CN105624834A - Barium zirconate fiber and method for preparing same - Google Patents

Abstract

The invention relates to a barium zirconate fiber and a method for preparing the same. The diameter of the barium zirconate fiber is 1-20 micrometers, and crystalline phases of the barium zirconate fiber are cubic phases and can keep stable under the condition of high temperatures of 1500 DEG C. The method includes proportionally sufficiently stirring basic zirconium carbonate, barium sources, acid sources and solvents under the condition of temperatures of 10-90 DEG C until solution is clear and transparent, and concentrating the solution under vacuum conditions to obtain barium zirconate precursor spinning solution; carrying out high-speed centrifugal thread throwing on the precursor spinning solution to obtain a diameter precursor fiber and carrying out high-temperature heat treatment on the diameter precursor fiber to obtain the barium zirconate fiber. The barium zirconate fiber and the method have the advantages of simple processes, low cost, high yield, environmental friendliness and the like. Besides, the barium zirconate fiber is reliable in quality, has the uniform diameter and has a broad application prospect in the field of high-temperature heat-insulation materials, high-temperature proton conductors, fuel batteries and the like.

Description

A kind of barium zirconate fiber and preparation method thereof

technical field

The invention relates to a barium zirconate fiber and a preparation method thereof, belonging to the field of inorganic non-metallic materials.

Background technique

Barium zirconate (BaZrO ₃ ) belongs to the cubic perovskite structure with a theoretical density of 6.23g/cm ³ . The melting point is as high as 2690°C, the thermal expansion coefficient is small, about 7.9×10 ^-6 K ^-1 (30-1000°C), low heat capacity, low sintering activity, no phase change from -269°C to 1327°C, good thermal stability , is an excellent thermal coating material; refer to CN101319383A for the preparation of barium zirconate powder. On the other hand, barium zirconate does not react chemically with yttrium barium copper oxide superconductor, and is an ideal crucible material for growing yttrium barium copper oxide superconductor; see CN103979979A for a preparation method of barium zirconate crucible. In addition, barium zirconate has low thermal conductivity, good mechanical and structural stability under extreme environmental conditions, thermal shock resistance, and good thermal shock resistance. It is an excellent high-temperature insulation material; currently, as a high-temperature insulation material, zirconium There have been many reports on the preparation of barium zirconate ceramic materials. For example, CN103864419A discloses a method for preparing high-density barium zirconate ceramics. However, compared with ceramic fibers, ceramic bulk materials have high density, high thermal conductivity, and poor thermal shock resistance. But so far there is no report about barium zirconate fiber technology.

In recent years, global environmental and energy issues have attracted widespread attention. Energy conservation and environmental protection have become an inevitable requirement of social development. The advantages of ceramic fiber, such as light weight, small specific heat capacity, resistance to mechanical vibration, and high use efficiency, have attracted widespread attention. At present, ceramic fiber materials have been widely used in metallurgy, machinery, petroleum, chemical industry, electronics, shipping, transportation, and light industry. It is also used in cutting-edge science and technology fields such as aerospace and atomic energy. It is an important research and development task in the field of materials to give full play to the advantages of fiber materials, use appropriate materials in appropriate environments, improve the efficiency of materials and energy use, reduce costs and energy waste, and improve the environment. In order to make up for the deficiency in the field of barium zirconate materials, the present invention is proposed.

Contents of the invention

Aiming at the deficiencies of the prior art, the invention provides a high-temperature-resistant barium zirconate fiber material and a preparation method thereof, and provides a new type of barium zirconate high-temperature insulation material.

Explanation of terms:

The barium zirconate has a molecular formula of BaZrO ₃ ;

The high temperature refers to a high temperature condition up to 1500°C.

Technical scheme of the present invention is as follows:

A barium zirconate fiber with a diameter of 1-20 μm, the crystal phase of the barium zirconate fiber is a cubic phase, and the crystal phase remains stable under high temperature conditions up to 1500°C. The XRD pattern of the barium zirconate fiber was tested at different temperatures at 1300°C, 1400°C and 1500°C respectively, and the results are shown in Figure 5, indicating that the barium zirconate is in a cubic phase, and the crystal phase is stable under high temperature conditions.

