Production Methods of Ceramic Fibers

Ceramic fibers are classified into two main categories based on composition: vitreous (amorphous) fibers and polycrystalline (crystalline) fibers.

1. Production Method of Vitreous Fibers

The production method of vitreous ceramic fibers involves melting the raw materials in a resistance furnace. The high-temperature molten stream flows out from the discharge port and is spun into fiber-like material by centrifugal force on high-speed spinning rollers of a multistage centrifuge. Alternatively, the high-temperature molten stream can be rapidly cooled and blown into fiber-like material under the force of high-speed airflow.

2. Production Methods of Polycrystalline Fibers

There are two methods for producing polycrystalline ceramic fibers: the sol-gel method and the precursor method.

• Sol-Gel Method: Soluble aluminum salts, silicon salts, etc., are processed into colloid solutions of certain viscosity. The solution stream is spun into fibers using compressed air blowing or centrifugal disk spinning methods, followed by high-temperature heat treatment to transform them into aluminum silicate crystal fibers.
• Precursor Method: Soluble aluminum salts, silicon salts are processed into colloid solutions of certain viscosity. The colloid solution is uniformly absorbed by expanded organic fibers, followed by heat treatment to transform them into aluminum silicate crystal fibers.

3. Operating Temperatures of Ceramic Fibers

The maximum operating temperature of ceramic fibers refers to the extreme temperature they can withstand for a short period, used to characterize the heat resistance of ceramic fiber products. The temperature at which ceramic fiber products can be used for long periods is generally about 200°C lower than the maximum operating temperature. For example, the long-term operating temperature of 1260°C type fiber products is around 1000°C.

Internationally, ceramic fiber products are commonly divided into four grades based on temperature: 1000°C type, 1260°C type, 1400°C type, and 1600°C type. Domestically, ceramic fiber products are further subdivided based on fiber composition and maximum operating temperature to meet the insulation requirements of different grades.