A high-strength high-toughness amorphous carbon-based composite material

Abstract

This application relates to a high-strength, high-toughness amorphous carbon-based composite material. Specifically, this application discloses a high-strength, high-toughness amorphous carbon-based composite material and its preparation method. Spherical particles such as glass carbon powder, carbon black, onion carbon, or fullerene are used as a matrix, and small amounts of graphite, carbon nanotubes, chopped carbon fibers, or two-dimensional carbon fiber cloth are added as toughening agents. After uniform dispersion in a solvent, the mixture is stirred, evaporated to dryness, and sieved to obtain a precursor powder. The precursor powder is then subjected to pressure under a protective atmosphere or vacuum atmosphere and sintered at high temperature to obtain the amorphous carbon-based composite material. The obtained amorphous carbon-based composite material has a flexural strength of not less than 150 MPa and a fracture toughness of not less than 2 MPa. 1 / 2 It has a high temperature resistance greater than 2000℃ (vacuum or inert gas).

Description

Technical Field

[0001] This invention relates to the field of inorganic materials, and in particular to the field of carbon material preparation technology. Background Technology

[0002] Amorphous carbon, similar to inorganic silicate glass, has attracted much attention due to its high strength, high hardness, impermeability, isotropy, high-temperature stability, and chemical inertness, and is widely used in semiconductors, medicine, metallurgy, and ultrapure materials. However, due to the disordered arrangement of its internal atoms, amorphous carbon exhibits long-range disorder asymmetry and lacks deformation mechanisms such as dislocations, thus hindering its ductile behavior. Under external forces, the high internal energy of amorphous carbon causes the principal shear band to fail rapidly, leading to crack formation. This results in rapid fracture after elastic deformation, causing room-temperature brittleness and potentially catastrophic and unpredictable failures. Solving these challenges may require in-depth research into the structure-property relationship of amorphous carbon, adjustments to the preparation process, and improvements in material design to enhance its toughness and crack resistance, thereby promoting safer and more reliable applications.

[0003] In ceramics, improving toughness usually relies on adding metals, polymer toughening phases, or other minerals. For example, Guo Lin et al. (Chen K, Ding J, Li L, et al. Amorphous alumina nanosheets / polylactic acid artificial nanosheets[J]. Matter, 2019, 1(5): 1385-1398.) obtained a high-strength and high-toughness amorphous alumina / polylactic acid composite material by adding polylactic acid to amorphous alumina. Its tensile plasticity can reach 500%. Although the addition of polylactic acid makes the composite material exhibit certain plastic behavior, it also greatly reduces its high-temperature stability and limits its application range. In addition, Hortense Le Ferrand et al. (Le Ferrand H, Bouville F, Niebel TP, et al. Magnetically assisted slip casting of bioinspired heterogeneous composites[J]. Nature Materials, 2015, 14(11): 1172-1179.) obtained a high-strength and high-toughness alumina nanosheet / silica composite material by combining casting technology with directional assembly of magnetic particles. The material is nacreous layered alumina (11.5 MPa m 1 / 2 The fracture toughness of the alumina ceramic is increased by 3 times compared to that of ordinary fine-grained alumina ceramics, while the fracture strength remains at a level comparable to that of the strongest alumina (650 MPa).

[0004] To date, no material has been found on a macroscopic scale that simultaneously possesses high strength (>150 MPa) and high toughness (>2 MPa m). 1 / 2 It possesses properties such as high temperature resistance (>2000℃). Therefore, this type of material is something the industry has long desired to obtain. Summary of the Invention

[0005] One technical problem that this invention aims to solve is to provide a high-strength, high-toughness, and high-temperature resistant material and its preparation method.

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides an amorphous carbon-based composite material, wherein the structure of the amorphous carbon-based composite material includes a matrix phase and a toughening phase; the matrix phase is formed by a phase transformation of spherical powdered carbon material under high temperature conditions; the toughening phase is composed of one-dimensional or two-dimensional carbon material and uniformly embedded in the matrix phase. This amorphous carbon-based composite material has been found to have high flexural strength (>150 MPa) and high fracture toughness (>2 MPa). 1 / 2 It also has good high temperature resistance (>2000℃, measured under vacuum or inert gas conditions).

