Carbon fiber composite materials in various fields of new applications (Figure)

　　For the carbon fiber industry, 2016 is a brilliant year for achievements. In addition to achieving the production of T800 kilotons of carbon fiber, carbon fiber composite materials have also made some achievements in various fields such as aviation, transportation, industry and civil use Surprising new progress.

　　Aerospace: The largest carbon fiber solid rocket motor housing

　　On September 22, 2016, the successful ground test of the first-class solid-propellant rocket engine, developed by nine of the fourth institutes of the China Aerospace Science and Industry Corporation, was successfully completed. It has become the largest size and largest amount of powder coated carbon fiber composite shell technology in China, Solid rocket engine. The engine diameter 2.2m, total length 9.7m, charge 45t, with high quality ratio, high specific impulse, high thrust and so on. The test confirmed the key technologies such as large-size carbon fiber composite shell, high-flow nozzle and large-tonnage charge to realize the leapfrog promotion of large-size carbon fiber composite shell engine engineering application.

　　Navigation: The first carbon fiber reinforced sandwich structure hull push watertight cover

　　Shanghai Hu Zhou Industrial Co., Ltd. independently developed a carbon fiber 艏 side push watertight cover, the technology access to China's utility model patents, is currently the first in the international community. Cover body with multi-axis carbon fiber and reinforced resin composite materials, with high strength, light weight, anti-seawater corrosion and other characteristics of the DNVGL test center passed the strength test and obtained DNVGL strength certificate. In addition, the product is a honeycomb sandwich structure, the proportion of side watertight cover is 1, the entire watertight cover can be suspended in water, to facilitate divers underwater operation. To ensure that the watertight cover and the hull linear match, the scene using 3D scanning and computer modeling, calculated by finite element method cover strength, design a reasonable structure, weighing only one-fifth of the weight of the same type of cover abroad , And the intensity to meet the underwater 15 meters to 25 meters operating requirements. The product is mainly for shipping companies in the case of not docked on the side of the ship to promote line maintenance and repair, which greatly saves the cost of docking repair and voyage maintenance time.

　　High-speed Rail: Flame-retardant carbon fiber composite structure to achieve mass production

　　Wuxi VIA New Material Technology Co., Ltd. developed a new type of carbon fiber composite with flame retardant, fire retardant, toughening and other properties, the carbon fiber composite materials made of high-speed rail structure has entered the high-volume production stage. In many accidents of aviation, automobile and rail transportation, the accidental collision easily causes the car body to burn. The smoke and harmful substances formed after burning the car body material often result in the increase of the lethality rate, and the new type of carbon fiber composite material can achieve EU EN45545 rail vehicle fire test standards, in case of spontaneous combustion after the fire, the amount of smoke is minimal, does not release harmful gases, can effectively reduce the hazards of accidents on the human body. Moreover, the average speed of China's high-speed railways exceeds 200km / h and the maximum speed reaches 350km / h or above. The ultra-high speed has strict requirements on the structure of the vehicle body and the material of the carriage body. All physical properties of the material must meet the higher standards. Carbon fiber composite parts made of very light quality, but its strength is larger than steel, with its replacement of metal materials, can greatly reduce the weight of the body, while reducing body energy consumption while running, but also enhance the body Security.

　　Wind power: the first 68 meters long carbon fiber fan blades

　　From Lianyungang in Jiangsu Lianzhong Composite Materials Group Co., Ltd. independent research and development, the first 68 meters long 6 MW wind turbine blades shipped to Europe recently. It is reported that the blade innovative use of carbon fiber beam vacuum infusion process to overcome the domestic production of large-scale 12K carbon fiber carbon fiber fabric problems, the blade can be widely used in coastal wind farms for the offshore wind turbines in China to lay the foundation for the domestic carbon fiber The application of high-power carbon fiber blade manufacturing to solve the international problems, help to increase our high ground to seize the global wind power industry.

