阅读说明：本技术 一种介孔吸音多孔陶瓷的制备方法 (Preparation method of mesoporous sound-absorbing porous ceramic ) 是由 张生国 岳建设 李祯 张生贤 符裕桑 于 2019-10-25 设计创作，主要内容包括：本发明提供一种介孔吸音多孔陶瓷的制备方法,包括以下步骤：S1、陶瓷粉料的制备：将氧化铝粉末与碳纳米管混合,加入液体球磨介质、固体球磨介质和烧结助剂,球磨后制得陶瓷料浆；S2、造粒：将陶瓷料浆进行烘干,然后采用聚乙烯醇水溶液对陶瓷粉体进行造粒,制得陶瓷粉体；S3、成型：将造粒好的陶瓷粉体进行模压成型,烘干；S4、烧结：将成型后的陶瓷体,以15-25℃/min速率升温到150-250℃,再以3-8℃/min速率升温到1400-1600℃,保温2～5h后随炉冷却,制得成品。本发明制得多孔陶瓷材料,具有良好的吸音效果,而且能够承受800℃以上高温,保持不变形,而且吸音效果保持良好,为优质的耐高温吸音材料,能够较好应用于高温环境。(The invention provides a preparation method of mesoporous sound-absorbing porous ceramic, which comprises the following steps: s1, preparing ceramic powder: mixing alumina powder and carbon nanotubes, adding a liquid ball milling medium, a solid ball milling medium and a sintering aid, and performing ball milling to obtain ceramic slurry; s2, granulating: drying the ceramic slurry, and then granulating the ceramic powder by adopting a polyvinyl alcohol aqueous solution to obtain ceramic powder; s3, molding: carrying out compression molding on the granulated ceramic powder, and drying; s4, sintering: and heating the formed ceramic body to the temperature of 150-. The porous ceramic material prepared by the invention has good sound absorption effect, can bear the high temperature of more than 800 ℃, can not deform, has good sound absorption effect, is a high-quality high-temperature-resistant sound absorption material, and can be better applied to high-temperature environment.)

1. The preparation method of the mesoporous sound-absorbing porous ceramic is characterized by comprising the following steps:

s1, preparing ceramic powder: mixing alumina powder and carbon nanotubes, adding a liquid ball milling medium, a solid ball milling medium and a sintering aid, and performing ball milling to obtain ceramic slurry;

s2, granulating: drying the ceramic slurry, and then granulating the ceramic powder by adopting a polyvinyl alcohol aqueous solution to obtain ceramic powder;

s3, molding: carrying out compression molding on the granulated ceramic powder, and drying;

s4, sintering: and heating the formed ceramic body to the temperature of 150-.

2. The method of claim 1, wherein in the step S1, the amount of carbon nanotubes added is 5-20% by mass of the alumina powder.

3. The method of claim 1 or 2, wherein the gradient porous ceramic is prepared by granulating to obtain ceramic powders with different carbon nanotube contents, sequentially stacking the ceramic powders according to the addition of the carbon nanotubes from low to high, integrally molding, and integrally sintering.

4. The method of claim 1, wherein in the step S1, the liquid ball milling medium is an ethanol solution, the solid ball milling medium is corundum balls, and the sintering aid is yttrium oxide.

5. The method of claim 1 or 4, wherein in the step S1, the addition amount of the liquid ball milling medium is 2-3 times of the mass of the alumina powder, the addition amount of the solid ball milling medium is 2-3 times of the mass of the alumina powder, and the addition amount of the sintering aid is 0.03-0.08% of the mass of the alumina powder.

6. The method for preparing the mesoporous sound-absorbing porous ceramic according to claim 1, wherein in the step of S1, the ball milling time is 36-60 h.

7. The method for preparing the mesoporous sound-absorbing porous ceramic according to claim 1, wherein in the step of S2, the drying temperature is 70-90 ℃; the mass concentration of the polyvinyl alcohol aqueous solution is 3-8%, and the addition amount of the polyvinyl alcohol aqueous solution is 5-10% of the mass of the alumina powder.

8. The method of claim 1, wherein in the step S3, the compression molding pressure is 0.3 to 2 MPa; the drying temperature is 150 ℃ and 200 ℃, and the drying time is 3-8 h.

9. The method of claim 1, wherein in the step S4, the sintering temperature is raised from room temperature at a rate of 20 ℃/min; when the temperature reaches 200 ℃, the heating rate is 5 ℃/min, and the furnace is cooled after the temperature is kept for 4 hours until 1500 ℃.

10. The method of claim 3, wherein the gradient porous ceramic is prepared by placing ceramic powder with 5% of carbon nanotube in the first layer, ceramic powder with 10% of carbon nanotube in the second layer, and ceramic powder with 15% of carbon nanotube in the third layer, and integrally molding and sintering the ceramic powder.

Technical Field

The invention relates to the field of sound-absorbing materials, in particular to a preparation method of mesoporous sound-absorbing porous ceramic.

Background

The sound-absorbing and noise-reducing material is a novel environment-friendly material, requires a good sound-absorbing effect, and can obviously reduce the influence of noise on the environment. The traditional sound-absorbing material mainly uses porous materials composed of rock wool fibers, and the rock wool is made of fibers formed by drawing silicate materials and has good strength and certain fire resistance. However, when the temperature is higher than 600 ℃, the rockwool is decomposed into bead-like shapes, thereby deteriorating the sound-absorbing effect of the sound-absorbing material. The polymer material has high porosity and good sound absorption effect, but the high temperature resistance of the polymer material is poor. Therefore, there is a need for a sound-absorbing material that can withstand high temperatures without deformation and maintain a good sound-absorbing effect in high-temperature environments.

