Alumina Fiber （Polycrystalline Mullite Fiber ）

The alumina short fiber is mainly composed of alumina and silica, and adopts the internationally leading "sol gel" preparation process. Its performance indicators are at the international leading level, and it has excellent flexibility and fire resistance and thermal insulation performance.

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Characteritics

Excellent resistance to high and low temperatures

The service temperature of α-Al₂O₃ Fibre is up to 1400℃-1800℃; After treatment with liquid nitrogen (- 196℃) for 24 hours, the strength did not decrease.
Acid and alkali resistance

Retention of fiber strength after 24h immersion in 10% alkaline solution: NaOH--40%; KOH--65%; NH₄OH--95%; Retention of fiber strength after 24h immersion in 10% acid solution: HCl--96%; H₂SO₄--95%; HNO₃--96%; H₃PO₄--95%.
No slag ball

Our fibers are free of slag balls (≥45μm), which makes the strength of the fibers improved to a certain extent, and at the same time, since the thermal insulation and refractoriness of the fibers are inversely proportional to the content of slag balls, the lower the content of slag balls, the higher the thermal insulation and refractoriness performance.
Excellent electrical properties and insulation

The resistance of alumina fiber decreases with the increase of temperature, and above 600℃, the resistance tends to be constant; the dielectric constant and dielectric loss of alumina fiber are basically stable at high temperature, which is suitable for making high-temperature wave-transparent materials.
Excellent flexibility

The fibers are highly flexible and do not break easily during the needling process.
Strong design

By regulating the chemical composition and heat treatment process, products with different properties can be obtained to meet different application requirements.

Performance Index Table

Product Type		Type 72-F	Type 72-M	Type 85	Type 95-M	Type 95-N
Chemical CompositionAI₂O₃：SiO₂（%）		72-75:25-28	72-75:25-28	85-88:12-15	＞95:＜5	＞95:＜5
Mineral Structure		δ-AI₂O₃ or γ-AI₂O₃	Mullite	Mullite+α-AI₂O₃	γ-AI₂O₃	α-AI₂O₃
Classification Temperature（℃）		1600	1600	1800	1600	1800
Molten Point （℃）		＞1800	＞1800	＞1800	＞2000	＞2000
Density （g/cm³）		3.1	3.1	3.2	2.8	3.4
Average Fibre Diameter（μm）		5.5-7.5	5.5-7.5	4-7	3-4	3-4
Shot Content （%）	≥45μm	0-2	0-2	0-2	0-2	0-2
Impurity（%）		＜0.5	＜0.5	＜0.5	＜0.5	＜0.5
Monofilament tensile strength （MPa）		≥1200	≥1000	—	—	—
Monofilament tensile modulus（GPa）		≥100	≥100	—	—	—

Performance Test

Physical and chemical performance test

Chemical composition of type 72 polycrystalline alumina fibre: the content of Al₂O₃ is 72%-75%, the content of SiO₂ is 25%-28%, and the content of other impurities such as Fe and Na is less than 0.5%. Under the microscope, it can be visually observed that the fibre diameter is uniform without slag balls, and the fibre diameter can be stably controlled at 5.5-7.5 μ m. Monofilament strength ≥ 1000MPa, and all indexes can reach the international advanced level.
Scanning electron microscopy detection

Microstructure: under the scanning electron microscope, the surface of polycrystalline alumina fibre is smooth and dense without holes and cracks. It indicates that the internal bonding of the fibre is dense, and there is no obvious grain boundary.


SEM of DH fibre after heat treatment at 1200 ° C	SEM of DH fibre after heat treatment at 1400 ° C	SEM of DH fibre after heat treatment at 1600 ° C

XRD atlas of δ-Al₂O₃ phase fibre

Chemical composition of 72-type polycrystalline alumina fibre cotton

Detection of specific surface area of polycrystalline alumina fibre

Shot Content inspection report

Product APPLICATION

Aerospace Field

Alumina continuous fiber can be used for hypersonic aircraft, antenna covers, and radar transmission covers. Using alumina continuous fiber as a new generation material with higher temperature requirements has become a trend. European and American countries have already applied this material to space shuttles, interstellar spacecraft, and weapon equipment, which can play a good role in temperature resistance and thermal insulation.

Automotive Industry Field

The mat of the three-way catalyst is widely used in vehicle exhaust emission systems to protect and seal the honeycomb ceramic carrier. The Dongheng three-way catalytic converter liner is applied in gasoline vehicles for TWC (three-way catalytic converter) and GPF (gasoline particulate trap); Applied in diesel vehicles for DOC (diesel oxidation catalyst), DPF (diesel particulate trap), and SCR (selective catalytic reduction).

Industrial Refractory Material Field

Alumina short fibers can be used at temperatures ranging from 1200 ℃ to 1800 ℃. Their fiber products, such as fiber blankets, felts, paper, modules, and shaped parts, have low density and heat capacity, low thermal conductivity, and good thermal shock resistance. They can also be directly used as insulation filling materials for high-temperature kilns, such as furnace sidewalls, roofs, and doors, and as insulation seals for high-temperature components.