Graphene material doped with lead zirconate titanate ceramic material and preparation method thereof

Abstract

The application discloses a graphene-doped lead zirconate titanate ceramic material and a preparation method thereof, and belongs to the technical field of functional ceramic materials. In order to solve the problems of low fracture toughness, poor conductivity and poor temperature stability of traditional lead zirconate titanate (PZT) ceramics, and the problems of easy aggregation and poor compatibility of graphene in the PZT matrix, the application adopts sodium dodecyl benzene sulfonate and polyethylene glycol as a composite modifier, modifies graphene through non-covalent bond synergistic effect, mixes the modified graphene with PZT ceramic powder, and obtains a composite material through ball milling dispersion, compression molding, segmented degassing and sintering processes. The fracture toughness and the bending strength of the composite material are increased by more than 147% and 79% respectively, the dielectric loss is less than 0.03, the piezoelectric strain coefficient d 33 is increased by 40% compared with traditional undoped PZT, the thermal conductivity is increased by 133%, the performance is stable in a wide temperature range, and the density is more than 98%. The application has a simple process and is suitable for industrial production, and the product can be widely applied to the fields of high-frequency sensing and ferroelectric storage.

Description

Technical Field

[0001] This invention belongs to the field of functional ceramic materials technology, and relates to a graphene-doped lead zirconate titanate ceramic material and its preparation method. Background Technology

[0002] Lead zirconate titanate (PZT) ceramics, as typical perovskite ferroelectric materials, are widely used in sensors, transducers, and memory devices due to their high dielectric constant and piezoelectric coefficient. However, traditional PZT ceramics have significant performance defects, such as low fracture toughness, insufficient flexural strength, and susceptibility to brittle fracture; poor electrical conductivity, leading to charge accumulation under high voltage; poor temperature stability, with large performance fluctuations over a wide temperature range; and high grain boundary defects and porosity, affecting device reliability and making it difficult to meet the comprehensive performance requirements of modern high-end applications. Graphene, as a novel nanomaterial, possesses excellent mechanical, electrical, and thermal properties, and is considered an ideal reinforcing phase for ceramic materials. However, graphene's high surface energy makes it prone to layer-by-layer aggregation through van der Waals forces during preparation. This not only fails to achieve the nano-reinforcing effect but also becomes a stress concentration point in the composite material, severely affecting the mechanical uniformity and the stability of its dielectric and piezoelectric properties. Furthermore, the modification effects of existing single modifiers have significant limitations. For example, while single surfactants can temporarily reduce the surface energy of graphene, they cannot construct a stable interfacial bonding layer, which is prone to failure during subsequent sintering. Single coupling agents are difficult to effectively inhibit graphene aggregation and cannot achieve its uniform dispersion in the PZT matrix. This makes it difficult for traditional single modification strategies to simultaneously solve the two core problems of dispersion and interfacial bonding. Based on this, the core objective of this invention is to overcome the defects of the prior art and provide a graphene-doped lead zirconate titanate ceramic material and its preparation method. Through the synergistic effect of sodium dodecylbenzene sulfonate (SDBS) and polyethylene glycol (PEG) composite modifier, uniform dispersion and good interfacial bonding of graphene in PZT ceramic matrix are achieved. Combined with optimized component ratio and preparation process, a composite material with high mechanical strength, low dielectric loss, excellent piezoelectric properties, wide temperature range stability and high density is prepared to meet the comprehensive performance requirements of modern high-end functional electronic devices. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a graphene-doped lead zirconate titanate ceramic material and its preparation method. By modifying graphene with SDBS and PEG, uniform dispersion and good compatibility of graphene in a PZT matrix are achieved, resulting in a composite material with excellent mechanical, dielectric, piezoelectric, and thermal stability properties.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A graphene-doped lead zirconate titanate ceramic material is composed of the following components, by weight percentage: 0.5-3 parts modified graphene and 97-99.5 parts lead zirconate titanate ceramic powder. The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 10-30% of the mass of the graphene. The composite modifier includes sodium dodecylbenzenesulfonate and polyethylene glycol, wherein the mass ratio of sodium dodecylbenzenesulfonate to polyethylene glycol is 1:2~4.

[0005] Preferably, the polyethylene glycol has a molecular weight of 6000.

