High-temperature Alumina ceramic bushings are made primarily from alumina, using a special process to create tubular ceramic products with excellent properties such as high-temperature and corrosion resistance. The following is a detailed introduction:

Performance and Features

High-Temperature Resistance: The maximum operating temperature varies depending on the alumina purity and production process. Generally, it can withstand long-term use in high-temperature environments of 1600°C-1700°C. Some high-purity alumina ceramic bushings can withstand short-term thermal shocks of 1800°C.

High Hardness and Wear Resistance: Alumina ceramic has a Mohs hardness of 9, second only to diamond, and a Vickers hardness of 15.7 GPa. It

offers excellent wear resistance and effectively resists erosion and wear from materials.

Corrosion Resistance: With the exception of hydrofluoric acid, it is resistant to 99% of acids and alkalis, molten metals, and halogen gases, demonstrating excellent chemical stability. Excellent electrical insulation: Alumina ceramic casings, for example, in Huawei's 5G base station filters, boast a volume resistivity of 10¹⁴Ω・cm, effectively isolating electromagnetic interference and suitable for applications requiring high electrical insulation.

Production Process

Alumina powder is typically formed into a tubular blank using processes such as isostatic pressing, hot die casting, dry pressing, and slip casting. This is then sintered at high temperatures to densify the alumina particles, resulting in a ceramic casing with excellent performance. Some high-end products also utilize two-step sintering processes and gradient sintering techniques to further enhance performance.

Applications

Electronics Industry: Used in semiconductor wafer diffusion furnaces, it maintains stability in a hydrogen atmosphere at 1300°C, keeps metal ion contamination below 0.1ppm, and improves chip yield. It can also be used as cooling ducts for circuit boards and as housings for electronic components, leveraging its insulation and thermal shock resistance to ensure stable operation of electronic equipment. Chemical Industry: Alumina Ceramic Tubes can be used as chemical reaction tubes and pipelines for handling corrosive chemicals such as strong acids and alkalis. For example, in sulfuric acid production, they can operate stably for years, significantly reducing pipe replacement costs and the risk of production downtime.

New Energy Industry: In lithium battery production, they are used in lithium iron phosphate sintering furnaces. Silicon nitride coating can extend their lifespan to over two years, improving the purity of the cathode material. In the photovoltaic industry, they are used to manufacture high-temperature furnace pipes, providing a stable high-temperature environment for silicon wafer production.

Metallurgical Industry: Able to withstand temperatures of 1600°C, they can be used to transport blast furnace gases and slag in steelmaking. For example, Baosteel Special Steel has reduced consumable costs by over 8 million yuan per production line annually after trialing composite ceramic tubes.

Power Industry: They can be used as tubes for high-temperature tube furnaces. Hefei Kejing's high-purity alumina ceramic tubes, for example, are standard equipment or replacement parts for laboratory tube furnaces in universities, research institutes, and other institutions. 

Common Specifications

Outer diameters typically range from 4-120mm, and lengths from 0-2500mm. Specific specifications can be customized according to customer needs.

Key attributes