阅读说明：本技术 具有多形状及弧度的微通孔泡沫陶瓷吸音材料及制备方法 (Micro-through-hole foamed ceramic sound-absorbing material with multiple shapes and radians and preparation method thereof ) 是由 史俊勇 史婷菁 于 2021-09-26 设计创作，主要内容包括：本发明公开了具有多形状及弧度的微通孔泡沫陶瓷吸音材料及制备方法,所述吸音材料包括位于底部的多孔层、位于中部的过渡层以及位于上部的加固层,所述多孔层包括聚氨酯泡沫和涂覆在所述聚氨酯泡沫表面的浆料,所述多孔层的厚度为3-4mm,所述过渡层的厚度为0.6-0.8mm,所述加固层的厚度为1.8-2.4mm。所述制备方法包括以下步骤：S1多孔层制备；S2过渡层制备；S3加固层制备；S4综合煅烧。本发明的微通孔泡沫陶瓷吸音材料通过设置底部多孔层、中部过渡层以及上部加固层能够提高泡沫陶瓷的吸音效果,同时大大提高了其力学性能和耐高温性能,具有良好的保温隔热吸音效果,且连接牢固,整体性强,具有广阔的应用前景。(The invention discloses a micro-through-hole foamed ceramic sound-absorbing material with multiple shapes and radians and a preparation method thereof, wherein the sound-absorbing material comprises a porous layer positioned at the bottom, a transition layer positioned at the middle and a reinforcing layer positioned at the upper part, the porous layer comprises polyurethane foam and slurry coated on the surface of the polyurethane foam, the thickness of the porous layer is 3-4mm, the thickness of the transition layer is 0.6-0.8mm, and the thickness of the reinforcing layer is 1.8-2.4 mm. The preparation method comprises the following steps: preparing a porous layer S1; s2 preparing a transition layer; s3 preparing a reinforcing layer; and S4 comprehensive calcination. The sound absorption effect of the foamed ceramic can be improved by arranging the bottom porous layer, the middle transition layer and the upper reinforcing layer, the mechanical property and the high temperature resistance of the sound absorption material are greatly improved, the sound absorption material has good heat preservation, heat insulation and sound absorption effects, is firm in connection and strong in integrity, and has wide application prospect.)

1. The sound absorbing material is characterized by comprising a porous layer positioned at the bottom, a transition layer positioned in the middle and a reinforcing layer positioned at the upper part, wherein the porous layer comprises polyurethane foam and slurry coated on the surface of the polyurethane foam, and the slurry comprises 18-22 parts by weight of fly ash, 16-18 parts by weight of clay and ZrO₂1-2 parts of, Y₂O₃0.5-1 part of additive and 3 parts of additive, wherein the water content of the slurry is 23-26%, the additive comprises 0.6 part of cross-linking agent, 0.4 part of dispersing agent, 1 part of pH regulator, 0.2 part of initiator and 0.8 part of catalyst in parts by weight, the transition layer comprises 3-5 parts of black mud, 2-3 parts of red soil and 1-2 parts of coal slag or slag in parts by weight, and the reinforcing layer comprises alpha-Al in parts by weight₂O₃10-15 parts of mullite powder and 1-2 parts of additive auxiliary materials, wherein the additive auxiliary materials comprise 0.5 part of expanded perlite, 0.25-0.75 part of calcium borate and 0.25-0.75 part of zeolite in parts by weight.

2. The sound absorbing material of claim 1, wherein the polyurethane foam has an open cell ratio of > 99% and a pore diameter of 0.4 to 0.8 mm.

3. The micro-perforated foamed ceramic sound absorbing material with multiple shapes and radians as claimed in claim 1, wherein the cross-linking agent is N, N-methylene bisacrylamide, the dispersing agent is polyacrylamide, the pH adjusting agent is NaOH solution and HCl solution with a mass concentration of 20%, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine.

4. The method for preparing the micro-perforated foamed ceramic sound absorbing material with multiple shapes and radians as claimed in any one of claims 1 to 3, comprising the steps of:

preparation of the porous layer of S1:

s1-1 polyurethane foam pretreatment: washing the surface of polyurethane foam by using a NaOH solution with the mass concentration of 10%, then washing for 3 times by using deionized water, modifying the surface of the polyurethane foam by using a silica sol solution with the mass concentration of 5%, mechanically stretching the polyurethane foam for 0.5-1h, wherein the stretching length is 125% of the original length, and then carrying out low-temperature plasma treatment to obtain a polyurethane foam framework;

