The world graphite mold industry has gone through a period of rapid development, into the mature stage. And the markets of developed countries have been saturated, and developing countries and regions have become the focus of competition for big companies because of their huge market potential. The world’s graphite mold production capacity of about 28 million tons, including building graphite mold accounted for 40%-50%, about 1100~1400 million tons around. In the industrial developed countries, the building graphite mold for the consumption ratio of the largest type of graphite mold, accounting for the total production of graphite mold about 50%. The U.S. building graphite mold production in the past 10 years has been maintained at about 2.7 million tons, accounting for the total output of graphite mold 52%.
Europe and Japan are basically at that level. According to the U.S. Freedonia Group forecast, by 2013, the world’s graphite mold demand annual growth rate of 3.7%, will reach 28 million tons. Asia-Pacific markets are growing faster, although Latin America and Eastern Europe have an average annual growth rate. In the Asia-Pacific region, although India, South Korea and China also have relatively fast growth, China will grow at a faster rate, with an annual growth of 6.6% per cent.
Japan’s demand growth rate is expected to be lower than the world average. Eastern Europe Graphite Mold Market annual growth rate of about 8%, will have a faster growth, such as polish per capita graphite mold annual consumption of 8kg/people, while Western Europe is 16kg/people. The annual growth rate of graphite mold market in western Europe, North America and Japan is 2%-3%.
North America and Western Europe will continue to account for more than half of the global demand for graphite molds. In order to compete for the future graphite mold market, the world’s graphite mold giant has already opened the strategic strategy, summed up is nothing more than two points: first, through the purchase and restructuring, strength, reduce costs, improve competitiveness: second, the development of new technologies, new products, especially green products, seize the commanding heights.
Scientists at the Georgia Institute of Technology and the French Academy of Sciences have made use of graphite to successfully create a theoretical model of transistors, electronic circuits and integrated circuits. The electronic devices they manufacture have the advantages of carbon nanotubes, but they can be made with the current microelectronics technology. If it succeeds, it will lay the groundwork for large-scale industrial applications of nanotechnology. At the March meeting of the American Physics Conference, the researchers read out their findings, which have been published in the Journal of Chemical Physics.
We are not unfamiliar with graphite, the pencil core is made of it. Scientists have also found a big use for graphite: they have made graphite into new electronic components, making it possible for the graphite to be the next generation of nano-electronic components. The fabrication of carbon nanotubes using graphite layer sheets can be used to obtain all the properties of nanotubes, because these properties are formed by graphite layers and other electronic constraints, not by nanotube structures. Graphene carbon nanotubes simply roll the graphite layer into a cylindrical structure. The researchers heated the silicon-carbon compound in a vacuum, allowing the silicon atoms to escape from the surface and leaving a thin layer of graphite on the surface. They use current circuit printing technology to carve the graphite layer into a graphite layer circuit with a line width up to 80 nm. The circuit shows high electronic mobility and shows performance stability in greenhouse conditions. The researchers also used this method to create a full graphite layer planar effect transistor, as well as a quantum interference device. The researchers predict that graphene carbon nanotubes and graphite-layer circuits will have great potential for application. It produces more contact surfaces than electronic devices made from a variety of materials, with a huge advantage of using only one material to create a system, which not only does not cause resistance to heat in contact surfaces, but also uses existing microelectronics technology to make their systems. The researchers say that the components they want to make are not copies of silicon-based electronic components, but rather a new way of looking at electronics. Their ultimate goal is to create an integrated circuit that uses electrons to move in diffraction rather than in a way that propagates, which will produce small, highly efficient gadgets.
The lithium ion is freely inserted and interpolated between the layers of graphite to form graphite interlayer compound and can be used as anode material of lithium ion two battery. Natural graphite used as anode material has the characteristics of stable discharge performance, high capacity and low price, which can replace the expensive MCMB. Natural graphite can improve the irreversible capacity of natural microcrystalline graphite through proper purification, particle size control, shape control of micro-powder and surface modification. The study of natural microcrystalline graphite as anode material has been close to pilot product.
