Graphene ceramic composite material as well as preparation method and application thereof
By incorporating graphene oxide, zirconium boride particles, silicon carbide particles, and lanthanum-doped cerium oxide into zirconium boride ceramic matrix composites, graphene ceramic composites were prepared. This solved the problems of brittleness and thermal shock resistance of zirconium boride ceramic matrix composites, achieving improved relative density and flexural strength, making them suitable for heat-resistant materials in extreme thermal environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO BAIDUN SPECIAL CERAMICS TECH CO LTD
- Filing Date
- 2026-01-20
- Publication Date
- 2026-05-12
AI Technical Summary
The intrinsic brittleness and poor thermal shock resistance of zirconium boride ceramic matrix composites limit their wide range of engineering applications, and the tendency of graphene oxide nanosheets to aggregate in composites leads to a decrease in flexural strength.
Graphene ceramic composites were prepared by adding graphene oxide, zirconium boride particles, silicon carbide particles, yttrium oxide, and lanthanum-doped cerium oxide to zirconium boride ceramic matrix composites, and then using ball milling and sintering processes to form continuous load transfer channels, replace brittle interface phases, and improve flexural strength.
This study achieved improved relative density and flexural strength in graphene ceramic composites, making them suitable for heat-resistant materials in extreme thermal environments.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of refractory materials technology, specifically relating to a graphene ceramic composite material, its preparation method, and its application. Background Technology
[0002] Zirconium boride ceramic matrix composites are considered promising non-ablative ultra-high temperature heat-resistant materials due to their excellent thermophysical properties. However, the intrinsic brittleness and poor thermal shock resistance of zirconium boride ceramic matrix composites limit their widespread engineering applications. To improve the toughness of zirconium boride ceramic matrix composites, graphene nanosheets are added. To achieve uniform dispersion of graphene nanosheets in zirconium boride ceramic matrix composites, the abundant hydrophilic oxygen-containing groups on the surface of graphene oxide are utilized, combined with an in-situ thermal reduction method to achieve uniform dispersion of graphene nanosheets in zirconium boride ceramic matrix composites.
[0003] It is known in existing technology that graphene can promote densification through a carbothermic reaction with oxides on the surface of zirconium boride. As the graphene oxide content increases, the relative density of the resulting composite material continuously increases. Therefore, to obtain a higher relative density, the graphene oxide content can be maximized. Simultaneously, with the increase of graphene oxide content, the flexural strength and fracture toughness of the composite material also improve.
[0004] However, due to the limited grain boundaries in the composite material, and the tendency of graphene oxide nanosheets to aggregate through weak van der Waals forces, when the graphene oxide content increases to an excessive level (more than 5v%), the graphene oxide nanosheets in the composite material will aggregate / agglomerate, causing the flexural strength of the composite material to begin to decline. Summary of the Invention
[0005] To address the problems existing in the background art, the present invention provides a graphene ceramic composite material, its preparation method and application. By increasing the content of graphene oxide, the relative density of the prepared composite material is increased, while its flexural strength is further improved.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a graphene ceramic composite material includes the following steps: adding zirconium boride particles, silicon carbide particles, yttrium oxide and lanthanum-doped cerium oxide to a graphene oxide dispersion, ball milling, drying to obtain raw material powder; loading the raw material powder into a graphite mold for sintering to obtain the graphene ceramic composite material. By volume, the raw material powder comprises 5.6-6 parts graphene oxide, 70-72 parts zirconium boride particles, 20-21 parts silicon carbide particles, 1.5-2 parts yttrium oxide, and 1-1.3 parts lanthanum-doped cerium oxide.
[0007] Furthermore, the graphene oxide dispersion is prepared by ultrasonically dispersing graphene oxide powder with alcohol.
[0008] Furthermore, a planetary ball mill is used for ball milling for 8-9 hours at a speed of 250-270 rpm.
[0009] Furthermore, the drying temperature is 45±2℃, and the drying time is 3-5h.
