Precautions for selecting a tubular CVD electric furnace for experiments

When selecting a tubular CVD electric furnace for experiments, it is necessary to comprehensively evaluate it from multiple dimensions such as application requirements, equipment performance, safety and reliability, and maintenance costs. The following are specific precautions:

1. Clarify experimental requirements and determine core parameters
Temperature range and accuracy
Select the upper temperature limit based on the characteristics of the experimental materials (such as high-temperature CVD requiring ≥ 1200 ℃, and some experiments requiring above 1600 ℃).
Prioritize equipment with PID automatic control and multi-stage programmable temperature curves to ensure temperature fluctuations of ≤ ± 1 ℃ and meet high-precision coating or nanomaterial synthesis requirements.
Furnace tube material and size
Material: Choose quartz tube for high temperature or corrosive environments (high temperature resistant, transparent and easy to observe); Choose metal tubes (such as stainless steel) for high vacuum requirements.
Size: Select the inner diameter of the furnace tube (usually between 60 and 100mm) and length (usually ≤ 1000mm) based on the sample size to ensure uniform heating of the sample and sufficient operating space.
Heating method and components
Resistance heating: Low cost, widely applicable, but slow heating rate (recommended 5-15 ℃/min).
Induction heating: It heats up quickly (up to 50 ℃/min) and is suitable for rapid heat treatment, but the equipment cost is relatively high.
Heating element: Choose Fe Cr Al alloy (≤ 1250 ℃), silicon carbon rod (1300-1600 ℃) or silicon molybdenum rod (1600-1800 ℃) according to the temperature. Note that silicon molybdenum rod should not be used below 800 ℃ for a long time.

2. Key system configuration and performance
Gas supply and mixing system
Equipped with a multi gas supply system, supporting the proportional mixing of at least two gases (such as H ₂, Ar, SiH ₄).
Use a mass flow meter (MFC) to precisely control the flow rate (accuracy ± 1% FS) and ensure gas mixing uniformity.
vacuum system
Select low vacuum (10 ⁻³ -10 ⁻¹ Pa) or high vacuum system (<10 ⁻⁴ Pa) according to process requirements, equipped with molecular pumps or diffusion pumps. The vacuum gauge monitors the pressure inside the furnace in real-time to prevent equipment damage caused by excessive pressure (≤ 0.02MPa). Temperature zone design Single temperature zone: With a simple structure, it is suitable for single temperature processes. Multi temperature zone: gradient heating is achieved through independent temperature control (such as high in the front and low in the back), optimizing the gas reaction path. Increasing the length of the constant temperature zone can improve sample uniformity.

3. Safety and usability design
Safety protection device
Essential functions: Over temperature alarm, leakage protection, emergency stop, pressure protection. Special scenario: Toxic gas operations require ventilation equipment and explosion-proof devices; At high temperatures (>1000 ℃), the furnace tube needs to maintain normal pressure to avoid a vacuum state.
Operating Interface and Automation
Prioritize touch screen control, support remote monitoring and data recording, simplify the operation process.
Automated functions such as automatic heating and cooling programs can improve experimental reproducibility and reduce human error.
Cooling system
Water cooling is more efficient than air cooling, but the laboratory needs to have water cooling facilities.
The cooling rate should match the heating rate to avoid cracking of the furnace tube caused by thermal stress.

4. Brand and after-sales service
Brand Choice
Priority should be given to selecting well-known brands such as Kejia Electric Furnace and Tube Furnace (Kejia Furnace Industry) to ensure equipment quality stability and technical reliability.
Refer to user reviews to understand the actual performance and common issues of the device.
After sales service policy
Confirm the warranty period (usually 1-3 years), repair response time (such as on-site visits within 24 hours), and technical support methods (such as telephone or remote assistance).
Understand the cost and supply cycle of replacing vulnerable parts such as heating elements and sealing rings.