[0006] A method for preparing graphene-doped lead zirconate titanate ceramic material as described in any of the preceding claims includes the following steps: S1. Modified graphene and lead zirconate titanate ceramic powder are mixed at a mass ratio of 0.5~3:97~99.5 to obtain a powder mixture; S2. Add anhydrous ethanol to the above powder mixture, ball mill for 12-24 hours, with a ball-to-material ratio of 10-15:1 and a rotation speed of 300-500 rpm. After ball milling, vacuum dry and pass through a 200-300 mesh sieve to obtain composite powder. S3. Add polyvinyl alcohol to the above composite powder, mix evenly, and then press into shape. The molding pressure is 80~120MPa, and the pressure is held for 5~10min to obtain the green blank. S4. The green blank is debinded and then sintered at 1150~1250℃ for 4~8h, and then naturally cooled to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material.

[0007] Preferably, the modified graphene and lead zirconate titanate ceramic powder described in step S1 are mixed at a mass ratio of 0.5~2:98~99.5 to obtain a powder mixture.

[0008] Preferably, the ball milling in step S2 uses zirconia balls; the mass ratio of anhydrous ethanol to the powder mixture is 1~2:1.

[0009] Preferably, the vacuum drying in step S2 is performed with a vacuum degree ≤ -0.08 MPa, a drying temperature of 60~70℃, and a drying time of 6~10 h.

[0010] Preferably, the polyvinyl alcohol in step S3 has a mass fraction of 5-8% and an addition amount of 8-12% of the composite powder.

[0011] Preferably, in the glue removal process described in step S4, a segmented heating method is adopted. First, the temperature is raised from room temperature to 300-400℃ at a heating rate of 2-5℃ / min and held for 1-2 hours; then, the temperature is raised to 600-800℃ at a heating rate of 3-5℃ / min and held for 2-4 hours.

[0012] Preferably, the specific preparation method of the modified graphene in step S1 is as follows: (1) Graphene is dispersed in deionized water and ultrasonically dispersed to obtain a graphene dispersion with a concentration of 0.5~2 mg / mL. (2) Add a composite modifier to the above graphene solution and stir at 60~80℃ for 2~4h to obtain a graphene pretreatment solution; (3) The graphene pretreatment liquid was ultrasonically treated for 40-80 minutes, centrifuged, washed, and vacuum dried to obtain modified graphene.

[0013] Preferably, in step (3), the vacuum degree of vacuum drying is ≤-0.09Mpa, the drying temperature is 60~80℃, the drying time is 8~12h, and after drying, the modified graphene powder is ground through a 100~200 mesh sieve to obtain uniformly dispersed modified graphene powder.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses a composite modifier of SDBS and PEG. Through the synergistic effect of non-covalent bonds such as π-π stacking, hydrogen bonding, and steric hindrance, it not only fully preserves the sp² hybrid structure and excellent properties of graphene, but also solves the problems of poor compatibility and uneven dispersion with PZT ceramic matrix. The modified graphene forms a "sheet-particle" interwoven structure, which greatly enhances its mechanical properties, with fracture toughness and flexural strength increasing by more than 150% and 80%, respectively; the dielectric loss is reduced to ≤0.03, and the piezoelectric strain coefficient d 33 It improves thermal conductivity by more than 40% and thermal conductivity by 120%, maintains stable performance in a wide temperature range of -80℃ to 250℃, and has a density of over 98%, thus overcoming the defects of traditional PZT ceramics such as brittleness, poor conductivity, and poor temperature stability.

[0015] (2) The present invention does not require complex equipment, the process parameters are easy to control, and it is suitable for industrial production. The graphene-doped lead zirconate titanate ceramic composite material prepared has high mechanical strength, low dielectric loss, excellent piezoelectric properties, wide temperature range stability and high density. It can be widely used in high frequency piezoelectric sensors, ferroelectric memory, wide temperature range energy harvester, high voltage energy storage device and other fields, and has broad market application prospects. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0017] To achieve the above-mentioned objectives of the present invention, the technical solution of the present invention will be further described in detail below, but the scope of protection of the present invention is not limited to the following description.

[0018] A graphene-doped lead zirconate titanate ceramic material is composed of the following components, by weight percentage: 0.5-3% modified graphene and 97-99.5% lead zirconate titanate ceramic powder; The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 10-30% of the mass of the graphene. The composite modifier includes sodium dodecylbenzenesulfonate (SDBS) and polyethylene glycol (PEG) with a molecular weight of 6000, wherein the mass ratio of sodium dodecylbenzenesulfonate to polyethylene glycol is 1:2~4.