[0010] Furthermore, the specific sintering operation is as follows: holding the temperature in a vacuum hot-pressing sintering furnace for 1-1.2 hours at a temperature of 1950±10℃ and a pressure of 30±2MPa, under an inert atmosphere, with a heating rate of 15-20℃ / min.
[0011] Furthermore, the method for preparing the lanthanum-doped cerium oxide is as follows: A1. Dissolve 12.99g of lanthanum nitrate hexahydrate and 31.79g of cerium nitrate hexahydrate in deionized water to obtain a mixed solution with a volume of 1L. A2. While stirring, heat the mixed solution obtained in A1 to 70±2℃, and add 14mL of 85% formic acid solution dropwise to the mixed solution to fully precipitate the metal ions and obtain a white suspension. A3. Centrifuge the white suspension obtained in A2, wash with ethanol, dry and calcine in a muffle furnace to obtain the lanthanum-doped cerium oxide.
[0012] Furthermore, in A3, the calcination temperature is 400±10℃, and the calcination time is 3-3.2h.
[0013] A graphene ceramic composite material is prepared by the above-described preparation method.
[0014] An application of the above-mentioned graphene ceramic composite material for use as a heat-resistant material in extreme thermal environments.
[0015] This application has the following beneficial effects: In the preparation of the graphene ceramic composite material of this invention, lanthanum-doped cerium oxide and yttrium oxide are introduced simultaneously; on the one hand, Ce in lanthanum-doped cerium oxide... 4+ / Ce 3+ Its variable valence property makes its surface rich in oxygen vacancies, which can preferentially adsorb onto the graphene surface, forming a physical barrier layer that prevents Y from being absorbed. 3+ Direct contact with graphene mitigates the negative effects of introducing yttrium oxide; On the other hand, lanthanum doping further expands the lattice constant of cerium oxide and enhances its chemical affinity with yttrium oxide. During sintering, lanthanum-doped cerium oxide bridges yttrium oxide and graphene through Ce-OY bonding, constructing a continuous load transfer channel to replace the original brittle interface phase, thereby synergistically improving the flexural strength of the composite material. Detailed Implementation
[0016] The present application will be further described in detail below with reference to the embodiments.
[0017] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.
[0018] Example 1 First, lanthanum-doped cerium oxide is prepared using the following method: A1. Dissolve 12.99g of lanthanum nitrate hexahydrate and 31.79g of cerium nitrate hexahydrate in deionized water to obtain a mixed solution with a volume of 1L.
[0019] A2. While stirring, heat the mixed solution obtained in A1 to 70°C, and add 14 mL of 85% formic acid solution dropwise to the mixed solution to allow the metal ions to precipitate fully, resulting in a white suspension.
[0020] A3. Centrifuge the white suspension obtained in A2, wash with ethanol, dry it, and then calcine it in a muffle furnace at a temperature of 400℃ for 3 hours to obtain lanthanum-doped cerium oxide.
[0021] Then, the graphene ceramic composite material is prepared, and the preparation method includes the following steps: S1. Take 5g of flake graphite in a flask, add 2.5g of sodium nitrate and stir well. Pour in 115mL of concentrated sulfuric acid and stir to obtain the first mixture. Add 15g of potassium permanganate to the first mixture to obtain the second mixture. During the addition of potassium permanganate, use an ice-water bath to keep the temperature of the second mixture below 15℃. Heat the second mixture to 35℃ to start the initial oxidation. After holding at this temperature for 7h, add 40ml of concentrated sulfuric acid and 5g of potassium permanganate to the second mixture and hold at 35℃ for 12h for the second oxidation to obtain the third mixture. Pour the third mixture into ice water and add hydrogen peroxide to terminate the reaction to obtain the fourth mixture. Then, use 1L of 5% dilute hydrochloric acid solution to acid wash and centrifuge the fourth solution, and use 3L of deionized water to wash and centrifuge until the washing solution is neutral. Finally, sonicate for 2h to obtain a graphene oxide solution. Place the graphene oxide solution in a drying oven to dry and obtain graphene oxide powder.