s1-2 slurry preparation: mixing the dispersing agent with fly ash, clay and ZrO₂、Y₂O₃Mixing, ball-milling until the particle size is 2.3-2.5 μm, adding a cross-linking agent, an initiator and a proper amount of water, stirring, adjusting the pH value to 7.2-7.4 by a pH regulator, and continuously stirring for 15-30min to obtain slurry;

s1-3 impregnation and calcination: soaking a polyurethane foam framework in a mold filled with slurry, adding a catalyst, simultaneously vacuumizing and standing for 2h, removing redundant slurry, drying, then putting the dried slurry into a high-temperature calcining furnace, heating to 850 ℃ at the heating rate of 120-;

preparation of S2 transition layer: mixing and ball-milling the components of the transition layer, and then stacking the components above the porous layer green body obtained in the step S1-3 for later use;

s3 reinforcement layer preparation: mixing and ball-milling the components of the reinforcing layer, adding a proper amount of deionized water to enable the water content of the mixture to be 38-42%, then cooling to-33-35 ℃ at a cooling rate of 30-40 ℃/h, and preserving heat for 2h to obtain a green body of the reinforcing layer;

s4 comprehensive calcination: and (4) placing the reinforcing layer green body obtained in the step S3 above the transition layer obtained in the step S2, then quickly heating to 1450-.

5. The method for preparing the sound absorbing material of foamed ceramics with micro through holes in various shapes and arcs according to claim 4, wherein the working pressure of the low temperature plasma treatment in step S1-1 is 40-50Pa, the discharge power is 70-90W, the treatment time is 15-30min, the polyurethane foam is secondarily mechanically stretched while the low temperature plasma treatment is performed, and the stretching length is 110% of the original length.

6. The method for preparing the micro through hole ceramic foam sound absorbing material with multiple shapes and radians as claimed in claim 4, wherein the ball-to-material ratio of the ball mill in the step S1-2 is 1: 1, the rotating speed is 300r/min, and the stirring rotating speed is 600-800 r/min.

7. The method for preparing the sound absorbing material of claim 4, wherein the transition layer has a powder particle size of 2.1-2.3 μm in step S2, and the bonding between the transition layer and the porous layer green body is strengthened by laser beam drilling during stacking, comprising the steps of:

s2-1: marking punching hole sites on the powder surface of the transition layer, wherein the hole sites are arranged at equal intervals;

s2-2: focusing a laser beam emitted by a laser emitter to the marked perforating hole position, carrying out laser perforation, melting the powder of the transition layer under the action of laser, and enabling a part of the transition layer material to downwards penetrate into the porous layer green body so as to connect the transition layer with the porous layer green body;

s2-3: after the punching of all the hole sites is finished, standing for 0.5h, and storing at the temperature of 0-5 ℃.

8. The method for preparing the sound absorbing material of claim 7, wherein the laser beam is a Gaussian beam with a beam mass m in step S2-2²1-1.4, wavelength range 1070-1090 and focused spot diameter 50-150 μm.

9. The method as claimed in claim 4, wherein the temperature increase rate in step S4 is 260-280 ℃/h.

Technical Field

The invention relates to the technical field of ceramics and sound-absorbing materials, in particular to a micro-through hole foamed ceramic sound-absorbing material with multiple shapes and radians and a preparation method thereof.

Background

With the continuous development of society and the continuous progress of industrialization level, noise pollution is becoming one of the main factors influencing normal production activities of people, for example, noise caused by machine operation, automobile driving, building construction and the like has great influence on the health of people, and how to solve the noise pollution scientifically and reasonably becomes one of the starting points of environmental protection. The sound-absorbing material is one of main means for controlling noise pollution, the sound-absorbing material absorbs and digests noise by utilizing abundant pore structures and shapes, the sound-absorbing quantity is large, the corrosion resistance effect is good, the high-temperature resistance performance is strong, and the existing porous sound-absorbing material is suitable for various choices and is very important.

The porous sound-absorbing material is internally provided with a large number of mutually-communicated micropores, when sound waves are incident to the surface of the porous material, one part of incident sound energy is reflected by the surface, the other part of the incident sound energy is absorbed into the material, the sound waves incident to the inside of the material cause the air in the micropores to vibrate in the propagation process, and the air and the solid rib generate relative motion, so that the sound waves are subjected to viscous resistance from gas near the rib wall and are continuously converted into internal energy; when the air is compressed in a heat insulation way, heat exchange is also carried out between the air and the hole wall, so that part of sound energy is converted, and the absorption of noise is completed.