[0019] A method for preparing the above-mentioned graphene-doped lead zirconate titanate ceramic material includes the following steps: S1. Modified graphene and lead zirconate titanate (PZT) ceramic powder are mixed in a mass ratio of 0.5~3:97~99.5, preferably with a mass ratio of 0.5~2:98~99.5 (excess graphene sheets are prone to stacking through van der Waals forces to form micron-sized agglomerates, which become stress concentration points and dielectric defect centers), and mixed evenly to obtain a powder mixture; S2. Add anhydrous ethanol as a dispersion medium to the above powder mixture, transfer it to a ball mill, use zirconia balls as the ball milling medium, the ball-to-material ratio is 10~15:1, the rotation speed is 300~500 rpm, and the ball milling time is 12~24 h. After ball milling, vacuum dry it under vacuum conditions ≤-0.08MPa and temperature 60~70℃ for 6~10 h. Place the dried product in an agate mortar for grinding and pass it through a 200~300 mesh sieve to obtain a uniform composite powder; the mass ratio of anhydrous ethanol to the powder mixture is 1~2:1. S3. Add 5-8% by mass of polyvinyl alcohol (PVA) aqueous solution to the above composite powder as a binder. The amount of PVA added is 8-12% by mass of the composite powder. Mix the two for 20-30 minutes to obtain a uniform powder. Press the powder into a mold with a molding pressure of 80-120 MPa and hold the pressure for 5-10 minutes to obtain a green blank with a molding density ≥2.8 g / cm³. S4. Place the green blank in a box-type atmosphere furnace and introduce high-purity nitrogen (purity ≥99.99%, gas flow rate 50~100mL / min) as a protective atmosphere for debinding treatment (to remove organic components from PVA). Use segmented heating. First, heat from room temperature to 300~400℃ at a heating rate of 2~5℃ / min and hold for 1~2h (to remove organic components from PVA). Then, heat to 600~800℃ at a heating rate of 3~5℃ / min and hold for 2~4h (to thoroughly remove residual organic matter and adsorbed water). After debinding, keep the nitrogen atmosphere constant and sinter at 1150~1250℃ for 4~8h. After sintering, keep the nitrogen flow rate constant and allow it to cool naturally to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material.

[0020] The method for preparing the modified graphene in step S1 is as follows: (1) Graphene is ultrasonically added to deionized water and ultrasonically dispersed evenly to obtain a graphene solution with a concentration of 0.5~2 mg / mL. (2) Add SDBS and PEG to the above graphene solution, preferably PEG with a molecular weight of 6000 (PEG-6000 has a moderate molecular chain length, and can form a uniform spatial barrier after being adsorbed on the graphene surface, which can both inhibit agglomeration and avoid affecting the mixing uniformity with PZT powder due to excessive viscosity), stir at 60~80℃ for 2~4h to obtain graphene pretreatment solution; the total amount of the composite modifier of SDBS and PEG is 10~30% of the mass of graphene; (3) Centrifuge the graphene pretreatment solution at 8000~10000rpm for 10~20min, remove the supernatant, wash the precipitate with deionized water 3 times to remove the unadsorbed free modifier, place the washed target product in a vacuum drying oven, dry it at 60~80℃ and vacuum degree ≤-0.09MPa for 8~12h, grind it through a 100~200 mesh sieve to obtain uniformly dispersed modified graphene powder.

[0021] Example 1 A graphene-doped lead zirconate titanate ceramic material is composed of the following components by mass percentage: 0.5% modified graphene and 99.5% lead zirconate titanate ceramic powder; The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 18% of the mass of the graphene. The composite modifier comprises sodium dodecylbenzenesulfonate and polyethylene glycol, wherein the mass ratio of sodium dodecylbenzenesulfonate to polyethylene glycol is 1:2.

