Graphite rod surface by potential cycling. No interference effect of the most common ions such as sodium, potassium, chloride, nitrate, iodide, calcium, zinc, aluminum, sulfate and sorbitol was observed during electrochemical determination of fluoride. The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution. The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated with FT-IR, On the other hand, the PAPBA/GR electrode showed not only good sensitivity and selectivity, but also relatively rapid response to changes of analyte concentrations in the range of 20s.

　　The PAPBA-modified graphite rod (PAPBA/GR) electrode prepared in this way was used for potentiometric fluoride determination. The linear calibration range was from 5x10(-4) to 5x10(-2)M with the slope of the linear part of the calibration curve of 42.5mV/logC. SEM, XPS, BET, cyclic voltammetry and testing VRB system, respectively. The results show that the molar ratio of O to C increases from 0.085 to 0.15 due to the increase of —COOH functional groups during electrochemical oxidation treatment, and the GF surface is eroded by electrochemical oxidation, resulting in the surface area increase from 0.33 m2/g to 0.49 m2/g. The VRB with modified GF electrode exhibits excellent performance under a current density of 30 mA/cm2. The average current efficiency reaches 94% and average voltage efficiency reaches 85%. The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of —COOH group and the special surface of GF.

　　 Flexible graphite sheet is wildly used in all kinds of industry field. Flexible graphite roll uses: composite panels, cylinder head gaskets, packing, and so made ​​manufacturing gaskets, sealing elements such as static gauge, mold, flange gasket. Attached to a variety of metal surfaces, improving sealing performance. Flexible graphite sheet / plate, after high purity natural flake graphite by chemical and heat treatment, made ​​of molded rolling, without any binder. In the harsh working conditions still has excellent sealing performance, long life, low maintenance costs.

　　Character and Appearance: black with metallic luster, high dispersion, never bonded graphite powder. Touch greasy feel can heat and good thermal stability, rich conductivity, thermal conductivity, chemical stability, acid and alkali plasticity and organic solvents, corrosion, and has outstanding lubricity.

　　Main purpose:

　　1: Powder metallurgy and metal alloy materials of carbon

　　2: Seal Manufacturing (high temperature, high pressure washer machine and even oil)

　　3: Base material for high temperature lubrication, corrosion-resistant lubricating base

　　Characteristics and Specs：

• 　　Heat and fire resistant
• 　　Chemical resistant, compatible with most chemicals
• 　　Compressible, conformable, low creep relaxation
• 　　Thermal conductive, electrical conductive
• 　　Reinforced structure to handle high pressure applications

　　Working Temperature Range:

　　Oxidizing Atmosphere, such as air: -400° F to 950° F (-240°C to 510°C)

　　Mild Oxidizing Atmosphere of most gasket applications: -400° F to 1500° F(-240°C to 850° C)

　　Non-Oxidizing Atmosphere: -400° F to 5400° F (-240°C to 3000° C)

　　Thermal Conductivity:

　　Parallel to Sheet Surface: 960 BTU-in/ft2.h.F (140 W/m.K)

　　Through Thickness: 36 BTU.in/ ft2.h.F (5W/m.K)

High speed railway pantograph assembly

　　The pantograph system of high speed electrified railway need to have good follow properties and stable performance. Pantograph offline rate is one of the characters of the high speed flow stability. In recent years, our company developed various types of good quality pantograph and got good praise from domestic and foreign railway companies.

　　1.carbon/carbon composites, refers to in carbon fiber (or graphite) and its fabric as the reinforced material, carbon (or graphite) as matrix, through processing and handling all the carbon composite material made of carbide.

　　Carbon/carbon composite material is carbon fiber reinforced carbon composites, light quality, good erosion resistance, good thermal shock, high damage tolerance, high temperature and high strength, can be designed as a prominent feature, is used in aviation, spaceflight, circuit level and the production of solar energy silicon, high temperature furnace and other applications.

　　2. carbon - carbon composite material performance characteristics

　　(1) physical properties: C/C composites at high temperature after heat treatment, the chemical composition of carbon element is higher than 99%, low density, with strong affinity, high melting point, due to carbon with high temperature resistance, corrosion resistance and thermal shock performance good characteristic, acid, alkali, salt.