The focus of the present invention is to investigate the crystal phase stability of the barium zirconate fiber under high temperature conditions up to 1500°C; it goes without saying that the crystal phase of the barium zirconate fiber is also very stable at normal temperature.

On the other hand, the present inventors also unexpectedly found that the barium zirconate fiber still maintains a good fiber shape under high temperature conditions up to 1500° C. and no sintering adhesion occurs between the fibers. As shown in Figure 4. It is very important to be able to achieve this. Only when the fiber shape is good at high temperature and no adhesion between fibers occurs can the convenience of application and good processing performance be guaranteed.

Preferably in the present invention, the diameter of the barium zirconate fiber is 2-15 μm; more preferably, the diameter of the barium zirconate fiber is 4-8 μm.

According to the present invention, a kind of preparation method of barium zirconate fiber comprises steps as follows:

(1) According to the ratio of basic zirconium carbonate according to the molar ratio: barium source: acid source=1: (1～1.5): (2～6), take basic zirconium carbonate, barium source and acid source respectively, at 10 Add it into the solvent under the temperature of ~90°C and stirring condition, carry out the solution reaction, react for 1~12h, and obtain the barium zirconate precursor solution;

(2) Concentrate the barium zirconate precursor solution obtained in step (1) under reduced pressure at a temperature of 30-70°C until a colorless, transparent, uniform barium zirconate precursor fiber with a viscosity of 10-50 Pa·s is obtained for spinning liquid;

(3) performing centrifugal spinning on the barium zirconate precursor fiber spinning solution prepared in step (2) to obtain the barium zirconate precursor fiber;

(4) heat up the barium zirconate precursor fiber obtained in step (3) to 600-800°C at a heating rate of 1-3°C/min under air conditions, and keep warm for 10-50min; Raise the temperature to 1200-1500°C at a heating rate of 1-2 hours, and keep it warm for 1-2 hours to obtain barium zirconate fibers.

Preferably, according to the present invention, the amount of solvent described in step (1) is acid source:solvent=100:100～1000 by volume; the solvent described in step (1) is methanol, ethanol or a combination thereof.

Preferably according to the present invention, the barium source described in step (1) is one of barium carbonate, barium acetate or a combination thereof. When the barium source is barium carbonate, the molar ratio of raw materials is preferably basic zirconium carbonate: barium carbonate: acid source=1:1: (4～6); when the barium source is barium acetate, the molar ratio of raw materials is preferably alkali Formula zirconium carbonate: barium acetate: acid source=1:1: (2～4).

Preferably according to the present invention, the acid source described in step (1) is glacial acetic acid, trifluoroacetic acid or a combination thereof. When using the mixed acid of glacial acetic acid and trifluoroacetic acid, the mass ratio of glacial acetic acid and trifluoroacetic acid is 3:5-6.5.

Preferably according to the present invention, the reaction temperature of the solution described in step (1) is 20-60°C.

Preferably according to the present invention, the decompression concentration temperature described in step (2) is 40-60°C;

Preferably according to the present invention, the centrifugal silk spinning process conditions described in step (3) are: spinning temperature 10～35°C, humidity 15～45%, centrifuge speed 12000～30000r/min, spinning hole linear speed 30 ～50m/s, the diameter of spinning wire is 0.2mm～0.5mm.

The diameter of the barium zirconate fiber prepared by the present invention is 1-20 μm, preferably 2-15 μm, most preferably 4-8 μm; the crystal phase of the barium zirconate fiber is a cubic phase, and the crystal phase is maintained under high temperature conditions up to 1500 ° C Stable, good fiber shape and no sintering adhesion between fibers.

The excellent effects of the present invention are as follows:

1. The barium zirconate fiber of the present invention has good crystallization performance, uniform diameter, stable crystal phase, good fiber shape and no sintering adhesion between fibers under high temperature conditions up to 1500 ° C, and has good high temperature heat insulation performance. The barium zirconate fiber of the invention has wide applications in the fields of high-temperature heat insulation materials, high-temperature proton conductors or/and fuel cells.

