Process application of vacuum furnace in sintering field
01-13-2025 Author: KJ technology
Vacuum furnaces have a variety of process applications in the sintering field, covering metal materials, ceramic materials, composite materials and other aspects. The following is a detailed introduction:
Metal material sintering
Powder metallurgy: In the manufacture of powder metallurgy parts, metal powder is pressed into shape and then placed in a vacuum furnace for sintering. The vacuum environment can prevent metal powder from oxidizing at high temperatures, allowing metal powder particles to achieve necking growth through atomic diffusion, and eventually form dense metal parts. For example, some gears, sprockets and other parts in automobile engines are manufactured through the powder metallurgy process of vacuum furnace sintering, which can improve material utilization, reduce costs, and ensure the accuracy and performance of parts.
Refractory metal sintering: For refractory metals such as tungsten and molybdenum, due to their extremely high melting points, sintering is difficult and easy to oxidize under ordinary conditions. The vacuum furnace provides a high-temperature, low-oxygen sintering environment for it, which can effectively promote the diffusion and bonding of refractory metal atoms and make them dense. For example, in the manufacture of electron tubes, the use of vacuum furnaces to sinter tungsten wires, molybdenum electrodes and other parts can ensure their performance and stability at high temperatures.
Metal Injection Molding (MIM): In the MIM process, after the metal powder is mixed with the binder and injected into the mold, it needs to be degreased and sintered in a vacuum furnace. The vacuum furnace can gradually remove the binder and sinter the metal powder at different temperature stages. The precise control of the process parameters can ensure the dimensional accuracy and performance of the parts. It is widely used in the manufacture of small precision metal parts, such as metal components in electronic products such as mobile phones and watches.
Sintering of Ceramic Materials
Sintering of Structural Ceramic: For structural ceramics such as alumina and silicon nitride, vacuum furnace sintering can improve the density and performance of ceramics. In a vacuum environment, gas impurities in the ceramic raw materials are easier to discharge, reducing the formation of pores and defects. For example, in the manufacture of ceramic tools, silicon nitride ceramic tools sintered in a vacuum furnace have higher hardness, wear resistance and toughness, and excellent cutting performance.
Sintering of Functional Ceramic: For functional ceramics such as piezoelectric ceramics and thermistor ceramics, sintering in a vacuum furnace can accurately control their chemical composition and microstructure, thereby achieving the regulation of their electrical, thermal and other functional properties. For example, barium titanate-based thermistor ceramics sintered in a vacuum furnace have good resistance-temperature characteristics and can be used to manufacture electronic components such as temperature sensors.
Composite material sintering
Metal-based composite materials: In the preparation of metal-based composite materials, the metal matrix is mixed with the reinforcing phase (such as carbon fiber, ceramic particles, etc.) and then sintered in a vacuum furnace. The vacuum environment helps to uniformly distribute the reinforcing phase in the metal matrix and improve the interface bonding strength between the reinforcing phase and the metal matrix, thereby improving the comprehensive performance of the composite material. For example, in the field of aerospace, aluminum-based silicon carbide particle-reinforced composite materials prepared by vacuum furnace sintering have the advantages of high specific strength and high specific modulus, and can be used to manufacture aircraft wings, fuselage structural parts, etc.
Ceramic-based composite materials: For ceramic-based composite materials, vacuum furnace sintering can better combine the ceramic matrix with the reinforcing fibers or particles, and improve the fracture toughness and thermal shock resistance of the material. For example, silicon carbide fiber-reinforced silicon carbide ceramic-based composite materials can be used to manufacture high-temperature components such as thermal barrier coatings for aircraft engines and blades for gas turbines through vacuum furnace sintering.
Other applications
Cemented carbide sintering: Cemented carbide is a composite material composed of refractory metal carbides (such as tungsten carbide, titanium carbide, etc.) and bonding metals (such as cobalt, nickel, etc.). Vacuum furnace sintering can effectively remove impurities and gases in cemented carbide, and improve the hardness, wear resistance and toughness of cemented carbide. In the fields of cutting tools, molds, etc., cemented carbide products sintered in vacuum furnaces have better cutting performance and service life.
Magnetic material sintering: For magnetic materials such as permanent magnetic materials and soft magnetic materials, vacuum furnace sintering can control their microstructure and chemical composition and improve magnetic properties. For example, in the production of NdFeB permanent magnetic materials, the vacuum furnace sintering process can enable the material to obtain higher remanence, coercive force and maximum magnetic energy product, which is widely used in motors, electronic equipment and other fields.