[0022] A method for preparing the above-mentioned graphene-doped lead zirconate titanate ceramic material includes the following steps: S1. Mix 0.5g of modified graphene and 99.5g of PZT ceramic powder evenly to obtain a powder mixture; S2. Add 100 mL of anhydrous ethanol to the above powder mixture, transfer it to a ball mill, use zirconia balls as the ball milling medium, the ball-to-material ratio is 12:1, the speed is 400 rpm, and the ball milling is carried out for 18 h. After ball milling, vacuum dry it at 65℃ and -0.085 MPa for 8 h. Place the dried product in an agate mortar for grinding, and pass it through a 250 mesh sieve to obtain a uniform composite powder. S3. Add 15 mL of 7% PVA aqueous solution to the above composite powder, with PVA as a binder. Mix the composite powder and PVA aqueous solution for 25 min to obtain a uniform powder. Press the powder under 80 MPa pressure for 8 min to obtain a blank with a molding density of 2.9 g / cm³. S4. Place the green blank in a box-type atmosphere furnace and introduce high-purity nitrogen gas with a purity of 99.99% and a flow rate of 80 mL / min for debinding. Use segmented heating: first, heat to 350℃ at 2℃ / min and hold for 1.5 h, then heat to 700℃ at 3℃ / min and hold for 3 h. After debinding, keep the nitrogen atmosphere constant and sinter for 6 h. After sintering, keep the nitrogen flow rate constant and allow it to cool naturally to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material.

[0023] The method for preparing the modified graphene in step S1 is as follows: (1) Add 1g of graphene to 1000mL of deionized water and disperse it evenly by ultrasonication to obtain a graphene solution with a concentration of 1mg / mL. (2) Add 0.06g SDBS and 0.12g PEG-6000 to the above graphene solution in sequence, stir at 70℃ for 3h, and then sonicate for 60min to obtain a uniformly dispersed graphene pretreatment solution. (3) Centrifuge the graphene pretreatment solution at 8000 rpm for 15 min, remove the supernatant, wash the precipitate with deionized water 3 times to remove the unadsorbed free modifier, place the washed target product in a vacuum drying oven and dry it at 60℃ and -0.09MPa for 10 h, grind it through a 100~200 mesh sieve to obtain uniformly dispersed modified graphene powder. Example 2 A graphene-doped lead zirconate titanate ceramic material is composed of the following components by mass percentage: 1% modified graphene and 99% lead zirconate titanate ceramic powder; The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 30% of the mass of the graphene. The composite modifier comprises sodium dodecylbenzenesulfonate and polyethylene glycol, wherein the mass ratio of sodium dodecylbenzenesulfonate to polyethylene glycol is 1:3.

[0024] A method for preparing the above-mentioned graphene-doped lead zirconate titanate ceramic material includes the following steps: S1. Mix 1g of modified graphene and 99g of PZT ceramic powder evenly to obtain a powder mixture; S2. Add 200 mL of anhydrous ethanol to the above powder mixture, transfer it to a ball mill, use zirconia balls as the ball milling medium, ball-to-material ratio of 15:1, speed of 500 rpm, and ball mill for 12 h; after ball milling, vacuum dry at 70℃ and -0.08 MPa for 6 h, place the dried product in an agate mortar for grinding, and pass it through a 300-mesh sieve to obtain a uniform composite powder. S3. Add 15 mL of 8% PVA aqueous solution to the above composite powder, with PVA as a binder. Mix the composite powder and PVA aqueous solution for 20 min to obtain a uniform powder. Press the powder at 120 MPa for 5 min to obtain a blank with a molding density of 3.0 g / cm³. S4. Place the green blank in a box-type atmosphere furnace and introduce high-purity nitrogen gas with a purity of 99.99% and a flow rate of 100 mL / min for debinding. Use segmented heating. First, heat to 400℃ at 5℃ / min and hold for 1 hour. Then, heat to 800℃ at 5℃ / min and hold for 2 hours. After debinding, keep the nitrogen atmosphere constant and sinter for 4 hours. After sintering, keep the nitrogen flow rate constant and allow it to cool naturally to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material. The method for preparing the modified graphene in step S1 is as follows: (1) Add 1g of graphene to 500mL of deionized water and disperse it evenly by ultrasonication to obtain a graphene solution with a concentration of 2mg / mL. (2) Add 0.06g SDBS and 0.24g PEG-6000 to the above graphene solution in sequence, stir at 70℃ for 3h, and then sonicate for 60min to obtain a uniformly dispersed graphene mixed solution. (3) Centrifuge the graphene mixture at 10,000 rpm for 10 min, remove the supernatant, wash the precipitate with deionized water 3 times to remove the unadsorbed free modifier, place the washed target product in a vacuum drying oven and dry it at 70℃ and -0.09MPa for 8 h, grind it through a 200-mesh sieve after drying to obtain uniformly dispersed modified graphene powder.