[0007] Secondly, this invention discloses a method for preparing an amorphous carbon-based composite material, which includes the following steps:

[0008] A) Weigh a certain mass ratio of spherical powder carbon material and one-dimensional or two-dimensional carbon material, grind and mix them evenly to obtain precursor powder;

[0009] B) Load the precursor powder into the mold, pre-press it into shape, and then place the pre-pressed blank into the sintering mold.

[0010] C) Place the pre-pressed billet from step B) together with the sintering mold into a spark plasma sintering equipment or a hot pressing sintering equipment, and then sinter it in a vacuum or inert gas environment.

[0011] D) After cooling, remove the mold and demold to obtain the amorphous carbon-based composite material.

[0012] Due to the adoption of the above technical solution, the technical progress achieved by this invention is: obtaining high strength (>150MPa) and high toughness (>2MPa m). 1 / 2 New materials that are resistant to high temperatures (>2000℃) can be used in many special environments with stringent material requirements. Attached Figure Description

[0013] Figure 1 This is a physical image of the high-strength, high-toughness amorphous carbon-based composite material prepared in Example 1 of this invention;

[0014] Figure 2(a) is a scanning electron microscope image of the amorphous carbon-based composite material of Example 1 of the present invention, and Figure 2(b) is a transmission electron microscope image of the amorphous carbon-based composite material of Example 1 of the present invention (i.e., a partial enlarged view of Figure 2(a)).

[0015] Figure 3 (a) is the X-ray diffraction pattern of the amorphous carbon-based composite material of Example 1 of the present invention. Figure 3 (b) shows the three-point bending data of the amorphous carbon-based composite material of Example 1 of the present invention;

[0016] Figure 4 (a) is the X-ray diffraction pattern of the amorphous carbon-based composite material of Example 2 of the present invention. Figure 4 (b) shows the three-point bending data of the amorphous carbon-based composite material in Example 2 of the present invention;

[0017] Figure 5 (a) is the X-ray diffraction pattern of the amorphous carbon-based composite material of Example 3 of the present invention. Figure 5 (b) shows the three-point bending data of the amorphous carbon-based composite material in Example 3 of the present invention. Detailed Implementation

[0018] Where numerical ranges are disclosed herein, these ranges are continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Additionally, where the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Furthermore, where multiple ranges are provided to describe a feature or characteristic, these ranges may be combined. That is, unless otherwise specified, all ranges disclosed herein should be understood to encompass any and all subranges contained herein. For example, the specified range of “1–10” should be considered to include any and all subranges between the minimum value of 1 and the maximum value of 10. Furthermore, the dosage ranges for each component of the invention include any combination of any lower and upper limits mentioned in the specification, all of which are covered within the scope of the invention.

[0019] When used herein, as will be understood by those skilled in the art, “about” means, in the specific scientific context of the term, that the number, parameter, or characteristic it defines is permissible with a range of positive or negative percentage errors (e.g., ±5%). Furthermore, because all numbers, values, and expressions relating to quantities used herein are subject to various measurement errors, unless otherwise indicated, all specific numerical values ​​recorded may be understood to be implicitly modified by the term “about.”

[0020] This invention provides an amorphous carbon-based composite material, the structure of which includes a matrix phase and a toughening phase; the matrix phase is formed by a phase transformation of spherical powdered carbon material under high temperature conditions; the toughening phase is composed of one-dimensional or two-dimensional carbon material and is uniformly embedded within the matrix phase. This has been found to be a high-strength, high-toughness amorphous carbon-based composite material: flexural strength not less than 150 MPa, and fracture toughness not less than 2 MPa. 1 / 2 It has good high temperature resistance (>2000℃, measured under vacuum or inert gas conditions) and can be used in the range of -196 to 3000℃.

[0021] In the context of this invention, "amorphous carbon-based composite material" refers to a material that, from a chemical composition perspective, is essentially composed of pure carbon elements, and from a microscopic structure perspective (e.g., observed by instruments such as scanning electron microscopy or transmission electron microscopy), exists in an amorphous form and contains two or more distinct phase structure regions within the material. "Amorphous carbon-based composite material" can also be referred to as "amorphous carbon multiphase material".

