Why Is Molybdenum Sheet Chosen as Heating Elements in Vacuum Furnaces?

As a typical product of the transition metal molybdenum, molybdenum sheet is a sheet-like material processed from molybdenum metal through rolling, cutting, and other techniques. Beyond its use in electronics and aerospace for manufacturing high-temperature electronic components and sputtering targets, it is also employed to create heating elements in vacuum furnaces.

Molybdenum sheet is an ideal material for vacuum furnace heating elements due to its multiple excellent properties: it has a high melting temperature, enabling stable operation in high-temperature environments; its moderate resistivity and stable temperature coefficient ensure uniform and efficient heat generation, improving temperature uniformity within the vacuum furnace; in vacuum or inert gas environments, molybdenum sheet exhibits good chemical stability and low vapor pressure, preventing the release of gases or particulate contaminants, thus maintaining high furnace cleanliness; additionally, it features a low thermal expansion coefficient, excellent thermal shock resistance, and good processability.

Heating elements, also known as heating components, are one of the core components of a vacuum furnace, serving as the key mechanism for converting electrical energy into heat to provide a high-temperature environment. Their performance directly impacts the furnace's heating rate, temperature uniformity, maximum operating temperature, and service life, with applications in sapphire crystal growth, metal heat treatment, semiconductor manufacturing, and more. The working principle of heating elements is based on Joule's law, where heat is generated as current flows through a resistive material.

In addition to molybdenum sheet, heating elements can also be made from tungsten. Tungsten offers a high melting point and good high-temperature tensile strength, but its large resistance temperature coefficient requires dynamic current adjustments for temperature control.

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