In order to keep good sound absorption effect and high temperature resistance of the material, the high temperature resistant sound absorption material prepared by the invention can bear high temperature of more than 800 ℃, is not deformed and keeps good sound absorption effect. The porous ceramic material has good porosity, and has good blocking and absorbing effects on the transmission of sound waves. The traditional porous ceramics have large pore size, usually in micron order, and have low obstruction and absorption efficiency for sound wave. The invention relates to a preparation process of mesoporous scale porous ceramic.

Disclosure of Invention

Therefore, the invention provides a preparation method of the mesoporous sound-absorbing porous ceramic, which can keep good sound-absorbing effect in a high-temperature environment.

The technical scheme of the invention is realized as follows:

a preparation method of mesoporous sound-absorbing porous ceramic comprises the following steps: s1, preparing ceramic powder: mixing alumina powder and carbon nanotubes, adding a liquid ball milling medium, a solid ball milling medium and a sintering aid, and performing ball milling to obtain ceramic slurry; the purity of the alumina powder is 96% or more, preferably 99% or more;

s2, granulating: drying the ceramic slurry, and then granulating the ceramic powder by adopting a polyvinyl alcohol aqueous solution to obtain ceramic powder;

s3, molding: carrying out compression molding on the granulated ceramic powder, and drying;

s4, sintering: and heating the formed ceramic body to the temperature of 150-.

Further, in the step S1, the amount of carbon nanotubes added is 5 to 20% by mass of the alumina powder.

Further, ceramic powder with different carbon nanotube contents is prepared by granulation, the ceramic powder is sequentially superposed according to the addition amount of the carbon nanotubes from low to high, and then the whole is molded by integral compression and sintered to prepare the gradient porous ceramic.

Further, in the step S1, the liquid ball milling medium is an ethanol solution, preferably absolute ethanol; the solid ball-milling medium is corundum balls, and the sintering aid is yttrium oxide.

Further, in the step S1, the addition amount of the liquid ball milling medium is 2 to 3 times the mass of the alumina powder, the addition amount of the solid ball milling medium is 2 to 3 times the mass of the alumina powder, and the addition amount of the sintering aid is 0.03 to 0.08%, preferably 0.05%, of the mass of the alumina powder.

Further, in the step S1, the ball milling time is 36 to 60 hours, preferably 48 hours.

Further, in the step S2, the drying temperature is 70-90 ℃; the mass concentration of the polyvinyl alcohol aqueous solution is 3-8%, and the addition amount of the polyvinyl alcohol aqueous solution is 5-10% of the mass of the alumina powder.

Further, in the step S3, the compression molding pressure is 0.3 to 2 MPa; the drying temperature is 150 ℃ and 200 ℃, and the drying time is 3-8 h.

Further, in the step S4, the sintering temperature is increased from room temperature, and the heating rate is 20 ℃/min; when the temperature reaches 200 ℃, the heating rate is 5 ℃/min, and the furnace is cooled after the temperature is kept for 4 hours until 1500 ℃.

Further, ceramic powder with 5% of carbon nano tube addition is placed on the first layer, ceramic powder with 10% of carbon nano tube addition is placed on the second layer, ceramic powder with 15% of carbon nano tube addition is placed on the third layer, and the ceramic powder is integrally molded and sintered to obtain the gradient porous ceramic.

Compared with the prior art, the invention has the beneficial effects that:

the carbon nano tubes are used as the pore-forming agent, have fine volume and good dispersibility, and are dispersed and uniformly distributed among alumina ceramic particles by adopting the process, so that the size of pores in the ceramic is obviously reduced; the carbon nano tubes and the alumina powder are ball-milled together, and a liquid ball-milling medium, a solid ball-milling medium and a sintering aid are added, so that the further refinement of the alumina powder can be ensured, the sufficient mixing of the alumina and the carbon nano tubes can be ensured, and the uniformity of pores of the final porous ceramic can be ensured; setting a specific sintering procedure, and oxidizing the carbon nano tube to form porous alumina with fine holes; the prepared porous ceramic material has good porosity, good blocking and absorbing effects on the transmission of sound waves, and good silencing effect; the sound-absorbing material can bear the high temperature of over 800 ℃, is not deformed, has good sound-absorbing effect, is a high-quality high-temperature-resistant sound-absorbing material, and can be well applied to high-temperature environment.

In addition, the invention adopts gradient arrangement, and a continuous gradient density change process is carried out from the surface to the inside to form a multilayer sound insulation barrier, so that the material has better sound attenuation and sound insulation effects.

Drawings

Fig. 1 is a microscopic structure view of the mesoporous sound-absorbing porous ceramic prepared in example 3 of the present invention, and it can be seen from the figure that the porous structure is fine and uniform, and when sound waves contact the inner wall of the porous structure, the fine pore walls can effectively block the sound waves from vibrating, so as to achieve dissipation of sound energy, and significantly improve the sound-absorbing effect.

FIG. 2 is a graph showing the change in density of the gradient mesoporous acoustical porous ceramic according to example 4 of the present invention, in which the density distribution from the surface to the inside is continuously changed.

FIG. 3 is a graph showing the relationship between the sound absorption coefficient and the porous alumina ceramics with different porosities prepared in examples 1, 2, 3 and 4 of the present invention, wherein the curves are sequentially shown in examples 1, 2, 3 and 4 as viewed from the bottom. As can be seen from the figure, the sound absorption coefficient gradually increases as the porosity increases.

Detailed Description

In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.

The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

The materials, reagents and the like used in the examples of the present invention can be obtained commercially without specific description.