　　Infrastructure: The successful development of insulated carbon fiber composite core wire

　　In 2016, September 22, Hohhot Power Supply Bureau Wonshan line line reconstruction project in Hohhot Jinchuan Development Zone cable construction. This line adopts Inner Mongolia Haoyuan New Material Co., Ltd. newly designed and manufactured JKLRXYJQ / F1A-10170/20 insulated carbon fiber composite core wire. This type of wire can be widely used in 10kV and below distribution network capacity expansion transformation and infrastructure lines. It is reported that this new type of wire is still the first application in Inner Mongolia, the carbon fiber composite core wire with light weight, high strength, corrosion resistance, high temperature, large carrying capacity, sag, cost advantages, the annual production capacity 20,000 kilometers, the product is now widely used in power lines of different voltage levels of new lines and old network renovation project.

　　Civil: the world's first carbon fiber smart robot electric car

　　Recently, the world's first carbon fiber intelligent robot electric car, by the Eagle Eagle Carbon Bicycle Co., Ltd. independent research and development success, and the public to meet. The carbon fiber smart robot electric car frame with all-carbon fiber materials and advanced molding process, free to shrink and stretch, all-inclusive battery weighs only 15 kg, lightweight body, easy to carry, up to 20 km / h, the largest Load 150 kg, 4 hours charging life can be 30 kilometers, with spare batteries up to 60 km. Automatic folding design concept makes the body easier to fold and more compact, easy to carry, whether it is by bus, subway, or into the elevator, even with the shopping mall are not a problem.

Electric bus lightweight, high strength, a major breakthrough in security (Figure)

　　From April 15 to April 17, 2016, the "2016 Tianjin International Buses, Buses and Parts Exhibition" was held in Tianjin Meijiang Convention and Exhibition Center. The most attractive meeting of this meeting was the exhibition of Shandong Taiqi Investment Holding Co., Ltd. A new high-strength carbon fiber composite body bus, the car through the use of high-strength carbon fiber composite body for the car, with strong resistance and lightweight, at the same time, can quickly charge 40 minutes and 1 charge mileage up to 240km, Achieved zero emissions, pollution and other outstanding features.

　　Shock

　　From the television being shown more thrilling, wonderful picture: I saw a coach fixed on the rollover test bench, with the rollover angle increases, with a roar vehicle then side rollover on the ground, only See all broken glass, but the body did not see any distortion, tearing and deformation, especially in the top of the car 200kWh nearly two tons of batteries and boxes not only intact, still firmly fixed in the roof, the presence of all personnel Make a surprise call. At the scene, a staff member was hammering a piece of material that made the electric bus body with a sledgehammer. After the smashing, there was no deformation and rupture.

　　This is a new type of high-strength carbon fiber composite body, not only has a lightweight, more high-strength. This is the new brand new carbon fiber structural electric passenger car exhibited by Shandong Taifeng Electric Vehicles (Group) Co., Ltd.

　　Lightweight

　　According to South Korean experts, the show car uses super-lightweight, high-strength composite body, compared to the same level of vehicle body weight reduction of about 2.5-3 tons. Due to its 25% -30% lighter body weight and 11-meter bus weight reduction of nearly 3 tons, the mileage of 240kW at the same 200kWh battery capacity is more than 20% of the domestic bus mileage , But also because the vehicle weight to reduce, making the remaining battery power in less than 25% of the circumstances can be normal driving.

　　Anti-rollover

　　As the car body with carbon fiber structure, the overall body with superior structural strength, high instantaneous impact resistance, it has good anti-roll performance, the roll angle up to 38 ° or more, than the domestic car index optimization 20 % Or more; better rollover resistance due to higher roll angle.

　　Flame retardant isolation

　　Nearly two tons of battery box using the world's first roof mode, fully prove the body's high-strength performance; the same time as a result of the flame retardant technology, in the case of accidental combustion of the battery case, the battery compartment and body passenger area isolation and resistance Burning isolated, so will not endanger the passengers in the car.

　　Low floor

　　In the power transfer demonstration, through a dedicated top replacement with 45 seconds to end the power exchange. At the same time the car selection of low-floor structure (minimum distance from the ground 150mm), making passengers more convenient to get off, in the humane design with the disabled access to the car.

　　Super climbing ability

　　The car has a maximum speed of 85 km, 30% higher than the domestic car of the same type of high-speed performance; the same time, due to the weight reduction, reduce the center of gravity, making the vehicle driving stability, turning inertia and a series of driving performance has been greatly optimized And improve, especially the vehicle climbing performance with over 28 ° climbing ability.