Patent CN103787688A discloses a preparation method of zirconia foamed ceramics, relating to the technical field of production of high-tech ceramic products, namely foamed ceramics. Stirring polyether or polyester polyol, a catalyst, a surfactant and a foaming agent, adding zirconia ceramic powder, stirring uniformly, adding a curing agent, mixing uniformly, placing in a forming container for reaction and curing, carrying out open-cell treatment on a cured foam ceramic sponge body, and sintering at high temperature to obtain the zirconia foam ceramic. The three-dimensional reticular foamed ceramic blank is directly formed through a polymerization reaction and a foaming process, so that the production procedures are greatly reduced, the obtained zirconia foamed ceramic has uniform and consistent structure, the manpower requirement and the manual labor amount can be greatly reduced, and the stability of the product performance can be improved while the production period is shortened. However, the sound absorption effect of the foamed ceramic is general, and the application range of the foamed ceramic is influenced.

Disclosure of Invention

Aiming at the problems, the invention provides a micro-through hole foamed ceramic sound absorption material with multiple shapes and radians and a preparation method thereof.

The technical scheme of the invention is as follows:

the sound absorbing material comprises a porous layer positioned at the bottom, a transition layer positioned at the middle and a reinforcing layer positioned at the upper part, wherein the porous layer comprises polyurethane foam and slurry coated on the surface of the polyurethane foam, the thickness of the porous layer is 3-4mm, the thickness of the transition layer is 0.6-0.8mm, the thickness of the reinforcing layer is 1.8-2.4mm, and the slurry comprises 18-22 parts by weight of fly ash, 16-18 parts by weight of clay, and ZrO₂1-2 parts of, Y₂O₃0.5-1 part of additive and 3 parts of additive, wherein the water content of the slurry is 23-26%, the additive comprises 0.6 part of cross-linking agent, 0.4 part of dispersing agent, 1 part of pH regulator, 0.2 part of initiator and 0.8 part of catalyst in parts by weight, the transition layer comprises 3-5 parts of black mud, 2-3 parts of red soil and 1-2 parts of coal slag or slag in parts by weight, and the reinforcing layer comprises alpha-Al in parts by weight₂O₃10-15 parts of mullite powder and 1-2 parts of additive auxiliary materials, wherein the additive auxiliary materials comprise 0.5 part of expanded perlite, 0.25-0.75 part of calcium borate and 0.25-0.75 part of zeolite in parts by weight.

Furthermore, the open porosity of the polyurethane foam is more than 99%, the pore diameter is 0.4-0.8mm, and the porous layer ceramic obtained by the organic foam impregnation method has high porosity, good sound absorption performance and strong stability.

Furthermore, the cross-linking agent is N, N-methylene-bisacrylamide, the dispersing agent is polyacrylamide, the pH regulator is a NaOH solution and an HCl solution with the mass concentration of 20%, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine. Can promote to form the mesh ceramics with three-dimensional mesh skeleton structure, and has low use cost.

The preparation method of the micro-through hole foamed ceramic sound-absorbing material with multiple shapes and radians comprises the following steps:

preparation of the porous layer of S1:

s1-1 polyurethane foam pretreatment: washing the surface of polyurethane foam by using a NaOH solution with the mass concentration of 10%, then washing for 3 times by using deionized water, modifying the surface of the polyurethane foam by using a silica sol solution with the mass concentration of 5%, mechanically stretching the polyurethane foam for 0.5-1h, wherein the stretching length is 125% of the original length, and then carrying out low-temperature plasma treatment to obtain a polyurethane foam framework; the surface roughness of the polyurethane foam is obviously increased, the slurry hanging amount of a polyurethane matrix is obviously increased, and the mechanical property and the high-temperature property are obviously improved.

S1-2 slurry preparation: mixing the dispersing agent with fly ash, clay and ZrO₂、Y₂O₃Mixing, ball-milling until the particle size is 2.3-2.5 μm, adding a cross-linking agent, an initiator and a proper amount of water, stirring, adjusting the pH value to 7.2-7.4 by a pH regulator, and continuously stirring for 15-30min to obtain slurry; obtaining the slurry with high solid phase volume content, low viscosity and high fluidity.

S1-3 impregnation and calcination: soaking a polyurethane foam framework in a mold filled with slurry, adding a catalyst, simultaneously vacuumizing and standing for 2h, removing redundant slurry, drying, then putting the dried slurry into a high-temperature calcining furnace, heating to 850 ℃ at the heating rate of 120-;

preparation of S2 transition layer: mixing and ball-milling the components of the transition layer, and then stacking the components above the porous layer green body obtained in the step S1-3 for later use;

s3 reinforcement layer preparation: mixing and ball-milling the components of the reinforcing layer, adding a proper amount of deionized water to enable the water content of the mixture to be 38-42%, then cooling to-33-35 ℃ at a cooling rate of 30-40 ℃/h, and preserving heat for 2h to obtain a green body of the reinforcing layer;

s4 comprehensive calcination: and (4) placing the reinforcing layer green body obtained in the step S3 above the transition layer obtained in the step S2, then quickly heating to 1450-.

