Can a lifting bell jar furnace be evacuated?

The lifting bell jar furnace can be evacuated, and models with vacuum function have significant advantages in material processing, scientific research experiments, and other fields. The specific explanation is as follows:

1. Technical Implementation of Vacuum Function
Vacuum system configuration
Part of the lifting bell jar furnace is equipped with an independent vacuum pump system, which achieves a vacuum environment through the air inlet/exhaust port on the side wall or bottom of the furnace body. For example, a certain model uses a domestically produced vacuum pump with a vacuum degree of up to 5Pa, meeting high vacuum requirements.
Sealing structure design
The furnace door adopts double-layer sealing (such as ceramic fiber+high-temperature resistant silicone pressure strip), combined with a vacuum pump or gas inlet system, which can achieve inert gas protection (such as nitrogen, argon) or vacuum environment to prevent sample oxidation or contamination.
Optimization of furnace materials
The furnace lining is made of refractory materials such as alumina fiber or mullite, combined with vacuum forming technology, to ensure that there is no slag falling or cracking at high temperatures, while improving insulation performance.

2. The core advantage of vacuum function
Prevent material oxidation
In a vacuum environment, materials such as metals (such as titanium alloys) and active metals (such as zirconium and hafnium) can avoid reacting with oxygen, maintaining surface smoothness and performance stability. For example, the elongation of aviation aluminum alloy is significantly improved after vacuum annealing.
Support special processes
High vacuum welding: suitable for welding materials such as diamond grinding wheels and hard cutting tools, with high strength and strong stability.
Solid state electrolyte synthesis: High temperature solid-state reaction is completed under inert gas or vacuum to avoid material performance degradation.
Wafer oxidation/diffusion: Accurate alignment between the wafer and the furnace is achieved through a lifting sample stage, ensuring uniform temperature field and reducing lattice defects.
Improve experimental controllability
Some models are equipped with back mirrors or observation windows, supporting 360 ° observation of material melting and shrinkage processes without blind spots. At the same time, a vacuum environment can reduce gas convection interference and improve temperature field balance.

3. Typical application scenarios
Metal heat treatment
Annealing in vacuum or inert gas to eliminate internal stress in metals, improve plasticity and toughness. For example, the electrical resistivity of copper material decreases after annealing, making it suitable for the manufacturing of wires and cables.
Ceramics and Hard Alloy Sintering
Aluminum oxide ceramics and silicon nitride ceramics are sintered under vacuum to avoid performance degradation caused by oxidation. Tungsten cobalt hard alloys have higher density and enhanced wear resistance in a vacuum environment.
Calcination of lithium battery materials
Optimize the heating curve and insulation time of positive and negative electrode materials (such as ternary materials) to improve battery energy density and cycle life. A vacuum environment can prevent materials from reacting with moisture and oxygen in the air.
Scientific research experiment
In scenarios such as solid-state electrolyte synthesis and catalyst carrier calcination, vacuum function can avoid performance degradation caused by material contact with air, supporting high-precision experimental requirements.

4. Selection and safety precautions
Process requirement matching
If dealing with easily oxidizable materials (such as titanium alloys), priority should be given to models with vacuum function.
For large-sized samples (such as ceramic discs with a diameter>300mm), it is necessary to confirm the furnace opening size and load-bearing capacity.
Heating element selection
Silicon molybdenum rods have a longer lifespan and higher cost, but are suitable for long-term high load operation; Silicon carbon rods (1000-1500 ℃) have a slightly shorter lifespan and lower cost.
Safety operation standards
Do not open the furnace door when the furnace temperature is ≥ 200 ℃ to avoid burns.
The pressure inside the furnace shall not exceed 0.02 MPa (absolute pressure) to prevent equipment damage.
When the temperature of the furnace body is higher than 1000 ℃, the furnace tube needs to maintain a normal pressure state and cannot be in a vacuum state.