Ceramic matrix composite heating material and preparation method thereof

Abstract

This invention relates to the field of heating materials technology, specifically disclosing a ceramic-based composite heating material and its preparation method. The ceramic-based composite heating material comprises the following raw material components in parts by weight: 25-40 parts ceramic powder; 8-18 parts graphene microsheets; 10-20 parts carbon nanotube dispersion; 15-25 parts polyvinyl alcohol solution; 5-10 parts water glass; 0.2-0.6 parts dispersant; and 10-20 parts water. Research shows that the ceramic-based composite heating material of this invention has good heating performance and significant application value.

Description

Technical Field

[0001] This invention relates to the field of heating materials technology, specifically to a ceramic-based composite heating material and its preparation method. Background Technology

[0002] With the increasing demand for efficient, energy-saving, and safe heating materials in modern industrial and civilian sectors, traditional metal resistance wires, carbon fibers, and ordinary ceramic heating elements have gradually revealed many limitations in practical applications. For example, metal resistance wires suffer from problems such as easy oxidation, short service life, and low thermal efficiency; carbon fiber heating elements, although possessing good conductivity and flexibility, have insufficient mechanical strength and are prone to aging at high temperatures; while conventional ceramic heating materials, although possessing good high-temperature resistance and chemical stability, generally suffer from poor conductivity, slow heating rate, and low power density, making it difficult to meet the needs of high-power, fast-response, and long-life application scenarios.

[0003] Composite heating materials with ceramics as the matrix and graphene, carbon nanotubes, etc., as the conductive phase are widely used due to their advantages such as high temperature resistance, corrosion resistance, and uniform heating. The core performance of these materials lies in the structure and stability of the conductive network. In currently used technologies, organic binders (such as polyvinyl alcohol PVA) are usually regarded as temporary binders during sintering. The amorphous carbon structure formed after pyrolysis is loose and has poor conductivity, contributing little to the overall conductive network, thus resulting in unsatisfactory heating performance, which urgently needs further improvement. Summary of the Invention

[0004] In order to overcome at least one technical problem existing in the prior art, the present invention provides a ceramic-based composite heating material and its preparation method.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention first provides a ceramic-based composite heating material, which comprises the following raw material components in parts by weight: 25-40 parts of ceramic powder; 8-18 parts of graphene microplates; 10-20 parts of carbon nanotube dispersion; 15-25 parts of polyvinyl alcohol solution; 5-10 parts of water glass; 0.2-0.6 parts of dispersant; and 40-60 parts of water.

[0007] This invention provides a novel ceramic-based composite heating material; research shows that the ceramic-based composite heating material of this invention has good heating performance.

[0008] In some preferred embodiments, the carbon nanotube dispersion is prepared by the following method:

[0009] Carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion.

[0010] In some preferred embodiments, the carbon nanotube dispersion contains 1-3% carbon nanotubes by weight.

[0011] In some preferred embodiments, the carbon nanotube dispersion contains 2% carbon nanotubes by weight.

[0012] In some preferred embodiments, the sodium dodecylbenzenesulfonate aqueous solution contains 0.5-1.5% sodium dodecylbenzenesulfonate by weight.

[0013] In some preferred embodiments, the sodium dodecylbenzenesulfonate aqueous solution contains 1% sodium dodecylbenzenesulfonate by weight.

[0014] In some preferred embodiments, the polyvinyl alcohol solution is an aqueous solution of polyvinyl alcohol;

[0015] The polyvinyl alcohol in the aqueous solution is 5-15% by weight.

[0016] In some preferred embodiments, the polyvinyl alcohol in the aqueous solution is 10% by weight.

[0017] In some preferred embodiments, the polyvinyl alcohol is modified polyvinyl alcohol.

[0018] In some preferred embodiments, the modified polyvinyl alcohol is prepared by the following method:

[0019] Polyvinyl alcohol is added to water and heated to 80-90℃ to dissolve, then cooled to 40-60℃. Phthalic anhydride and catalyst are then added, and the mixture is stirred at 70-80℃ for 6-10 hours under inert gas protection. After the reaction is complete, the mixture is poured into ethanol to precipitate the product. The precipitate is then dried to obtain the modified polyvinyl alcohol.