[0022] However, those skilled in the art will understand that "amorphous carbon-based composite material" does not exclude unavoidable traces of impurity elements present in the raw materials themselves or unintentionally introduced during processing. For the purposes of this invention, "consisting essentially of pure carbon" means that the mass of carbon accounts for at least 97% of the total mass of the material, preferably at least 98%, more preferably at least 99%, and most preferably at least 99.9% or close to 100%.

[0023] The amorphous carbon-based composite material of this application, from a microstructural perspective, comprises a matrix phase and a toughening phase, preferably consisting of only these two phases. The phrase "the toughening phase is uniformly embedded within the matrix phase" in the amorphous carbon-based composite material of this application refers to its microstructure. Specifically, "the toughening phase is uniformly embedded within the matrix phase" means that, as observed under a high-resolution electron microscope, the material is clearly divided into two phases: a matrix phase and a toughening phase. The matrix phase, as the main phase, is distributed almost continuously, while the toughening phase is generally uniformly and discretely embedded within the matrix phase, essentially randomly distributed within it.

[0024] Those skilled in the art will understand that various techniques exist for obtaining information about the microstructure of materials (e.g., the phase structure of amorphous carbon materials). For example, direct observation can be performed using instruments such as scanning electron microscopes or transmission electron microscopes, or analysis can be conducted using X-ray spectroscopy. For accurate characterization, it is preferable to analyze samples from within the material; furthermore, to avoid interference from trace amounts of contaminants that may be present in the nanoparticles, multiple random samples (e.g., more than 3 or 5 times) of the raw material can be analyzed.

[0025] In this document, "high strength" refers to a material's flexural strength of not less than 150 MPa, such as not less than 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 300 MPa, etc., preferably not less than approximately 200 MPa. The flexural strength is preferably measured using the three-point bending method; specific test conditions can be found in the examples provided.

[0026] In this article, "high toughness" refers to a material's fracture toughness of not less than 2 MPa / m. 1 / 2 For example, not less than 2 MPa 1 / 2 2.2 MPa m 1 / 2 2.4 MPa m 1 / 2 2.6 MPa m 1 / 2 2.8 MPa m 1 / 2 3.0MPa m 1 / 2 3.2 MPa m 1 / 2 3.4MPam 1 / 2 3.6 MPa m 1 / 2 3.8 MPa m 1 / 2 4.0 MPa m 1 / 2 4.2 MPa m 1 / 2 4.4 MPa m 1 / 2 4.6 MPa m 1 / 2 4.8MPam 1 / 2 5.0 MPa m 1 / 2 etc., preferably not less than about 4 MPa m 1 / 2 The fracture toughness is preferably determined using the single-sided V-notched beam (SEVNB) method, and the specific test conditions can be found in the examples described above.

[0027] As used herein, "high temperature resistance" means that the material can be used at temperatures up to 2000°C, preferably up to 2500°C or higher, under vacuum or inert gas conditions. The operating temperature is preferably measured using differential scanning calorimetry (DSC) under an inert atmosphere. The density of the amorphous carbon-based composite material of this application is typically higher than 1.3 g / cm³. 3 Typically below 2.0 g / cm³ 3 For example, it can be 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, or 2.0 g / cm³. 3Or, it can be any density within the density interval formed by any two density values ​​above as endpoints.

[0028] In the amorphous carbon-based composite material of this application, the mass ratio of the toughening phase to the matrix phase can be selected and adjusted as needed, and can vary within a wide range, thereby allowing technicians to design and prepare amorphous carbon-based composite materials with various properties. However, the amount of the toughening phase is usually less than the amount of the matrix phase. The mass ratio of the toughening phase to the matrix phase is typically greater than 0.01:1 and typically less than 0.9:1, for example, it can be 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, or any ratio within the range of proportions formed by the endpoints of any two of the above ratios; the mass ratio of the toughening phase to the matrix phase is preferably 0.02:1 to 0.6:1, and most preferably 0.03:1 to 0.4:1. The mass ratio of the toughening phase to the matrix phase in amorphous carbon-based composite materials can be determined by those skilled in the art using conventional techniques. For example, multiple regions of the material can be observed using microscopic imaging techniques (such as SEM or TEM), and the mass ratio can be estimated based on the area ratio of the two phases in the microscopic images of the material in each region. The average value of multiple regions can then be calculated to determine the mass ratio of the two phases. Alternatively, the ratio of the two phases can be estimated based on the amount of starting materials used in the preparation reaction of the amorphous carbon-based composite material.

