Preparation method of zirconic acid lanthanum ceramic fiber

Abstract

The invention relates to a preparation method of a zirconic acid lanthanum ceramic fiber. The method comprises the following steps: preparing a gel fiber through a colloidal sol centrifugal fiber forming technology by using zirconium nitrate as a zirconium source, lanthanum nitrate as a lanthanum source, citric acid as a chelating agent, and water as a solvent, and calcining the gel fiber to form the zirconic acid lanthanum ceramic fiber. A precursor prepared by the invention has stable colloidal sol property and is good in filamentation property with no need of adding a polymer spinning additive. The prepared zirconic acid lanthanum ceramic fiber is good in flexibility, compact in microstructure, good in phase stability an low in heat conductivity coefficient and can be used for high-temperature thermal-insulation material, and the crystal form of the zirconic acid lanthanum ceramic fiber is pyrochlore form.

Description

technical field

[0001] The invention relates to a preparation method of lanthanum zirconate ceramic fiber, which belongs to the field of inorganic non-metallic materials. Background technique

[0002] In recent years, with the rapid development of aerospace technology and the need for energy saving and emission reduction, the requirements for thermal insulation materials are getting higher and higher. Among the various existing heat insulation materials, ceramic fiber has become the first choice for heat insulation materials due to its outstanding light weight and high temperature resistance. It has both the high temperature resistance of inorganic materials and the low thermal conductivity and low Density, high heat capacity, and various product forms, as a high-temperature insulation material, it has been widely used in various heat protection projects.

[0003] At present, the widely used high-temperature insulation fiber materials mainly include aluminum silicate-based ...

Examples

Embodiment 1

[0036] (1) Preparation of spinnable precursor sol

[0037] 78.6g zirconium nitrate (Zr(NO 3 ) 4 ·3H 2 O), 86.6g lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) and 42.0g citric acid (C 6 h 8 o 7 ·H 2 O) Adding them to an appropriate amount of water, stirring until clear and transparent; mixing the three solutions at room temperature, stirring until clear and transparent, then aging in a water bath at 60°C to a viscosity of 80Pa·s to obtain a spinnable sol;

[0038] (2) Centrifugal fiber formation to prepare gel fibers

[0039] The sol prepared in step (1) is centrifuged into fibers, and the process conditions are: the diameter of the spinning hole is 0.3mm, the spinning speed is 9000r / min, the temperature in the spinning barrel is 25°C, and the relative humidity is 25%;

[0040] (3) The gel fiber prepared in step (2) is ceramicized. The process conditions are: the temperature is raised from room temperature to 600 ° C at a heating rate of 3 ° C / min, and the temperature is ...

Embodiment 2

[0044] As described in Example 1, the difference is:

[0045] In step (1), citric acid (C 6 h 8 o 7 ·H 2 O) is 50.2g; Step (2) is with embodiment 1.

[0046] The process condition of gel fiber ceramicization in step (3) is: the temperature rises from room temperature to 600° C. at a rate of 1° C. / min, keeps at this temperature for 2 hours, and then rises to 900° C. at a rate of 5° C. / min. At this temperature for 1h, lanthanum zirconate (La 2 Zr 2 o 7 ) ceramic fibers, and finally raised to 1100°C at a heating rate of 15°C / min, and kept at this temperature for 2 hours to obtain pyrochlore-type lanthanum zirconate (La 2 Zr 2 o 7 )Ceramic fiber.

[0047] The obtained ceramic fiber is lanthanum zirconate (La 2 Zr 2 o 7 ) fibers with a diameter of 2 to 5 μm, the appearance of the fibers is fluffy, and the thermal conductivity is 0.062W / (m·K).

Embodiment 3

[0049] As described in Example 1, the difference is: in step (1), lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) is 82.2g; Step (2) is with embodiment 1.