[0020] In further research, the inventors discovered that adding modified polyvinyl alcohol prepared by the above-described method to the ceramic-based composite heating material can significantly improve the heating performance of the ceramic-based composite heating material compared to adding unmodified polyvinyl alcohol.

[0021] In some preferred embodiments, the ratio of polyvinyl alcohol to water, phthalic anhydride and catalyst is 80-120g:800-1000g:15-25g:100-200mL.

[0022] In some preferred embodiments, the ratio of polyvinyl alcohol to water, phthalic anhydride and catalyst is 100g:900g:20g:150mL.

[0023] In some preferred embodiments, the catalyst is pyridine.

[0024] In some preferred embodiments, the dispersant is ammonium polyacrylate.

[0025] This invention also provides a method for preparing a ceramic-based composite heating material, comprising the following steps:

[0026] A slurry is obtained by uniformly mixing ceramic powder, graphene microsheets, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water.

[0027] The slurry is formed into a green body by casting or screen printing, and then sintered under an inert atmosphere; after sintering, the ceramic-based composite heating material is obtained.

[0028] In some preferred embodiments, the sintering refers to heating to 700-750°C at a heating rate of 0.4-4°C / min, holding at that temperature for 60-120 minutes, and then cooling down to obtain the ceramic-based composite heating material.

[0029] In some preferred embodiments, the sintering refers to heating to 720°C at a heating rate of 2°C / min, holding at that temperature for 60 minutes, and then cooling down to obtain the ceramic-based composite heating material.

[0030] In some preferred embodiments, the sintering refers to first heating to 150°C at a heating rate of 1°C / min and holding at that temperature for 30 min; then heating to 350°C at a heating rate of 0.4°C / min and holding at that temperature for 90 min; and finally heating to 720°C at a heating rate of 2°C / min and holding at that temperature for 60 min before cooling down to obtain the ceramic-based composite heating material.

[0031] Further research by the inventors revealed that the sintering method of the ceramic-based composite heating material of the present invention is crucial; the ceramic-based composite heating material obtained by the gradient sintering method described above has significantly higher heating performance than the ceramic-based composite heating material obtained by sintering directly at 720°C.

[0032] Furthermore, the selection of the gradient in the gradient sintering method of the present invention is also crucial; the ceramic-based composite heating material obtained by the gradient sintering method described above must have a significantly higher heating performance than the ceramic-based composite heating material obtained by sintering directly at 720°C; however, the ceramic-based composite heating material obtained by other gradient sintering methods cannot have a significantly higher heating performance than the ceramic-based composite heating material obtained by sintering directly at 720°C.

[0033] Beneficial effects: This invention provides a novel ceramic-based composite heating material; research shows that the ceramic-based composite heating material of this invention has good heating performance and has important application value. Detailed Implementation

[0034] The present invention will be further explained below with reference to specific embodiments, but the embodiments do not limit the scope of protection of the present invention.

[0035] Example 1: Ceramic-based composite heating material

[0036] Raw material composition by weight: 32 parts ceramic powder; 12 parts graphene micro flakes; 15 parts carbon nanotube dispersion; 18 parts polyvinyl alcohol solution; 8 parts water glass; 0.5 parts dispersant; 14.5 parts water.

[0037] The carbon nanotube dispersion is prepared by the following method: carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion; the weight percentage of carbon nanotubes in the carbon nanotube dispersion is 2%; the weight percentage of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 1%.

[0038] The polyvinyl alcohol solution is an aqueous solution of polyvinyl alcohol (PVA-1788); the weight percentage of polyvinyl alcohol (PVA-1788) in the aqueous solution is 10%.

[0039] The dispersant is ammonium polyacrylate.

[0040] Preparation method:

[0041] (1) A slurry is obtained by uniformly mixing ceramic powder, graphene micro flakes, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water;

[0042] (2) The slurry is formed into a green body by casting or screen printing, and sintered under an inert atmosphere; after sintering, the ceramic-based composite heating material is obtained; wherein, the sintering refers to heating to 720°C at a heating rate of 2°C / min, holding at the temperature for 60min and then cooling down to obtain the ceramic-based composite heating material.

[0043] Example 2: Ceramic-based composite heating material

[0044] Raw material composition by weight: 32 parts ceramic powder; 12 parts graphene micro flakes; 15 parts carbon nanotube dispersion; 18 parts polyvinyl alcohol solution; 8 parts water glass; 0.5 parts dispersant; 14.5 parts water.

