pyrolytic graphite
Pyrolytic graphite is a new type of carbon material. It is a pyrolytic carbon with high crystal orientation, which is deposited by chemical vapor deposition of high-purity hydrocarbon gas on a graphite matrix at 1800 ° C ~ 2000 ° C under a certain furnace pressure. It has high density. (2.20g/cm³), high purity (impurity content (0.0002%) and thermal, electrical, magnetic and mechanical properties anisotropy. It can still maintain a vacuum of 10mmHg at around 1800°C.
What is the production process of pyrolytic graphite?
Raw material
Gaseous or liquid hydrocarbons. Such as methane, acetylene, propane, natural gas, benzene, toluene, etc., can be used as raw materials for depositing carbon. The carrier gas or diluent gas includes inert gases such as nitrogen and argon. The matrix is refractory metals and their compounds, artificial graphite, the latter is usually used.
Process parameters
Deposition temperature: 1750 ~ 2250 ℃, furnace pressure: 0.67 ~ 67hPa, gas flow: according to the size of the deposition furnace, determined by experiments. The above deposition temperature, furnace pressure and gas flow have a decisive impact on the quality of the product, and must be strictly maintained within the following fluctuation ranges: pressure ±0.6hPa, flow ±5%, and temperature ±20°C.
The deposition rate depends on the above-mentioned process parameters. The temperature is high, the furnace pressure is large, the flow rate is large, and the deposition speed is fast. The specific parameters should be determined by the experiment according to the size of the deposition furnace.
Heating method
It can be divided into direct heating method and indirect heating method. (1) Direct heating method The substrate itself is energized to generate high temperature. This method is suitable for parts with thin deposition body, simple shape and small volume. Suitable for research work. (2) Indirect heating method The substrate is placed inside or outside the heating body and heated to a high temperature by the radiation of the heating body. This heating method can be used with resistance heating and induction heating. This method, especially induction heating, is more suitable for producing parts with large size, large thickness and complex shape. The hot zone of the large deposition furnace has a diameter of 2500mm and a height of about 3000mm.
What is pyrolytic graphite used for?
Used to coat graphite cuvettes (tubes) in graphite furnace atomic absorption furnaces to decrease heat stress, thus increasing cuvette lifetimes. Pyrolytic carbon is used for several applications in electronic thermal management: thermal-interface material, heat spreaders (sheets) and heat sinks (fins).
How do you make pyrolytic graphite?
To make pyrolytic graphite, methane gas at low pressure (about 1 Torr) is heated to 2000 degrees Celsius. Very slowly, (one thousandth of an inch per hour) a layer of graphite grows. The graphite made this way is very highly ordered, and the layers of carbon atoms form like a crystal of hexagonal sheets.
High quality pyrolytic graphite supplier
Luoyang Moon & Star New Energy Technology Co., LTD, founded on October 17, 2008, is a high-tech enterprise committed to developing, producing, processing, selling, and technical services of lithium-ion battery anode materials. After more than 10 years of development, the company has gradually developed into a diversified product structure with natural graphite, artificial graphite, composite graphite, intermediate phase, and other negative materials (silicon-carbon materials, etc.). The products are widely used in high-end lithium-ion digital power and energy storage batteries.
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