[0022] S2. Weigh out graphene oxide powder and ultrasonically disperse it with alcohol for 2 hours to obtain a uniformly dispersed graphene oxide dispersion. Add zirconium boride particles, silicon carbide particles, yttrium oxide and lanthanum-doped cerium oxide to the graphene oxide dispersion, and ball mill it using a planetary ball mill for 8.5 hours at a speed of 260 rpm. Then dry it at a temperature of 45°C for 4 hours to obtain the raw material powder. By volume, the raw material powder includes 5.7 parts graphene oxide, 71 parts ZrB2 particles, 20.5 parts SiC particles, 1.6 parts yttrium oxide, and 1.2 parts lanthanum-doped cerium oxide.
[0023] S3. The raw material powder is loaded into a graphite mold for sintering. The specific sintering operation is as follows: the heating rate is 15℃ / min, the temperature is raised to 1950℃, the pressure is 30MPa, the inert atmosphere is used, and the temperature is held in a vacuum hot pressing sintering furnace for 1.1h to obtain the graphene ceramic composite material.
[0024] Example 2 The difference between this embodiment and Embodiment 1 is that, by volume, the raw material powder includes 5.6 parts of graphene oxide, 70 parts of zirconium boride particles, 20 parts of silicon carbide particles, 1.5 parts of yttrium oxide, and 1 part of lanthanum-doped cerium oxide.
[0025] The specific preparation method is the same as in Example 1: the preparation of graphene ceramic composite material includes the following steps: S1. Take 5g of flake graphite in a flask, add 2.5g of sodium nitrate and stir well. Pour in 115mL of concentrated sulfuric acid and stir to obtain the first mixture. Add 15g of potassium permanganate to the first mixture to obtain the second mixture. During the addition of potassium permanganate, use an ice-water bath to keep the temperature of the second mixture below 15℃. Heat the second mixture to 35℃ to start the initial oxidation. After holding at this temperature for 7h, add 40ml of concentrated sulfuric acid and 5g of potassium permanganate to the second mixture and hold at 35℃ for 12h for the second oxidation to obtain the third mixture. Pour the third mixture into ice water and add hydrogen peroxide to terminate the reaction to obtain the fourth mixture. Then, use 1L of 5% dilute hydrochloric acid solution to acid wash and centrifuge the fourth solution, and use 3L of deionized water to wash and centrifuge until the washing solution is neutral. Finally, sonicate for 2h to obtain a graphene oxide solution. Place the graphene oxide solution in a drying oven to dry and obtain graphene oxide powder.
[0026] S2. Weigh the graphene oxide powder and ultrasonically disperse it with alcohol for 2 hours to obtain a uniformly dispersed graphene oxide dispersion. Add zirconium boride particles, silicon carbide particles, yttrium oxide and lanthanum-doped cerium oxide to the graphene oxide dispersion, and ball mill it using a planetary ball mill for 8.5 hours at a speed of 260 rpm. Then dry it at a temperature of 45°C for 4 hours to obtain the raw material powder.
[0027] S3. The raw material powder is loaded into a graphite mold for sintering. The specific sintering operation is as follows: the heating rate is 15℃ / min, the temperature is raised to 1950℃, the pressure is 30MPa, the inert atmosphere is used, and the temperature is held in a vacuum hot pressing sintering furnace for 1.1h to obtain the graphene ceramic composite material.
[0028] Example 3 The difference between this embodiment and Embodiment 1 is that, by volume, the raw material powder includes 6 parts of graphene oxide, 72 parts of zirconium boride particles, 21 parts of silicon carbide particles, 2 parts of yttrium oxide, and 1.3 parts of lanthanum-doped cerium oxide.
