A high-temperature aluminum nitride sintering furnace creates a vacuum inside the furnace chamber by using a vacuum system (assembled from vacuum pumps, vacuum gauges, vacuum valves, and other components). After partial gases are removed and the pressure drops below one atmosphere, the chamber reaches a vacuum state — this is what forms a vacuum furnace.
It is a heating device that operates in a vacuum environment. The sealed furnace chamber—made of a metal enclosure or quartz glass cover—is connected to a high-vacuum pumping system. The vacuum level in the furnace can reach 133 × (10⁻² to 10⁻⁴) Pa. The heating system inside the furnace may use resistance heating (such as tungsten filaments) or high-frequency induction heating. The maximum temperature can reach about 3000°C. It is mainly used for ceramic sintering, vacuum smelting, degassing of vacuum electronic components, annealing, metal brazing, as well as ceramic-to-metal sealing processes.
Structure
A sintering furnace is generally composed of a main unit, furnace chamber, heating elements, sealed furnace shell, vacuum system, power supply system, temperature control system, and external material-transport cart.
The sealed furnace shell is welded from carbon steel or stainless steel, and any detachable joints are sealed with vacuum sealing materials. To prevent deformation of the furnace shell or deterioration of sealing materials due to high temperature, the furnace shell is usually cooled by water or air.
The furnace chamber is located inside the sealed shell. Depending on its intended application, various heating elements may be installed inside—such as resistance heaters, induction coils, electrodes, or electron guns.
Vacuum furnaces used for metal smelting are equipped with crucibles, and some also include automatic casting systems or robotic handling devices for loading and unloading materials.
The vacuum system is mainly composed of vacuum pumps, vacuum valves, and vacuum gauges.