　　(2) mechanical properties: reflect the mechanical behavior of C/C composites is strength and modulus of elasticity, resistance to friction and wear performance is good.

　　(3) the high temperature stability: C/C composites at room temperature strength can keep up to 2500 ℃, is not sensitive to the thermal stress, ablation resistance performance is good.

　　(4) comprehensive performance evaluation: C/C composites at room temperature strength and elastic modulus, good production C/C composites link, saves materials and manufacturing cost, safety and high reliability.

　　3. carbon carbon composite material manufacturing technology

　　In the choice of technology to the preparation of C/C composites, should according to the requirements of the C/C application first choose to use what kind of fiber and matrix, and then determine the preparation of the fiber and matrix material to be used.

　　(1) carbon fiber preparation technology, the preparation of carbon fibers using different raw materials, the process is slightly different. If use polyacrylonitrile, acrylonitrile polymerization, spinning, used as flame treatment, carbonization, eventually forming products. If use asphalt, coarse asphalt refining, melt spinning, the final carbonization. The quality of C/C first depends on the quality of carbon fiber.

　　(2) weaving technology: weaving techniques can be divided into one-way weaving and knitting garment. Weaving for at least 2 to garment, to up to 11. Also can be divided into machine weaving and knitting. And subdivided into radial knitting machine and weft knitting. Machine knitting technology was unable to get their products fluff or break easily and widely used; Hand-woven technology because of its product does not exist the faults of knitwear and widely used at home and abroad. Currently use more is wound by hand woven and cross weaving, more advanced weaving is targeted.

　　(3) technology: the formation of woven textiles after for the densification process. Dense technology is divided into liquid impregnation, solid immersion and gas impregnation technology. The current application more is chemical vapor deposition technology.

　　(4) the development of the technology: chemical vapor infiltration process, computer simulation, the C/C composite material density technology, carbon/carbon technology.

　　TE. GW GROUP LTD focus on the production carbon carbon composite material, We have customers all over the world, we have very good reputation, product quality is proved by customers.

　　If you have any enquiry, please feel free to contact us

　　　　High purity graphite is refers to the carbon content is more than 99. 99% which is high strength, high density, high purity, high chemical stability, compact structure, high temperature resistance and high conductive rate,also has a good wear resistance.

　　High purity graphite is widely used in metallurgy, chemical industry, aerospace, Electronics, Mechanics, Nuclear power industry etc.

　　Graphite purification method is mainly divided into two categories,one is the wet purification, including flotation, acid-alkali, hydrofluoric acid.The other is the fire purification method, including chlorination roasting method and high temperature method.In addition,with petroleum coke as raw materials to produce high grade fine particles of high purity graphite is also widely used.

　　The production process is:

　　Raw material→calcinations→crocus→ingredients→mix and knead→fine powder→molding→baking→dipping→graphitization.

　　Under the 2000~2800℃ high temperature, freon gases and chlorine gas are bubbled into it,to make impurity elements form chloride and fluoride volatile escape,when the temperature dropped to1800℃,pure nitrogen is bubbled into,and excess chlorine, fluorine gas discharged,to get the purpose of purification.

　　The fine structure and high purity graphite’s particle size is going to be smaller and smaller, particles of 5~l0μm structure of the graphite material has been industrialized production. Small pitch mesophase sphere as raw material to make the fine structure of high purity graphite which has been used.

　　When choosing purification methods, should consider the nature of the raw material, process characteristics and environmental factors.

　　The graphite crucibles can be divided into two major kinds by the raw material , the first kind is the pure graphite crucibles , with the raw material of the pure graphite blocks and rods , with the different uses and dimensions requirements of the crucibles , we can decide which kind of the graphite material be used , such as the isostatic graphite blocks and rods , moulded graphite blocks and rods , vibracation graphite blocks and rods , extruded graphite blocks and rods . We can aslo make the production and machining of required dimensions and drawings by the customers ; The second kind is the pressed graphite crucibles , it can be divided into the Clay graphite crucibles and the SIC graphite crucibles , in China market the customers always use the Clay graphite crucibles as it is with much lower prices and higher cost performance and for SIC graphite crucibles are widely accepted by the foreign customers with the much longer use life and reliable quality .