Further, in the step S1-1, the working pressure of the low-temperature plasma treatment is 40-50Pa, the discharge power is 70-90W, the treatment time is 15-30min, the polyurethane foam is mechanically stretched for the second time while the low-temperature plasma treatment is performed, and the stretching length is 110% of the original length. The surface roughness is obviously increased, the slurry hanging amount of a polyurethane matrix is obviously increased, and the mechanical property and the high-temperature property are obviously improved.

Further, the ball-to-material ratio of the ball milling in the step S1-2 is 1: 1, the rotating speed is 300r/min, and the stirring rotating speed is 600-800 r/min. Obtaining the slurry with high solid phase volume content, low viscosity and high fluidity.

Further, in step S2, the component powder of the transition layer has a particle size of 2.1-2.3 μm, and the bonding between the transition layer and the green porous layer is strengthened by laser beam drilling during stacking, which includes the following steps:

s2-1: marking punching hole sites on the powder surface of the transition layer, wherein the hole sites are arranged at equal intervals;

s2-2: focusing a laser beam emitted by a laser emitter to the marked perforating hole position, carrying out laser perforation, melting the powder of the transition layer under the action of laser, and enabling a part of the transition layer material to downwards penetrate into the porous layer green body so as to connect the transition layer with the porous layer green body;

s2-3: after the punching of all the hole sites is finished, standing for 0.5h, and storing at the temperature of 0-5 ℃.

Further, the laser beam in the step S2-2 is a Gaussian beam with a beam quality m²1-1.4, wavelength range 1070-1090, focused spot diameter 50-150 μm, and Gaussian beam to improve the connection stability of the transition layer.

Further, the temperature rise rate in the step S4 is 260-.

The invention has the beneficial effects that:

(1) the sound absorption effect of the foamed ceramic can be improved by arranging the bottom porous layer, the middle transition layer and the upper reinforcing layer, the mechanical property and the high temperature resistance of the sound absorption material are greatly improved, the sound absorption material has good heat preservation, heat insulation and sound absorption effects, is firm in connection and strong in integrity, and has wide application prospect.

(2) According to the micro-through-hole foamed ceramic sound-absorbing material, the surface roughness of polyurethane foam is obviously increased by a method of modifying the surface of the polyurethane foam, the slurry hanging amount of a polyurethane matrix is obviously increased by low-temperature plasma treatment, the mechanical property and the high-temperature property are obviously improved, the diameter of a ceramic rib body is gradually increased by mechanical stretching, so that the internal pore structure is improved, the top of a pore has a certain radian, the concentration of stress on the top of the pore is reduced, and the compressive strength of a sample is improved.

(3) The micro-through hole foamed ceramic sound absorbing material provided by the invention strengthens the connection between the transition layer and the porous layer green body by a laser beam punching method during stacking, so that the powder of the transition layer is melted under the action of laser, and a part of the material of the transition layer is downwards penetrated into the porous layer green body, thereby realizing the effective and stable connection of the transition layer, the porous layer and the reinforcing layer.

Drawings

FIG. 1 is a schematic structural view of a ceramic foam sound absorbing material according to the present invention;

FIG. 2 is a schematic view illustrating the principle of laser beam drilling in step S2 of manufacturing the sound-absorbing material of ceramic foam according to the present invention;

FIG. 3 is a schematic diagram of laser beam drilling holes in step S2 of manufacturing the sound-absorbing material of ceramic foam according to the present invention;

FIG. 4 is a schematic view of the microstructure of the pores inside the porous layer of the sound-absorbing material of ceramic foam according to the present invention.

Detailed Description

Example 1

As shown in fig. 1, the sound absorbing material of micro-perforated foamed ceramics with multiple shapes and arcs comprises a porous layer at the bottom, a transition layer at the middle and a reinforcing layer at the upper part;

the porous layer comprises polyurethane foam and slurry coated on the surface of the polyurethane foam, the thickness of the porous layer is 3.5mm, the open porosity of the polyurethane foam is 99.5%, the pore diameter is 0.6mm, and the slurry comprises 20 parts by weight of fly ash, 17 parts by weight of clay and ZrO₂1.5 parts of, Y₂O₃0.7 part of additive and 2.3 parts of additive, wherein the water content of the slurry is 25 percent, the additive comprises 0.6 part of cross-linking agent, 0.4 part of dispersing agent, 1 part of pH regulator, 0.2 part of initiator and 0.8 part of catalyst in parts by weight, the cross-linking agent is N, N-methylene-bisacrylamide, the dispersing agent is polyacrylamide, the pH regulator is NaOH solution and HCl solution with the mass concentration of 20 percent, the initiator is ammonium persulfate, and the catalyst is tetramethyl ethylenediamine;