Flexible graphite can be used as sealing material because of its unique sealing property and chemical stability. However, it has good conductivity, heat conduction and corrosion resistance, and can be directly pressed into a proton exchange membrane fuel cell with a specific flow field bipolar plate. By improving the process of preparing materials, the conductive property, thermal conductivity and strength of bipolar plates are improved. The present study shows that the preparation of the bipolar plate for proton exchange membrane fuel cell with flexible graphite is a promising prospect.
Porous activated carbon material is the carrier of the double layer of supercapacitors. Porous activated carbon materials used as supercapacitors require high surface area, high chemical stability, and low resistance. At the same time, it is necessary to control the pore size distribution of porous activated carbon materials to improve the efficiency of punching discharge, and to reduce the resistance of forming double layers in deep pores.
Graphite electrodes do have a lot of advantages, but how do you put the advantages into play? How to really improve efficiency, reduce costs. Therefore, in the application of graphite materials should first solve the following problems:
First, dust. Because graphite is the structure of fine particles, so in the production time will produce the old dust, to the surrounding and the factory environment has a great impact; The most important is the impact of dust on the equipment, because the graphite conductivity is very good, if the power box after the easy to cause short-circuit fault. This has two processing methods: One is the oil after processing, buy graphite after the first soak in the spark oil for a period of time, and then processing. The graphite dust will not fly. Another is the modification of the processing center: the so-called conversion, mainly in the ordinary processing center to install vacuum cleaners.
Second, because graphite is more brittle than copper, it is easy to cause an electrode to collapse, especially when processing a thin rib electrode, if the graphite is machined with a method of processing copper electrodes. Mainly through the tool selection, the way of walking the knife, as well as the reasonable configuration of processing parameters to achieve. It is recommended to choose Diamond Tool or diamond coated tool as far as possible.
Third, discharge processing of the discharge gap: unlike copper, because the graphite electrode discharge speed faster, the unit time corrosion out more processing slag, how to effectively discharge slag become a problem; Therefore, the discharge clearance is larger than copper. In general, when the discharge gap is set, the discharge clearance of graphite is larger than that of copper $number.
Four, the correct understanding of its shortcomings: in addition to dust, graphite there are some deficiencies. For example, in the processing of mirror mold, compared to the copper electrode, graphite electrode is not easy to achieve the desired effect, and to achieve a better surface effect, it is necessary to select the most fine particles of graphite, and the cost of this graphite is often higher than the general graphite to $number times.
Flexible graphite material belongs to non fiber material. Graphite powder flexible graphite made of plate after molded into sealed filler use. Flexible graphite, also known as expanded graphite, is to remove impurities from natural flake graphite.
After the strong oxidation mixed acid treatment, it becomes the oxidized graphite. The oxidized graphite decomposes the carbon dioxide, the volume expands rapidly, becomes the loose, soft and toughness flexible graphite. The main features are:
First, excellent heat resistance and cold resistance. Flexible graphite from 270 degrees of ultra-low temperature to 3650 degrees (in the oxidation of gas), the physical properties of almost no change in the air can also be used to about 600 degrees; Graphite Powder
Second, excellent chemical resistance. In addition to corrosion in strong oxidizing medium such as nitric acid and concentrated sulfuric acid, flexible graphite has little corrosion in other acids, alkalis and solvents.
Third, there is good self-lubricating. As with natural graphite, the graphite powder layer is easy to produce sliding under external force, so it has lubricating property, good antifriction property and small friction coefficient.
Third, rebound rate is high. When the shaft or bushing due to manufacturing, installation, such as the existence of eccentric radial circular runout, with sufficient floating performance, even if the graphite cracks, can also be very good close, so as to ensure that the paste tight, to prevent leakage.