[0029] The high-strength, high-toughness amorphous carbon-based composite material of the present invention can be obtained by the following preparation method, which mainly includes the following steps:

[0030] A) Weigh a certain mass ratio of spherical powder carbon material and one-dimensional or two-dimensional carbon material, grind and mix them evenly to obtain precursor powder;

[0031] B) Load the precursor powder into the mold, pre-press it into shape, and then place the pre-pressed blank into the sintering mold.

[0032] C) Place the pre-pressed billet from step B) together with the sintering mold into a spark plasma sintering equipment or a hot pressing sintering equipment, and then sinter it in a vacuum or inert gas environment.

[0033] D) After cooling, remove the mold and demold to obtain the amorphous carbon-based composite material.

[0034] In step A), "spherical powdered carbon material" and "one-dimensional or two-dimensional carbon material" are used as raw materials. Here, "spherical," "one-dimensional," and "two-dimensional" refer to the arrangement of carbon atoms in the basic structural unit constituting the carbon material. In some preferred embodiments of the present invention, the spherical powdered carbon material in step A) is selected from glassy carbon, carbon black, onion carbon, fullerene, or mixtures thereof, which undergoes a phase transformation to amorphous carbon at high temperatures; the one-dimensional or two-dimensional carbon material in step A) is selected from chopped carbon fibers, carbon nanotubes, graphite, two-dimensional carbon fiber cloth, or mixtures thereof, which does not undergo a phase transformation at high temperatures and plays a toughening role.

[0035] In some preferred embodiments of the present invention, the uniform mixing in step A) is achieved by the following operation: grinding spherical powder carbon material and one-dimensional or two-dimensional carbon material and mixing them, adding them to a solvent, ultrasonically treating or stirring them, drying to remove the solvent, and then sieving the resulting powder to obtain the precursor powder.

[0036] For example, as an example of the present invention, a preferred method for preparing an amorphous carbon-based composite material includes the following steps:

[0037] A) Weigh a certain mass of spherical powders such as glass carbon powder, carbon black, onion carbon or fullerene, weigh a small amount of graphite, chopped carbon fiber or two-dimensional carbon fiber cloth, grind and mix them, add them to a solvent, sonicate for 30 minutes, and dry them by magnetic stirring or freeze drying; sieve the obtained powder through a stainless steel standard sieve to obtain the precursor powder of amorphous carbon-based composite materials.

[0038] B) Load the precursor powder into the mold, pre-press it into shape, and then place the pre-pressed blank into the sintering mold.

[0039] C) Place the pre-pressed billet from step B) together with the sintering mold into a spark plasma sintering equipment or a hot pressing sintering equipment, and then sinter it in a vacuum or inert gas environment.

[0040] D) After cooling, remove the mold and demold to obtain a high-strength and high-toughness amorphous carbon-based composite material.

[0041] This invention preferably uses glass carbon powder, carbon black, onion carbon, or fullerene powders as the matrix phase and graphite, carbon nanotubes, chopped carbon fibers, and two-dimensional carbon fiber cloth as the toughening phase. It has been found that glass carbon powder, carbon black, onion carbon, or fullerene powders can transform into amorphous carbon at high temperatures, exhibiting excellent strength. Graphite, carbon nanotubes, carbon fibers, and two-dimensional carbon fiber cloth, as allotropes of carbon, have been found to maintain good mechanical properties even at temperatures up to 3000℃. Graphite, carbon nanotubes, chopped carbon fibers, and two-dimensional carbon fiber cloth are uniformly dispersed in amorphous carbon and remain stable at high temperatures, allowing the material to fracture along a long and tortuous path, increasing energy dissipation and thus improving toughness. In other words, using graphite, carbon nanotubes, carbon fibers, and two-dimensional carbon fiber cloth as toughening phases can improve material toughness without reducing the high-temperature resistance of amorphous carbon.

