Desktop Mini Tube Furnace Sintering Experiment

Desktop mini tube furnace sintering experiment is an efficient and flexible experimental method in the field of materials science. Its core principle is to convert electrical energy into thermal energy through resistance heating elements (such as resistance wires and silicon carbon rods), and use thermal radiation and convection to evenly transfer heat to the samples inside the furnace tube, achieving high-temperature sintering. The following analysis will be conducted from four aspects: experimental principles, operating procedures, precautions, and typical applications:

1. Experimental principle
Resistance heating:
The heating element operates based on Joule’s law (Q=I ² Rt), and generates heat when current passes through the resistive element. By adjusting the current magnitude and energization time, the furnace temperature can be precisely controlled. For example, small tube furnaces used in 1200 ℃ laboratories typically use silicon carbon rods as heating elements to achieve efficient heating.
Thermal radiation and convection:
The heat generated by the heating element is transferred to the furnace tube and sample in the form of thermal radiation, while the gas inside the furnace circulates through forced convection to ensure temperature uniformity. This dual heat transfer mechanism enables the temperature difference inside the furnace to be controlled within ± 5 ℃, meeting the requirements of high-precision sintering.
Atmosphere control:
By using gas flow controllers and vacuum pumps, the atmosphere inside the furnace can be precisely adjusted (such as nitrogen, argon protection, or hydrogen reduction). For example, in metal powder metallurgy sintering, introducing hydrogen gas can reduce metal oxides and improve powder purity; In ceramic sintering, introducing nitrogen gas can prevent material oxidation.

2. Operation steps
Experimental preparation:
Place the tube furnace on a well ventilated and dry surface, and check the power cord and switch status.
Select appropriate furnace tubes (such as quartz and corundum tubes) and heating chambers according to experimental requirements, ensuring that the distance between the sample and the heating source is reasonable.
Prepare samples for sintering, such as metal powder compacts, ceramic bodies, etc., and confirm that there is no impurity contamination.
Installation sample:
Place the sample carefully in the center of the furnace tube to avoid uneven temperature caused by contact with the furnace wall.
Seal the flanges at both ends of the furnace tube to ensure airtightness and prevent external air from entering.
Set parameters:
Set the heating program through the temperature control instrument (such as heating up to 1200 ℃ at a rate of 5 ℃/min and holding for 2 hours).
Select the atmosphere mode according to the experimental requirements (such as inert protection, reducing atmosphere, or vacuum environment).
Run experiment:
Start the power supply, and the electric furnace will heat up according to the preset program.
Real time monitoring of temperature changes, automatic adjustment of heating power through PID control algorithm to maintain temperature stability.
Experiment completed:
After the experiment is completed, adjust the temperature control knob to the minimum and gradually cool down.
After the furnace temperature drops below 200 ℃, open the furnace door and take out the sample.
Turn off the power, clean the furnace and shell.

3. Precautions
Safe operation:
It is strictly prohibited to cross the maximum temperature of the equipment (such as 1200 ℃) to avoid damage to the furnace tube or experimental failure.
When collecting samples, the power must be cut off and heat-resistant gloves must be worn to prevent electric shock or burns.
Keep the furnace door closed for the shortest possible time to reduce the service life loss of the electric furnace.
Sample processing:
The sample should be dry and free of oil stains, and the fixture should be clean and dry to avoid the risk of fire.
Do not inject any liquid into the furnace to prevent tube rupture.
Atmosphere control:
During the ventilation experiment, a stable airflow is required, and an anti backflow device and exhaust gas collection system should be installed at the outlet.
During vacuum experiments, it is necessary to check the sealing to prevent air leakage from causing experimental failure.
Equipment maintenance:
Regularly clean the furnace and heating elements, check the power lines and switch status.
Rest after prolonged use to avoid overheating and affecting the performance of the equipment.

4. Typical applications
Metal powder metallurgy:
Sintering stainless steel powder in a hydrogen atmosphere with low porosity, used for 3D printing of metal parts.
Example: A laboratory obtained high-density components with high tensile strength by sintering iron-based powder in a tube furnace.
Preparation of ceramic materials:
Sintering alumina ceramics at 1400 ℃ in a nitrogen atmosphere results in high density and is used for electronic packaging substrates.
Example: A research team used a tube furnace to sinter silicon nitride ceramics, which have higher hardness and are suitable for cutting tools.
Preparation of catalyst support:
Calcination of γ – Al ₂ O3 in a nitrogen atmosphere at 800 ℃, with a large specific surface area, is used for automobile exhaust purification.
Example: A certain enterprise prepares Pt/Al ₂ O3 catalyst through a tube furnace, which has a higher CO conversion rate.
Nanomaterial synthesis:
Synthesize high-purity TiO ₂ nanoparticles by pyrolyzing the precursor in an argon atmosphere at 1000 ℃.
Example: A certain university uses a tube furnace to synthesize graphene with less than 5 layers, resulting in better conductivity.