The thermal conductivity of natural graphite is mostly in 300-700w/m. K, and the thermal conductivity of synthetic graphite is mostly in 700-1500w/m. K, which can even be achieved even higher.
Graphite also has grading: natural graphite and synthetic graphite have different thermal conductivity
Synthetic graphite is the polymer as raw material, made into thin film, and then by oxidation, high-temperature carbonization and other complex process preparation, the price of synthetic graphite is higher than natural graphite, but compared to natural graphite microstructure is more structured, more detailed. So it can be done thinner, the heat conduction effect is better.
1. Avoid the side of the charging side of the long time to play mobile phone. Charge of the mobile phone in a lot, this time to use the mobile phone is on the charging current to increase the use of a current, according to the mobile phone design to withstand this current is no problem, but long time in this large current working condition, the fever is also difficult to avoid. So when you recharge your cell phone, don’t play big games or watch videos, let yourself and your phone take a break.
In addition to mobile phone manufacturers to use a large number of different heat dissipation materials, users usually good use of machine habits also play an important role. To get rid of some bad habits, there will be unexpected results.
As in other industries, the solution to the problem of heat dissipation is mainly the use of high thermal conductivity materials. Traditional thermal conductivity materials are mainly metal materials, such as copper, aluminum, silver, etc., however, the metal material density, high expansion coefficient, in the demand for high thermal conductivity of the occasion is not satisfied with the requirements in the field of aerospace, electronic and electrical appliances, the use of more high, more efficient conduction of conductive graphite. The thermal conductivity of the graphite heat transfer film is 2-4 times that of copper, which will greatly accelerate heat conduction and save space.
Comparison of natural graphite and synthetic graphite
Following the development of smartphones, hardware promotion, the larger the program can run, the more complex, so long, high load running program when the hardware load is higher, the corresponding heat generated more quickly. The temperature of the module of the fever increased rapidly, the last temperature through high and then affect the mobile phone does not run.
3. Avoid running a large number of applications at the same time. The Android system has a significant feature is that many applications in the open, you think that the exit is closed, but he’s still in the background. This is said to be to promote the processing speed of the system, when the user enters again, the software data still exists, can call processing directly. However, this will take up a limited amount of memory space, the processor each address space increase or decrease, intangible increased processing data.
Graphene is an ideal two-dimensional crystal with regular six square symmetry, which has been discovered in recent years by covalent bonding of single layer carbon atoms. is a new type of low dimensional carbon material after fullerene and CNTs. Because of the extraordinary electrical, thermal and mechanical functions of graphite and broad application prospects, graphene is considered to be strategically
New materials have rapidly become the most active research frontier in the fields of material science and condensed State physics. In this paper, the experimental test, numerical simulation and theoretical analysis of the mechanical properties of graphene are first introduced.
With solid polystyrene as carbon source, the double treatment of copper foil by mechanical polishing and electrochemical polishing is a substrate, the results of the research on controllable growth of graphene by CVD method. The graphene was characterized by optical microscope, atomic force microscope, Raman spectroscopy, optical transmission spectrum, scanning tunneling microscope and field emission scanning electron microscope.
Composed of one layer of single atom structure carbon material, the most characteristic is that the light transmittance is better than the traditional CMOS sensor, and there will be good imaging performance in low illumination environment. Graphite sensor Another feature is thin, as we all know, Nokia 808 thickness is achieved. 9mm, the lens position is a large bulge, and the stone graphite ink sensor can let the next generation using 4100W PureView lens of the mobile phone do thinner, in addition, the production of graphite sensor is simpler than CMOS, And the materials are cheaper.
Performance of carbon products and graphite products at ambient temperature
Carbon-graphite materials are a subject of interest to crystallography scientists and materials scientists in recent decades. In addition to the two common allotrope (diamond and graphite), there are many types of crystals in the range of graphite that are almost amorphous to highly crystalline. Structural changes bring about qualitative differences, making carbon materials successful in many ways.