the thickness of the transition layer is 0.7mm, and the transition layer comprises 4 parts of black mud, 2.5 parts of red mud and 1.6 parts of coal slag or slag in parts by weight;

the thickness of the reinforcing layer is 2.2mm, and the reinforcing layer comprises alpha-Al in parts by weight₂O₃13 parts of mullite powder and 1.5 parts of additive auxiliary materials, wherein the additive auxiliary materials comprise 0.5 part of expanded perlite, 0.5 part of calcium borate and 0.5 part of zeolite in parts by weight.

The preparation method of the micro-through hole foamed ceramic sound-absorbing material with multiple shapes and radians comprises the following steps:

preparation of the porous layer of S1:

s1-1 polyurethane foam pretreatment: the method comprises the steps of washing the surface of polyurethane foam by using a NaOH solution with the mass concentration of 10%, then washing for 3 times by using deionized water, modifying the surface of the polyurethane foam by using a silica sol solution with the mass concentration of 5%, mechanically stretching the polyurethane foam, wherein the stretching length is 125% of the original length, the treatment time is 0.8h, then obtaining a polyurethane foam framework through low-temperature plasma treatment, the working air pressure of the low-temperature plasma treatment is 44Pa, the discharge power is 75W, the treatment time is 20min, and the polyurethane foam is mechanically stretched for the second time while being treated by the low-temperature plasma treatment, wherein the stretching length is 110% of the original length;

s1-2 slurry preparation: mixing the dispersing agent with fly ash, clay and ZrO₂、Y₂O₃Ball milling is carried out after mixing untilThe grain diameter is 2.4 μm, the ball-milling ball-material ratio is 1: 1, the rotating speed is 300r/min, the stirring rotating speed is 700r/min, a cross-linking agent, an initiator and a proper amount of water are added and stirred, the pH value is adjusted to 7.3 by a pH regulator, and the stirring is continued for 20min to obtain slurry;

s1-3 impregnation and calcination: soaking a polyurethane foam framework in a mold filled with slurry, adding a catalyst, simultaneously vacuumizing and standing for 2h, removing redundant slurry, drying, then putting in a high-temperature calcining furnace, heating to 850 ℃ at a heating rate of 130 ℃/h, and preserving heat for 3h to obtain a porous layer green body;

preparation of S2 transition layer: mixing and ball-milling the components of the transition layer, and then stacking the components above the porous layer green body obtained in the step S1-3 for later use;

s3 reinforcement layer preparation: mixing the components of the reinforcing layer, performing ball milling, adding a proper amount of deionized water to enable the water content of the mixture to be 40%, then cooling to-34 ℃ at a cooling rate of 35 ℃/h, and preserving heat for 2h to obtain a reinforcing layer green body;

s4 comprehensive calcination: and (4) placing the reinforcing layer green body obtained in the step S3 above the transition layer in the step S2, then heating to 1500 ℃ at a heating rate of 270 ℃/h, and preserving heat for 3h to obtain the micro-through hole foamed ceramic sound absorbing material.

Example 2

This embodiment is substantially the same as embodiment 1, except that: the porous layer has different slurry component ratios.

The slurry comprises 22 parts of fly ash, 18 parts of clay and ZrO₂2 parts of, Y₂O₃1 part of additive and 3 parts of additive, wherein the water content of the slurry is 26%, the additive comprises 0.6 part of cross-linking agent, 0.4 part of dispersing agent, 1 part of pH regulator, 0.2 part of initiator and 0.8 part of catalyst in parts by weight, the cross-linking agent is N, N-methylene-bisacrylamide, the dispersing agent is polyacrylamide, the pH regulator is NaOH solution and HCl solution with the mass concentration of 20%, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine.

Example 3

This embodiment is substantially the same as embodiment 1, except that: the porous layer has different slurry component ratios.

The slurry comprises 18 parts of fly ash, 16 parts of clay and ZrO by weight₂1 part of, Y₂O₃0.5 part of additive and 3 parts of additive, wherein the water content of the slurry is 23%, the additive comprises 0.6 part of cross-linking agent, 0.4 part of dispersing agent, 1 part of pH regulator, 0.2 part of initiator and 0.8 part of catalyst in parts by weight, the cross-linking agent is N, N-methylene-bisacrylamide, the dispersing agent is polyacrylamide, the pH regulator is NaOH solution and HCl solution with the mass concentration of 20%, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine.

