Porous si c matrix, si c / al composite material and preparation method and application thereof

Abstract

The application provides a porous SiC substrate, which comprises a porous silicon carbide framework; a TiB2 layer is loaded on the surface of the pore wall of the porous silicon carbide framework; and a TiC layer is loaded on the surface of the TiB2 layer. The application provides a preparation method of the porous SiC substrate. The application also provides a SiC / Al composite material, which comprises the porous silicon carbide substrate, and pores of the porous silicon carbide substrate are filled with metallic aluminum. The application also provides a preparation method of the SiC / Al composite material. The application also provides an application of the SiC / Al composite material.

Description

Technical Field

[0001] This invention belongs to the field of ceramic and ceramic-metal composite material preparation, and particularly relates to a high thermal conductivity modified porous SiC matrix. This invention also relates to a high-strength, high thermal conductivity SiC / Al composite material suitable for use in electronic packaging, spacecraft optical platforms, and new energy vehicles. This invention further relates to the preparation methods and applications of the aforementioned porous SiC matrix and SiC / Al composite material. Background Technology

[0002] 3D-SiC / Al composite materials are a class of high-performance materials that use porous SiC ceramics as a framework and achieve densification through the infiltration of Al alloys. With their high specific strength, high thermal conductivity, low coefficient of thermal expansion, and good dimensional stability, this material demonstrates irreplaceable application value in many high-end equipment fields. In the field of electronic packaging, it is widely used as a heat sink and packaging substrate for high-power IGBT modules, laser diodes, and phased array radars. Furthermore, in the aerospace field, it is used to manufacture precision optical platforms, space mirrors, and structural components. In the fields of new energy vehicles and rail transportation, it serves as a core material for lightweight, wear-resistant brake discs.

[0003] Currently, various mature process routes and modification technologies have been developed in the industry to prepare high-performance 3D-SiC / Al composite materials. The mainstream pressure infiltration method forces molten aluminum to fill the pores of the framework using mechanical or gas pressure, effectively ensuring material density and production efficiency. Meanwhile, to address the poor wettability between SiC and Al, alloying treatments (such as adding Si or Mg) are widely used, utilizing active elements to reduce surface energy and improve interfacial bonding. Furthermore, surface oxidation treatment promotes wetting by generating a SiO2 layer; and the construction of ceramic transition layers optimizes performance by utilizing the properties of different materials.

[0004] The high cost of pressure infiltration equipment limits the complexity of component size and shape, and a single interface modification method is difficult to simultaneously achieve excellent wettability, suppress brittle interface reaction (Al4C3), and maintain high thermal conductivity / high strength.

[0005] Patent application CN118242378A discloses an aluminum-silicon carbide brake disc body. Its upper and lower surfaces are made of aluminum-silicon carbide material with a SiC volume fraction of 70-75%. The increased silicon carbide volume fraction significantly improves the material's high-temperature friction performance, resulting in a friction coefficient ≥0.28 at 480℃ (while aluminum-silicon carbide material with a SiC volume fraction of 42-58% has a friction coefficient of only 0.2 at 480℃). The intermediate layer and the joint portion of the aluminum-silicon carbide brake disc body provided by this invention are made of aluminum-silicon carbide material with a SiC volume fraction of 42-58%. The lower silicon carbide volume fraction gives the aluminum-silicon carbide brake disc better impact toughness ≥26KJ / m.2 (While aluminum silicon carbide materials with a SiC volume fraction of 70-75% have an impact toughness of 13 KJ / m) 2 Therefore, the multi-layered aluminum-silicon carbide brake disc provided by this invention has superior high-temperature friction performance and impact toughness compared to traditional brake discs, resulting in higher brake disc reliability. However, Al4C3 will be generated during the aluminizing process of this composite material.