[0045] The carbon nanotube dispersion is prepared by the following method: carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion; the weight percentage of carbon nanotubes in the carbon nanotube dispersion is 2%; the weight percentage of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 1%.

[0046] The polyvinyl alcohol solution is an aqueous solution of modified polyvinyl alcohol (PVA-1788); the weight percentage of modified polyvinyl alcohol (PVA-1788) in the aqueous solution of polyvinyl alcohol (PVA-1788) is 10%.

[0047] The modified polyvinyl alcohol (PVA-1788) was prepared by the following method: polyvinyl alcohol (PVA-1788) was added to water, heated to 85°C to dissolve, and then cooled to 50°C; phthalic anhydride and catalyst were then added, and the mixture was stirred at 75°C for 7 hours under inert gas (nitrogen) protection; after the reaction was completed, the mixture was poured into ethanol for precipitation, and the precipitate was dried to obtain the modified polyvinyl alcohol (PVA-1788); wherein the ratio of polyvinyl alcohol (PVA-1788) to water, phthalic anhydride and catalyst was 100g:900g:20g:150mL; the catalyst was pyridine.

[0048] The dispersant is ammonium polyacrylate.

[0049] Preparation method:

[0050] (1) A slurry is obtained by uniformly mixing ceramic powder, graphene micro flakes, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water;

[0051] (2) The slurry is formed into a green body by casting or screen printing, and sintered under an inert atmosphere; after sintering, the ceramic-based composite heating material is obtained; wherein, the sintering refers to heating to 720°C at a heating rate of 2°C / min, holding at the temperature for 60min and then cooling down to obtain the ceramic-based composite heating material.

[0052] Example 3: Ceramic-based composite heating material

[0053] Raw material composition by weight: 32 parts ceramic powder; 12 parts graphene micro flakes; 15 parts carbon nanotube dispersion; 18 parts polyvinyl alcohol solution; 8 parts water glass; 0.5 parts dispersant; 14.5 parts water.

[0054] The carbon nanotube dispersion is prepared by the following method: carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion; the weight percentage of carbon nanotubes in the carbon nanotube dispersion is 2%; the weight percentage of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 1%.

[0055] The polyvinyl alcohol solution is an aqueous solution of modified polyvinyl alcohol (PVA-1788); the weight percentage of modified polyvinyl alcohol (PVA-1788) in the aqueous solution of polyvinyl alcohol (PVA-1788) is 10%.

[0056] The modified polyvinyl alcohol (PVA-1788) was prepared by the following method: polyvinyl alcohol (PVA-1788) was added to water, heated to 85°C to dissolve, and then cooled to 50°C; phthalic anhydride and catalyst were then added, and the mixture was stirred at 75°C for 7 hours under inert gas (nitrogen) protection; after the reaction was completed, the mixture was poured into ethanol for precipitation, and the precipitate was dried to obtain the modified polyvinyl alcohol (PVA-1788); wherein the ratio of polyvinyl alcohol (PVA-1788) to water, phthalic anhydride and catalyst was 100g:900g:20g:150mL; the catalyst was pyridine.

[0057] The dispersant is ammonium polyacrylate.

[0058] Preparation method:

[0059] (1) A slurry is obtained by uniformly mixing ceramic powder, graphene micro flakes, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water;

[0060] (2) The slurry is formed into a green body by casting or screen printing, and sintered under an inert atmosphere. After sintering, the ceramic-based composite heating material is obtained. The sintering refers to first heating to 150°C at a heating rate of 1°C / min and holding for 30 min; then heating to 350°C at a heating rate of 0.4°C / min and holding for 90 min; and finally heating to 720°C at a heating rate of 2°C / min and holding for 60 min before cooling to obtain the ceramic-based composite heating material.

[0061] Comparative Example 1: Ceramic-based composite heating material

[0062] Raw material composition by weight: 32 parts ceramic powder; 12 parts graphene micro flakes; 15 parts carbon nanotube dispersion; 18 parts polyvinyl alcohol solution; 8 parts water glass; 0.5 parts dispersant; 14.5 parts water.

[0063] The carbon nanotube dispersion is prepared by the following method: carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion; the weight percentage of carbon nanotubes in the carbon nanotube dispersion is 2%; the weight percentage of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 1%.

