According to the carbon fiber material , carbon fiber cloth can be divided into: PAN based carbon fiber cloth, rayon based carbon fiber cloth and pitch based carbon fiber cloth, wherein PAN based carbon fiber cloth accounted for more than 90% of the market, so we talk about PAN based carbon fiber cloth mainly.

　　In accordance with the specifications of carbon fiber cloth, it can be divided into: 1K carbon fiber cloth, 3K carbon fiber cloth, 6K carbon fiber cloth, 12K carbon fiber cloth, 24K and above large tow carbon fiber cloth, the number of single carbon fiber tow, 1K=1000 (root), 3K=3000 (root), 6K=6000 (root), 12K=12000 (root).

　　Carbon fiber cloth according to the woven pattern, it can be divided into: plain weave, twill, satin, the former two are the most common.

　　The plain carbon fiber cloth, the characteristics of plain weave is the warp and the weft up and down according to the rule of interleaving. The plain fabric density can not be too high, relatively thin, good wear resistance, good air permeability, and it is opposite the same cloth uniform. The fiber bundle of the carbon fiber cloth has been in a state of ups and downs, the bending point of the fiber is more, and the elongation at break is higher in the process of drawing.

　　The twill carbon fiber cloth , the twill weave fabric has the diagonal lines with a certain angle with the fiber arrangement direction, the ridge orientation does not exist on the fiber bundle, but because fiber warp knitting, warp or weft fibers over two zonal or meridional fibers in knitting. This kind of diagonal appearance has a very strong sense of three-dimensional, it is used to make car modification products, such as panels, hood, exhaust tube, etc.

　　The satin carbon fiber cloth, the satin weave has separate, discrete by interlacing points (or weft intersection points) evenly distributed regularly in the organization in circulation, this form is called satin weave. This kind of weaving structure makes the fabric density higher, so the fiber cloth is more thick. This satin cloth surface is smooth, even, soft, shiny or slightly lower than the strength of grain, plain and twill.

　　Carbon carbon composite material is reinforced by carbon fiber and matrix carbon,and the quality of the carbon fiber is the key point to the carbon carbon composite material. And the most important process of the carbon fiber graphitization is the graphitization equipment and the high temperature treating technology.

　　Carbon fiber is a fibrous carbon materials, has high specific strength, high specific modulus, high temperature resistance, ablation resistance, fatigue resistance, creep resistance, electrical and thermal conductivity, low density and thermal expansion coefficient and other a series of excellent properties, is advanced composite structures are the most important reinforcing material, is widely used in spacecraft, spacecraft, satellites, military and high-end sports activities.

　　The industrial production of carbon fiber raw materials mainly asphalt fiber and viscose and polyacrylonitrile (Pan) three categories, a variety of different raw materials, after spinning, oxidation, carbonization and surface treatment processes were prepared various properties of carbon fiber.

　　Graphite fiber is made from carbon fiber under the protection of inert gas at 2000 to 3000 C. In the process of graphite, carbon fiber can be further removed about 5% of the non carbon elements, while the graphite structure of carbon atoms arranged in the micro level by the two-dimensional graphite structure to the three-dimensional structure of the orderly transformation

　　Compared with other materials, graphite fiber has a low mass and high elastic modulus. As a high performance structural composites reinforced materials with wide application prospect, but because of the high cost of production, the applications in commercial and industrial areas are seriously restricted. It is mainly used for aerospace industry and military industry and small batch, variety.

　　In order to expand the field of commercial application of graphite fiber, we must find ways to reduce manufacturing costs. During the stage of graphite, it is mainly to reduce the energy consumption of the universal tubular graphite furnace heat treatment equipment, and to improve its thermal efficiency and service life.

　　In July 2012, scientists at the Keel University and the University of Hamburg, Germany, developed the Flying graphite

　　The world's lightest material "flying graphite" (Aero graphite), its density is only 0.2 mg / cubic centimeter, replaced the air gel became the world's lightest material. Looks like a black opaque sponge, made up of 99.99% air.