[0006] Patent application CN103074507A discloses a method for preparing a silicon-aluminum alloy matrix composite material for brake discs reinforced with externally added silicon carbide particles. The aluminum-based composite material prepared by this invention is lightweight, has high specific strength and specific stiffness, low coefficient of thermal expansion, good thermal conductivity and wear resistance, and is relatively easy and low-cost to prepare. Furthermore, the reinforcing phase is dispersed and isotropic within the matrix, making it suitable for various complex stress states. However, Al₄C₃ is also generated during aluminizing of this composite material. Summary of the Invention

[0007] Therefore, the first objective of the present invention is to provide a porous SiC matrix with high thermal conductivity and high wettability to aluminum.

[0008] The second objective of this invention is to provide a method for preparing a porous SiC matrix by in-situ deposition of a TiB2-TiC composite interface layer on the pore walls of a porous SiC framework through a precursor impregnation heat treatment process.

[0009] The third objective of this invention is to provide a high-strength, high-thermal-conductivity SiC / Al composite material.

[0010] The fourth objective of this invention is to provide a method for preparing SiC / Al composite materials that achieve complete densification and infiltration of Al melt without the need for external pressure.

[0011] A fifth object of the present invention is to provide an application of the SiC / Al composite material.

[0012] This invention is achieved through the following technical solution:

[0013] A porous SiC matrix, comprising a porous silicon carbide framework;

[0014] The porous silicon carbide framework has a TiB2 layer loaded on the surface of its pore walls.

[0015] The surface of the TiB2 layer is loaded with a TiC layer.

[0016] The porosity of the porous silicon carbide framework is 20%-40%;

[0017] The thickness of the TiB2 layer is 1-2 μm;

[0018] The thickness of the TiC layer is 1-2 μm.

[0019] The method for preparing the porous SiC matrix includes the following steps:

[0020] S1 mixes titanate, borate and chelating agent in alcohol and then adds water to obtain a first precursor solution. The porous silicon carbide framework is first vacuum impregnated in the first precursor solution and then first dried. After the first heat treatment is performed in vacuum, a porous silicon carbide framework loaded with TiB2 layer is obtained.

[0021] S2 mixes titanate, carbon source and chelating agent in alcohol and then adds water to obtain a second precursor solution. The porous silicon carbide framework loaded with TiB2 layer is then subjected to a second vacuum impregnation and a second drying in the second precursor solution, followed by a second heat treatment in vacuum to obtain the porous SiC matrix.

[0022] In S1, the molar ratio of titanium atoms to boron atoms in the first precursor solution is 1:2;

[0023] The alcohols mentioned in S1 include ethanol;

[0024] In S1, the molar ratio of alcohol to titanium atoms in the first precursor solution is 30:1;

[0025] In S1, the molar ratio of alcohol to water in the first precursor solution is 30:2;

[0026] The chelating agent described in S1 includes acetylacetone;

[0027] In S1, the molar ratio of acetylacetone to titanium atoms in the first precursor solution is 1:1;

[0028] The pressure of the first vacuum impregnation is -0.1 MPa;

[0029] The first vacuum impregnation time is 30 minutes;

[0030] The temperature of the first drying step is 80°C;

[0031] The first drying time is 2 hours;

[0032] The temperature of the first heat treatment is 1300℃;

[0033] The first heat treatment lasted for 2 hours.

[0034] In S2, the molar ratio of titanium atoms to carbon atoms in the second precursor solution is 1:1;

[0035] The alcohols mentioned in S2 include ethanol;

[0036] In S2, the molar ratio of alcohol to titanium atoms in the second precursor solution is 30:1;

[0037] The carbon source mentioned in S2 includes furfuryl alcohol;

[0038] In S2, the molar ratio of alcohol to water in the second precursor solution is 30:2;

[0039] The chelating agent mentioned in S2 includes acetylacetone;

[0040] In S2, the molar ratio of acetylacetone to titanium atoms in the second precursor solution is 1:1;

[0041] The pressure of the second vacuum impregnation is -0.1 MPa;

[0042] The second vacuum impregnation time is 30 minutes;

[0043] The second drying temperature is 80°C;

[0044] The second drying time is 2 hours;

[0045] The temperature of the second heat treatment is 1300℃;

[0046] The second heat treatment lasted for 2 hours.