[0064] The polyvinyl alcohol solution is an aqueous solution of modified polyvinyl alcohol (PVA-1788); the weight percentage of modified polyvinyl alcohol (PVA-1788) in the aqueous solution of polyvinyl alcohol (PVA-1788) is 10%.

[0065] The modified polyvinyl alcohol (PVA-1788) was prepared by the following method: polyvinyl alcohol (PVA-1788) was added to water, heated to 85°C to dissolve, and then cooled to 50°C; phthalic anhydride and catalyst were then added, and the mixture was stirred at 75°C for 7 hours under inert gas (nitrogen) protection; after the reaction was completed, the mixture was poured into ethanol for precipitation, and the precipitate was dried to obtain the modified polyvinyl alcohol (PVA-1788); wherein the ratio of polyvinyl alcohol (PVA-1788) to water, phthalic anhydride and catalyst was 100g:900g:20g:150mL; the catalyst was pyridine.

[0066] The dispersant is ammonium polyacrylate.

[0067] Preparation method:

[0068] (1) A slurry is obtained by uniformly mixing ceramic powder, graphene micro flakes, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water;

[0069] (2) The slurry is formed into a green body by casting or screen printing, and sintered under an inert atmosphere. After sintering, the ceramic-based composite heating material is obtained. The sintering refers to first heating to 200°C at a heating rate of 1°C / min and holding for 30 min; then heating to 300°C at a heating rate of 0.4°C / min and holding for 90 min; and finally heating to 720°C at a heating rate of 2°C / min and holding for 60 min before cooling down to obtain the ceramic-based composite heating material.

[0070] Comparative Example 2: Ceramic-based composite heating material

[0071] Raw material composition by weight: 32 parts ceramic powder; 12 parts graphene micro flakes; 15 parts carbon nanotube dispersion; 18 parts polyvinyl alcohol solution; 8 parts water glass; 0.5 parts dispersant; 14.5 parts water.

[0072] The carbon nanotube dispersion is prepared by the following method: carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion; the weight percentage of carbon nanotubes in the carbon nanotube dispersion is 2%; the weight percentage of sodium dodecylbenzenesulfonate in the aqueous solution of sodium dodecylbenzenesulfonate is 1%.

[0073] The polyvinyl alcohol solution is an aqueous solution of modified polyvinyl alcohol (PVA-1788); the weight percentage of modified polyvinyl alcohol (PVA-1788) in the aqueous solution of polyvinyl alcohol (PVA-1788) is 10%.

[0074] The modified polyvinyl alcohol (PVA-1788) was prepared by the following method: polyvinyl alcohol (PVA-1788) was added to water, heated to 85°C to dissolve, and then cooled to 50°C; phthalic anhydride and catalyst were then added, and the mixture was stirred at 75°C for 7 hours under inert gas (nitrogen) protection; after the reaction was completed, the mixture was poured into ethanol for precipitation, and the precipitate was dried to obtain the modified polyvinyl alcohol (PVA-1788); wherein the ratio of polyvinyl alcohol (PVA-1788) to water, phthalic anhydride and catalyst was 100g:900g:20g:150mL; the catalyst was pyridine.

[0075] The dispersant is ammonium polyacrylate.

[0076] Preparation method:

[0077] (1) A slurry is obtained by uniformly mixing ceramic powder, graphene micro flakes, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water;

[0078] (2) The slurry is formed into a green body by casting or screen printing, and sintered under an inert atmosphere. After sintering, the ceramic-based composite heating material is obtained. The sintering refers to first heating to 350°C at a heating rate of 1°C / min and holding for 120 min; then heating to 720°C at a heating rate of 2°C / min and holding for 60 min before cooling to obtain the ceramic-based composite heating material.

[0079] The ceramic-based composite heating materials prepared in Examples 1-3 and Comparative Examples 1-2 were connected to a 10V power supply and their highest heating temperature was tested; the results are shown in Table 1.