　　This new material has a stable performance, good electrical conductivity, ductility and very strong. It is composed of a porous carbon annotate in the nanometer and micron scale, which is composed of a mesh structure. Although its quality is very light, but the flexibility is very good, has a strong anti compression capacity and tension load. It can be compressed to 95%, and then restored to the original size. It can absorb almost all the light.

　　Advantage

　　1, stable performance;

　　2, with good electrical conductivity;

　　3, strong extension

　　4, very stable

　　Purpose

　　1. Flying graphite is mounted on the electrode of lithium ion battery, the battery need electrolyte solution becomes less and less, battery quality thus greatly reduced, small cell can be used in electric car or bike.

　　2 can make the composite material with electrical conductivity, so as to avoid electrostatic interference.

　　3 can also be applied to the electronic equipment used in the aerospace and satellite fields, because these devices must be able to withstand a large number of vibration.

　　4 is expected to be used in water purification, as an adsorbent for the adsorption of pollutants in water, because it can oxidize or decompose and remove pollutants in water.

　　5 can be used in the constant temperature box or ventilation equipment to purify the environment air.

　　Beijing Great Wall Co., ltd is a leading company of graphite product. We always offer the best quality and the competitive price for our customer. We are looking forward to your enquiry and cooperation in the future.

　　Recently, the author is commissioned by the company to develop a kind of can meet the high performance of high-speed brakes brake piece, raw material is used in continuous filament untwisted PAN based carbon fiber T300 and its tensile strength is more than 3400 mpa, tensile modulus of 230 gpa, elongation is 115%, the density of 1175 g/cm3, carbon content over 94%, fiber diameter between 6 ~ 8 lm, count is 6 k.

　　The needled felt manufacturing process and requirements are as follows: 1.1 short carbon fiber net tire manufacturing will long carbon fiber bundle of short cut in 68 ~ 70 mm long short carbon fiber bundle, and then folded into a net shop on network, made into uniform short carbon fiber net. 1.2 needled felt manufacturing as a whole According to a layer of short carbon fiber net, a layer of long fiber without weft cloth for layer overlapping, no weft cloth layer Angle between 90 b, each lay a layer of short carbon fiber net acupuncture again, needle density [3 mm, acupuncture depth is 10 ~ 12 mm, to achieve the overall needled felt each needle density uniform, long fiber and short fiber ratio is 75/25.

　　Overall needled felt volume density in 0160 ~ 0163 g/cm3, layer density of between 12 ~ 13 units/cm. Made of carbon fiber needled felt through the test, has high strength and good antistatic performance, can satisfy the requirement of high-speed buffer braking.

　　The carbon carbon composite material has a big difference to the superalloy and ceramic materials. Under inert conditions,even the temperature reach 20000C,the strength of the C/C material can still remain unchanged situation,the strength will not reduce.

　　The carbon carbon composite material have a good resistance to thermal shocks and excellent mechanical properties. However, the fatal weakness of CFC material is the low oxidation resistance.although the C/C material has a high specific strength, high specific stiffness and high temperature stability,as one attractive structure material,when the temperature reach 4000C,the carbon carbon composite material start to oxidize. So the most researches on the C/C composite is how to avoid or reduce the degree of oxidation,and also many researches on the processing of the material,structure and the activity, quantitative relationship and the comparison between the C/C with protective layer and without protective layer. One of the most important results is that the physical properties have a big influence to the carbon carbon composite material activity.

　　The flow chart of C/C material below：

　　The different processing between carbon cloth and carbon felt can lead to the different C/C composite material,although they have the similar structure and graphitization degree and same heating treatment,they still have the different properties,the main reason is the oxidation direction,as the two different carbon fiber,they have the different surface area and pore volume.

　　So before using the carbon cloth or carbon felt to make C/C composite material,it’s also important to research the different fiber physical property.