[0025] Example 3 A graphene-doped lead zirconate titanate ceramic material is composed of the following components by mass percentage: 1.5% modified graphene and 98.5% lead zirconate titanate ceramic powder; The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 24% of the mass of the graphene. The composite modifier includes SDBS and PEG-6000, and the mass ratio of SDBS to PEG-6000 is 1:3.

[0026] A method for preparing the above-mentioned graphene-doped lead zirconate titanate ceramic material includes the following steps: S1. Mix 1.5g of modified graphene and 98.5g of PZT ceramic powder evenly to obtain a powder mixture; S2. Add 150 mL of anhydrous ethanol to the above powder mixture, transfer it to a ball mill, use zirconia balls as the ball milling medium, the ball-to-material ratio is 10:1, the speed is 300 rpm, and the ball milling is carried out for 24 h. After ball milling, vacuum dry it at 60℃ and -0.08 MPa for 10 h. Place the dried product in an agate mortar for grinding, and pass it through a 200-mesh sieve to obtain a uniform composite powder. S3. Add 16 mL of a 5% PVA aqueous solution (by mass) to the above composite powder, using PVA as a binder. Mix the composite powder and PVA aqueous solution for 30 min to obtain a uniform powder. Press the powder under a pressure of 100 MPa for 10 min to obtain a green blank with a molding density of 2.8 g / cm³. 3 ; S4. Place the green blank in a box-type atmosphere furnace and introduce high-purity nitrogen gas with a purity of 99.99% and a flow rate of 50 mL / min for debinding. Use segmented heating. First, heat to 300℃ at 3℃ / min and hold for 2 hours. Then, heat to 600℃ at 4℃ / min and hold for 4 hours. After debinding, keep the nitrogen atmosphere constant and sinter for 8 hours. After sintering, keep the nitrogen flow rate constant and allow it to cool naturally to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material. The method for preparing the modified graphene in step S1 is as follows: (1) Add 1g of graphene to 2000mL of deionized water and disperse it evenly by ultrasonication to obtain a graphene solution with a concentration of 0.5mg / mL. (2) Add 0.06g SDBS and 0.18g PEG-6000 to the above graphene solution in sequence, stir at 60℃ for 4h, and then sonicate for 80min to obtain a uniformly dispersed graphene mixed solution. (3) Centrifuge the above graphene mixed solution at 9000 rpm for 20 min, remove the supernatant, wash the precipitate with deionized water 3 times to remove the unadsorbed free modifier, place the washed target product in a vacuum drying oven and dry it at 80℃ and -0.095MPa for 12 h, grind it through a 100-mesh sieve after drying to obtain uniformly dispersed modified graphene powder.

[0027] Comparative Example 1 (Single SDBS Modifier) Compared with Example 1, in the process of preparing modified graphene in step S1, the composite modifier was replaced with a single modifier, and only 0.2g of SDBS (the amount used is 20% of the graphene mass) was added. The remaining steps and parameters were the same as in Example 1. Comparative Example 2 (Single PEG Modifier) Compared with Example 1, in the process of preparing modified graphene in step S1, the composite modifier was changed to a single modifier, and only 0.2g of PEG (the amount is 20% of the graphene mass) was added. The remaining steps and parameters were completely consistent with Example 1. Comparative Example 3 (without modifier treatment) Compared with Example 1, in step S1, no graphene modification treatment is performed. The graphene is directly dispersed in deionized water, and the graphene dispersion obtained by ultrasound is directly centrifuged, washed, and dried. The remaining steps and parameters are completely consistent with Example 1. Comparative Example 4 (Traditional undoped PZT ceramic) Compared with Example 1, steps S1 and S2 were removed, graphene was not added, and PZT ceramic powder was used for subsequent experiments. 100g of PZT ceramic powder was directly added to a 6% PVA aqueous solution, and steps S3 and S4 were performed directly to obtain pure PZT ceramic material.