[0047] A SiC / Al composite material includes the porous SiC matrix, wherein the pores of the porous SiC matrix are filled with metallic aluminum.

[0048] The method for preparing the SiC / Al composite material includes a step of aluminizing the porous SiC matrix in a protective atmosphere.

[0049] The raw materials used in the aluminizing process include aluminum or aluminum alloys;

[0050] The aluminum alloy includes ZL109 aluminum alloy.

[0051] The protective atmosphere includes argon;

[0052] The aluminizing temperature is 800℃;

[0053] The aluminizing time is 2 hours.

[0054] The SiC / Al composite material is used in the fabrication of IGBT modules; or

[0055] Applications include the fabrication of laser diodes; or

[0056] Applications include heat sinks and packaging substrates for phased array radar; or

[0057] Used in the manufacture of precision optical platforms; or

[0058] Applications include the fabrication of space mirrors; or

[0059] It is used in the manufacture of brake discs.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] This invention provides a porous SiC matrix with a composite interface layer consisting of TiB2 and TiC interfaces on the pore wall surface of its porous silicon carbide framework. The TiB2-TiC composite interface layer achieves precise control and optimization of the interface structure based on a multi-scale synergistic mechanism. The TiB2 phase anchors the SiC surface through strong covalent bonds, increasing the bonding strength between titanium carbide and silicon carbide. TiC and TiB2 have good lattice matching and atomic arrangement similarity, and the two phases synergistically nucleate and co-grow to form a dense and stable transition layer. Moreover, the metal-like properties of TiC significantly reduce the interface energy, greatly improving the wettability of Al melt on the SiC framework. This structure not only repairs surface defects in the framework but also constructs channels conducive to phonon transport by pinning dislocations and deflecting crack propagation paths, effectively reducing interfacial thermal resistance.

[0062] This invention provides a method for preparing a porous SiC matrix based on a precursor impregnation-heat treatment process to construct a TiB2-TiC composite interface layer. In the preparation of the TiB2 layer, TiB2 anchors the SiC surface through strong covalent bonds. In the preparation of the TiC layer, TiB2 and TiC have excellent lattice matching. Therefore, TiB2 can induce TiC co-growth to form a dense and defect-free transition zone, eliminating the micropores and physical gaps that exist in traditional interfaces due to poor wettability.

[0063] This invention provides a SiC / Al composite material, comprising at least a porous silicon carbide matrix, wherein the pores of the porous silicon carbide matrix are filled with metallic aluminum. Based on phonon dynamics, the lattice vibration spectra of TiB2 and TiC lie between those of ceramics (covalent bonds) and metals (metallic bonds). Therefore, TiB2 and TiC act as a phonon impedance matching layer, alleviating the frequency mismatch of phonons at the SiC-Al interface. This gradient energy transition significantly reduces phonon scattering, and combined with the metallogenic conductivity of TiC to aid electronic heat transfer, a highly efficient composite heat transfer channel is ultimately constructed at the interface.

[0064] This invention provides a method for preparing high-strength, high-thermal-conductivity SiC / Al composite materials. Compared to traditional single-interface modification methods (such as oxidation treatment or single-metal plating), which suffer from the sacrifice of thermal conductivity or the limitations of complex processes requiring high-pressure melting, this invention provides a porous SiC matrix with an in-situ TiB2-TiC composite coating. Due to the metallogenic properties of TiC, which significantly reduces interfacial energy, the wettability of the porous SiC matrix to Al melt is greatly improved. During aluminizing, the formation of defects can be reduced, increasing the density of the SiC / Al composite material. The TiB2 phase anchors the SiC surface through strong covalent bonds, effectively preventing direct contact between Al melt and SiC during aluminizing, fundamentally inhibiting the formation of the brittle and harmful Al4C3 phase, and improving interfacial bonding strength. Due to the presence of the TiB2-TiC composite interfacial layer, the method provided by this invention can achieve complete densification and melting of Al melt onto thick-section, large-size, and complex-shaped skeletons without external pressure, significantly reducing preparation costs and improving production efficiency.