　　Pure Graphite crucibles are most widely usded in the melting of the precious metals , such as the gold , silver and so on . the pressed graphite crucibles can be divided into the crucibles for the use of melting copper and the crucibles for the use of melting aluminum , and also the crucibles that can be used to melting both the copper and aluminum. The advantages of the clay graphite crucibels as The Abnormity -Crucible contains spouted crucible and heightened crucible and thinned crucible. The heightened crucible is applicable in deep chamber and the spouted crucible is applicable in tilting furnace. Large volume and fast heat conduction. The SIC graphite crucibles are with better performance and longer use life. its working lifetime is increased 3-5 times over normal clay-crucible due to the compact body formed under high pressure. new heat conduction material ensures faster heat conductivity and pollution-free product and reduces adherent slag. high-density body and low apparent porosity greatly improve its heat conductivity. The SIC graphite crucibles is with better anti-corrosion than normal clay-crucible and the advanced process dramatically improves its oxidation resistance, which ensures persistent heat conductivity and long working lifetime. high-density body and logical structure make the product better compression property. The sic graphite crucibles Can be used in induction graphite crucible furnace. Please feel free to contact us for the inquiry or demand of the graphite crucibles.

　　Graphite and astronomical silicate material are computed using available laboratory and astronomical data. The exfoliation of graphite is a phase transition involving the vaporization of the intercalate in the graphite. Exfoliated graphite is an expanded graphite with a low density. It is noted that the magnetic dipole contribution to absorption in the infrared wavelengths can be important for conducting particles such as graphite. Formulas are given for evaluating electric and magnetic dipole cross-sections for small particles. Absorption cross-sections are evaluated for graphite and silicate particles with sizes between 0.003 and 1.0 microns, and wavelengths from 300 A to 1000 microns. On the basis of polarization profiles computed for both prolate and oblate graphite-silicate spheroids, it is concluded that interstellar silicate grain are predominantly oblate. Extinction curves are calculated for Mathis-Rumpl-Nordsieck graphite-silicate grain mixtures and are compared to observations. The model is found to be in good agreement with available infrared observations.

　　This paper reviews the process of the exfoliation of graphite and the exfoliated graphite material. It surveys the applications of exfoliated graphite, covers both reversible and irreversible exfoliation and reviews the methods and mechanism of exfoliation. Other topics include the structure and properties of exfoliated graphite, graphite foils, exfoliated carbon fibres and composites.

　　As a leading Chinese graphite manufacturer and supplier, we specialize in providing high quality graphite material, carbon carbon composites and graphite parts.We have specialized account managers and technicians for each customer who are aligned with their business and can design and deliver solutions and drawings to meet the customers requirements. Our value criterion clearly puts forward the view of customer: We put the customer at the heart of everything we offer.

　　　　As the top graphite manufacturer of China ,Beijing Greatwall Co,.ltd has widely ranged of graphite products production capacity,includes wide range of carbon and graphite products.

　　The graphite is a good conductor of electricity and heat. It can be made into an excellent resistance heating element in the absence of oxygen. High strength can be maintained even when it is used under high temperature. The graphite matrix binds the reinforcement as a whole and transmits the load to the reinforcement, which enables the chemical vapor deposition to complete successfully.

　　The chemical vapor deposition (CVD) is actually a gaseous mass transfer process in the atomic field. The reacting matters react in the gaseous condition and the produced solid matter deposits on the surface of the heated solid substrate, thus obtaining the desired solid material.

　　The high purity graphite (like RINGSDORFF), carbon fiber composite materials (like SIGRABOND) and thermal insulation materials (like SIGRATHERM) are often used in the devices used to produce single crystal silicon, single crystal germanium and group III-V compound single crystal. These devices include crucible, heater, heat shield, draft tube, conductive connecting parts, etc.