[0050] Obtain the lanthanum zirconate (La 2 Zr 2 o 7 ) ceramic fiber and finally raised to 1200°C at a heating rate of 15°C / min, and kept at this temperature for 1h to obtain lanthanum zirconate (La 2 Zr 2 o 7 )Ceramic fiber.

[0051] The obtained ceramic fiber is lanthanum zirconate (La 2 Zr 2 o 7 ) fibers with a fiber diameter of 2-5 μm and a thermal conductivity of 0.059W / (m·K).

technical field

[0001] The invention relates to a preparation method of lanthanum zirconate ceramic fiber, which belongs to the field of inorganic non-metallic materials. Background technique

[0002] In recent years, with the rapid development of aerospace technology and the need for energy saving and emission reduction, the requirements for thermal insulation materials are getting higher and higher. Among the various existing heat insulation materials, ceramic fiber has become the first choice for heat insulation materials due to its outstanding light weight and high temperature resistance. It has both the high temperature resistance of inorganic materials and the low thermal conductivity and low Density, high heat capacity, and various product forms, as a high-temperature insulation material, it has been widely used in various heat protection projects.

[0003] At present, the widely used high-temperature insulation fiber materials mainly include aluminum silicate-based ...

Examples

Embodiment 1

[0036] (1) Preparation of spinnable precursor sol

[0037] 78.6g zirconium nitrate (Zr(NO 3 ) 4 ·3H 2 O), 86.6g lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) and 42.0g citric acid (C 6 h 8 o 7 ·H 2 O) Adding them to an appropriate amount of water, stirring until clear and transparent; mixing the three solutions at room temperature, stirring until clear and transparent, then aging in a water bath at 60°C to a viscosity of 80Pa·s to obtain a spinnable sol;

[0038] (2) Centrifugal fiber formation to prepare gel fibers

[0039] The sol prepared in step (1) is centrifuged into fibers, and the process conditions are: the diameter of the spinning hole is 0.3mm, the spinning speed is 9000r / min, the temperature in the spinning barrel is 25°C, and the relative humidity is 25%;

[0040] (3) The gel fiber prepared in step (2) is ceramicized. The process conditions are: the temperature is raised from room temperature to 600 ° C at a heating rate of 3 ° C / min, and the temperature is ...

Embodiment 2

[0044] As described in Example 1, the difference is:

[0045] In step (1), citric acid (C 6 h 8 o 7 ·H 2 O) is 50.2g; Step (2) is with embodiment 1.

[0046] The process condition of gel fiber ceramicization in step (3) is: the temperature rises from room temperature to 600° C. at a rate of 1° C. / min, keeps at this temperature for 2 hours, and then rises to 900° C. at a rate of 5° C. / min. At this temperature for 1h, lanthanum zirconate (La 2 Zr 2 o 7 ) ceramic fibers, and finally raised to 1100°C at a heating rate of 15°C / min, and kept at this temperature for 2 hours to obtain pyrochlore-type lanthanum zirconate (La 2 Zr 2 o 7 )Ceramic fiber.

[0047] The obtained ceramic fiber is lanthanum zirconate (La 2 Zr 2 o 7 ) fibers with a diameter of 2 to 5 μm, the appearance of the fibers is fluffy, and the thermal conductivity is 0.062W / (m·K).

Embodiment 3

[0049] As described in Example 1, the difference is: in step (1), lanthanum nitrate (La(NO 3 ) 3 ·6H 2 O) is 82.2g; Step (2) is with embodiment 1.

[0050] Obtain the lanthanum zirconate (La 2 Zr 2 o 7 ) ceramic fiber and finally raised to 1200°C at a heating rate of 15°C / min, and kept at this temperature for 1h to obtain lanthanum zirconate (La 2 Zr 2 o 7 )Ceramic fiber.

[0051] The obtained ceramic fiber is lanthanum zirconate (La 2 Zr 2 o 7 ) fibers with a fiber diameter of 2-5 μm and a thermal conductivity of 0.059W / (m·K).

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