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).