[0080] Table 1. Test results of the highest temperature of ceramic-based composite heating materials

[0081] highest temperature Ceramic-based composite heating material prepared in Example 1 195℃ Ceramic-based composite heating material prepared in Example 2 285℃ Ceramic-based composite heating material prepared in Example 3 360℃ Ceramic-based composite heating material prepared in Comparative Example 1 310℃ Ceramic-based composite heating material prepared in Comparative Example 2 305℃

[0082] As can be seen from the experimental results in Table 1, the highest temperature of the ceramic-based composite heating material prepared in Example 2 under 10V power supply is significantly higher than that of the ceramic-based composite heating material prepared in Example 1. This indicates that adding modified polyvinyl alcohol prepared by the above method of the present invention to the ceramic-based composite heating material can significantly improve the heating performance of the ceramic-based composite heating material compared to adding unmodified polyvinyl alcohol.

[0083] As can be seen from the experimental results in Table 1, the highest heating temperature of the ceramic-based composite heating material prepared in Example 3 under 10V power supply is significantly higher than that of the ceramic-based composite heating material prepared in Example 2. This indicates that the sintering method of the ceramic-based composite heating material of the present invention is crucial. The heating performance of the ceramic-based composite heating material obtained by the gradient sintering method of the present invention is significantly higher than that of the ceramic-based composite heating material obtained by directly heating to 720℃.

[0084] As can be seen from the experimental results in Table 1, the maximum heating temperature of the ceramic-based composite heating materials prepared in Comparative Examples 1 and 2 under 10V energization is higher than that of the ceramic-based composite heating material prepared in Example 2, but the increase is not significant, and the increase is much smaller than that of the ceramic-based composite heating material prepared in Example 3. This indicates that the gradient selection of the gradient sintering method of the present invention is also crucial; the heating performance of the ceramic-based composite heating material sintered by the gradient sintering method described above must be significantly higher than that of the ceramic-based composite heating material sintered by directly heating to 720℃; however, the heating performance of the ceramic-based composite heating material sintered by other gradient sintering methods is not significantly higher than that of the ceramic-based composite heating material sintered by directly heating to 720℃.

Claims

1. A ceramic-based composite heating material, characterized in that, The raw material components include the following parts by weight: 25-40 parts ceramic powder; 8-18 parts graphene microplates; 10-20 parts carbon nanotube dispersion; 15-25 parts polyvinyl alcohol solution; 5-10 parts water glass; 0.2-0.6 parts dispersant; and 10-20 parts water.

2. The ceramic-based composite heating material according to claim 1, characterized in that, The carbon nanotube dispersion was prepared by the following method: Carbon nanotubes are added to an aqueous solution of sodium dodecylbenzenesulfonate and dispersed evenly to obtain the carbon nanotube dispersion.

3. The ceramic-based composite heating material according to claim 2, characterized in that, The carbon nanotube dispersion contains 1-3% carbon nanotubes by weight.

4. The ceramic-based composite heating material according to claim 2, characterized in that, The sodium dodecylbenzenesulfonate aqueous solution contains 0.5-1.5% sodium dodecylbenzenesulfonate by weight.

5. The ceramic-based composite heating material according to claim 1, characterized in that, The polyvinyl alcohol solution is an aqueous solution of polyvinyl alcohol; The polyvinyl alcohol in the aqueous solution is 5-15% by weight.

6. The ceramic-based composite heating material according to claim 5, characterized in that, The polyvinyl alcohol mentioned is a modified polyvinyl alcohol.

7. The ceramic-based composite heating material according to claim 6, characterized in that, The modified polyvinyl alcohol is prepared by the following method: Polyvinyl alcohol is added to water and heated to 80-90℃ to dissolve, then cooled to 40-60℃. Phthalic anhydride and catalyst are then added, and the mixture is stirred at 70-80℃ for 6-10 hours under inert gas protection. After the reaction is complete, the mixture is poured into ethanol to precipitate the product. The precipitate is then dried to obtain the modified polyvinyl alcohol.

8. The ceramic-based composite heating material according to claim 7, characterized in that, The ratio of polyvinyl alcohol to water, phthalic anhydride and catalyst is 80-120g:800-1000g:15-25g:100-200mL.

9. The ceramic-based composite heating material according to claim 1, characterized in that, The dispersant is ammonium polyacrylate.

10. A method for preparing a ceramic-based composite heating material, characterized in that, It includes the following steps: A slurry is obtained by uniformly mixing ceramic powder, graphene microsheets, carbon nanotube dispersion, polyvinyl alcohol solution, water glass, dispersant and water. The slurry is formed into a green body by casting or screen printing, and then sintered under an inert atmosphere; after sintering, the ceramic-based composite heating material is obtained.