The core of the high-temperature process: Classification and composition of the molybdenum heating zone
In the high-temperature industrial fields under vacuum or protected atmospheres, such as semiconductor crystal growth, vacuum heat treatment and the photovoltaic industry, the molybdenum heat zone is the core system for achieving and maintaining a high-temperature environment. The term "heat zone" refers to the overall assembly structure composed of high-temperature-resistant materials and directly surrounding the processed workpiece in the high-temperature furnace chamber. Among them, the heat zone made of molybdenum and molybdenum alloys, due to its high melting point (2622℃), excellent high-temperature strength, low vapor pressure and good corrosion resistance, becomes the preferred choice for applications above 1600℃. Depending on the structure and application purpose, the molybdenum heat zone can be mainly divided into two categories, laying the foundation for its wide application.
The first category is the closed molybdenum heating zone used for sintering and heat treatment. These zones are typically designed as nearly enclosed chambers, with the main purpose of creating a uniform, stable, and protected high-temperature environment inside. They are widely used in processes such as high-temperature sintering (e.g. tungsten carbide, ceramics), vacuum annealing, and purification treatment. The key to the design of the closed heating zone lies in minimizing heat loss and ensuring a highly consistent internal temperature field, thereby allowing all workpieces to be processed under exactly the same conditions and achieve uniform product quality.
The second type is the open or specific flow channel type of molybdenum heating zones used for crystal growth, with the most typical application being in the direct pulling single crystal silicon (CZ method) furnaces. In these applications, the design of the heating zone not only needs to provide heat but also requires precise control of the temperature gradient and melt flow. Therefore, its structure is usually open or has specific airflow channels, facilitating observation, seed crystal introduction, and control of the thermal field distribution during the crystal pulling process. The complexity of this design is much higher than that of the closed heating zones, aiming to meet the strict requirements of crystal growth for precise dynamic control of the thermal field.
No matter what type of molybdenum heat zone it is, they are all composed of a series of precise components with different functions. The core components usually include: the molybdenum insulation screen, which is made up of multiple thin layers of molybdenum sheets or molybdenum meshes, and effectively reduces heat loss by reflecting thermal radiation. It is the key to maintaining high temperature and reducing energy consumption; the molybdenum heater, as the "heart" of the system, converts electrical energy into thermal energy. Its shape (such as mesh-like, rod-like, or tube-like) is carefully designed to achieve precise temperature control; and the molybdenum crucible/laboratoryware system, which is used to hold the processed raw materials, melts, or workpieces.
In addition, a complete molybdenum heat zone also includes a variety of important auxiliary components. Molybdenum supporting parts, such as bolts, nuts, and hangers, molybdenum heat elements, are responsible for securely assembling all the components together. Their design must fully consider the impact of thermal expansion. The molybdenum flow guide tubes are used in single crystal furnaces to guide the flow of inert gases and the distribution of the thermal field. In some systems, molybdenum electrodes and temperature measurement protective sleeves, etc. are also equipped. In summary, the molybdenum heat zone is a complex system precisely coupled by multiple molybdenum components. The design and manufacturing level of this system directly determines the performance and technological achievements of high-temperature equipment, and is an indispensable key technology carrier in modern high-end manufacturing.
The molybdenum hot zone is in high demand in various parts of the world, such as: USA, Canada, Chile, Brazil, Argentina, Colombia, Germany, France, United Kingdom, Italy, Sweden, Austria, Netherlands, Belgium, Switzerland, Spain, Czech Republic, Poland.
As a Chinese Manufacturer, Mosten Alloy can produce molybdenum crucible, molybdenum tube, molybdenum target, molybdenum sheet, molybdenum block, molybdenum foil, molybdenum wire, molybdenum rod, molybdenum processing workpiece according to customer demand. If you have any questions, please send email to info@mostenalloy.com.