　　1、Density is small, light quality. Mainly depends on the density of carbon fiber carbonization temperature, PAN based carbon fiber after 1000 E processing is 117 g/cm3 density, the temperature is above 2300 E processing, generally is 210 ~ 210 g/cm3 density, type and E glass fiber density of 2155 g/cm3, metal steel fiber density of 7180 g/cm3.

　　2、High modulus (200 ~ 700 gpa), good rigidity, fatigue resistance, self-lubrication, small friction coefficient, wear-resisting performance is good. High modulus carbon fiber is also called the graphite fiber (GRF), generally between 92% ~ 96%, the carbon content PAN fiber M70J cornerstone ink for the theoretical value of modulus of 1020 gpa) (6717%, made in mitsubishi company recently K13C20 modulus # # 39 Beijing textile 22 (6) 900 gpa, 8812% of the theoretical value, the graphite fiber modulus continues to improve. Tests show that in the copper mixed with 25% of the carbon fiber can make its attrition rate down to the original l / 100, and add in plastic products, the attrition rate could be reduced to 1/1000 of the original.

　　3、Thermal conductivity (10 to 213-1 K - 1), no heat, small thermal expansion coefficient (10-6 K - 1-111 @), dimension stability, especially in an inert atmosphere of excellent heat resistance. Thermal conductivity of carbon fiber with the temperature rising and falling, in 1500 when e is only when the room temperature of 15% ~ 30%. Its coefficient of thermal expansion anisotropy, parallel to the axial thermal expansion coefficient of fiber was much lower than perpendicular to the fiber axial, this defect with the epoxy resin composite and composite material is easy to produce cracks.

　　4、Excellent conductivity (5 ~ 17 l8m), a non-magnetic, has the function of shielding electromagnetic wave at the same time of X-ray permeability is good. In addition, the carbon fiber also has to vibration absorption, is excellent for vibration attenuation function. 215 they can withstand oil, acid, corrosion resistant performance is good, good compatibility with biological performance. In addition to the strong oxidizer, generally such as concentrated hydrochloric acid, 30% sulfuric acid, and base on the doesn't work. The corrosion resistance of carbon fiber is better than glass fiber. 216 low axial shear modulus, breaking elongation is small, the impact resistance is poor, and after processing more difficult.

　　The mechanical properties of CFRP depends mainly on the matrix, the mechanical properties of common epoxy resin , the surface properties of carbon fiber, and the nature of the fiber and the matrix bonding interface, and the performance of the matrix and fiber surface properties directly related to the interface bonding and adhesive performance, the following described from two aspects:

　　1、Matrix: CFRP commonly used epoxy resin as matrix, its good adhesion, excellent mechanical properties, but the general type of epoxy resin after curing, brittle hard, shock resistance is poor, poor heat resistance. At present, the toughening method is relatively mature will cure before can compatible rubber and epoxy resin dissolved in resin, curing, rubber to precipitate, a two phase structure. At present commonly used are RLP type rubber, small molecular weight (1000 ~ 10000), with epoxy resin with reaction of functional groups, so as to produce strong chemical junction. We can make the epoxy resin matrix containing aromatic ring main chain structure and increase the crosslinking density method, such as epoxy resin to improve use temperature and thermal stability, at the same time improve its and adhesive properties of carbon fiber.

