What gases can be passed through a high-temperature gas vacuum tube furnace?

The high-temperature gas vacuum tube furnace can be filled with a variety of gases, including inert gases, reducing gases, oxidizing gases, and mixed gases, as follows:

1. Inert gas
Nitrogen (N ₂)
Purpose: To provide an anaerobic environment and prevent oxidation of materials such as metals and ceramics at high temperatures.
Application scenarios: metal annealing, ceramic sintering, semiconductor material preparation, etc.
Advantages: Low cost, easy to obtain, suitable for experiments with low purity requirements.
Argon gas (Ar)
Usage: As a high-purity inert protective gas, it prevents material oxidation or contamination.
Application scenarios: aircraft engine blade annealing, carbon nanotube synthesis, high-purity metal purification, etc.
Advantages: Stable chemical properties, suitable for experiments with high purity requirements.
Helium (He)
Purpose: As a backup protective gas, it can quickly fill the furnace cavity to respond to emergency situations.
Application scenario: Emergency protection when replacing reaction tubes at high temperatures.
Advantages: Good thermal conductivity, can quickly and uniformly maintain the temperature inside the furnace.

2. Reducing gas
Hydrogen (H ₂)
Usage: As a reducing agent, it removes oxygen from the surface of metal oxides or promotes reduction reactions.
Application scenarios: Metal oxide semiconductor doping, catalyst preparation, etc.
Attention: It is necessary to strictly control the concentration and flow rate to prevent the risk of explosion.
Carbon monoxide (CO)
Usage: As a reducing gas, it participates in specific chemical reactions.
Application scenarios: High temperature reactions of chemical raw materials, synthesis of special materials, etc.
Attention: Toxic gases require exhaust gas treatment equipment.

3. Oxidizing gas
Oxygen (O ₂)
Purpose: To provide an oxidizing environment in specific processes, such as metal oxidation or catalyst activation.
Application scenarios: preparation of metal oxide films, surface oxidation treatment of catalysts, etc.
Caution: It should be mixed with other gases to avoid excessive oxidation.
Carbon dioxide (CO ₂)
Usage: As an oxidizing medium, it participates in carburizing or oxidation reactions.
Application scenarios: nitrogen based atmosphere carburizing process, special material oxidation treatment, etc.

4. Mixed gas
Nitrogen hydrogen mixture (N ₂+H ₂)
Purpose: To protect heating while providing a reducing environment, prevent oxidation, and promote reduction reactions.
Application scenarios: metal heat treatment, semiconductor material preparation, etc.
Nitrogen hydrocarbon mixture (N ₂+hydrocarbons)
Purpose: To protect heating or serve as a carburizing carrier gas, increasing the surface carbon content of materials.
Application scenarios: Powder metallurgy sintering, metal surface carburizing treatment, etc.
Nitrogen carbon hydrogen oxidation mixture (N ₂+hydrocarbons+CO ₂/H ₂ O/air)
Purpose: To control carbon potential and optimize material properties in carburizing process.
Application scenarios: high-precision gear manufacturing, carburizing treatment of mold steel, etc.
Nitrogen methanol mixture (N ₂+CH ∝ OH)
Purpose: To protect heating or serve as a carburizing carrier gas, providing a controllable carbon source.
Application scenarios: Precision parts carburizing, synthesis of special materials, etc.