[0042] In step A), the spherical powder carbon material and the one-dimensional or two-dimensional carbon material used are preferably high-purity raw materials. In this application, "high purity" is understood to mean a purity of at least, for example, 97%, preferably at least 98%, more preferably at least 99%, and most preferably at least 99.9% or close to 100%. To obtain the aforementioned "high-purity" raw material, the raw material can be purified or refined. The purification process can be, for example, acid washing, heating, filtration, etc.

[0043] The mass ratio of spherical carbon powder to one-dimensional or two-dimensional carbon material used in step A) can be selected and adjusted as needed, and can vary within a wide range, allowing technicians to design and prepare amorphous carbon-based composite materials with various properties. Typically, the amount of one-dimensional or two-dimensional carbon material used is less than the amount of spherical carbon powder. Generally, the mass ratio of one-dimensional or two-dimensional carbon material to spherical carbon powder is greater than 0.01:1 and less than 0.9:1, for example, it can be 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, or any ratio within the range of any two of the above ratios. The preferred mass ratio of one-dimensional or two-dimensional carbon material to spherical powder carbon material is 0.02:1 to 0.6:1, and the most preferred mass ratio is 0.03:1 to 0.4:1.

[0044] The mold used in step B) is preferably a graphite mold. Preferably, the graphite mold is wrapped with carbon felt, which surrounds the gap in the middle of the graphite mold, thereby reducing heat dissipation in the graphite mold and reducing the temperature gradient inside the graphite mold, thus avoiding inhomogeneity in the microstructure and mechanical properties of the sintered body.

[0045] In step B), the pre-pressed billet can be of any shape, such as a cylinder, block, or sphere, preferably cylindrical. Pre-pressing can be performed on a conventional pressing machine or hydraulic press, usually at room temperature, but can be done in air or an inert atmosphere if necessary. The pre-pressing pressure in step two of this invention is not particularly limited, as long as the billet is compacted. However, for better results, in some preferred embodiments of this invention: in step B), pre-pressing involves applying pressure bidirectionally, with a pressure of 2–5 MPa and a holding time of 1–5 minutes.

[0046] In step C), a vacuum or inert gas environment is used to prevent the carbon material from being oxidized at high temperatures. The sintering pressure in step C) is typically 5–100 MPa, and the sintering temperature is typically 800–3000°C.

[0047] Preferably, the sintering pressure is set to 10-80 MPa. Within this pressure range, it is possible to obtain a high-strength sintered body at a lower temperature, while applying less pressure, reducing industrial costs and facilitating mass production. At the same time, this pressure range can control the phase transformation rate of spherical nanopowders and prevent excessively rapid grain growth.

[0048] The sintering temperature can be, for example, 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃, 1900℃, 2000℃, 2100℃, 2200℃, 2300℃, 2400℃, 2500℃, 2600℃, 2700℃, 2800℃, 2900℃, or 3000℃, or any temperature within the temperature range defined by any two of the above temperature values. Preferably, the sintering temperature is 900~2200℃, which is beneficial for controlling the phase transformation rate of spherical nanoparticles and preventing excessively rapid grain growth.

[0049] The holding time during sintering is not critical and can be determined as needed, typically ranging from 5 to 120 minutes. The heating rate can also be adjusted as needed, typically set from 1 to 100°C / min.

[0050] In some preferred embodiments of the present invention: the sintering step in step C) is performed by evacuating to a vacuum level higher than 1×10⁻⁶. -1 After Pa, the pressure is increased to the sintering pressure. Once the sintering pressure stabilizes, the temperature is increased to the sintering temperature. After high-temperature sintering, the heating program is turned off and the pressure is released.

[0051] This invention yields a material with high strength (>150MPa) and high toughness (>2MPa m). 1 / 2New materials with high temperature resistance (>2000℃) can meet the requirements of many special use environments with stringent material requirements, such as the aerospace industry, and have broad application prospects.

[0052] Example

[0053] The present invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described below are only some, not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate specific embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without departing from the principles of the invention or making inventive effort are within the scope of protection of the present invention.

[0054] For the sake of simplicity, some materials, equipment, and methods commonly used in the art are not described in the examples. All processes and analytical testing procedures (and related parameters) not specifically described in the examples are performed in accordance with those commonly used by those skilled in the art; materials and equipment not specifically sourced are all conventional laboratory materials and equipment.