　　2、The carbon fiber surface properties: Without the surface treatment of carbon fiber surface is smooth, small friction coefficient, surface presents abhorred liquidity, leading to poor wettability with matrix, bond is low, the interlaminar shear strength (ILSS) of composite materials, interfacial shear strength (IFSS) are low, can not meet the actual demand. Commonly used the surface treatment of oxidation and coating processing, electrical aggregation and the electroplating treatment, plasma treatment and so on. Using the method of electrochemical oxidation, anodic oxidation surface treatment, moderate reaction, easy to control, the treatment effect is good. After surface treatment of carbon fiber with effective scanning tunneling electron microscope (STM) surface analysis found that the edge of the surface of graphite layer of oxidation, large-area edge active point number increase, is more advantageous to the uneven surface and bonding of matrix, and the shear properties of composite materials. At the same time, its surface can increase, significantly improved the wettability between carbon fiber and matrix, the contact Angle decreases, and surface present a lyophilic sex. In addition, after surface treatment, its surface appear a large number of hydroxyl, carboxyl, quinones and pyranoid ketone functional groups, improve the polarity of the carbon fiber surface, increase with the wettability between substrate and adhesive. Carbon fiber reinforced polymer (CFRP) has been quite widely in the field of aerospace and defense force. Such as CFRP can be used in the manufacture of artificial satellite support, satellite antenna, the wing of the shuttle, the rocket's crater, strategic missile final boosters, the robot's shell, etc. Aircraft to meet the light, strong, strong resistance to distortion, a Boeing 767 aircraft, its fuselage drive door, landing gear doors, hood, main wing, the top of the flap, the back of the tablet and other parts are made from carbon fiber and CFRP, total more than 1 ton. Automobile manufacturing, automobile shell, joystick, flake spring made of CFRP, can make the total weight of the car to reduce 70%. Sports leisure aspects, fishing rod, tennis rackets, skis, racing, pole high jump are made of CFRP, greatly enhance the performance. Frame structure of the high-rise buildings by using CFRP can rise to enhance, increase, reduce the load of building base, and so on, the other party # 40 # in December 2001, such as bicycle beam, the sword of rapier loom belt, under heavy load of elevated intersection beam, column, etc are made using CFRP available.

      This way has an advantage of stable oxidation reaction and easy control,the graphite felt after electrochemistry treatment shows that the voltage efficiency can be reach 85%,and the current efficiency can reach 95%,and the circle property is very stable.after the analysis of XPS and FT-IR,the results show that the effect of electrochemistry treatment mainly increase the quality of the O/C rate on the surface of graphite felt,especially to the number of COOH.the results of SEM and (BET)/N2 show that the electrochemistry treatment can increase the surface area of the graphite felt,and increase the reaction area of the electrode.the electrochemistry treatment reduce the electric resistance of the graphite felt,the reason is mainly from the increasing of the COOH number on the surface of the graphite felt.

　　The nitrogen treatment is make the graphite felt under the 180℃ situation of heating in water bath.after the experiment,the result shows that the best treatment time is about 15h,and.use the graphite felt after treatment as electrode in the vanadium redox flow battery,it can charge and discharge in the range of 20~60 mA/cm2.when the current density reach the 20 mA/cm2,the voltage efficiency can reach 83.7%,and the electric energy efficiency can reach 85.3%.

　　Through the electrochemistry research and test,the result shows the reason why it can improve the activity of the graphite felt:the nitrogen containing functional groups on the surface of the carbon fiber increased,the functional groups improve the acid base property of the functional groups and the charge density of the carbon atom,reduce the electric resistance,so the activity of the graphite felt is been improved,and increase the efficiency of the vanadium redox flow battery.

Carbon fiber is one kind of special fiber consists of carbon element.it has high temperature resistant,good wear resistance,electrical conductivity,thermal conductivity,corrosion resistance etc.It’s fiber in shape,flexible,and could be machined into fabric.

Along the fiber axis direction,it has a high strength and modulus.density of the carbon fiber is low,so it has a high specific strength and specific modulus.

The most important use of carbon fiber is to be the reinforce which be manufactured as advanced composite materials with resin,metal,ceramic and carbon etc.

The carbonization processing of the precursor fiber,the raw material,carbon content below:

precursor fiber

The procedure of the 3 process above includes:

1. stabilizing treatment(200~400℃)
2. carbonization treatment(400~1400℃)
3. graphitization treatment(>1800℃)

In order to improve the bonding performance between carbon fiber and composite material,the surface treatment,sizing and drying are usually used. Another way to manufacture the carbon fiber is The vapor phase growth method. Under 1000℃,the mixed gas of methane and hydrogen with catalyzer could meet discontinuous and chopped carbon fiber,the max length is about 50cm. The structure of chopped carbon fiber is different from PAN or PITCH ones,it has an easy graphitization,good conductivity property etc.