A high-pressure crucible is an experimental vessel designed specifically for high-temperature and high-pressure environments, which achieves stable operation under conditions through high-strength materials and precision structures. The core design concept is to withstand the dual challenges of high temperature (usually above 1750 ℃) and high pressure (up to 15MPa), while maintaining sealing to prevent gas leakage or external pollution.
Working principle: Dual guarantee of materials and structure
The material selection of high-pressure crucible is the key to its performance. The mainstream materials include nickel chromium titanium alloy (NiCr20TiAl), stainless steel, and high-purity graphite. For example, nickel chromium titanium alloy improves high-temperature strength and creep resistance through alloying design, while stainless steel relies on its excellent corrosion resistance and mechanical stability. Graphite crucibles are divided into two types: natural flake graphite and artificial graphite. The former has significantly enhanced thermal shock resistance after adding refractory materials such as clay, while the latter is suitable for high-purity metal refining due to its low impurity content.
Structurally, the high-pressure crucible adopts isostatic pressing technology to uniformly transmit pressure through a liquid medium, forming a dense microcrystalline phase structure of the material and eliminating internal defects. Sealing design typically combines metal gaskets with threaded locking mechanisms to ensure airtightness even under high pressure. For example, the TA series high-pressure crucible controls the leakage rate below 10 ⁻⁹ Pa · m ³/s by optimizing the sealing ring material and thread angle.
Core application areas: Intersection of scientific research and industry
Materials Science: Used for synthesizing high-temperature superconducting materials, ceramic based composite materials, etc., achieving directional growth of crystal structures through precise control of pressure and temperature gradients.
Metallurgical industry: In the smelting of non-ferrous metals, high-pressure environment can suppress the evaporation of volatile elements and improve the purity of alloys. For example, during the melting of copper aluminum alloys, high-pressure crucibles can reduce compositional deviations to within 0.1%.
Chemical safety research: Providing a safe environment for thermal stability testing of hazardous chemicals through gas-phase diffusion of high-pressure explosion suppression reactions.
Thermal analysis technology: In differential scanning calorimetry (DSC), the high-pressure crucible can be reused more than 20 times, and the sealed design can accurately capture weak thermal effects, such as enthalpy change measurement of polymer glass transition.