Hi, I am working on the home-made ALD system at college. I am looking for an insulating material with high-temperature resistance for vacuum operation. We plan to use the stepper motor to rotate the heating plate. The problem is that most stepper motors have around 100~150C as maximum operating temperature. Our working temperature is around a maximum 400C. Some of the vacuum stepper motors have a relatively higher maximum working temperature, however, the price is more than $2k. Therefore, I decided to place insulating material below the heater so that the motor could work under maximum working temperature. I was thinking about Teflon or Bakelite as insulating material, but it couldn't meet the our working temperature. I was thinking about simply place a glass under the heater since the glass price is cheap. However, we need to hold the heating plate with insulating material, and the glass is pretty much limited to apply bolts and nuts since it is fragile.
I wonder if you folks have any recommendations.
Considering factors
1. Market Price: Maximum several hundred dollars is desirable (Size: 4" OD, the thickness depends on thermal conductivity)
2. Temperature resistance: up to 400C (For example, polymers which have melting or glass temperature higher than 400C, or any fiber included materials which can handle 400C)
3. Insulating material: Low thermal conductivity.(I know it is vague. thickness is also a limited factor. We are looking to find the insulating material which has less than 3 inch)
I am not working in that area any more, but I think
https://elmelin.com/comparing-5-types-of-high-temperature-industrial-insulation-materials/
gives you an idea what to look for.
Best regards,
Harald
Hello Youngjoon,
I was thinking about YTong building blocks (or any other variants of expanded concrete construction materials). They are resistant to 1200°C and since they contain expanded gas, are well insulating. However, you should consider that tightening nuts to hard on this material will pulverize it as well.
Hope it helps!
For the development and manufacturing of vacuum insulating materials may be used homegrown renewable materials such as wood wool and wool fiber materials. The structure of wood fiber samples is more suitable for evacuation procedure. 2. Vacuum insulating materials are working effectively in the range of vacuum pressure from 10 kPa to 0,1 kPa. Thermal conductivity of measured materials in these range varies from 0,020 W/(m·K) to 0,006 W/(m·K). 3. For the choice of core for vacuum insulating materials the great importance has the cost of material and its derivation.
Vacuum itself is the best possible thermal insulator. You just need to protect your motors from infra-red radiation using reflective aluminum foil, and to thermally anchor them to the system's case.
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