[0065] The SiC / Al composite material provided by this invention, mediated by the TiB2-TiC composite interface, successfully overcomes the mutually exclusive bottleneck of "wetting properties, thermal conductivity, and toughness" that is difficult to balance in traditional preparation techniques. Based on the coupled effect of interfacial bonding strengthening and interfacial reactant dispersion strengthening, this material significantly improves flexural strength and fracture toughness while maintaining excellent thermal conductivity and a low coefficient of thermal expansion. Therefore, this composite material exhibits excellent service performance and resistance to high-temperature performance degradation in high-end fields such as electronic packaging heat sinks, spacecraft optical platforms, and new energy vehicle brake discs, and has significant industrial application value. Attached Figure Description

[0066] Figure 1 The XRD pattern of the SiC / Al composite material prepared in Example 1;

[0067] Figure 2 Scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Example 1;

[0068] Figure 3 Scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Example 2;

[0069] Figure 4 This is a scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Example 3;

[0070] Figure 5 This is a scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Example 4;

[0071] Figure 6 This is a scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Example 5;

[0072] Figure 7 The flexural strength test results are for the SiC / Al composite materials prepared in Examples 1, 2, 3, 4, and 5.

[0073] Figure 8 The thermal conductivity test results are for the SiC / Al composite materials prepared in Examples 1, 2, 3, 4, and 5.

[0074] Figure 9 The results of the thermal expansion coefficient test are for the SiC / Al composite materials prepared in Examples 1, 2, 3, 4, and 5.

[0075] Figure 10 The interfacial thermal resistance calculation results are for the SiC / Al composite materials prepared in Examples 1, 2, 3, 4, and 5.

[0076] Figure 11 The image shows a scanning electron microscope (SEM) image of the microstructure of the SiC / Al composite material prepared in Comparative Example 1.

[0077] Figure 12 Scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Comparative Example 2;

[0078] Figure 13 Scanning electron microscope image of the microstructure of the SiC / Al composite material prepared in Comparative Example 3;

[0079] Figure 14 The flexural strength test results are for the SiC / Al composite materials prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0080] Figure 15 The results show the thermal conductivity test results of the SiC / Al composite materials prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0081] Figure 16 The results of the thermal expansion coefficient test of the SiC / Al composite materials prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown.

[0082] Figure 17 The interfacial thermal resistance calculation results are for the SiC / Al composite materials prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Detailed Implementation

[0083] The present invention will be further described below with reference to specific embodiments.

[0084] To quantitatively characterize the improvement in heat transfer efficiency brought about by the composite interface layer, this invention introduces interfacial thermal resistance (R0). cThe analysis was conducted based on the Differential Effective Medium Model (DEM) and the Phonon Mismatch Model (AMM). The effective thermal conductivity of the composite material depends not only on the intrinsic thermal conductivity of the matrix and the reinforcement, but also on the interfacial thermal resistance.

[0085] The DEM model equation for the effective thermal conductivity of composite materials is:

[0086]

[0087]

[0088] Where ρ represents the theoretical density of the material. v represents the phonon velocity. c represents the specific heat capacity. The subscripts m and r represent the matrix (Al alloy) and the reinforcing phase (SiC ceramic), respectively. φ is the interfacial wetting and bonding coefficient (0 < φ < 1), which depends on the wetting state and bonding density of the interface. R AMM R represents the interfacial thermal resistance in the phonon mismatch model. c The wetting coefficient is used to correct the interfacial thermal resistance.

[0089] Example 1

[0090] This embodiment provides a method for preparing a high-strength, high-thermal-conductivity SiC / Al composite material based on a TiB2-TiC composite interface layer. The method includes the following steps:

[0091] 1) Skeleton preparation

[0092] Connected porous SiC ceramic with a porosity of 30% was selected as the composite material skeleton. The silicon carbide porous skeleton was then ultrasonically cleaned in acetone and anhydrous ethanol for 30 min each. Subsequently, the silicon carbide porous skeleton was dried in a 60℃ oven for 2 h.

