Can a small experimental high-temperature tube furnace be ventilated with gas?

The high-temperature tube furnace used in small experiments can pass gas, and the gas inlet function is one of its core characteristics, which can meet various experimental needs. The following is a detailed analysis of its gas inlet function:

1. Implementation method of gas inlet function
Gas supply system
Small high-temperature tube furnaces are typically equipped with independent gas supply modules, including gas cylinders, pressure reducing valves, mass flow controllers (MFCs), and gas pipelines. Gas cylinders store the gases required for experiments (such as argon, nitrogen, hydrogen, oxygen, etc.), and pressure reducing valves regulate the gas pressure to a stable value. MFC precisely controls the gas flow rate (with an accuracy of ± 1% or higher) to ensure the repeatability of experimental conditions.
Furnace inlet design
The furnace body is designed with a dedicated air inlet, usually located at one end or both sides of the furnace tube, connected to the gas pipeline through flanges. The position of the air inlet can be adjusted according to experimental requirements to optimize gas distribution. For example, in the fluidization experiment, the air inlet may be located at the bottom of the furnace tube and coordinated with the distribution plate to achieve uniform fluidization; In the atmosphere protection experiment, the air inlet may be located at both ends of the furnace tube, forming convection to quickly replace the air inside the furnace.
Exhaust and safety system
The other end of the furnace body is equipped with an exhaust port, which is connected to a tail gas treatment device (such as a gas washing cylinder, vacuum pump, or burner) to safely discharge reaction gases or by-products. At the same time, the equipment is equipped with pressure sensors and safety valves to prevent danger caused by excessive pressure inside the furnace. For example, in hydrogen experiments, the system will monitor the pressure and automatically release it to avoid the risk of explosion.

2. Application scenarios of gas inlet function
Atmosphere Protection Experiment
During high-temperature sintering, heat treatment, or crystal growth processes, introducing inert gases such as argon and nitrogen can isolate oxygen and prevent material oxidation. For example:
Metal powder sintering: Under argon protection, metal powders (such as stainless steel and titanium alloys) can be sintered at 1200-1500 ℃ to avoid performance degradation caused by oxidation.
Preparation of ceramic materials: Ceramics such as alumina and silicon nitride are prone to react with oxygen at high temperatures, and introducing nitrogen or argon gas can protect the purity of the materials.
Reducing atmosphere experiment
Introducing reducing gases such as hydrogen and carbon monoxide can achieve material reduction reactions or catalytic research. For example:
Metal oxide reduction: Under a hydrogen atmosphere, copper oxide (CuO) can be reduced to metallic copper (Cu) for the preparation of high-purity metal materials.
Catalytic reaction research: Study the activity and selectivity of catalysts (such as platinum and palladium) for reactions in a hydrogen or carbon monoxide atmosphere.
Oxidative atmosphere experiment
Introducing oxygen or air can simulate an oxidizing environment and study the oxidation behavior or catalytic oxidation reaction of materials. For example:
High temperature corrosion experiment: Study the corrosion rate of metal materials in high-temperature oxygen, providing a basis for material selection.
Catalytic oxidation reaction: Study the catalytic oxidation degradation efficiency of volatile organic compounds (VOCs) in an oxygen atmosphere.
Carbonization/Nitriding Experiment
Introducing gases containing carbon or nitrogen (such as methane and ammonia) can achieve carbonization or nitriding treatment of materials. For example:
Preparation of Silicon Carbide (SiC): In a methane atmosphere, silicon powder reacts with carbon to produce silicon carbide, which is used to prepare high-temperature structural materials.
Titanium nitride (TiN) coating: In an ammonia atmosphere, a titanium nitride coating can be formed on the surface of titanium metal to improve wear resistance and corrosion resistance.
Fluidized bed experiment
Combined with gas inlet function, small high-temperature tube furnaces can be transformed into vertical fluidized beds for fluidized treatment of powder materials. For example:
Powder mixing and reaction: By gas fluidization, powder particles are vigorously mixed to promote contact between reactants and improve reaction efficiency.
Fluidized bed coating: In a fluidized state, the coating material (such as metal or ceramic powder) is uniformly deposited on the surface of the substrate.

3. Key operating points for gas inlet function
Gas purity control
The purity of the gas required for the experiment usually needs to reach 99.99% or above to avoid the influence of impurities on the experimental results. For example, in the preparation of semiconductor materials, even trace amounts of oxygen may lead to a decrease in material properties.
Flow and pressure regulation
Accurately adjust the gas flow rate and furnace pressure according to experimental requirements. For example:
Low flow experiments: For catalytic reaction studies, gas flow rates may be as low as 1-10 sccm (standard cubic centimeters per minute).
High flow experiments, such as fluidized bed experiments, may have gas flow rates as high as 10-100 L/min.
Atmosphere switching and pre-processing
When switching gases, it is necessary to first evacuate to the target pressure (such as 10 ⁻ ³ Pa), and then introduce new gas to avoid interference from residual gases. For example, when switching from an inert atmosphere to an oxidizing atmosphere, it is necessary to completely eliminate the inert gas inside the furnace.
Safety protection measures
Explosion proof design: In experiments with flammable gases such as hydrogen, equipment must have explosion-proof functions, such as using explosion-proof motors and electrostatic grounding.
Gas leakage detection: equipped with gas leakage alarm device, real-time monitoring of gas concentration around the furnace body to ensure experimental safety.