Example 4

This embodiment is substantially the same as embodiment 1, except that: the transition layer and the reinforcing layer have different component proportions.

The transition layer comprises 5 parts of black mud, 3 parts of red mud and 2 parts of coal slag or slag in parts by weight;

the reinforcing layer comprises alpha-Al in parts by weight₂O₃15 parts of mullite powder and 2 parts of additive auxiliary materials, wherein the additive auxiliary materials comprise 0.5 part of expanded perlite, 0.75 part of calcium borate and 0.75 part of zeolite in parts by weight.

Example 5

This embodiment is substantially the same as embodiment 1, except that: the transition layer and the reinforcing layer have different component proportions.

The transition layer comprises 3 parts of black mud, 2 parts of red mud and 1 part of coal slag or slag in parts by weight;

the reinforcing layer comprises alpha-Al in parts by weight₂O₃10 parts of mullite powder and 1 part of additive auxiliary material, wherein the additive auxiliary material comprises 0.5 part of expanded perlite, 0.25 part of calcium borate and 0.25 part of zeolite in parts by weight.

Example 6

This embodiment is substantially the same as embodiment 1, except that: the layer thickness of each layer is different.

As shown in FIG. 1, the sound-absorbing material is a micro-perforated ceramic foam sound-absorbing material having a plurality of shapes and arcs, and comprises a porous layer located at the bottom, a transition layer located at the middle, and a reinforcement layer located at the upper, wherein the porous layer has a thickness of 3mm, the polyurethane foam has an open porosity of 99.5%, a pore diameter of 0.4mm, the transition layer has a thickness of 0.6mm, and the reinforcement layer has a thickness of 1.8 mm.

Example 7

This embodiment is substantially the same as embodiment 1, except that: the layer thickness of each layer is different.

As shown in FIG. 1, the sound-absorbing material is a micro-perforated ceramic foam sound-absorbing material with multiple shapes and arcs, and comprises a porous layer positioned at the bottom, a transition layer positioned at the middle and a reinforcing layer positioned at the upper part, wherein the thickness of the porous layer is 4mm, the open porosity of polyurethane foam is 99.5%, the pore diameter is 0.8mm, the thickness of the transition layer is 0.8mm, and the thickness of the reinforcing layer is 2.4 mm.

Example 8

This embodiment is substantially the same as embodiment 1, except that: and step S1-1, the polyurethane foam pretreatment process parameters are different.

S1-1 polyurethane foam pretreatment: the method comprises the steps of washing the surface of polyurethane foam by using a NaOH solution with the mass concentration of 10%, washing for 3 times by using deionized water, modifying the surface of the polyurethane foam by using a silica sol solution with the mass concentration of 5%, mechanically stretching the polyurethane foam, wherein the stretching length is 125% of the original length, the treatment time is 0.5h, and obtaining a polyurethane foam framework by low-temperature plasma treatment, wherein the working air pressure of the low-temperature plasma treatment is 40Pa, the discharge power is 70W, the treatment time is 15min, the polyurethane foam is mechanically stretched for the second time during the low-temperature plasma treatment, and the stretching length is 110% of the original length.

Example 9

This embodiment is substantially the same as embodiment 1, except that: and step S1-1, the polyurethane foam pretreatment process parameters are different.

S1-1 polyurethane foam pretreatment: the method comprises the steps of washing the surface of polyurethane foam by using a NaOH solution with the mass concentration of 10%, then washing for 3 times by using deionized water, modifying the surface of the polyurethane foam by using a silica sol solution with the mass concentration of 5%, mechanically stretching the polyurethane foam, wherein the stretching length is 125% of the original length, the treatment time is 1h, then obtaining a polyurethane foam framework through low-temperature plasma treatment, the working air pressure of the low-temperature plasma treatment is 50Pa, the discharge power is 90W, the treatment time is 30min, and the polyurethane foam is mechanically stretched for the second time while the low-temperature plasma treatment is carried out, and the stretching length is 110% of the original length.

Example 10

This embodiment is substantially the same as embodiment 1, except that: the process parameters in steps S1-2 and S1-3 are different.

S1-2 slurry preparation: mixing the dispersing agent with fly ash, clay and ZrO₂、Y₂O₃Ball-milling the mixture until the particle size is 2.3 mu m, wherein the ball-milling ratio is 1: 1, the rotating speed is 300r/min, the stirring rotating speed is 600r/min, a cross-linking agent, an initiator and a proper amount of water are added and stirred, the pH value is adjusted to 7.2 by a pH regulator, and the stirring is continued for 15min to obtain slurry;

s1-3 impregnation and calcination: soaking a polyurethane foam framework in a mold filled with slurry, adding a catalyst, simultaneously vacuumizing and standing for 2h, removing redundant slurry, drying, then putting in a high-temperature calcining furnace, heating to 850 ℃ at a heating rate of 120 ℃/h, and preserving heat for 3h to obtain a porous layer green body.

