High temperature vacuum atmosphere tube furnace tube material

The material of the furnace tube in a high-temperature vacuum atmosphere tube furnace needs to be selected comprehensively based on the operating temperature, atmosphere environment, and experimental requirements. The following are common materials and their characteristic analysis:

1. High temperature stable material
Corundum tube (Al ₂ O ∝)
Temperature resistance range: Long term use ≤ 1600 ℃, short-term can withstand 1700 ℃.
Characteristics: High temperature resistance, chemical corrosion resistance (excluding hydrofluoric acid), strong thermal shock resistance, good transparency for easy observation of reactions.
Applicable scenarios: Vacuum, inert atmosphere (such as argon, nitrogen) or weakly reducing atmosphere (such as hydrogen), commonly used in ceramic sintering, semiconductor material preparation, etc.
Attention: Mechanical impact and sudden cooling and heating should be avoided. It is recommended that the heating and cooling rate be ≤ 5 ℃/min.
Silicon carbide tube (SiC)
Temperature resistance range: Long term use ≤ 1600 ℃, some high-performance pipes can withstand 1800 ℃.
Characteristics: Excellent thermal conductivity (5-10 times that of corundum tube), fast heating rate, and good temperature uniformity; High mechanical strength, wear resistance, and strong thermal shock resistance; Strong corrosion resistance and can tolerate some reducing atmospheres (such as CO).
Applicable scenarios: Experiments with high temperature and high thermal conductivity requirements, such as metal heat treatment, crystal growth, etc.
Attention: Long term use in a strongly oxidizing atmosphere may result in oxidation.
Zirconia tube (ZrO ₂)
Temperature resistance range: can withstand up to 2000 ℃ or above.
Characteristics: Low thermal conductivity and high chemical inertness, excellent high temperature resistance.
Applicable scenarios: Metal melting or ceramic sintering in ultra-high temperature environments.
Attention: The cost is relatively high and it is mostly used for precision experiments or special industrial fields.

2. Metal material
Molybdenum tube (Mo)
Temperature resistance range: Long term use ≤ 1700 ℃, can withstand above 2000 ℃ under vacuum or inert atmosphere.
Characteristics: High melting point (2610 ℃), stable strength at high temperatures, excellent conductivity and thermal conductivity.
Applicable scenarios: Ultra high temperature vacuum or inert atmosphere experiments, such as sintering of refractory metals and heat treatment of high-temperature alloys.
Attention: It is prone to oxidation at room temperature and should be used in a vacuum or inert atmosphere; High cost, poor corrosion resistance (not suitable for acidic atmosphere).
Tungsten tube (W)
Temperature resistance range: Long term use ≤ 2200 ℃, can withstand above 2500 ℃ under vacuum or inert atmosphere.
Characteristics: The highest melting point (3422 ℃), excellent high-temperature strength, good thermal and electrical conductivity.
Applicable scenarios: Extreme high temperature experiments, such as research on nuclear fusion materials.
Attention: High density, high cost, prone to oxidation at room temperature, requiring strict vacuum or inert atmosphere protection.
310S stainless steel pipe
Temperature resistance range: Long term use ≤ 800 ℃, some models can withstand 1000 ℃.
Characteristics: High mechanical strength, strong deformation resistance, good corrosion resistance (resistant to atmosphere, water, and weak acid and alkali).
Applicable scenarios: Low temperature, non oxidizing atmosphere (such as nitrogen) or experiments that require corrosion resistance, such as metal annealing and simple atmosphere protection treatment.
Attention: Limited oxidation resistance at high temperatures (prone to oxidation above 800 ℃), average thermal conductivity.

3. Special material
GRAPHITE TUBE
Temperature resistance range: ≤ 1800 ℃ (vacuum or inert atmosphere).
Characteristics: Good thermal conductivity, low coefficient of thermal expansion, excellent high temperature resistance.
Applicable scenarios: High temperature treatment in reducing atmosphere, such as high-temperature carbonization and graphitization treatment in the semiconductor and photovoltaic industries.
Attention: Easy to oxidize, strict control of atmosphere is required.
Boron nitride tube (BN)
Temperature resistance range: ≤ 1000 ℃ (inert atmosphere).
Characteristics: Good chemical stability, strong thermal shock resistance, and avoidance of metal ion contamination.
Applicable scenarios: semiconductor materials or high-purity material experiments.

4. Material selection suggestions
Temperature priority:
Above 1600 ℃: choose corundum tube, silicon carbide tube or molybdenum/tungsten tube.
Below 1200 ℃: quartz tube or stainless steel tube can be selected.
Atmosphere compatibility:
Oxidative atmosphere: Avoid metal tubes (molybdenum, tungsten) and prioritize using quartz or corundum.
Acidic atmosphere: Avoid quartz/corundum tubes (except hydrofluoric acid), and confirm the material’s corrosion resistance for reducing atmospheres (such as silicon carbide having better CO resistance than corundum).
Cost and practicality:
Conventional experiment: Prioritize corundum or quartz tubes, with lower cost and stable performance.
Ultra high temperature or special requirements: Choose metal pipes or special ceramic pipes (such as zirconia, silicon carbide composite pipes).