阅读说明：本技术 一种CSiNB基多元一体化纤维毡材料的制备方法 (Preparation method of CSiNB-based multielement integrated fiber felt material ) 是由 王志江 兰晓琳 于 2020-12-29 设计创作，主要内容包括：一种CSiNB基多元一体化纤维毡材料的制备方法,它涉及一种纤维毡材料的制备方法。本发明要解决Si-B-C-N系陶瓷的方法工艺复杂、产量低,成本高的问题。制备方法：一、碳纤维毡的活化处理；二、灌注硼粉；三、高温烧结反应。本发明用于CSiNB基多元一体化纤维毡材料的制备。(A preparation method of a CSiNB-based multielement integrated fiber felt material relates to a preparation method of a fiber felt material. The invention aims to solve the problems of complex process, low yield and high cost of the method for preparing the Si-B-C-N ceramic. The preparation method comprises the following steps: firstly, activating a carbon fiber felt; secondly, pouring boron powder; thirdly, high-temperature sintering reaction. The preparation method is used for preparing the CSiNB-based multielement integrated fiber felt material.)

1. A preparation method of a CSiNB-based multielement integrated fiber felt material is characterized by comprising the following steps:

firstly, activation treatment of carbon fiber felt:

soaking the carbon fiber felt in an inorganic salt ion aqueous solution, and performing activation treatment for 0.5 to 6 hours at the temperature of between 20 and 80 ℃ to obtain an activated carbon fiber felt;

the mass percentage of the inorganic salt ion aqueous solution is 1-10%;

secondly, pouring boron powder:

dipping the activated carbon fiber felt into boron powder dispersion liquid, and ultrasonically dispersing for 30-60 min under the condition that the ultrasonic power is 35-50W, or pouring for 24-48 h under the vacuum condition to obtain the boron powder-dipped carbon fiber felt;

the boron powder dispersion liquid is a mixed liquid of boron powder and alcohol, and the mass ratio of the boron powder to the alcohol is (0.5-7) g:20 mL;

thirdly, high-temperature sintering reaction:

laying reaction silicon source powder at the bottom of a graphite crucible to obtain a reaction silicon source layer, then covering a carbon fiber felt soaked with boron powder on the surface of the reaction silicon source layer, putting the graphite crucible which is not covered with a graphite crucible cover and contains reactants into a tubular furnace, introducing nitrogen as reaction gas at the flow rate of 80-160 mL/min, heating to 1400-1700 ℃ at the heating rate of 1-5 ℃/min, carrying out sintering reaction for 4-8 h at the reaction temperature of 1400-1700 ℃, and naturally cooling to room temperature after the reaction is finished to obtain the CSiB multielement integration fiber felt material;

the mass ratio of the carbon fiber felt dipped with the boron powder to the reaction silicon source powder is 4 (1-6).

2. The method for preparing a CSiNB-based multielement integrated fiber felt material as claimed in claim 1, wherein the carbon fiber felt in the first step has a unit mass of 200g/m²～800g/m²The carbon fiber felt of (1); the thickness of the carbon fiber felt in the step one is 3 mm-10 mm.

3. The method according to claim 1, wherein the aqueous solution of inorganic salt ions in the step one is one or a mixture of sodium chloride, calcium chloride, sodium fluoride and calcium fluoride.

4. The preparation method of the CSiNB-based multielement integration fiber felt material as claimed in claim 1, characterized in that in the step one, the carbon fiber felt is immersed in an inorganic salt ion aqueous solution, and is subjected to activation treatment for 1-6 h at a temperature of 20-80 ℃ to obtain an activated carbon fiber felt.

5. The method for preparing a CSiNB-based multielement integrated fiber felt material according to claim 1, characterized in that the mass percentage of the aqueous solution of inorganic salt ions in the first step is 5-10%.

6. The preparation method of the CSiNB-based multielement integration fiber felt material according to claim 1, characterized in that in the second step, the activated carbon fiber felt is immersed in a boron powder dispersion liquid, and under the condition that the ultrasonic power is 35W, ultrasonic dispersion is carried out for 30min, so as to obtain the boron powder-impregnated carbon fiber felt.

