Sintering Furnaces

Vacuum Furnace Solution #1 – Small Tubes

For small-diameter vacuum vessels, typically less than 5-10 centimeters (although sometimes larger), it is possible to use a metallic or ceramic tube with moderate wall thickness. Such a tube contains the vacuum while applying heat externally to the tube. This is the least expensive approach to construction of a vacuum furnace. It is commonly used in university research laboratories worldwide. The maximum temperature using this method is dependent on the tube diameter, quality, and wall thickness. For steel, nickel alloy, and quartz tubes, it is typically 1000° C, and for ceramic tubes, it is typically 1600° C. Such a vacuum furnace design has been perfected and is widely employed in the semiconductor industry, where tube diameters exceeding 20 centimeters are available for temperatures below 1000° C.

RD-M Vacuum Furnace Temperature

Typical Tube Furnace Design

It is true that this is a cost-effective approach to vacuum furnace design, making it useful in some laboratory and limited industrial applications (largely semiconductors). However, this choice is not without its problems. There are temperature and diameter limitations, and risk of tube failure. These factors can lead to potential damage of vacuum pumps, workload, heating elements, and personnel, as well as release of toxic materials to the environment. Because of these risks, this approach is primarily selected for general laboratory use, where limited funds are available, and for semiconductor applications, where particulate control is the chief advantage.