[0029] The specific preparation method is the same as in Example 1: the preparation of graphene ceramic composite material includes the following steps: S1. Take 5g of flake graphite in a flask, add 2.5g of sodium nitrate and stir well. Pour in 115mL of concentrated sulfuric acid and stir to obtain the first mixture. Add 15g of potassium permanganate to the first mixture to obtain the second mixture. During the addition of potassium permanganate, use an ice-water bath to keep the temperature of the second mixture below 15℃. Heat the second mixture to 35℃ to start the initial oxidation. After holding at this temperature for 7h, add 40ml of concentrated sulfuric acid and 5g of potassium permanganate to the second mixture and hold at 35℃ for 12h for the second oxidation to obtain the third mixture. Pour the third mixture into ice water and add hydrogen peroxide to terminate the reaction to obtain the fourth mixture. Then, use 1L of 5% dilute hydrochloric acid solution to acid wash and centrifuge the fourth solution, and use 3L of deionized water to wash and centrifuge until the washing solution is neutral. Finally, sonicate for 2h to obtain a graphene oxide solution. Place the graphene oxide solution in a drying oven to dry and obtain graphene oxide powder.
[0030] S2. Weigh the graphene oxide powder and ultrasonically disperse it with alcohol for 2 hours to obtain a uniformly dispersed graphene oxide dispersion. Add zirconium boride particles, silicon carbide particles, yttrium oxide and lanthanum-doped cerium oxide to the graphene oxide dispersion, and ball mill it using a planetary ball mill for 8.5 hours at a speed of 260 rpm. Then dry it at a temperature of 45°C for 4 hours to obtain the raw material powder.
[0031] S3. The raw material powder is loaded into a graphite mold for sintering. The specific sintering operation is as follows: the heating rate is 15℃ / min, the temperature is raised to 1950℃, the pressure is 30MPa, the inert atmosphere is used, and the temperature is held in a vacuum hot pressing sintering furnace for 1.1h to obtain the graphene ceramic composite material.
[0032] Comparative Example 1 The difference between this comparative example and Example 1 is that, by volume, the raw material powder includes 5 parts of graphene oxide, 74.5 parts of zirconium boride particles, and 20.5 parts of silicon carbide particles.
[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that, by volume, the raw material powder includes 5.7 parts of graphene oxide, 73.8 parts of zirconium boride particles, and 20.5 parts of silicon carbide particles.
[0034] Comparative Example 3 The difference between this comparative example and Example 1 is that, by volume, the raw material powder includes 5.7 parts of graphene oxide, 72.2 parts of zirconium boride particles, 20.5 parts of silicon carbide particles, and 1.6 parts of yttrium oxide.
[0035] Comparative Example 4 The difference between this comparative example and Example 1 is that, by volume, the raw material powder includes 5.7 parts of graphene oxide, 72.6 parts of zirconium boride particles, 20.5 parts of silicon carbide particles, and 1.2 parts of lanthanum-doped cerium oxide.
[0036] Test case Test subjects: Graphene ceramic composite materials prepared in Examples 1-3 and Comparative Examples 1-4. Test items: Relative density (%) and flexural strength (MPa). Test results: See Table 1.
[0037] Table 1. Test Data for Experimental Examples
[0038] Results Analysis: Analysis of Examples 1-3 and the data in Table 1 shows that the relative density of the graphene ceramic composite material prepared by the present invention (Examples 1-3) reaches over 98.7% and the flexural strength is over 770.3 MPa.
[0039] Analysis of Example 1 and Comparative Examples 1-4, combined with the data in Table 1, specifically comparing Comparative Examples 1 and 2, shows that compared to the volume fraction of graphene oxide in Comparative Example 1 (5%), the volume fraction of graphene oxide in Comparative Example 2 increased to 5.7%. As a result, the relative density of the graphene ceramic composite material was increased, but the flexural strength was significantly reduced.