　　The graphite electrode can be used for the deposition of polysilicon. The graphite used in this process should have excellent electrical conductivity, a certain degree of thermal conductivity, high mechanical strength, high purity, and high machining precision.

　　Carbon brushes are critical to the operation of the paper machine with direct current (dc) motors.Worn or failed brushes cost thousands of dollars per hour.Proper application of carbon brushes, for varying conditions, will provide optimal brush life and minimal commutator wear electrographitic and graphite(resin-bonded) are the two carbon brush families used extensively.

　　Electrographitic brushes are made from lampblack or carbon black with pitch and tar binders. The carbon material may be kiln fired twice at 1100 degrees Centigrade to burn off the volatiles. Then,it is placed in electric induction or resistive furnaces to graphitization and the temperatures is about 2600 to 3000 degrees Centigrade.

　　Electrographitic grades can also impregnated with resins to enhance their brush life and improve friction characteristics.

　　properties:

　　1、 High Carbon Brush to Commutator Contact Drop

　　2、 Good Commutatio

　　3、 Low Friction

　　4、 Low Abrasiveness

　　5、Current Rating of Approximately 80 APSI.

　　Graphite grades, also called resin-bonded grades, are processed at lower temperatures than electrographitic grades. To manufacture resin-bonded grades, natural graphite or artificial graphite is mixed and bonded with pitch and resins.

　　The graphite materials are baked at temperatures ranging from 200 to 800 degrees Centigrade.

　　Graphite grades can also be impregnated with resins to enhance brush performance.

　　properties:

　　1、 Reduce Threading

　　2、 Good Filming

　　3、 Polishing Action

　　4、 Wider Resistivity Range

　　5、 Current Range of 10 to 65 APSl

　　6、 Laminated Structure

　　Sometimes,various grades operate satisfactory when mixed together in the same motor, but we don’t advocate this. When different brush grades are installed in a dc machine,the electrical and magnetic balance can be affected.

　　The brush holder spring is used to properly hold the carbon brush in contact with the commutator to allow electrical current to flow. It also has an affect on the brush life.The recommended spring pressure for commutator brushes is 3 to 6 PSI.If the brush pressure is below 3 PSI, arcing will occur between the brush and commutator. If the pressure is above 6 PSI,the brush friction will increase, affecting commutator and brush wear.

　　　　Graphite Electrode is mainly usded for steel-making in electric furnace,mineral hot furnace and electric resistance furnace.Graphite electrode conducts electric current into the furnace.Electric current produces arc in the smelting district in the electric furnace,when the temperature increase to about 2000℃,smelting begins.Our a series of graphite electrode is applicable to the common furnace and high power furnace with high pressure and short arc.

　　The graphite electrode must be stored in a clean and dry room. If the graphite electrode is pilled up outdoor, it must be covered with the waterproof cloth and the floors of the pile is prohibited more than 4. In the delivery of graphite electrodes, a waterproof cloth must be covered on the graphite electrodes. When workers are delivering and pilling up graphite electrodes by forklift, collision is prohibited. Only one floor is allowed put each time, and the workers must pay more attention to the balance of the graphite electrodes, it can avoid the graphite electrodes sliding and broken

　　When loading and unloading the graphite electrodes by crane, a steel wire must be used as assistant tool. Hooking the bend of the package directly is prohibited. Before using the graphite electrodes, they need to dry near the electric furnace, the temperature should not exceed 150℃,the time should beyond 24 hours. When using the graphite electrodes, the workers must nip the steel bend by special tool, not by forklift.

　　In the use of graphite electrodes , Clean open socket with compressed air, Screw nipple into socket carefully, not to damage threads. Bring down upper graphite electrode until opening between two electrode becomes 20 to 30mm. Clean out opening between graphite electrodes with compressed air. To avoid the graphite electrode breakage, remove any nonelectro conductive material from furnace. To avoid graphite electrode breakage be sure to place large scrap at furnace bottom and small scrap at top. Graphite electrodes should be stored in dry and clean place. To avoid shock and collision . Be sure to dry them up before use. Please feel free to contact us for the inquiry or demand of the graphite electrodes.