　　Meet international standards

　　In the case of vehicle weight reduction of 25%, all the performance of the vehicle has been greatly optimized and improved, making the car has unparalleled performance. It is learned that the car once listed, by Japan, Singapore, Hong Kong, the EU area of ??great interest and concern at the end of last year with Japan's Mitsubishi Corporation three car has passed the Japanese tests, put into operation.

　　According to experts, the company also developed a plug-in electric bus, battery automatic replacement, online electric plug-in bus technology, while the company developed a high-tech wheel motor, and through the use of high-strength carbon fiber composite body to achieve Lightweight, with zero emissions, pollution-free, 40 minutes fast charge, with excellent power consumption performance and significantly reduce the cost of operating a bus. And through the body's lightweight technology, improved driving safety and ride comfort, for the driver and passenger safety and convenience provided a meticulous care.

　　According to experts, the successful development of new high-strength carbon fiber composite materials in passenger cars will be a subversive revolution in passenger cars and even in the automotive industry as a whole new milestone in the automotive industry.

China successfully developed T800 carbon fiber catching up Japan's efforts more than one generation (Figure)

　　Recently, the media reported that the T800 carbon fiber, which has been monopolized by foreign countries, has also declared low-cost localization in Harbin and its production cost is only one-third of the international price. While gradually replacing foreign products in the low-end market, it also broke the monopoly of foreign enterprises in the mid-to-high-end market. More valuable is that, according to the relevant units of the papers and test results, domestic T800-type carbon fiber performance is completely not lost in the same company in Japan Toray products, but in the local technical parameters is more has some advantages. Although China's carbon fiber industry is in a period of development today, it has experienced ups and downs so far.

　　Dilemma of independent research and development, technology introduction halvars sand

　　In 1959, Japan invented the method of making carbon fiber by using the raw material of polyacrylonitrile as a raw fiber and tension drafting. The West started commercialization in the 1970s and was subsequently applied to civil aviation and military applications due to the excellent properties of carbon fiber.

　　The research on China's carbon fiber began in the early 1960s. However, due to the harsh international environment at that time and the high technology blockade imposed by the West on such dual-use technologies as carbon fiber, coupled with the shortage of domestic resources, progress in carbon fiber research was relatively limited.

　　Until 1975, under the general deployment of General Zhang Aiping, joint research by more than 20 research institutes and enterprises finally solved the problem. However, these products also have certain flaws, such as mechanical properties relative to similar foreign products is relatively limited, the cost is relatively higher than similar foreign products.

　　In the following years, the state has invested more than 26 million yuan in research and development and production of carbon fibers to some extent to meet the needs of some national defense workers. However, there is a big problem - while the quality of products can not be compared with that of Japan, the cost is much higher than that of Japanese products, and the technical gap is getting bigger and bigger ...

　　It is precisely because of this situation, coupled with the immense worship of foreign technology in that particular era, many units pin their hopes on the introduction of advanced foreign technologies. A unit has also promised to provide financial support for the introduction of advanced foreign technologies.

　　However, as a result of the Treaty of the Treaty of Paris (Paris Co-ordination, an international organization that imposes embargoes and trade restrictions on socialist countries), the large international companies that are technologically the first tier are reluctant to China transfers technology and often suffers from political barriers even for the purchase of small quantities of equipment - the move by Shanghai Carbon Factory to try to import equipment from the United States ends with the U.S. Defense Department's intervention.

　　Therefore, the object of technology introduction can only be selected from those Western companies whose technologies are not mature enough in the middle and lower reaches. Eventually, the two units located in Jilin and Beijing chose RK in the UK. However, RK's technology is slightly higher than that in China, but Japan and the United States are not advanced at all. And although there is no clear evidence of RK's technical reservation or deliberate mischief, it is hard to keep people from conspiracy theories from the result point of view.

　　The two projects costed a total of about 9 million U.S. dollars. By 1990, the charring furnace of that unit in Jilin had not been able to operate normally. Beijing's unit had not succeeded in spending 7 years until it was "checked and accepted" in 1993, and the equipment remained the same Not working

　　Last resort, in the case of two sets of imported equipment are not functioning, the last can only be sold when the scrap metal. The failure of the introduction of technology not only cost a lot of money, but also a waste of valuable time, the tuition is not expensive. And because of the failure of the introduction of technology, leading to Japan and the technology gap even greater.

