Vacuum pumping of tube muffle furnace

The tubular muffle furnace can be evacuated, and its vacuuming function is achieved through an integrated vacuum system (such as mechanical pumps, diffusion pumps). The core purpose is to create an oxygen free or specific atmosphere environment, prevent materials from reacting with oxygen at high temperatures, and meet process requirements such as degassing and special reactions. The following is a detailed explanation:

1. The necessity of vacuuming
Avoid oxidation: At high temperatures, materials are prone to react with oxygen in the air, leading to performance degradation or failure. Vacuuming can eliminate oxygen and protect materials.
Degassing treatment: Removing adsorbed gases or volatile impurities from the material to improve its purity.
Special reaction: Supports processes such as chemical vapor deposition (CVD) and sputtering coating under vacuum to achieve the preparation of nanomaterials and thin films.

2. Steps for vacuuming
preparation:
Check the sealing of the tube furnace to ensure that all connecting parts are leak free.
Connect the vacuum pump and inert gas cylinders (such as nitrogen and argon), prepare pressure gauges and flow meters.
Pre vacuuming:
Close all valves, start the vacuum pump, and open the vacuum valve.
Observe the pressure gauge, wait for the vacuum degree to stabilize, and then close the vacuum valve and vacuum pump.
Fill with inert gas:
Open the valve of the inert gas cylinder and slowly fill it with gas.
Observe the pressure gauge and wait for the furnace pressure to return to normal before closing the gas valve.
Repeat vacuuming and inflation:
Repeat the above steps of vacuuming and inflating to further improve the purity of the inert gas in the furnace and eliminate residual oxygen.
According to experimental requirements, this process may need to be repeated multiple times.
High vacuum extraction (if required):
For experiments that require higher vacuum levels, the diffusion pump can be turned on, the switch of the vacuum unit can be pushed in, and the cooling water can be turned on at the same time.
When the vacuum degree reaches the required level, heating begins.
Heating and insulation:
Heat treatment is carried out in a vacuum environment, and the temperature, heating rate, and holding time are set according to the process requirements.
Cooling and Sampling:
After the program is completed, the device will automatically cool down or manually start air/water cooling.
When the temperature drops to a safe range (such as ≤ 100 ℃), prepare to take samples.
Turn off the diffusion pump (if used), pull out the vacuum unit switch, and turn off the cooling water and mechanical pump after the diffusion pump cools down.
After venting, open the furnace door and take out the sample.

3. Precautions for Vacuum Extraction
Sealing inspection: Before vacuuming, it is necessary to check whether the various connection parts of the tube furnace are well sealed to avoid gas leakage.
Pressure control: During the process of vacuuming and inflating, close attention should be paid to the reading of the pressure gauge to avoid damage to the equipment caused by rapid pressure changes.
Vacuum pump selection: Choose the appropriate vacuum pump and vacuum degree according to the experimental requirements to avoid the impact of too high or too low vacuum degree on the experiment.
Safe operation: Follow the safety operation procedures and avoid opening the furnace door in a vacuum state to prevent sudden air influx and damage to the sample or equipment.
Equipment maintenance: Regularly maintain the tube furnace, including replacing heating elements, cleaning the vacuum system, checking power lines, etc., to ensure the normal operation and service life of the equipment.

4. Application scenarios of vacuum pumping
Metal material processing: such as vacuum annealing and quenching, to prevent metal oxidation at high temperatures.
Ceramic material sintering: Sintering ceramic materials under vacuum or inert gas protection to improve material properties.
Preparation of nanomaterials, such as carbon nanotubes and graphene, requires a vacuum environment to avoid impurity contamination.
Semiconductor material processing, such as cleaning silicon wafers and removing oxide films, requires a high-purity vacuum environment.