2. The present invention selects basic zirconium carbonate as the zirconium source, barium carbonate or barium acetate as the barium source, glacial acetic acid or trifluoroacetic acid as the acid source (ligand), methanol or ethanol as the solvent, at specific temperature, stirring, reducing The barium zirconate precursor fiber spinning solution is prepared under pressure and concentration conditions, and then the barium zirconate fiber is obtained by centrifugal spinning and high-temperature sintering. The preparation process is simple, low in cost, high in yield, and environmentally friendly. At the same time, the precursor sol is uniform and stable, and the quality of the obtained fiber is stable and reliable.

3. The barium zirconate fiber prepared by the present invention has a diameter of 1-20 μm. Compared with ceramic barium zirconate bulk materials, it has light weight, small specific heat capacity, resistance to mechanical vibration, and high use efficiency, which can realize energy saving and environmental protection of high temperature insulation materials Require.

Description of drawings

Figure 1 is a photo of the barium zirconate precursor fiber obtained in Example 1 of the present invention.

Fig. 2 is a photograph of the barium zirconate fiber obtained in Example 1 of the present invention.

Fig. 3 is an SEM photo of the barium zirconate fiber obtained in Example 1 of the present invention.

Fig. 4 is an SEM photo of the barium zirconate fiber obtained in Example 2 of the present invention.

Fig. 5 is an XRD pattern of barium zirconate fibers obtained in Example 1 of the present invention at different temperatures.

detailed description

The present invention will be further described below through the embodiments and in conjunction with the accompanying drawings, but not limited thereto.

The raw materials used in the examples are conventional raw materials, and the equipment used are conventional equipment, commercially available products.

Embodiment 1: prepare barium zirconate fiber with acetic acid as acid source

(1) Weigh 31.80g of basic zirconium carbonate and 19.74g of barium carbonate in a beaker, then add 24g of glacial acetic acid and 24g of methanol, and heat and stir at 60°C until dissolved to prepare a barium zirconate precursor solution.

(2) The obtained barium zirconate fiber solution was concentrated under reduced pressure at 40° C. to remove the solvent to obtain a barium zirconate precursor sol with a viscosity of 60 Pa·s, which was aged for 1 hour to obtain a spinning solution.

(3) At a temperature of 25°C, a humidity of 30%, a rotating speed of 18,000r/min, and a spinning hole diameter of 0.2mm, inject the obtained spinning solution into a high-speed spinning disk, and draw it into silk under the action of high-speed centrifugation , to obtain barium zirconate precursor fibers. The photo of the barium zirconate precursor fiber obtained by centrifugal spinning is shown in Figure 1.

(4) Raise the temperature of the obtained barium zirconate precursor fiber to 600°C at a heating rate of 1°C/min, and keep it for 30 minutes; then raise the temperature to 1200°C at 3°C/min, keep it for 2 hours, and cool down naturally to obtain zirconic acid barium fiber. The photo of the barium zirconate fiber is shown in Figure 2, and the SEM photo is shown in Figure 3. The diameter of the fiber is 4-8 μm.

Crystal phase stability experiment:

The barium zirconate fibers in Example 1 were heated to 1300°C, 1400°C and 1500°C at 4°C/min respectively, and then the XRD patterns of different temperatures were tested. The results are shown in Figure 5, indicating that the barium zirconate is a cubic phase. And the crystal phase is stable under high temperature conditions.

Example 2:

As described in Example 1, the difference is step (4): the obtained barium zirconate precursor fiber is heated up to 600 ° C at a heating rate of 1 ° C / min, and kept at 30 min; then heated to 1500 ° C at 3 ° C / min ℃, keep it warm for 2 hours, and cool down naturally to get barium zirconate fiber, the SEM photo of which is shown in Figure 4. Barium zirconate fibers can still maintain good shape and no sintering adhesion occurs between fibers.

Embodiment 3: prepare barium zirconate fiber with trifluoroacetic acid as acid source:

As described in Example 1, the difference is that the acid source was changed from glacial acetic acid to trifluoroacetic acid, and 45.6 g of trifluoroacetic acid was weighed and dissolved in a solvent, and then added to basic zirconium carbonate and barium carbonate. The spinning solution preparation, centrifugal spinning and sintering process are the same as in Example 1.