[0055] Methods for analyzing and testing raw materials, equipment and materials

[0056] The manufacturers and models of the main raw materials and equipment used in each embodiment are as follows:

[0057] Carbon black: Aladdin Reagents (Shanghai) Co., Ltd. (G103921)

[0058] Onion Carbon: Inokai Technology Co., Ltd. (R166730)

[0059] Fullerenes: Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. (100433)

[0060] Graphite: Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. (100039)

[0061] Short-cut carbon fiber: Beijing Innocare Technology Co., Ltd. (I13868)

[0062] Two-dimensional carbon fiber cloth: Beijing Innocare Technology Co., Ltd. (C-00-FC-000180)

[0063] Spark plasma sintering equipment: Sumitomo Coal Mining Co., Ltd.'s SPS-3.20MK-IV

[0064] Hot pressing sintering equipment: HIGH-MULTI-5000 from Fuji Denpa Kogyo Co., Ltd., Japan

[0065] The main analytical and detection methods and instruments used in each embodiment are as follows:

[0066] X-ray diffraction: XRD patterns were determined using an X-ray diffractometer (Smartlab Rigaku, Japan). The scanning speed was 2 degrees per minute, and the range was 10–90 degrees.

[0067] SEM: Tests were performed using a Thermo Fisher Scientific Verios scanning electron microscope (ThermoFisher, USA) at an accelerating voltage of 5 kV.

[0068] TEM: TEM samples (5×10×0.06μm) were prepared using focused ion beam (FIB) and tested using a JEM-ARM300F2 from Nippon Electronics with an accelerating voltage of 300KV.

[0069] Flexural strength measurement method: The three-point bending method was used to measure the flexural strength. The flexural strength test was conducted at room temperature using a mechanical property testing system (MTII / Fullman SEMtester 2000). The specimen was machined into a cuboid of 1 mm × 2 mm × 14 mm. The span length was 11 mm, and the indenter loading rate was set to 0.1 mm·min. -1 .

[0070] Fracture toughness measurement method: The fracture toughness of the specimens was determined using the single-sided V-notched beam (SEVNB) method. The specimens were machined into cuboids with dimensions of 1 mm × 1.5 mm × 14 mm. A femtosecond laser (Astrilla-1K-USP, USA) was used to cut a straight-through V-shaped notch with a depth of approximately 0.5 mm into the specimen. The radius of the notch tip was less than 10 μm. The span length was 11 mm, and the loading rate was 0.1 mm·min. -1 .

[0071] Density measurement method: Measure the mass and volume of the cylindrical sample separately, and then calculate the density according to the formula density = mass / volume.

[0072] High temperature resistance measurement method: The test was conducted under a nitrogen atmosphere by differential scanning calorimetry (DSC).

[0073] Example 1

[0074] This embodiment describes a method for preparing a high-strength, high-toughness amorphous carbon-based composite material, which includes the following steps:

[0075] A) Mixing: Weigh 1.1g of carbon black and 0.4g of graphite, grind and mix them, add them to the solvent, sonicate for 30 minutes, and dry them by magnetic stirring or freeze drying; sieve the resulting powder through a stainless steel standard sieve to obtain the precursor powder of amorphous carbon-based composite material.

[0076] B) Loading: Place the precursor powder in a mold with an inner diameter of 15mm, apply pressure in both directions to pre-press it into shape, the pressure is 2MPa, the holding time is 5min, and then place the pre-pressed blank into a graphite mold for sintering, with graphite paper separating the pre-pressed blank from the graphite mold.

[0077] C) Sintering: The pre-pressed blank from step B) along with the sintering mold is placed into a spark plasma sintering apparatus for sintering. The sintering method is spark plasma sintering, and the vacuum level is evacuated to a level higher than 1×10⁻⁶. -1 After Pa, a sintering pressure of 80 MPa is applied. After the sintering pressure stabilizes, the temperature is raised to the sintering temperature at a rate of 10 °C / min. The sintering temperature is 900 °C and the holding time is 120 min. After high-temperature sintering, the heating program is turned off and the pressure is released.

