Alumina fiber is a kind of polycrystalline inorganic fiber whose main component is alumina. Because of its high strength, high modulus, low thermal conductivity, low thermal expansion coefficient, chemical corrosion resistance, extraordinary heat resistance and high-temperature oxidation resistance, it can maintain good tensile strength at high temperature, and has good surface activity. It is easy to composite with resin, metal and ceramic matrix. Therefore, it has been considered as the most potential high-temperature material.

There are two main types of alumina fibers: one is alumina short fiber; The second is alumina continuous fiber. As a high-end product in special refractory materials, alumina continuous fibers can be cut into short cut fibers only a few centimeters long, can also be used alone in the form of woven fabrics, and can also be manufactured into a variety of composite materials for use. The form is very convenient and flexible.

Because of its excellent cost performance ratio and great commercial value, alumina continuous fiber has been paid attention to in the military and civil composite material fields, and can be applied to high-temperature binding, high-temperature filtration, high-temperature composite materials, high-temperature insulation materials and other fields. For this reason, many countries have invested a lot of human and material resources to develop and produce alumina continuous fibers. However, due to the high threshold of preparation difficulty, there are few domestic enterprises that can make alumina continuous fibers.

Alumina continuous fiber is a new type of high-temperature resistant oxide ceramic based fiber material. The product has excellent high-temperature resistance, low elongation and shrinkage under high temperature conditions, excellent dielectric properties, and also has advantages of corrosion resistance, low thermal conductivity, thermal shock resistance and low porosity. Our alumina continuous fiber has good weaving performance and can be made into cloth, belt, sleeve, three-dimensional braided preform and other products through special textile process.

Alumina continuous fibers are divided into four categories according to the oxide content:

The alumina content of type 72 alumina continuous fiber is ≥ 72%, because the silica content is high and the fiber is soft, which is conducive to the manufacture of textile articles. The disadvantage is that the strength at high temperature (1250 ℃) will be reduced. The purpose is to make heat insulation seals of different shapes by weaving, coating and sewing thick, which is suitable for fiber reinforced resin matrix composite materials.

Type 80 alumina continuous fiber has 80% alumina content, good fiber toughness, and good weaving performance. It can be used in high temperature environment (1250 ℃) for a long time. It is not only suitable for producing temperature resistant fabrics of various shapes, but also can form temperature resistant composite materials with resins and ceramics.

The alumina content of type 85 alumina continuous fiber is 85%. It can be used for a long time at 1250 ℃ and its strength is reduced. It is suitable for the application of ceramic matrix composite materials. Its ceramic products have the best thermal shock resistance and thermal creep resistance. It can be used for a long time at 1375 ℃ under oxygen and steam environment and for a short time at 1700 ℃.

The alumina content of Type 99 alumina continuous fiber is 99%, which is suitable for the application of metal matrix composites. The strength at room temperature is good. The 99% alumina content is favorable for the purity of aluminum products, but the disadvantages are poor bending resistance and high temperature strength; The products are mainly high denier untwisted roving, and light and high-strength aluminum alloy products are produced by winding or wire laying.