Embodiment 4: prepare barium zirconate fiber with the mixed acid of trifluoroacetic acid and acetic acid as acid source:

As described in Example 1, the difference is that 12g of glacial acetic acid and 12g of methanol are dissolved in 31.80 zirconium basic carbonate, and 22.8g of trifluoroacetic acid and 22.8g of methanol are dissolved in 19.74g of barium carbonate. heating and stirring under the condition of ℃ until they are respectively dissolved, and then the two solutions are mixed to prepare a barium zirconate precursor solution. The spinning solution preparation, centrifugal spinning and sintering process are the same as in Example 1. The obtained barium zirconate fiber still maintains a stable crystal phase, good fiber shape and no sintering adhesion between fibers under high temperature conditions up to 1500°C.

Example 5:

As described in Example 1, the difference is that 19.74g of barium carbonate is replaced with 25.54g of barium acetate in step (1), the quality of glacial acetic acid is 18g, and the amount of solvent methanol is 18g. The spinning solution preparation, centrifugal spinning and sintering process are the same as in Example 1. The obtained barium zirconate fiber still maintains a stable crystal phase, good fiber shape and no sintering adhesion between fibers under high temperature conditions up to 1500°C.

Claims (10)

1. A barium zirconate fiber, characterized in that the fiber diameter is 1-20 μm, the crystal phase of the barium zirconate fiber is a cubic phase, and the crystal phase remains stable under high temperature conditions up to 1500°C. 2. The barium zirconate fiber according to claim 1, characterized in that the barium zirconate fiber still maintains a good fiber shape under high temperature conditions up to 1500° C. and no sintering adhesion occurs between the fibers. 3. The barium zirconate fiber according to claim 1, characterized in that the diameter of the barium zirconate fiber is 2-15 μm; preferably the diameter of the barium zirconate fiber is 4-8 μm. 4. a preparation method of barium zirconate fiber described in any one of claim 1-3, comprises steps as follows: (1) According to the ratio of basic zirconium carbonate according to the molar ratio: barium source: acid source=1: (1～1.5): (2～6), take basic zirconium carbonate, barium source and acid source respectively, at 10 Add it into the solvent under the temperature of ~90°C and stirring condition, carry out the solution reaction, react for 1~12h, and obtain the barium zirconate precursor solution; (2) Concentrate the barium zirconate precursor solution obtained in step (1) under reduced pressure at a temperature of 30-70°C until a colorless, transparent, uniform barium zirconate precursor fiber with a viscosity of 10-50 Pa·s is obtained for spinning liquid; (3) performing centrifugal spinning on the barium zirconate precursor fiber spinning solution prepared in step (2) to obtain the barium zirconate precursor fiber; (4) heat up the barium zirconate precursor fiber obtained in step (3) to 600-800°C at a heating rate of 1-3°C/min under air conditions, and keep warm for 10-50min; Raise the temperature to 1200-1500°C at a heating rate of min, and keep it warm for 1-2h to obtain barium zirconate fibers. 5. the preparation method of barium zirconate fiber as claimed in claim 4 is characterized in that, step (1) described solvent consumption is acid source by volume ratio: solvent=100:100～1000. 6. the preparation method of barium zirconate fiber as claimed in claim 4 is characterized in that, the solvent described in step (1) is methyl alcohol, ethanol or its combination; The barium source described in step (1) is barium carbonate, One or a combination of barium acetates. 7. the preparation method of barium zirconate fiber as claimed in claim 6 is characterized in that, when barium source is barium carbonate, raw material molar ratio is basic zirconium carbonate: barium carbonate: acid source=1:1:( 4～6); When the barium source is barium acetate, the raw material molar ratio is basic zirconium carbonate:barium acetate:acid source=1:1:(2～4). 8. The preparation method of barium zirconate fiber as claimed in claim 4, is characterized in that, the acid source described in step (1) is glacial acetic acid, trifluoroacetic acid or its combination. 9. The preparation method of barium zirconate fiber as claimed in claim 4, is characterized in that, the solution reaction temperature described in step (1) is 20～60 ℃; Preferably, the decompression concentration described in step (2) The temperature is 40-60°C. 10. The preparation method of barium zirconate fiber as claimed in claim 4, is characterized in that, step (3) described centrifuge filament spinning process condition is: spinning temperature 10～35 ℃, humidity 15～45%, centrifuge The rotating speed is 12000~30000r/min, the line speed of the spinning hole is 30~50m/s, and the diameter of the spinning hole is 0.2mm~0.5mm.