7. The method for preparing a CSiNB-based multielement integration fiber felt material according to claim 1, characterized in that the volume ratio of the boron powder to the alcohol in the second step is (2-7) g:20 mL.

8. The preparation method of the CSiNB-based multielement integration fiber felt material according to claim 1, characterized in that nitrogen is introduced as reaction gas at a flow rate of 80mL/min to 100mL/min in the third step, the temperature is raised to 1600 ℃ to 1700 ℃ at a temperature raising rate of 2.5 ℃/min to 5 ℃/min, and the sintering reaction is carried out for 4h to 8h at a reaction temperature of 1600 ℃ to 1700 ℃.

9. The preparation method of the CSiNB-based multielement integration fiber felt material as claimed in claim 1, characterized in that the mass ratio of the boron powder-impregnated carbon fiber felt to the reactive silicon source powder in the third step is 4 (4-6).

10. The preparation method of the CSiNB-based multielement integration fiber felt material according to claim 1, characterized in that the reaction silicon source powder in the third step is a mixture of silica powder and silicon powder with a molar ratio of 1 (1-6); the purity of the nitrogen in the third step is more than or equal to 99.99 percent.

Technical Field

The invention relates to a preparation method of a fiber felt material.

Background

The ceramic fiber material with high temperature resistance, non-ablation property, high reliability and long service life is an important high-technology new material, and plays an important role in promoting the rapid development in the fields of aviation, aerospace, metallurgy, chemical engineering, energy sources and the like. According to the research on a high-temperature resistant material system, a novel Si-B-C-N ceramic is found to have extremely high thermal stability. At present, the material system still has no obvious weight loss phenomenon at 1600 ℃ or higher. However, Si-B-C-N ceramics which are achieved at present are prepared on the basis of an organic polymer cracking method. The method has the advantages of complex process, low yield (the yield is only about 30 percent), and extremely high cost of the organic precursor polyborosilazane. The application prospect of preparing Si-B-C-N series ceramics by adopting an organic polymer cracking method is limited.

Disclosure of Invention

The invention provides a preparation method of a CSiNB-based multielement integrated fiber felt material, aiming at solving the problems of complex process, low yield and high cost of a method for preparing Si-B-C-N ceramic.

A preparation method of a CSiNB-based multielement integrated fiber felt material comprises the following steps:

firstly, activation treatment of carbon fiber felt:

soaking the carbon fiber felt in an inorganic salt ion aqueous solution, and performing activation treatment for 0.5 to 6 hours at the temperature of between 20 and 80 ℃ to obtain an activated carbon fiber felt;

the mass percentage of the inorganic salt ion aqueous solution is 1-10%;

secondly, pouring boron powder:

dipping the activated carbon fiber felt into boron powder dispersion liquid, and ultrasonically dispersing for 30-60 min under the condition that the ultrasonic power is 35-50W, or pouring for 24-48 h under the vacuum condition to obtain the boron powder-dipped carbon fiber felt;

the boron powder dispersion liquid is a mixed liquid of boron powder and alcohol, and the mass ratio of the boron powder to the alcohol is (0.5-7) g:20 mL;

thirdly, high-temperature sintering reaction:

laying reaction silicon source powder at the bottom of a graphite crucible to obtain a reaction silicon source layer, then covering a carbon fiber felt soaked with boron powder on the surface of the reaction silicon source layer, putting the graphite crucible which is not covered with a graphite crucible cover and contains reactants into a tubular furnace, introducing nitrogen as reaction gas at the flow rate of 80-160 mL/min, heating to 1400-1700 ℃ at the heating rate of 1-5 ℃/min, carrying out sintering reaction for 4-8 h at the reaction temperature of 1400-1700 ℃, and naturally cooling to room temperature after the reaction is finished to obtain the CSiB multielement integration fiber felt material;

the mass ratio of the carbon fiber felt dipped with the boron powder to the reaction silicon source powder is 4 (1-6).