Example 11

This embodiment is substantially the same as embodiment 1, except that: the process parameters in steps S1-2 and S1-3 are different.

S1-2 slurry preparation: mixing the dispersing agent with fly ash, clay and ZrO₂、Y₂O₃Ball-milling the mixture until the particle size is 2.5 mu m, wherein the ball-milling ratio is 1: 1, the rotating speed is 300r/min, the stirring rotating speed is 800r/min, a cross-linking agent, an initiator and a proper amount of water are added and stirred, the pH value is adjusted to 7.4 by a pH regulator, and the stirring is continued for 30min to obtain slurry;

s1-3 impregnation and calcination: soaking a polyurethane foam framework in a mold filled with slurry, adding a catalyst, simultaneously vacuumizing and standing for 2h, removing redundant slurry, drying, then putting in a high-temperature calcining furnace, heating to 850 ℃ at a heating rate of 140 ℃/h, and preserving heat for 3h to obtain a porous layer green body.

Example 12

This embodiment is substantially the same as embodiment 1, except that: the preparation method of the transition layer of step S2 is different.

Preparation of S2 transition layer: after mixing and ball milling the components of the transition layer, stacking the components on the porous layer green body obtained in the step S1-3 for standby, wherein the component powder of the transition layer has a particle size of 2.2 μm, and the connection between the transition layer and the porous layer green body is strengthened by laser beam drilling during stacking, as shown in fig. 2 and 3, comprising the following steps:

s2-1: marking punching hole sites on the powder surface of the transition layer, wherein the hole sites are arranged at equal intervals;

s2-2: focusing the laser beam emitted by the laser emitter to the marked drilling hole position for laser drilling, wherein the laser beam is a Gaussian beam and has a beam quality m²1.2, the wavelength range is 1080, the focused spot diameter is 100 mu m, the transition layer powder is melted under the action of laser, and a part of the transition layer material is made to penetrate downwards into the porous layer green body, so that the transition layer is connected with the porous layer green body.

Example 13

This embodiment is substantially the same as embodiment 12 except that: and step S2, the preparation process parameters of the transition layer are different.

Preparation of S2 transition layer: mixing and ball-milling the components of the transition layer, and then stacking the components on the porous layer green body obtained in the step S1-3 for standby, wherein the particle size of the component powder of the transition layer is 2.1 mu m, and the connection between the transition layer and the porous layer green body is strengthened by a laser beam punching method during stacking, and the method comprises the following steps:

s2-1: marking punching hole sites on the powder surface of the transition layer, wherein the hole sites are arranged at equal intervals;

s2-2: focusing the laser beam emitted by the laser emitter to the marked drilling hole position for laser drilling, wherein the laser beam is a Gaussian beam and has a beam quality m²1, wavelength range 1070, focused spot diameter 50 μm, and melting the transition layer powder under the action of the laser to allow a portion of the transition layer material to penetrate down into the porous layer green body, thereby connecting the transition layer to the porous layer green body.

Example 14

This embodiment is substantially the same as embodiment 12 except that: and step S2, the preparation process parameters of the transition layer are different.

Preparation of S2 transition layer: mixing and ball-milling the components of the transition layer, and then stacking the components on the porous layer green body obtained in the step S1-3 for standby, wherein the particle size of the component powder of the transition layer is 2.3 mu m, and the connection between the transition layer and the porous layer green body is strengthened by a laser beam punching method during stacking, and the method comprises the following steps:

s2-1: marking punching hole sites on the powder surface of the transition layer, wherein the hole sites are arranged at equal intervals;

s2-2: focusing the laser beam emitted by the laser emitter to the marked drilling hole position for laser drilling, wherein the laser beam is a Gaussian beam and has a beam quality m²1.4, wavelength range 1090, focused spot diameter 150 μm, and the transition layer powder is melted by the laser, allowing a portion of the transition layer material to penetrate down into the porous layer green body, thereby joining the transition layer to the porous layer green body.

Example 15

This embodiment is substantially the same as embodiment 1, except that: the process parameters of steps S3 and S4 are different.

S3 reinforcement layer preparation: mixing and ball-milling the components of the reinforcing layer, adding a proper amount of deionized water to enable the water content of the mixture to be 38%, then cooling to-33 ℃ at a cooling rate of 30 ℃/h, and preserving heat for 2h to obtain a green reinforcing layer;

s4 comprehensive calcination: and (4) placing the reinforcing layer green body obtained in the step S3 above the transition layer in the step S2, then heating to 1450 ℃ at the heating rate of 260 ℃/h, and preserving heat for 3h to obtain the micro-through hole foamed ceramic sound absorbing material.