[0093] 2) Preparation of TiB2 layer

[0094] Anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate were weighed into a beaker and stirred to prepare a mixed ethanol solution of tetraisopropyl titanate and triethyl borate (Ti:B molar ratio 1:2). A porous silicon carbide framework was then immersed in the solution and vacuum-impregnated at -0.1 MPa for 30 min. Subsequently, the porous silicon carbide framework was dried in an 80℃ oven for 2 h. Finally, it was heat-treated in a vacuum furnace at 1300℃ for 2 h.

[0095] 3) Preparation of TiC layer

[0096] Weigh anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol in a beaker according to a molar ratio of 30:1:1:2:1 and stir to prepare a mixed ethanol solution of tetraisopropyl titanate and furfuryl alcohol (Ti:C molar ratio 1:1).

[0097] A porous silicon carbide framework loaded with TiB2 layers was placed in a solution and vacuum impregnated in a -0.1 MPa environment for 30 min.

[0098] The porous silicon carbide framework was then dried in an 80°C oven for 2 hours. It was then heat-treated in a vacuum furnace at 1300°C for 2 hours.

[0099] A porous silicon carbide matrix with a composite interface layer loaded with a TiB2 / TiC molar ratio of approximately 1:1 was obtained.

[0100] 4) Pressureless melting and infiltration

[0101] A porous silicon carbide matrix and ZL109 aluminum alloy were placed in a boron nitride crucible and heated to 800℃ under argon protection, and held for 2 hours, allowing liquid Al to spontaneously infiltrate. The SiC / Al composite material was obtained by furnace cooling.

[0102] The anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, furfuryl alcohol, and triethyl borate were all of analytical grade, and the water was deionized water.

[0103] Figure 1 The X-ray diffraction (XRD) pattern of the SiC / Al composite material prepared for Case 1 is shown. The main peaks of SiC and Al are clearly observed in the spectrum, along with characteristic diffraction peaks of TiB2 and TiC. Notably, no diffraction peaks of brittle and harmful phases such as Al4C3 were found in the spectrum. This indicates that during the pressureless melting process at 800℃, the TiB2-TiC composite interface layer effectively prevented direct contact between the Al melt and the SiC framework, inhibiting harmful interfacial reactions and ensuring the interfacial stability of the material.

[0104] Figure 2 The image shows a scanning electron microscope (SEM) image of the microstructure of the SiC / Al composite material prepared for Case 1. It can be seen that the Al liquid completely fills the pores of the porous SiC matrix, resulting in a dense material structure without obvious porosity defects. A continuous and uniform transition layer structure (i.e., the TiB2-TiC composite interface layer) can be observed between the SiC particles and the Al matrix. This interface layer is tightly bonded to the matrix, and this good interfacial bonding is the key structural basis for achieving high strength and high thermal conductivity. Figure 7 , 8 The excellent performance data shown by 9 further corroborates the advantages of this microstructure.

[0105] Examples 2-5

[0106] Examples 2-5 are based on Example 1, with modifications and adjustments to some process parameters. The difference between Examples 2-5 and Example 1 lies in the molar ratios of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate, as well as the molar ratios of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol. Details are as follows:

[0107] In Example 2, the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate was 30:1:1:8:8; the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol was 30:1:1:2:1. The theoretical molar ratio of TiB2 / TiC was 4:1.

[0108] In Example 3, the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate was 30:1:1:6:6; the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol was 30:1:1:4:2. The theoretical molar ratio of TiB2 / TiC was 3:2.

[0109] In Example 4, the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate was 30:1:1:4:4; the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol was 30:1:1:6:3. The theoretical molar ratio of TiB2 / TiC was 2:3.

[0110] In Example 5, the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate was 30:1:1:2:1; the molar ratio of anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol was 30:1:1:8:4. The theoretical molar ratio of TiB2 / TiC was 1:4.