[0028] 1. Mechanical property testing: (1) Fracture toughness: The single-sided notched beam method (SENB method) is adopted, and the formula is: K 10 Where F is the fracture load (N), L is the support span (mm), a is the notch depth (mm), b is the specimen width (mm), and h is the specimen height (mm).

[0029] (2) Bending strength: The three-point bending method is adopted. The bending strength is calculated by the stress value through the maximum load. The formula is: σ Where F is the fracture load (N), L is the support span (mm), b is the specimen width (mm), and h is the specimen height (mm).

[0030] 2. Dielectric and piezoelectric property testing: (1) Dielectric loss (tanδ): Using the impedance analyzer method, tanδ=ε'' / ε' (ε'' is the loss factor, ε' is the relative permittivity). The lower the value, the more stable the dielectric properties of the material and the smaller the energy loss. (2) Piezoelectric strain coefficient d 33 (pC / N): Using quasi-static d 33 The testing instrument method involves placing the sample in d... 33 A low-frequency alternating pressure of 50Hz (pressure range 0.1-0.5N) is applied between the upper and lower electrodes of the testing instrument. The polarization charge generated in the sample under pressure is detected by the sensor, and the piezoelectric strain coefficient d is calculated. 33 .

[0031] 3. Thermal performance testing: Thermal conductivity (W / (m) K): Using the laser flare method, the formula is: Where t1 / 2 is the time (s) it takes for the temperature of the lower surface of the sample to reach half of the highest temperature, ρ is the sample density (g / cm³), and c p is the specific heat capacity (J / (g·K)), and L is the sample thickness (mm).

[0032] 4. Microstructure and stability testing: (1) Density and porosity: Archimedes drainage method was used.

[0033] First, measure the mass m1 of the sample in air; then, completely immerse the sample in distilled water (or anhydrous ethanol) and measure its suspended mass m2; finally, remove the sample, dry its surface, and measure its mass m3 after saturation with water absorption; formula: density = (ρ a / ρ t )×100%; Porosity = 1 - density; ρ t The true density is given; the theoretical density of PZT ceramics is approximately 7.6 g / cm³. a For apparent density, ρ a =m1 / (m3-m2); (2) The dielectric constant fluctuation (%) over a wide temperature range was measured using a combination of a high and low temperature chamber and an impedance analyzer.

[0034] The sample was placed in a high-low temperature chamber, with the temperature range controlled between -80℃ and 250℃. The temperature was increased at a rate of 10℃ / min. At key temperature points (e.g., -80℃, 0℃, 100℃, 200℃, 250℃), the relative permittivity ε' of the sample was measured using an impedance analyzer. The percentage fluctuation of ε' at different temperatures relative to ε'0 at room temperature (25℃) was calculated using the following formula: .

[0035] Key performance indicators of the graphene-doped lead zirconate titanate ceramic materials prepared in Examples 1-3 and Comparative Examples 1-3, and the conventionally undoped PZT material prepared in Comparative Example 4 were tested, mainly focusing on mechanical properties, dielectric and piezoelectric properties, and thermal properties. The specific test results are shown in Table 1. As can be seen from the data in Table 1, in terms of mechanical properties, the fracture toughness of Examples 1-3 can reach as low as 4.2±0.2 MPa·m¹ / ², and the flexural strength can reach as low as 142±5 MPa. However, when using a single modifier (such as Comparative Examples 1-2) or without a modifier (Comparative Example 3), the improvement in mechanical properties is limited due to the uneven dispersion of graphene and poor interfacial bonding, with the highest fracture toughness being only 2.5±0.2 MPa·m¹ / ². In terms of dielectric and piezoelectric properties, the dielectric loss of Examples 1-3 is only 0.025±0.002, and the piezoelectric strain coefficient d is also high. 33 The lowest value can reach 410±10 pC / N; the dielectric loss of comparative examples 1~4 all exceed 0.058±0.003, and the piezoelectric strain coefficient d 33 The highest value is only 325±9 pC / N. In terms of microstructure and stability, the thermal conductivity of Examples 1 to 3 all exceed 3.8±0.2 W / (m·K), the density exceeds 98.3±0.5%, the porosity is as low as 1.7±0.5%, and the dielectric constant fluctuation is less than 4.5% in a wide temperature range of -80℃ to 250℃. In contrast, the thermal conductivity of Comparative Examples 1 to 4 is as low as 1.8±0.1 W / (m·K), the density is less than 94.2±0.6%, the porosity exceeds 5.8±0.6%, and the dielectric constant fluctuation is as low as ≤12.8% in a wide temperature range of -80℃ to 250℃, which is not suitable for extreme conditions.