For example, graphite can be used as lubricant, also for high-temperature high-strength components, and can be made into an arc furnace steelmaking indispensable electrodes, after special chemical treatment, the flexible sealing material can be made, and the interlayer compound with higher conductivity than copper can be made. Diamond with its brilliant luster to make it an ornament, incomparable hardness and make it in the industry as abrasive cutting materials. Near amorphous, The lack of thermal conductivity of carbon black can be used as insulation material. With its ability to slow neutrons effectively, graphite is an indispensable material for atomic energy. Carbon fiber and graphite fibers are one of the most important materials for the development of aerospace. Therefore, carbon-graphite materials are widely used and have a broad future.
Physico-chemical properties of carbon and graphite the graphite crystal is a layered lattice, which is formed by a large number of carbon atoms with hexagonal rings, which are overlapped in parallel. The most common graphite crystals belong to six-square crystalline system, and the crystal structure has significant anisotropy.
The properties of carbon include the properties of the graphite crystal itself and the so-called structure-sensitive properties related to the microstructure of the Microcrystalline interface or the state of extraction. The structure-sensitive properties fluctuate greatly with the wide variation of carbon structure. A typical carbon product made of petroleum coke, graphite products and pyrolytic graphite are given. Pyrolytic Graphite-tensile strength can be seen with the temperature change, until the tensile strength of 2750 degree pyrolytic graphite increases with the increase of temperature.
General rubber is insulated, if need electric conductivity then need to add conductive material, graphite powder has superior conductivity and lubrication demoulding. Graphite is processed into graphite powder, with excellent lubrication, conductive properties, the higher the purity of graphite powder, the better the conductivity. Many special rubber products factory need conductive rubber, then with graphite powder added to the rubber inside can conductive? The answer is yes, but there is also a question, what is the proportion of graphite powder in rubber? Some enterprises use the proportion is not more than 30%, this kind of wear-resistant rubber products above, such as car tires and so on, there are special rubber factory ratio is 100%, such will be conductive, conductive basic responsibility is the conductive body can not be interrupted, like a wire, if the middle of the broken then will not power, conductive rubber inside the conductive graphite powder is the conductor, if the graphite powder is insulated rubber partition, then also do not conductive, so the proportion of graphite powder less conductive effect is not good.
Graphite powder is a very sensitive material of chemical reaction, in different circumstances, his resistivity will change, that is, his resistance value will change, but one thing is not changed, graphite powder is a good non-metallic conductive material, as long as in the insulating object inside to ensure that the graphite powder uninterrupted, like a thin line will also electrify, but, the value of the resistance is not a quasi but the number, because the thickness of graphite powder is not the same, used in different materials and ambient graphite powder resistance value will not be the same.
A graphite electrode coated with an antioxidant protective layer (a graphite electrode antioxidant). Forming both conductive and high-temperature oxidation protection layer, reduce the electrode consumption (19%~50%), prolong the service life of the electrode (22%~60%), reduce the electric energy consumption of the electrode. The use of this technology can bring about such economic and social effects:
1. Graphite electrode unit consumption is less, production cost has a certain reduction. For example, a steel-making plant, according to the whole year does not occur discontinued a LF refining furnace 35 graphite electrode per week, refining treatment 165 furnace consumption calculation, the use of graphite electrode antioxidant technology, each year can save 373 (153 tons) electrode, each ton of ultra-high power electrode 16,900 yuan calculation, can save 2.5857 million yuan.
2. Graphite electrode consumes less energy, saves the unit steelmaking electricity consumption, saves the production cost, energy-saving!
3. Because graphite electrode exchange is less, it is less labor and risk coefficient of workers, improve production efficiency.
4. Graphite electrodes are low consumption and lower pollution products, in the energy-saving and emission reduction environmental protection advocates today, has a very important social significance.
This technology is still in the domestic research and development stage, and some domestic manufacturers also began to produce. In Japan and other developed countries have been more widely used. At present, there is also a special import of this antioxidant protection coating company.