　　Summarize lessons learned to overcome difficulties

　　In 2000, carbon fiber research and development in China was at a low ebb. Only three units in China were reluctantly supporting it and only supplied small quantities to meet the needs of some part of the national defense industry.

　　In the midst of a critical crisis, Mr. Shi Changxu, a metallurgy and materials scientist, proposed to develop carbon fiber. Mr. Shi Changxu said: China's materials scientists have solved thousands of new materials needed for national defense. Carbon fiber preparation technology can not Breakthrough is a major mistake in material science and technology work ... Shi Changxu was nearly 80 years old at the time, after 80 years of age can have less control, but he would like to grab a carbon fiber, he did not think carbon fiber, Without any guarantee of national security, it will not be stopped.

　　Subsequently, a group headed by Mr. Shi Changxu was established, whose daily work was presided over by Professor Li Kejian, responsible for the research on the development strategy of polypropylene-based nitrile-based carbon fibers. After several joint departments and units, held several meetings to discuss the past mistakes in decision-making, research and development efforts scattered, the efficiency of funds and other issues were discussed and formed a four-point consensus: the importance of carbon fiber and the lack of technical difficulty is correct Estimates; Seriously inadequate investment, serious misuse; Failure to build a nation-wide research team; Lack of innovation and innovation environment (Professor Li Kejian's opinion, though not enough in depth, generally reflects the actual situation; if it is excessive, it may affect Team unity).

　　It is these efforts that are of great significance not only to avoid repeating the same mistakes but also to win the funding for the "Tenth Five-year" research. Later, the National Natural Science Foundation of China approved two key carbon fiber projects. In 2005, the carbon fiber project was approved as a major national basic research project.

　　In order to promote the study of carbon fiber, Mr. Shi Changxu proposed to concentrate superior forces, break the portal difference, organize the national team, the development of units controlled in 2-3, the establishment of competition mechanisms and other measures, these measures not only have a positive effect on the concentration of key enterprises , But also increased the efficiency of the use of funds and avoided the dilemma of "making a lot of efforts to separate and do everything". R & D at the same time, do not give up the opportunity to introduce technology, the introduction of the domestic equivalent of Toray T300 carbon fiber production line (after all, T300 is something in the 1970s, only the introduction of the 21st century hinder small), the development of the industry Has played a role.

　　It is Shi Changxu and a number of older scientists who strongly promote, and a large number of obscure young researchers of selfless dedication, and the state's attention and a lot of capital investment, and two-legged approach to China's carbon fiber industry Spent the hardest time

　　In recent years, the rapid development of China's carbon fiber industry, the steady growth of carbon fiber production, the specific situation as shown below.

　　However, we should also see the difference while seeing progress. Currently, half of the international carbon fiber market is occupied by Japan, with Japanese companies accounting for 49% of the world's small tow fiber production capacity and Japanese companies accounting for 52% of global capacity for large tow carbon fiber capacity.

　　Not only the production gap, in the product quality and use there is a gap, the current domestic commercial production can not match Toray T1000 products, in use, the domestic carbon fiber is mainly used for bicycles, golf clubs and fishing rods Sports and leisure products, and can be used for aerospace carbon fiber products are relatively small.

　　Domestic T800 can replace Toray similar products

　　The so-called T300, T800, T1000 and other titles, in fact, Japan's Toray's carbon fiber models, but because of Toray's position in the industry, leading to its models in the media coverage, virtually evolved into a similar intensity Carbon fiber benchmark. In fact, we can see that Japanese companies in the field of carbon fiber industry status.

　　In the field of integrated circuits, although Samsung's 14nm manufacturing process and 14nm 14nm manufacturing process of Intel belong to the same, but using Samsung technology out of the chip in terms of performance, power consumption and other aspects of Intel's comparison there is a certain gap. So, the domestic T800 and Japan Toray T800 also exist similar to the same T800, but product performance is inferior to a lot of situation?

