Small tube furnace sintering experiment for laboratory use

The small tube furnace used in the laboratory performs excellently in sintering experiments. It achieves uniform temperature control through resistance heating and radiation heat transfer. Combined with an efficient gas control system and sealing structure, it can meet the sintering needs of materials such as powder metallurgy, ceramics, and semiconductors. At the same time, strict adherence to operating procedures is required to ensure experimental safety and effectiveness. The following provides a detailed explanation from three aspects: technical principles, operating procedures, and safety precautions:

Technical Principle
Resistance heating: Small tube furnaces typically use resistance wires or silicon carbide rods as heating elements, which convert electrical energy into thermal energy based on Joule’s law (Q=I ² Rt) to regulate the temperature inside the furnace.
Radiant heat transfer: The heat generated by the heating element is transferred to the furnace tube and the sample inside the tube in the form of thermal radiation, without the need for a medium, and can also be carried out in vacuum to ensure uniform heating of the sample.
Temperature control: Using thermocouples or thermistors as temperature sensors to measure the temperature inside the furnace in real time, and adjusting the power supply of the heating element through PID control algorithm to stabilize the temperature near the set value.
Atmosphere control: Equipped with a high-precision mass flow controller, it can accurately control gas flow rate, support mixing and switching of single or multiple gases, and meet the requirements of different experimental atmosphere components.
Sealing structure: Both ends of the furnace tube are equipped with stainless steel flanges and high-temperature resistant sealing rings, which are fastened with bolts to achieve high airtightness and prevent external air from entering the furnace, ensuring that the experiment is not affected by external gas interference.

operating steps
Experimental preparation:
Check if the equipment is in normal condition, including whether the heating elements, furnace tubes, seals, and other components are intact.
Clean the furnace and heating elements of debris to ensure equipment cleanliness.
Prepare samples, boats, heating elements, gases, etc. according to experimental requirements.
Sample installation and sealing:
Open the inlet flange and place the sample in the sample boat to ensure good contact between the sample and the furnace tube.
Close the furnace door and tighten the flange screws evenly to ensure sealing.
Atmosphere setting:
Select appropriate gases as protective or reactive gases according to experimental requirements.
Connect the gas circuit and use soapy water to detect leaks at each joint to confirm that there is no air leakage.
Adjust the gas flow rate through a mass flow controller to ensure a stable gas environment is provided to the furnace according to experimental requirements.
Heating and insulation:
Start the device and wait for it to preheat to the specified temperature.
According to the experimental requirements, set the heating curve, holding time, and cooling curve.
Start the control system and initiate the sintering process.
During the experiment, closely observe parameters such as temperature and pressure inside the furnace to ensure the smooth progress of the experiment.
End of experiment and sampling:
After the experiment is completed, turn off the heating program and wait for the furnace temperature to drop to room temperature.
Turn off the gas source, take out the sample, and check the sintering effect.

Safety precautions
Equipment safety:
Operators must be familiar with the performance and operating procedures of the equipment, and untrained personnel are not allowed to operate the equipment.
Before operation, check whether the equipment is in normal condition. If there is any abnormality, stop the operation immediately and report to the relevant department in a timely manner.
During the operation, unrelated personnel are strictly prohibited from entering the operation area.
Personal protection:
Operators should wear protective equipment such as gloves, glasses, earplugs, etc.
During the operation, it is strictly prohibited to touch high-temperature components to prevent burns.
Experimental safety:
During the operation, if any equipment abnormalities are found, the operation should be stopped immediately and dealt with promptly.
It is strictly prohibited to carry out maintenance, adjustment and other operations during the operation of the equipment.
During the experiment, it is strictly prohibited to arbitrarily change the equipment parameters.
For experiments containing flammable and explosive gases, comprehensive safety measures should be equipped, such as gas leak detection sensors, explosion-proof valves, etc.
Environmental safety:
The instrument should be placed indoors with good ventilation, and no flammable or explosive materials should be placed around it.
After the experiment is completed, the experimental site should be cleaned up in a timely manner, and the power and gas sources should be turned off to ensure the safety of the equipment.