Working principle of large CVD furnace
Place the carbon fiber woven prefabricated body into the furnace, close the furnace cover and vacuum it. When the vacuum degree reaches the required level, start heating up by 1.
Raise the temperature to a certain level (such as 1050 ℃) and introduce carbon source gases, such as natural gas, methane, and other hydrocarbon gases. These gases undergo thermal decomposition at high temperatures to form carbon and hydrogen gas. The carbon is adsorbed and deposited in the pores of the preform, while the hydrogen gas is discharged through the exhaust port.
By precisely controlling parameters such as temperature, pressure, gas flow rate, and deposition time, the preform gradually densifies, ultimately forming carbon carbon composite materials.
Structural composition
Heating system: Resistance heating, graphite induction heating and other methods are usually used, such as isostatic pressing graphite, molded three high graphite, fine particle graphite and other heaters, which can raise the temperature inside the furnace and maintain it within the required deposition temperature range, generally reaching 1500 ℃ or even higher for 24 hours.
Furnace structure: including furnace shell, furnace liner, etc. The furnace shell is generally made of all carbon steel, inner stainless steel or all stainless steel material, which has good strength and corrosion resistance; The furnace liner is often made of materials such as soft carbon felt, soft graphite felt, or hard composite felt to provide insulation and reduce heat loss.
Gas path system: composed of inlet and outlet pipelines, valves, flow meters, etc., it can accurately control the flow and pressure of carbon source gas, protective gas (such as nitrogen), etc., so that the gas is evenly distributed in the furnace, ensuring the stability and consistency of the deposition process.
Vacuum system: Using vacuum pumps and vacuum gauges, such as anti fouling pumps or slide valve pumps combined with Roots pumps, the furnace can be pumped to the required high vacuum degree to eliminate air and other impurities, ensuring that the deposition process is carried out in a pure atmosphere and improving the quality of composite materials.
Control system: Through human-machine interfaces such as touch screens and industrial computers, as well as related electrical components and control software, precise settings and real-time monitoring of parameters such as temperature, pressure, gas flow rate, and deposition time inside the furnace are achieved to automate the deposition process and ensure the stability and repeatability of product quality.
Performance characteristics
High purity and uniformity: Carbon carbon composite materials with high purity and uniform distribution can be prepared, which have good chemical and structural uniformity and can meet the strict requirements for material performance in aerospace, high-end equipment manufacturing and other fields.
Precise control and repeatability: The sedimentation conditions, including temperature, pressure, gas flow rate, sedimentation time, and other parameters, can be precisely controlled to achieve a highly reproducible sedimentation process and ensure the stability of product quality.
Complex structure adaptability: suitable for preparing carbon carbon composite materials with complex structures, such as multi-layer structures, shaped components, etc., which can meet the diverse needs of different fields.
application area
Aerospace field: used for manufacturing aircraft brake discs, engine hot end components, rocket nozzles, satellite structural components, etc., which can reduce aircraft weight, improve performance and reliability.
In the field of energy, such as neutron absorbing materials in nuclear reactors, first wall materials in nuclear fusion devices, and heat absorbing tubes in solar water heaters, they have good high temperature resistance, corrosion resistance, and radiation resistance.
In the automotive industry, it can be used to manufacture brake pads, brake discs, engine components, etc., which can improve the braking performance and fuel economy of cars, while reducing the weight of the vehicle.
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