[0036] In summary, Examples 1-3, modified with SDBS and PEG-6000 composites, outperformed Comparative Examples 1-4 in terms of mechanical strength, dielectric properties, temperature stability, and density, exhibiting superior overall performance. Among them, Example 2 showed the most significant performance advantage, improving fracture toughness and flexural strength by 182% and 87% respectively compared to traditional undoped PZT materials; improving piezoelectric strain coefficient, thermal conductivity, and porosity by 40%, 133%, and 85% respectively; and reducing dielectric loss and wide-temperature-range dielectric constant by 67.6% and 80% respectively, providing reliable support for high-end electronic device applications.

[0037] Finally, it should be noted that although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A graphene-doped lead zirconate titanate ceramic material, characterized in that, It is composed of the following components, by weight percentage: 0.5-3 parts modified graphene and 97-99.5 parts lead zirconate titanate ceramic powder; The modified graphene comprises graphene and a composite modifier; the mass of the composite modifier is 10-30% of the mass of the graphene. The composite modifier includes sodium dodecylbenzenesulfonate and polyethylene glycol, wherein the mass ratio of sodium dodecylbenzenesulfonate to polyethylene glycol is 1:2~4.

2. The graphene-doped lead zirconate titanate ceramic material according to claim 1, characterized in that, The polyethylene glycol has a molecular weight of 2000, 4000 or 6000.

3. A method for preparing graphene-doped lead zirconate titanate ceramic material as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Modified graphene and lead zirconate titanate ceramic powder are mixed at a mass ratio of 0.5~3:97~99.5 to obtain a powder mixture; S2. Add anhydrous ethanol to the above powder mixture, ball mill for 12-24 h, ball-to-material ratio of 10-15:1, rotation speed of 300-500 rpm, vacuum dry after ball milling, and pass through a 200-300 mesh sieve to obtain composite powder. S3. Add polyvinyl alcohol to the above composite powder, mix evenly, and then press into shape. The molding pressure is 80~120 MPa, and the pressure is held for 5~10 min to obtain the green blank. S4. The green blank is debinded and then sintered at 1150~1250℃ for 4~8 h, and then naturally cooled to room temperature to obtain graphene-doped lead zirconate titanate ceramic composite material.

4. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, The modified graphene and lead zirconate titanate ceramic powder described in step S1 are mixed at a mass ratio of 0.5~2:98~99.5 to obtain a powder mixture.

5. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, The ball milling process in step S2 uses zirconia balls; the mass ratio of anhydrous ethanol to the powder mixture is 1~2:

1.

6. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, The vacuum drying described in step S2 is characterized by a vacuum degree ≤ -0.08 MPa, a drying temperature of 60~70℃, and a drying time of 6~10 h.

7. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, The polyvinyl alcohol in step S3 has a mass fraction of 5-8% and an addition amount of 8-12% of the composite powder.

8. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, In the glue removal process described in step S4, a segmented heating method is adopted. First, the temperature is raised from room temperature to 300-400℃ at a heating rate of 2-5℃ / min and held for 1-2 hours; then, the temperature is raised to 600-800℃ at a heating rate of 3-5℃ / min and held for 2-4 hours.

9. The method for preparing graphene-doped lead zirconate titanate ceramic material according to claim 3, characterized in that, The specific preparation method of the modified graphene mentioned in step S1 is as follows: (1) Graphene is dispersed in deionized water and ultrasonically dispersed to obtain a graphene dispersion with a concentration of 0.5~2 mg / mL. (2) Add a composite modifier to the above graphene solution and stir at 60~80℃ for 2~4 h to obtain a graphene pretreatment solution; (3) The graphene pretreatment liquid was ultrasonically treated for 40-80 min, centrifuged, washed, and vacuum dried to obtain modified graphene.

10. The graphene-doped lead zirconate titanate ceramic material according to claim 9, characterized in that, In step (3), the vacuum degree of vacuum drying is ≤-0.09Mpa, the drying temperature is 60~80℃, the drying time is 8~12 h, and after drying, it is ground through a 100~200 mesh sieve to obtain uniformly dispersed modified graphene powder.

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