Example 16

This embodiment is substantially the same as embodiment 1, except that: the process parameters of steps S3 and S4 are different.

S3 reinforcement layer preparation: mixing the components of the reinforcing layer, performing ball milling, adding a proper amount of deionized water to enable the water content of the mixture to be 42%, then cooling to-35 ℃ at a cooling rate of 40 ℃/h, and performing heat preservation for 2h to obtain a reinforcing layer green body;

s4 comprehensive calcination: and (4) placing the reinforcing layer green body obtained in the step S3 above the transition layer in the step S2, then heating to 1560 ℃ at a heating rate of 280 ℃/h, and preserving heat for 3h to obtain the micro-through hole foamed ceramic sound absorbing material.

Examples of the experiments

The sound absorption performance and the mechanical property of the micro-through hole foamed ceramic sound absorption material prepared in each embodiment are tested, and the test method of the sound absorption performance comprises the following steps: placing the micro-through-hole foamed ceramic sound-absorbing material at one end of the rigid wall of the sound-absorbing pipe, enabling the loudspeaker to emit pure sound with single frequency each time, enabling a part of sound waves to be reflected after meeting the surface of the material, enabling incident sound waves and reflected sound waves in the standing wave pipe to interfere to generate standing waves, enabling sound pressure to have peak values at every 1/4 wavelength, and obtaining sound pressure ratioWherein p is_maxIs the maximum sound pressure value, p_minThe minimum sound pressure value is measured by a movable detector, and the sound absorption coefficient is calculatedThe test results are shown in table 1:

sound absorption and mechanical properties of the sound absorbing material of micro-porous foamed ceramics in the examples of Table 1

Examples	Porosity%	Coefficient of sound absorption	Flexural strength MPa
				Example 1	74.68	0.86	58.74
Example 2	60.29	0.71	59.32
				Example 3	83.57	0.65	55.41
Example 6	75.21	0.78	55.26
				Example 7	74.15	0.91	60.34
Example 12	71.88	0.91	61.70
				Example 15	73.25	0.84	56.34
Example 16	71.89	0.77	55.20
				Comparative example 1	65.39	0.72	57.45

Compared with the examples 1-3, the three groups of examples have the same thickness, but the material proportion of the porous layers is different, so that the porosity is different, the too large or too small porosity is not beneficial to improving the sound absorption effect, the specific surface area and the bending degree of the structure of the porous material can be increased only by selecting the proper pore size, the propagation distance of sound waves in the porous ceramic is prolonged, the viscous resistance is increased, more sound wave energy is converted into heat energy, the higher the porosity is, the lower the bending strength is, and the material proportion in the example 1 is optimal comprehensively;

comparing examples 1, 6 and 7, it can be seen that the materials of the 3 groups of examples are the same, only the thicknesses are different, the porosity is the same, the sound absorption coefficient is increased along with the increase of the thickness, meanwhile, the increase of the thickness naturally improves the flexural strength of the material, but the thickness is not too large, the cost is increased if the thickness is too large, and the thickness is selected appropriately according to the needs, so that the thickness in example 1 is selected optimally in a comprehensive manner;

comparing examples 1 and 12, it can be seen that, after the laser beam in step S2 is used for drilling, the porosity is reduced to some extent, so that the sound absorption coefficient is greatly improved, and the improvement of the bending strength is also obvious, which indicates that the mechanical property of the material can be improved by laser beam drilling;

comparing examples 1, 15 and 16, it can be seen that the selection of a proper calcination temperature has a certain influence on both the sound absorption effect and the flexural strength of the material, and the calcination temperature in example 1 is most reasonable;

in addition, a group proportion of 1 is also set, wherein, a comparative example 1 is a result of no pretreatment of the polyurethane foam, and it can be seen that the sound absorption effect is greatly reduced and the breaking strength is also reduced under the condition of no pretreatment of the polyurethane foam, because the surface roughness of the polyurethane foam is obviously increased by the method of surface modification treatment of the polyurethane foam, the slurry hanging amount of the polyurethane matrix is obviously increased by low-temperature plasma treatment, the mechanical property and the high-temperature property are obviously improved, the diameter of the ceramic rib is gradually increased by mechanical stretching, the pore structure in the ceramic rib is improved, and the top of the pore has a certain radian, as shown in fig. 4, thereby reducing the concentration of stress on the top of the pore and improving the compressive strength of the sample.