What processes can gas filled tube furnaces be used for?

The gas filled tube furnace can achieve diversified functions in material processing, chemical reactions, and experimental control by controlling the type and flow rate of gas introduced. It is widely used in the following processes:

1. Material synthesis and preparation
Nanomaterial synthesis
Chemical Vapor Deposition (CVD): A precursor gas (such as silane or methane) is introduced at high temperatures to deposit nano films or nanowires on a substrate. For example, carbon nanotubes can be grown on a substrate by introducing acetylene gas.
Solvothermal method: In a closed tube furnace, high-temperature and high-pressure solvents are used to promote the dissolution and crystallization of reactants and control the size of nanoparticles.
Preparation of metal nanoparticles: high-purity metal nanoparticles (such as copper and silver) are prepared by introducing argon gas protection and another section of hydrogen gas for reduction reaction.
Ceramic material sintering
Preparation of high-performance ceramics: High temperature sintering of ceramics such as alumina, silicon nitride, boron carbide, etc. in inert gases (such as argon and nitrogen) to prevent powder oxidation or decomposition.
Nitriding/Carbonization Reaction: Nitrogen or carbon source gas (such as methane) is introduced to achieve the synthesis of silicon nitride or silicon carbide ceramics.
Semiconductor material growth
Epitaxial growth: Forming a single crystal thin film on a single crystal substrate by high-temperature deposition, used to manufacture high electron mobility transistors (HEMTs).

2. Metal Heat Treatment and Surface Modification
Annealing and quenching
Inert protection: Eliminating internal stress in metals in argon gas to improve processing performance (such as annealing of titanium alloy aviation parts).
Reaction gas participation: methane or carbon monoxide is introduced to achieve carburizing or nitriding of metal surfaces, improving hardness (such as tool surface hardening).
Metal reduction
Oxide reduction: In metallurgy or chemical engineering, reducing gases such as hydrogen and carbon monoxide are introduced to reduce metal oxides to metallic elements. For example, hydrogen can reduce copper oxide to copper while generating water vapor for discharge.

3. Chemical Analysis and Sample Preparation
Sample ashing
Oxidation of organic matter: During the ashing process of the sample, air is introduced into one section to oxidize the organic matter, and nitrogen is introduced into the other section to remove the oxidation products, achieving sample ashing and improving the accuracy and sensitivity of analysis.
Catalyst evaluation
Activity testing: Introduce methane and oxygen to test the methane combustion activity of the catalyst.
Carrier pretreatment: High temperature calcination of alumina carrier to remove surface impurities and adjust pore structure.

4. Development of new energy materials
Preparation of lithium-ion battery materials
Solid phase reaction: Promote the reaction between lithium salts and transition metal oxides at high temperatures to synthesize layered or spinel structured electrode materials.
Interface optimization: Improve electrode/electrolyte interface contact and reduce impedance through high-temperature treatment. For example, calcining lithium manganese based cathode materials in oxygen can increase capacity.
Hydrogen fuel cell materials
Heat treatment of electrode material: Heat treat carbon supported platinum catalyst at 800 ℃ in argon gas to enhance the activity of oxygen reduction reaction.

5. Special environment simulation and material testing
Corrosion resistance test
Corrosive atmosphere simulation: Introduce corrosive gases such as SO ₂, CO ₂, H ₂ S, and combine them with high-temperature accelerated corrosion processes to evaluate material life (such as sulfur corrosion resistance testing of boiler steel pipes).
Radiation damage simulation
Screening of nuclear waste container materials: Simulate irradiation damage at 900 ℃ in argon gas to test the anti swelling performance of the materials.

6. Other applications
Preparation of Carbon Fiber Reinforced Composite Materials
In situ reaction: promotes chemical reactions between the matrix and the reinforcement at high temperatures (such as the reaction of Si and C to form SiC), forming strong interfacial bonding.
Hot pressing molding: Combining high temperature and pressure to promote material densification and reduce porosity (such as carbon fiber reinforced silicon carbide composite materials for space shuttle nose cones).
Fluid transportation and product separation
Catalytic reaction carrier gas: In catalytic reactions, a gas (such as nitrogen) is used as a carrier gas to bring reactants into the reaction zone, ensuring uniform mixing and reaction efficiency.
Volatile product extraction: By controlling the gas flow rate, volatile products can be extracted in a timely manner to avoid reverse reactions or blockages.