[0111] Figures 3-6 Scanning electron microscope (SEM) images of the microstructure of the SiC / Al composite materials prepared in Examples 2-5 are shown. By adjusting the concentration of the precursor solution, the relative molar ratio of TiB2 to TiC in the interface layer was successfully controlled. The SEM images show that good densification was achieved in all examples, but in the sample with high TiB2 content (such as Example 2), the interface layer exhibited stronger mechanical interlocking characteristics; while in the sample with high TiC content (such as Example 5), the interface wettability was further improved, and the Al phase filling path was smoother.

[0112] Figures 7-9 The mechanical strength and thermophysical properties of the SiC / Al composites prepared in Examples 1-5 are summarized. The results show that adjusting the molar ratio of TiB2 to TiC in the interface layer can achieve precise control over the properties of the composites.

[0113] The composite material prepared in Example 2 has a flexural strength of up to 367.85 MPa, which is attributed to the high strength of TiB2 and the strong covalent bond anchoring effect formed with the SiC skeleton. However, since the thermal conductivity of TiB2 is slightly lower than that of TiC, its thermal conductivity is 135.59 W / (m·K).

[0114] With the increase of TiC ratio (Examples 3 and 4), the significant metal-like properties of TiC began to take effect, greatly improving the wettability of the Al liquid, eliminating interfacial microporosity, and the effective interfacial thermal resistance steadily decreased to 1.297 × 10⁻⁶. - 9 m 2 ·K / W and 1.157×10 -9 m 2 As the K / W ratio increases, the thermal conductivity also increases.

[0115] The composite material prepared in Example 5 exhibited the highest thermal conductivity, reaching 198.65 W / (m·K). The high TiC content maximally reduced the interfacial heat transfer barrier, providing not only optimal physical contact but also effectively mitigating the frequency mismatch between Al and SiC due to its phonon conduction velocity. In this state, the effective interfacial thermal resistance of the composite material was reduced to an extremely low 1.039 × 10⁻⁶. -9 m 2 • K / W. However, due to the lack of sufficient TiB2 underlying anchorage, its flexural strength has dropped to 197.78 MPa.

[0116] Example 1 (balanced type, molar ratio 1:1) achieved an optimal balance between strong bonding and low thermal resistance through the synergistic nucleation and co-growth of TiB2 and TiC. Its effective interfacial thermal resistance was maintained at 1.108 × 10⁻⁶. -9 m 2 The excellent K / W ratio allows the material to maintain a high strength of 266.17 MPa while achieving a high thermal conductivity of 177.31 W / (m·K), which best meets the stringent requirements for comprehensive performance in fields such as electronic packaging.

[0117] Comparative Example 1

[0118] This comparative example provides a method for preparing SiC / Al composite materials based on a TiB2 interface layer, the method comprising the following steps:

[0119] 1) Skeleton preparation

[0120] Connected porous SiC ceramic with a porosity of 30% was selected as the composite material skeleton. The porous silicon carbide skeleton was then ultrasonically cleaned in acetone and anhydrous ethanol for 30 min each. Subsequently, the porous silicon carbide skeleton was dried in a 60℃ oven for 2 h.

[0121] 2) Preparation of TiB2 layer

[0122] Weigh anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and triethyl borate into a beaker at a molar ratio of 30:1:1:2:2 and stir to prepare a mixed ethanol solution of tetraisopropyl titanate and triethyl borate (Ti:B molar ratio 1:2). Then, immerse the porous silicon carbide framework in the solution and vacuum impregnate the framework at -0.1 MPa for 30 min. Subsequently, dry the porous silicon carbide framework in an 80℃ oven for 2 h. Finally, heat-treat it in a vacuum furnace at 1300℃ for 2 h.

[0123] 3) Pressureless melting and infiltration

[0124] A porous silicon carbide framework loaded with a TiB2 layer and ZL109 aluminum alloy were placed in a boron nitride crucible and heated to 800℃ under argon protection, and held for 2 hours, allowing liquid Al to spontaneously infiltrate. The SiC / Al composite material was obtained by furnace cooling.