[0078] The spark plasma sintering equipment used in this embodiment is the SPS-3.20MK-IV from Sumitomo Coal Mining Co., Ltd.; while the hot pressing sintering equipment used in subsequent embodiments is the HIGH-MULTI-5000 from Fuji Denpa Kogyo Co., Ltd. of Japan.

[0079] D) Discharge: After the temperature inside the equipment has cooled down, remove the mold and demold to obtain a high-strength and high-toughness amorphous carbon-based composite material.

[0080] The present invention uses a material mechanical property testing machine to test the flexural strength and fracture toughness of the high-strength and high-toughness amorphous carbon-based composite material of the prepared product. Various performance tests are performed on the test sample at room temperature. The test sample is a cuboid with a size of 2×2×14mm.

[0081] The high-strength, high-toughness amorphous carbon-based composite material prepared in this embodiment is an opaque black bulk, as shown in the figure below. Figure 1 As shown in Figure 2, the scanning electron microscope and transmission electron microscope images are shown in Figure 2(a) and Figure 2(b), respectively. The bulk material is composed of two phases: matrix phase 1 and toughening phase 2. The matrix phase 1 is basically continuously distributed and constitutes the main body of the material, while the toughening phase 2 is embedded and distributed in the matrix phase 1 in a generally uniform and random manner.

[0082] The obtained bulk material was subjected to XRD analysis using an X-ray diffractometer (Smartlab Rigaku, Japan). The X-ray diffraction pattern is shown below. Figure 3 As shown in (a), only peaks for amorphous carbon and graphite phases were observed; peaks for other phases were not observed. Figure 3 (b) The three-point bending data of the product prepared in Example 1 shown in Figure 1 have a flexural strength of 182 MPa, and the curve exhibits obvious nonlinear characteristics; the fracture toughness is tested to be 2.8 MPa. 1 / 2 Its density was measured to be 1.86 g / cm³. 3Furthermore, DSC testing showed no mass loss observed in the sample at 2000°C (N2 atmosphere).

[0083] Example 2

[0084] This embodiment describes a method for preparing a high-strength and high-toughness amorphous carbon-based composite material. The process steps are similar to those in Example 1. The specific process parameters that differ from those in Example 1 are shown in the Example 2 column of Table 1.

[0085] like Figure 4 (a) shows the X-ray diffraction pattern of the product prepared in Example 2. Figure 4 (b) The three-point bending data of the product prepared in Example 1 shown in Figure 1 exhibits obvious nonlinear characteristics, with a flexural strength of 248 MPa and a fracture toughness of 3.1 MPa. 1 / 2 Its density was measured to be 1.45 g / cm³. 3 .

[0086] Example 3

[0087] This embodiment describes a method for preparing a high-strength and high-toughness amorphous carbon-based composite material. The process steps are similar to those in Example 1. The specific process parameters that differ from those in Example 1 are shown in the Example 2 column of Table 1.

[0088] like Figure 5 (a) shows the X-ray diffraction pattern of the product prepared in Example 3. Figure 5 (b) The three-point bending data of the product prepared in Example 3 shown in Figure 3 exhibits obvious nonlinear characteristics, with a flexural strength of 245 MPa and a fracture toughness of 4.2 MPa. 1 / 2 Its density was measured to be 1.55 g / cm³. 3 .

[0089] Table 1. Comparison of parameters for the preparation methods of high-strength and high-toughness amorphous carbon-based composite materials in Examples 1-3.

[0090]

[0091] Table 2 Comparison of the properties of high-strength and high-toughness amorphous carbon-based composite materials in Examples 1-3

[0092]

[0093] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0094] The specification of this invention lists various optional materials for the components; however, those skilled in the art should understand that the list of components is neither limiting nor exhaustive. All components can be replaced with equivalent materials not mentioned in this specification, and the objectives of this invention can still be achieved. The specific examples mentioned in the specification are merely illustrative and not intended to limit the scope of this invention.

[0095] The combination of the matrix and toughening agent in this invention can include pairwise combinations or multiple combinations. Furthermore, the dosage range of each component in this invention includes any combination of any lower and upper limits mentioned in the specification, as well as any range formed by combining the specific content of the component as an upper or lower limit in each specific embodiment; all these ranges are covered within the scope of this invention, but for the sake of brevity, these combined ranges are not listed one by one in the specification. Each feature of this invention listed in the specification can be combined with any other feature of this invention, and such combinations are also within the scope of disclosure of this invention; for the sake of brevity, these combined ranges are not listed one by one in the specification.

