The Research Of Electromagnetic Defence Composites Of Modified Cf/PET

With the population of electric products, the standard of people's living has improved, at the same time, radiation dangers people's health. Empoldering electrimagnetic defence materials is a needing orientation, although there are several kinds of electric or magnetic defence materials, the exactly needs aim at personal defence which is compound textile is rarely. Carbon fibres which have the advantages of high hardness, strength, toughness and low density are new kinds of materials, and are widely used in field defence materials.In the paper after being pretreated with alkalescence, and sensitized, activated, the surface of the textile has catalyzing properties. Make sure the apt temperature of the experiment, concentration and time in the technics. This paper introduces the process and mechanique of electroplating with nickel and coalt on carbon fiber, to the key point, that enhance the electhomagnetic properties of carbon fibres. The principle of plating and process of the technique are also introduced. By SEM and EDS analyses the microstructure of the product of carbon fibers coated by nickel and coalt.Carbon fibre was modified with electroless nickel and cobalt in different electroless solution. The behavior of modified carbon fibre is better defence function at C band of frequency than naked carbon fibre with PET composites. The results show that electromagnetic properties were affected by the difference of the relevant changes of conditions at the X band of frequency.In this paper, moreover, the effect of fabric distortion during fabrication of Cf/PET composites on the structure and mechanical properties of composites is investigated. The results show that the fiber which is not as the same density, fixed as original shape, is dispersed asymmetrically in composites, and this affects properties of Cf/PET composites, the difference of composites is high through fixed the fabric as original shape, and this is propitious to attain different effect of defence properties of the regular shape of composites with tin paper and an irregular ones. Compared with them, we can get a conclusion that the shape of composites affects the defence properties.Microwave defence properties of the composites containing parallel-arranged and orthogonal-arranged carbon fibers were investigated respectively. The mechanism of defence of carbon fibers and the factors affecting the defence properties were briefly discussed. The results show that the defence properties of the composites containing parallel-arranged carbon fibers which are affected by the way of arrangement and the lines of each bunch are good. The defence performances of the composites containing parallel and orthogonal-arranged carbon fibers are greatly affected by the space between fibers. In this research, the composite obtains a refraction loss below-30dB.Influence of the content of absorbent and the structure of circuit analogue on the mechanical properties was investigated. The results show that if the other design parameters are fixed in the resistance changing composite, with the increase of the size of CA (circuit analogue), the EM(electromagnetic) parameter and the thickness of the medium ply. Two premium designs were made to determine the two composite systems with circuit analogue with the best wave-defence properties and were verified through experiments. The mechanical properties testing results show that rational structural design improve the mechanical properties of the microwave-defence composite systems, and make the wave-defence and loading property integrative in microwave defence composite materials.Composited materials grain not only can have better defence effect but also can make material have better compatibility, thinner thickness, broader frequency band and so on. The test of electromagnetic defence effects proves that this fabric has good performances. This also demonstrates this film has special properties of material.