The invention has the beneficial effects that:

the invention relates to a method for preparing a CSiNB-based multi-element integrated fibrofelt, which is simple, convenient, low in cost and wide in industrialization prospect. Si, N, B and other elements permeate from outside to inside in sequence, the four elements are bonded with each other on the atomic scale, formed Si-C, Si-N, B-N bonds belong to covalent bonds, and the element B is positioned on the outer surface layer, so that high-temperature stability is facilitated, and the C-Si-N-B multi-element gradient ceramic fiber still has the high-strength mechanical property and the heat-proof and heat-insulating property of an atomic crystal. The method is simple, the obtained fiber felt generates new components on the basic appearance of the C fiber felt, and the fiber diameter is about 10-15 mu m. The CSiNB-based multielement integrated fiber mat has good high-temperature-resistant heat-proof and heat-insulating properties, and has good application prospects in the high-temperature application fields of aviation, aerospace, metallurgy, chemical industry and the like.

According to the preparation method, the Si-B-C-N multi-element integrated fibrofelt is prepared by taking the C fibrofelt as a template, so that the production cost is reduced, the heat insulation performance of the material is further improved, the heat conductivity of the fibrofelt is reduced to be comparable to that of an aerogel material, the heat conductivity at normal temperature is only 0.0913W/m.K, the heat conductivity value is far lower than the heat conductivity condition requirement of the heat insulation material, the good resilience performance is still kept after 100 cycles, the residual strain is only 5%, and the yield is as high as 90%.

The invention relates to a preparation method of a CSiNB-based multielement integrated fiber felt material.

Drawings

FIG. 1 is a 500-fold magnified micro-topography of a CSiNB-based multicomponent unitary fibrous mat material prepared in accordance with example one;

FIG. 2 is a 1500-fold magnified micro-topography of a CSiNB-based multicomponent unitary fibrous mat material prepared in accordance with example one;

fig. 3 is an EDS spectrum of a CSiNB-based multicomponent unitary fibrous mat material prepared in example one;

fig. 4 is a graph of elastic stress-strain curves of the CSiNB-based multicomponent fiber mat material prepared in the first example, wherein 1 is cycle 1, 2 is cycle 50, and 3 is 100.

Detailed Description

The first embodiment is as follows: the embodiment provides a preparation method of a CSiNB-based multielement integrated fiber felt material, which is completed by the following steps:

firstly, activation treatment of carbon fiber felt:

soaking the carbon fiber felt in an inorganic salt ion aqueous solution, and performing activation treatment for 0.5 to 6 hours at the temperature of between 20 and 80 ℃ to obtain an activated carbon fiber felt;

the mass percentage of the inorganic salt ion aqueous solution is 1-10%;

secondly, pouring boron powder:

dipping the activated carbon fiber felt into boron powder dispersion liquid, and ultrasonically dispersing for 30-60 min under the condition that the ultrasonic power is 35-50W, or pouring for 24-48 h under the vacuum condition to obtain the boron powder-dipped carbon fiber felt;

the boron powder dispersion liquid is a mixed liquid of boron powder and alcohol, and the mass ratio of the boron powder to the alcohol is (0.5-7) g:20 mL;

thirdly, high-temperature sintering reaction:

laying reaction silicon source powder at the bottom of a graphite crucible to obtain a reaction silicon source layer, then covering a carbon fiber felt soaked with boron powder on the surface of the reaction silicon source layer, putting the graphite crucible which is not covered with a graphite crucible cover and contains reactants into a tubular furnace, introducing nitrogen as reaction gas at the flow rate of 80-160 mL/min, heating to 1400-1700 ℃ at the heating rate of 1-5 ℃/min, carrying out sintering reaction for 4-8 h at the reaction temperature of 1400-1700 ℃, and naturally cooling to room temperature after the reaction is finished to obtain the CSiB multielement integration fiber felt material;

the mass ratio of the carbon fiber felt dipped with the boron powder to the reaction silicon source powder is 4 (1-6).

