinforcements, but as promoters to improve the infiltration performances of fiber preforms and consequently, increase the strength transfer efficiency of carbon fibers. The addition of particulates or whiskers can also improve other properties of the composites, such as hardness and wear resistance. 

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