　　A paper published by China Aviation Composites Co., Ltd., Beijing Institute of Aeronautical Materials, Key Laboratory of Advanced Composites, Institute of Physics and Chemical Engineering, Beijing University of Aeronautics and Astronautics, And Toray T800 carbon fiber made a very detailed test.

　　In the test, the researchers used S4800N cold field emission scanning electron microscope made by Japan Hitachi Company to observe the surface morphology of carbon fiber and calculate the fiber diameter. The D3000 atomic force microscope produced by Veeco Company of USA was used to observe the surface morphology of carbon fiber and analyze the surface roughness. The surface composition of the carbon fiber was analyzed by X-ray photoelectron spectrometer manufactured by UK Kratos Company. The micro-debonding testing machine developed by Beijing University of Aeronautics and Astronautics was used to test the interfacial shear strength between fiber and matrix resin. The 5982 material electronic universal testing machine produced by the American company Instron was used to test the dry mechanical properties of the composite at room temperature. Test shows that:

　　Compared with Toray T800H carbon fiber, the surface of domestic T800 carbon fiber is rough in surface physical state, with denser trenches distributed along the axial direction of fibers and deeper trenches, which is beneficial to improve Domestic T800 carbon fiber and the matrix resin mechanical meshing effect, thereby enhancing the interfacial properties of the composite material.

　　(T800H carbon fiber and domestic T800 carbon fiber AFM photos)

　　As the carbon-carbon ratio of domestic T800 carbon fiber is about 31.2% of that of T800 carbon fiber, which is about twice that of Toray T800H carbon fiber, the domestic T800 carbon fiber can interact with the matrix resin through chemical bonding or intermolecular force Improve the interfacial properties of composites. Coupled with the aforementioned differences in the surface physical state, making T800 carbon fiber and HT-280 resin can form a better interface bonding.

　　The test also proves this point, Toray T800H carbon fiber and HT-280 resin interfacial shear strength of about 92MPa, domestic T800 carbon fiber and HT-280 resin interfacial shear strength of about 117MPa, which is about 27 higher than the former %.

　　In terms of mechanical properties, mechanical properties such as 0 ° tensile, 90 ° tensile, flexural, in-plane shear and interlaminar shear of domestic T800 / HT-280 composites are generally higher than those of Toray T800 / HT-280 material. Among them, the 90 ° tensile strength is about 25% higher, the in-plane shear strength, the flexural strength about 12%, and the interlaminar shear strength about 7% higher.

　　(SEM images of T800H / HT-280 composite and domestic T800 / HT-280 composite at 90 ° tensile failure)

　　A Chinese University of Hong Kong doctoral thesis also shows that: T800 domestic carbon fiber tensile strength average of 5.63GPa (Toray T800 of 5.49GPa), the average elastic modulus of 292GPa, the average elongation at break 1.9%, and Toray T800 carbon fiber products, indicating that the mechanical properties of domestic carbon fiber fully reached the level of similar foreign products, and the indicators Cv values are lower, better stability. Domestic T800 carbon fiber 12K product elemental composition and surface activity and Toray T800 carbon fiber 12K products more consistent. Domestic T800 carbon fiber as a whole can be comparable to Japan Toray T800 products, can replace similar products to be promoted abroad.

　　Conclusion

　　At present, Japan is the main producer of high-grade carbon fiber materials. The T800 series carbon fiber from Japan Toray is the only carbon fiber approved by the FAA for use in the key flight components of the Boeing 777. The importance of carbon fiber in the aviation industry is self-evident.

　　Western countries have long imposed T800 series carbon fiber embargoes on China in order to prevent China from using them to improve the performance of military aircraft and gain competitiveness in international aerospace materials. In 2013, Chinese businessmen were accused of illegally purchasing T800 series carbon fibers in the United States.

　　It must be pointed out that although in the past domestic products can be made comparable with foreign countries, but the cost is often higher than similar foreign products. According to the website of Harbin People's Government January 16, Tianshun Chemical Co., Ltd. will control the cost of large-scale production of T800 carbon fiber to one-third of the international price, only 350 yuan / kg, which is technically able to compete with foreign countries Competing for similar products at the same time, pricing also take the initiative, which is the domestic T800 carbon fiber industry development and commercial application is particularly crucial.