In the third step of the embodiment, the graphite crucible cover is not added, so that the whole reaction system can be fully contacted with the inert gas.

The beneficial effects of the embodiment are as follows:

the embodiment is a simple and convenient method for preparing the CSiNB-based multi-element integrated fibrofelt with low cost and wide industrialization prospect, and the quaternary composite fibrofelt is subjected to high-temperature sintering reaction with a silicon source, a nitrogen source and a boron source on the basis of an original template carbon fibrofelt. Si, N, B and other elements permeate from outside to inside in sequence, the four elements are bonded with each other on the atomic scale, formed Si-C, Si-N, B-N bonds belong to covalent bonds, and the element B is positioned on the outer surface layer, so that high-temperature stability is facilitated, and the C-Si-N-B multi-element gradient ceramic fiber still has the high-strength mechanical property and the heat-proof and heat-insulating property of an atomic crystal. The method is simple, the obtained fiber felt generates new components on the basic appearance of the C fiber felt, and the fiber diameter is about 10-15 mu m. The CSiNB-based multielement integrated fiber mat has good high-temperature-resistant heat-proof and heat-insulating properties, and has good application prospects in the high-temperature application fields of aviation, aerospace, metallurgy, chemical industry and the like.

According to the embodiment, the Si-B-C-N multi-element integrated fiber mat is prepared by taking the C fiber mat as the template, so that the production cost is reduced, the heat insulation performance of the material is further improved, the heat conductivity of the fiber mat is reduced to be comparable to that of an aerogel material, the heat conductivity at normal temperature is only 0.0913W/m.K, the heat conductivity value is far lower than the heat conductivity condition requirement of the heat insulation material, the good resilience performance is still kept after 100 cycles, the residual strain is only 5%, and the yield is as high as 90%.

The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: the carbon fiber felt in the step one is 200g/m of unit mass²～800g/m²The carbon fiber felt of (1); the thickness of the carbon fiber felt in the step one is 3 mm-10 mm. The rest is the same as the first embodiment.

The third concrete implementation mode: this embodiment is different from the first or second embodiment in that: the inorganic salt ion aqueous solution in the step one is one or a mixture of more of a sodium chloride aqueous solution, a calcium chloride aqueous solution, a sodium fluoride aqueous solution and a calcium fluoride aqueous solution. The other is the same as in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: in the first step, the carbon fiber felt is immersed in an inorganic salt ion aqueous solution, and is activated for 1-6 h at the temperature of 20-80 ℃ to obtain the activated carbon fiber felt. The others are the same as the first to third embodiments.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: the mass percentage of the inorganic salt ion aqueous solution in the step one is 5-10%. The rest is the same as the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: and step two, dipping the activated carbon fiber felt into a boron powder dispersion liquid, and performing ultrasonic dispersion for 30min under the condition that the ultrasonic power is 35W to obtain the boron powder-dipped carbon fiber felt. The rest is the same as the first to fifth embodiments.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: and the volume ratio of the mass of the boron powder to the volume of the alcohol in the second step is (2-7) g:20 mL. The others are the same as the first to sixth embodiments.

The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: and in the third step, nitrogen is introduced as reaction gas at the flow rate of 80-100 mL/min, the temperature is raised to 1600-1700 ℃ at the temperature raising rate of 2.5-5 ℃/min, and the sintering reaction is carried out for 4-8 h at the reaction temperature of 1600-1700 ℃. The rest is the same as the first to seventh embodiments.

The specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: the mass ratio of the carbon fiber felt dipped with the boron powder to the reaction silicon source powder in the third step is 4 (4-6). The other points are the same as those in the first to eighth embodiments.

The detailed implementation mode is ten: the present embodiment differs from one of the first to ninth embodiments in that: the reaction silicon source powder in the third step is a mixture of silicon dioxide powder and silicon powder in a molar ratio of 1 (1-6); the purity of the nitrogen in the third step is more than or equal to 99.99 percent. The other points are the same as those in the first to ninth embodiments.