[0125] Comparative Example 2

[0126] This embodiment provides a method for preparing SiC / Al composite materials based on a TiC interface layer, the method comprising the following steps:

[0127] 1) Skeleton preparation

[0128] A porous SiC ceramic with a porosity of 30% was selected as the framework for the composite material. The porous silicon carbide framework was then ultrasonically cleaned in acetone and anhydrous ethanol for 30 min each. The porous silicon carbide framework was then dried in a 60℃ oven for 2 h.

[0129] 2) Preparation of TiC layer

[0130] Anhydrous ethanol, tetraisopropyl titanate, acetylacetone, deionized water, and furfuryl alcohol were weighed into a beaker and stirred to prepare a mixed ethanol solution of tetraisopropyl titanate and furfuryl alcohol (Ti:C molar ratio 1:1). A porous silicon carbide framework was then immersed in the solution and vacuum-impregnated at -0.1 MPa for 30 min. Subsequently, the porous silicon carbide framework was dried in an 80℃ oven for 2 h. Finally, it was heat-treated in a vacuum furnace at 1300℃ for 2 h.

[0131] 3) Pressureless melting and infiltration

[0132] A porous silicon carbide framework loaded with a TiC layer and ZL109 aluminum alloy were placed in a boron nitride crucible and heated to 800℃ under argon protection, and held for 2 hours, allowing liquid Al to spontaneously infiltrate. The SiC / Al composite material was obtained by furnace cooling.

[0133] Comparative Example 3

[0134] This embodiment provides a method for preparing SiC / Al composite materials, which includes the following steps:

[0135] 1) Skeleton preparation

[0136] Connected porous SiC ceramic with a porosity of 30% was selected as the composite material skeleton. The porous silicon carbide skeleton was then ultrasonically cleaned in acetone and anhydrous ethanol for 30 min each. Subsequently, the porous silicon carbide skeleton was dried in a 60℃ oven for 2 h.

[0137] 2) Pressureless melting and infiltration

[0138] A porous silicon carbide framework and ZL109 aluminum alloy were placed in a boron nitride crucible and heated to 800℃ under argon protection, and held for 2 hours, allowing liquid Al to spontaneously infiltrate. The SiC / Al composite material was obtained by furnace cooling.

[0139] The anhydrous ethanol is an organic solvent, tetraisopropyl titanate is a titanium source, acetylacetone is a chelating agent, deionized water is a hydrolyzing agent, furfuryl alcohol is a carbon source, and triethyl borate is a boron source; all are analytical grade, and the water is deionized water.

[0140] Figures 10-12 These are scanning electron microscope (SEM) images of the microstructure of the SiC / Al composite materials prepared in Comparative Examples 1-3. Figures 13-15 The test results were summarized. By extracting the measured thermal conductivity of the samples and substituting it into the theoretical model to calculate their effective interfacial thermal resistance (Rc), the underlying reasons why a single interfacial layer or no interfacial layer cannot achieve optimal comprehensive performance can be intuitively revealed from the microscopic dimension of energy transfer.

[0141] Comparative Example 1 (pure TiB2 interface layer) achieved a flexural strength of 215.87 MPa thanks to TiB2, but due to the lack of TiC to promote wetting of the molten metal, the interface contained numerous micropore defects indicating poor adhesion. The severe phonon mismatch caused by pure TiB2 resulted in intense diffuse scattering of heat flow at the interface, leading to an effective interfacial thermal resistance as high as 1.630 × 10⁻⁶. -9 m 2 With a thermal conductivity of only 115.45 W / (m·K), its thermal conductivity performance is significantly limited.

[0142] Comparative Example 2 (pure TiC interface layer) utilizes the metal-like properties of TiC to improve wettability to a certain extent, reducing the effective interfacial thermal resistance to 1.245 × 10⁻⁶. -9 m 2 The thermal conductivity reaches 145.36 W / (m·K) due to the lack of a high-strength TiB2 substrate anchoring, resulting in weak interfacial bonding and a significant deterioration in the material's flexural strength to 165.14 MPa, which fails to meet the requirements for high-strength service.

