Sapphire crystal growth furnace hot field

The thermal field in a gemstone crystal growth furnace refers to the temperature distribution and heat flow within the furnace during the sapphire crystal growth process. The design and control of the thermal field significantly impact the quality, growth rate, and defect density of the sapphire crystals.

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Sapphire(Sapphire)is composed of aluminum oxide(Al2O3)，which is formed by the covalent bonding of three oxygen atoms and two aluminum atoms,Its crystal structure is a hexagonal close-packed structure.Its commonly used cut surfaces areA-Plane, C-PlaneandR-Plane。Because sapphire has a very wide optical transmission band,from near ultraviolet light(190nm)to mid-infrared light, it has good light transmittance. Therefore, it is widely used in optical components, infrared devices, high-strength laser lens materials and mask materials. It has high sound velocity, high temperature resistance, corrosion resistance, high hardness, high light transmittance, high melting point (2045℃) and other characteristics. It is a relatively difficult material to process, so it is often used as a material for optoelectronic components.

Sapphires need to be grown at high temperatures in tungsten or molybdenum crucibles or hot-pressed sintering crucibles. In addition, we also provide different needsSapphire crystal growth furnace thermal field,Heat shield,Heaters and countless high-temperature furnace components
- Thermal field configuration and precautions
1.Sapphire crystal growth furnace thermal fieldComposition

-Heating element: Commonly used resistance heaters or induction heaters provide a high-temperature environment.

-Insulation material: such as graphite felt, ceramic fiber, etc., to reduce heat loss and maintain temperature stability.

-Crucible: Used to hold raw materials, usually made of high-temperature resistant materials such as tungsten and molybdenum.

-Thermal field structure: including heat shields, reflectors, etc., to optimize temperature distribution.

2.Sapphire crystal growth furnace thermal fieldDesign

-Temperature gradient: A reasonable temperature gradient is the key to crystal growth. A larger gradient is usually required near the growth interface, while other areas need to be uniform.

-Sapphire crystal growth furnace thermal fieldSymmetry: A symmetrical thermal field helps to grow uniform crystals and reduce stress.

-Sapphire crystal growth furnace thermal fieldStability: A stable thermal field can avoid temperature fluctuations and reduce crystal defects.

3.Sapphire crystal growth furnace thermal fieldControl

-Temperature control: Real-time monitoring through thermocouples or infrared thermometers to ensure temperature stability.

-Heating power adjustment: Adjust the heating power according to the growth stage to maintain the required temperature gradient.

-Cooling system: Control the furnace body temperature through water cooling or air cooling to prevent overheating.

4.Sapphire crystal growth furnace thermal fieldOptimization

-Numerical simulation: Optimize the thermal field design through simulation to reduce experimental costs.

-Experimental verification: Verify the simulation results through experiments to further optimize the thermal field parameters.

-Material improvement: Use new insulation materials and heating elements to improve the performance of the thermal field.

5.Common problems

-Uneven temperature: May lead to uneven crystal growth and defects.

-Unstable thermal field: Temperature fluctuations will introduce stress and affect crystal quality.

-Sapphire crystal growth furnace thermal fieldUnreasonable design: May lead to too slow or too fast growth rate, affecting crystal quality.
- Sapphire crystal growth furnace thermal fieldComponent materials
Because tungsten and molybdenum have the characteristics of high temperature resistance and low pollution, they are widely used to makeSapphire crystal growth furnace thermal fieldComponents, including tungsten crucibles/Molybdenum crucibles, heating elements, tungsten tubes, heat shields, supports, bases, seed crystal rods, crucible lids, etc. The heating element adopts a birdcage structure tungsten heating element or tungsten mesh heating element, which is conducive to providing uniform and stableSapphire crystal growth furnace thermal field。