Graphene growth using a small tube furnace in the laboratory

The small tube furnace used in the laboratory performs well in graphene growth, with advantages such as high-precision temperature control, flexible atmosphere control, and independent temperature zone design. However, it should be noted that there are limitations such as limited sample processing capacity and high maintenance costs. The following is a detailed analysis of its technical characteristics, application scenarios, and operational precautions:

1. Technical features
High precision temperature control system
Adopting PID intelligent temperature control technology, the temperature control accuracy can reach ± 1 ℃, supporting 30-50 stage program temperature control, and can accurately simulate the temperature gradient required for graphene growth (such as stress relief at 425 ℃ and lattice recombination at 735 ℃). For example, a 1200 ℃ dual tube three temperature zone tube furnace achieves independent temperature zone control through three independent PID controllers, ensuring a constant temperature zone length of 625mm and temperature uniformity of ± 5 ℃.
Flexible atmosphere control
Support precise ratio of inert gases (argon, nitrogen), reducing gases (hydrogen), and carbon source gases (methane, ethanol). Some models are equipped with three-way mass flow meters with a flow accuracy of ± 0.5%, which can dynamically adjust gas concentration (such as three-stage distribution per minute) to avoid the risk of explosion caused by excessive hydrogen content.
Dual tube and multi temperature zone design
The dual tube structure allows for two experiments to be conducted simultaneously (such as one tube growing graphene and the other tube undergoing annealing treatment), improving efficiency. The three temperature zone design can achieve temperature gradient control to meet the needs of different stages of graphene growth, such as preheating, reaction, and cooling.
Rapid temperature rise and fall capability
By sliding the furnace body or using an efficient air cooling system, rapid temperature rise and fall (such as a maximum heating rate of 20 ℃/min) can be achieved, shortening the experimental period. For example, the graphene specific growth furnace achieves rapid cooling through a sliding furnace body, which is suitable for rapid annealing processes.

2. Application scenarios
CVD method for graphene growth
Place a metal substrate such as copper foil in the center of the furnace tube, introduce a mixture of methane and hydrogen gas, decompose the carbon source at high temperature, and activate the metal lattice to catalyze the assembly of carbon atoms into graphene.
Nanomaterial synthesis
Used for synthesizing nanomaterials such as carbon nanotubes and boron nitride, precise control of material morphology and properties is achieved by controlling reaction temperature and atmosphere in multiple temperature zones.
heat treatment process
The heat treatment of metal materials (such as quenching and tempering) and ceramic materials (such as sintering) requires precise control of temperature and atmosphere to meet different process requirements and improve experimental efficiency.

3. Operation precautions
safe operation
The hydrogen content should not exceed the safety threshold (usually ≤ 5%) to avoid gas-liquid mixing and explosion.
The pressure inside the furnace tube should not exceed 0.02 MPa, and a pressure reducing valve should be installed when introducing gas.
When the temperature of the furnace body is higher than 1000 ℃, the furnace tube cannot be in a vacuum state and must be maintained at atmospheric pressure.
Sample placement optimization
Place the sample according to the temperature distribution curve calibrated by the thermocouple gauge, considering the influence of airflow direction on carbon source distribution. For example, using high-temperature resistant ceramic sample holders to fix copper foils, ensuring a smooth surface to obtain large grain graphene.
Maintenance and Care
Regularly replace heating elements (such as NiCrAl resistance wires) and quartz tubes.
Clean the alumina coating inside the furnace to avoid residual carbon sources affecting heating efficiency.
Check the vacuum pump and pneumatic system to ensure airtightness.