Claims

1. An amorphous carbon-based composite material, characterized in that: The structure of the amorphous carbon-based composite material includes a matrix phase and a toughening phase; the matrix phase is formed by the phase transformation of spherical powdered carbon material under high temperature conditions; the toughening phase is composed of one-dimensional or two-dimensional carbon material and is uniformly embedded in the matrix phase.

2. The amorphous carbon-based composite material as described in claim 1, characterized in that: Its flexural strength is not less than 150 MPa, and its fracture toughness is not less than 2 MPa m. 1 / 2 Its high temperature resistance is greater than 2000℃ under vacuum or inert gas conditions.

3. The amorphous carbon-based composite material as described in claim 1, characterized in that... The amorphous carbon-based composite material is prepared by a method comprising the following steps: using spherical powdered carbon material as the matrix raw material, adding a small amount of one-dimensional or two-dimensional carbon material as a toughening agent, and uniformly mixing to obtain a precursor powder; and then sintering the precursor powder under pressure and high temperature in a protective atmosphere or vacuum to obtain the amorphous carbon-based composite material.

4. A method for preparing an amorphous carbon-based composite material, characterized in that... Includes the following steps: A) Weigh a certain mass ratio of spherical powder carbon material and one-dimensional or two-dimensional carbon material, grind and mix them evenly to obtain precursor powder; B) Load the precursor powder into the mold, pre-press it into shape, and then place the pre-pressed blank into the sintering mold. C) Place the pre-pressed billet from step B) together with the sintering mold into a spark plasma sintering equipment or a hot pressing sintering equipment, and then sinter it in a vacuum or inert gas environment. D) After cooling, remove the mold and demold to obtain the amorphous carbon-based composite material.

5. The method for preparing the amorphous carbon-based composite material according to claim 4, characterized in that: The spherical powder carbon material in step A) is selected from glassy carbon, carbon black, onion carbon, fullerene or mixtures thereof, which undergoes a phase transformation to amorphous carbon at high temperature; the one-dimensional or two-dimensional carbon material in step A) is selected from chopped carbon fibers, carbon nanotubes, graphite, two-dimensional carbon fiber cloth or mixtures thereof, which does not undergo a phase transformation at high temperature and plays a toughening role.

6. The method for preparing the amorphous carbon-based composite material according to claim 4, characterized in that, The uniform mixing in step A) is achieved by grinding spherical carbon powder and one-dimensional or two-dimensional carbon material, mixing them, adding them to a solvent, ultrasonicating or stirring them, drying to remove the solvent, and then sieving the resulting powder to obtain the precursor powder.

7. The method for preparing the amorphous carbon-based composite material according to any one of claims 4 to 6, characterized in that: In step B), the pre-compression molding is performed by applying pressure in both directions. The preferred pressure is 2 to 5 MPa, and the preferred holding time is 0.1 to 5 min.

8. The method for preparing the amorphous carbon-based composite material according to any one of claims 4 to 6, characterized in that: In step C), the applied sintering pressure is 5–100 MPa and the sintering temperature is 800–3000 °C; preferably, the sintering pressure is 10–80 MPa, the sintering temperature is 900–2200 °C, the heating rate is 1–100 °C / min, and the holding time is 5–120 min.

9. The method for preparing the amorphous carbon-based composite material according to any one of claims 4 to 6, characterized in that: In step C), the sintering step involves first applying initial pressure and then evacuating to a vacuum level higher than 1×10⁻⁶. -1 After Pa, sintering pressure is applied, and after the sintering pressure stabilizes, the temperature is raised to the sintering temperature. After high-temperature sintering, the heating program is turned off, and the temperature is rapidly cooled and the pressure is released.

10. The method for preparing the amorphous carbon-based composite material according to any one of claims 4 to 6, characterized in that: In step A), the mass ratio of one-dimensional or two-dimensional carbon material to spherical powder carbon material is 0.01:1 to 0.9:1, preferably 0.02:1 to 0.6:1, and most preferably 0.03:1 to 0.4:1.

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