The following examples were used to demonstrate the beneficial effects of the present invention:

the first embodiment is as follows:

a preparation method of a CSiNB-based multielement integrated fiber felt material comprises the following steps:

firstly, activation treatment of carbon fiber felt:

soaking the carbon fiber felt in an inorganic salt ion aqueous solution, and performing activation treatment for 1h at room temperature to obtain an activated carbon fiber felt;

the mass percentage of the inorganic salt ion aqueous solution is 5 percent;

secondly, pouring boron powder:

dipping the activated carbon fiber felt into boron powder dispersion liquid, and performing ultrasonic dispersion for 30min under the condition that the ultrasonic power is 35W to obtain the carbon fiber felt dipped with the boron powder;

the boron powder dispersion liquid is a mixed liquid of boron powder and alcohol, and the mass ratio of the boron powder to the volume ratio of the alcohol is 2g:20 mL;

thirdly, high-temperature sintering reaction:

laying reaction silicon source powder at the bottom of a graphite crucible to obtain a reaction silicon source layer, then covering a carbon fiber felt soaked with boron powder on the surface of the reaction silicon source layer, putting the graphite crucible which is not covered with a graphite crucible cover and contains reactants into a tubular furnace, introducing nitrogen as reaction gas at the flow rate of 80mL/min, heating the temperature to 1600 ℃ at the heating rate of 2.5 ℃/min, carrying out sintering reaction for 4 hours at the reaction temperature of 1600 ℃, and naturally cooling to room temperature after the reaction is finished to obtain a CSiNB multi-component integrated fiber felt material;

the mass ratio of the carbon fiber felt dipped with the boron powder to the reaction silicon source powder is 1: 1;

the unit mass of the carbon fiber felt in the step one is 700g/m²The carbon fiber felt of (1); the thickness of the carbon fiber felt in the step one is 5 mm;

the inorganic salt ion aqueous solution in the step one is a sodium chloride aqueous solution.

The reaction silicon source powder in the third step is a mixture of silicon dioxide powder and silicon powder in a molar ratio of 1: 1; the purity of the nitrogen in the third step is more than or equal to 99.99 percent.

FIG. 1 is a 500-fold magnified micro-topography of a CSiNB-based multicomponent unitary fibrous mat material prepared in accordance with example one; FIG. 2 is a 1500-fold magnified micro-topography of a CSiNB-based multicomponent unitary fibrous mat material prepared in accordance with example one; as can be seen from the figure, the diameter of the fiber is about 12 μm, the boron simple substance is successfully loaded on the surface of the carbon fiber by the boron powder pouring method, and the microstructure of the fiber changes on the basis of the carbon fiber to generate other components.

Fig. 3 is an EDS spectrum of a CSiNB-based multicomponent unitary fibrous mat material prepared in example one; as can be seen from the figure, the fiber felt containing four elements of Si, B, C and N is successfully prepared in the examples.

According to the charge ratio, the yield is up to 90 percent.

The CSiNB-based multielement integration fiber mat prepared by the embodiment has the normal-temperature thermal conductivity of only 0.0913W/m.K, the thermal conductivity value is far lower than the thermal conductivity condition requirement of the heat-proof and heat-insulating material, and the CSiNB-based multielement integration fiber mat is an excellent heat-proof and heat-insulating material which is comparable to an aerogel material.

Fig. 4 is a graph of elastic stress-strain curves of the CSiNB-based multicomponent fiber mat material prepared in the first example, wherein 1 is cycle 1, 2 is cycle 50, and 3 is 100. After 100 fatigue loading-unloading cycles, each strain is 20%, and the loading rate is 0.8 mm/min. After the initial loading-unloading process of the compressive strain, the C-Si-N-B fibrofelt shows the rapid elastic recovery characteristic, and after 100 cycles, the good resilience performance is still maintained, and the residual strain is only 5%. The CSiNB-based multicomponent integrated fiber mat prepared in the example has high mechanical properties.