[0040] Specifically, comparing Comparative Examples 2 and 3 reveals that when the volume fraction of graphene oxide is 5.7%, the flexural strength of the graphene ceramic composite material decreases instead of increasing when yttrium oxide is introduced alone. This is mainly because the introduction of yttrium oxide alone has a negative impact. Specifically, although yttrium oxide, as a sintering aid, can promote the densification of the zirconium boride matrix through liquid-phase sintering, its γ-rays content... 3+Yttrium oxide readily reacts with oxygen-containing functional groups on the surface of graphene to form a brittle Y–O–C interfacial phase. This phase not only weakens the interfacial bonding strength between graphene and the matrix but also becomes a preferred path for crack propagation. At high temperatures, yttrium oxide readily forms a low-melting-point glass phase at grain boundaries. Although this is beneficial for mass transfer sintering, it leads to a decrease in high-temperature mechanical properties. In particular, it is prone to intergranular fracture under thermal shock conditions, resulting in a reduction in the strength of the composite material.
[0041] Specifically, by comparing Comparative Example 2 and Comparative Example 4, it can be seen that when the volume fraction of graphene oxide is 5.7%, the flexural strength of the graphene ceramic composite material prepared by simply introducing lanthanum-doped cerium oxide is significantly improved.
[0042] In comparison with Example 1, it can be seen that when the volume fraction of graphene oxide is 5.7%, the simultaneous introduction of yttrium oxide and lanthanum-doped cerium oxide can produce a synergistic effect, thereby synergistically improving the flexural strength of the obtained graphene ceramic composite material.
[0043] In summary, compared to the original Comparative Example 1 with a graphene oxide volume fraction of 5% (without the addition of yttrium oxide and lanthanum-doped cerium oxide), the increased graphene oxide content in Example 1 led to a higher relative density of the resulting composite material. At the same time, the added yttrium oxide and lanthanum-doped cerium oxide had a synergistic effect, further enhancing the flexural strength of the resulting composite material.
[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
[0045] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.
Claims
1. A method for preparing a graphene ceramic composite material, characterized in that, The process includes the following steps: adding zirconium boride particles, silicon carbide particles, yttrium oxide, and lanthanum-doped cerium oxide to a graphene oxide dispersion, ball milling, and drying to obtain raw material powder; loading the raw material powder into a graphite mold for sintering to obtain the graphene ceramic composite material. By volume, the raw material powder comprises 5.6-6 parts graphene oxide, 70-72 parts zirconium boride particles, 20-21 parts silicon carbide particles, 1.5-2 parts yttrium oxide, and 1-1.3 parts lanthanum-doped cerium oxide.
2. The method for preparing the graphene ceramic composite material according to claim 1, characterized in that, The graphene oxide dispersion was prepared by ultrasonic dispersion of graphene oxide powder with alcohol.
3. The method for preparing the graphene ceramic composite material according to claim 1, characterized in that, Use a planetary ball mill for ball milling, with a milling time of 8-9 hours and a rotation speed of 250-270 rpm.
4. The method for preparing the graphene ceramic composite material according to claim 1, characterized in that, The drying temperature is 45±2℃, and the drying time is 3-5h.
5. The method for preparing the graphene ceramic composite material according to claim 1, characterized in that, The specific sintering operation is as follows: the temperature is maintained in a vacuum hot-press sintering furnace for 1-1.2 hours at 1950±10℃ and 30±2MPa under an inert atmosphere, with a heating rate of 15-20℃ / min.
6. The method for preparing the graphene ceramic composite material according to claim 1, characterized in that, The method for preparing the lanthanum-doped cerium oxide is as follows: A1. Dissolve 12.99g of lanthanum nitrate hexahydrate and 31.79g of cerium nitrate hexahydrate in deionized water to obtain a mixed solution with a volume of 1L. A2. While stirring, heat the mixed solution obtained in A1 to 70±2℃, and add 14mL of 85% formic acid solution dropwise to the mixed solution to fully precipitate the metal ions and obtain a white suspension. A3. Centrifuge the white suspension obtained in A2, wash it, dry it, and then calcine it in a muffle furnace to obtain the final product.
7. The method for preparing the graphene ceramic composite material according to claim 6, characterized in that, In A3, the calcination temperature is 400±10℃ and the calcination time is 3-3.2h.
8. A graphene-ceramic composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.
9. An application of the graphene ceramic composite material as described in claim 8, characterized in that, Heat-resistant materials for use in extreme thermal environments.