[0143] Comparative Example 3 (pure SiC without modified layer) is almost impossible to densify under pressureless conditions, and the interface readily forms brittle Al4C3. These pores and harmful impurity phases constitute an excellent thermal barrier layer, causing its interfacial heat transfer network to be completely blocked, and the effective interfacial thermal resistance to surge to 13.951 × 10⁻⁶. -9 m 2 Its thermal conductivity plummeted to 35.79 W / (m·K), rendering its overall performance completely ineffective.

[0144] In contrast, the TiB2-TiC composite interface layer used in Example 1 of this invention successfully eliminated interfacial micropores and suppressed byproducts, constructing a continuous phonon-electron recombination transport bridge. Its effective interfacial thermal resistance is as low as 1.108 × 10⁻⁶. - 9 m 2 The K / W ratio is significantly lower than that of a single modified layer. This invention effectively overcomes the single-dimensional defects of traditional modification processes, such as poor wettability, low strength, or limited thermal conductivity, and achieves a perfect closed loop of high strength and high thermal conductivity in the control of the micro-interface.

Claims

1. A SiC / Al composite material, characterized in that: Includes a porous SiC matrix, wherein the pores of the porous SiC matrix are filled with metallic aluminum; The porous SiC matrix includes a porous silicon carbide framework; The porous silicon carbide framework has a TiB2 layer loaded on the surface of its pore walls. The surface of the TiB2 layer is loaded with a TiC layer.

2. The SiC / Al composite material as described in claim 1, characterized in that: The porosity of the porous silicon carbide framework is 20%-40%; The thickness of the TiB2 layer is 1-2 μm; The thickness of the TiC layer is 1-2 μm.

3. The SiC / Al composite material as described in claim 1, characterized in that: The method for preparing the porous SiC matrix includes the following steps: S1 mixes titanate, borate and chelating agent in alcohol and then adds water to obtain a first precursor solution. The porous silicon carbide framework is first vacuum impregnated in the first precursor solution and then first dried. After the first heat treatment is performed in vacuum, a porous silicon carbide framework loaded with TiB2 layer is obtained. S2 mixes titanate, carbon source and chelating agent in alcohol and then adds water to obtain a second precursor solution. The porous silicon carbide framework loaded with TiB2 layer is then subjected to a second vacuum impregnation and a second drying in the second precursor solution, followed by a second heat treatment in vacuum to obtain the porous SiC matrix.

4. The SiC / Al composite material as described in claim 3, characterized in that: In S1, the molar ratio of titanium atoms to boron atoms in the first precursor solution is 1:2; The alcohols mentioned in S1 include ethanol; In S1, the molar ratio of alcohol to titanium atoms in the first precursor solution is 30:1; In S1, the molar ratio of alcohol to water in the first precursor solution is 30:2; The chelating agent described in S1 includes acetylacetone; In S1, the molar ratio of acetylacetone to titanium atoms in the first precursor solution is 1:1; The pressure of the first vacuum impregnation is -0.1 MPa; The first vacuum impregnation time is 30 minutes; The temperature of the first drying step is 80°C; The first drying time is 2 hours; The temperature of the first heat treatment is 1300℃; The first heat treatment lasted for 2 hours.

5. The SiC / Al composite material as described in claim 3, characterized in that: In S2, the molar ratio of titanium atoms to carbon atoms in the second precursor solution is 1:1; The alcohols mentioned in S2 include ethanol; In S2, the molar ratio of alcohol to titanium atoms in the second precursor solution is 30:1; The carbon source mentioned in S2 includes furfuryl alcohol; In S2, the molar ratio of alcohol to water in the second precursor solution is 30:2; The chelating agent mentioned in S2 includes acetylacetone; In S2, the molar ratio of acetylacetone to titanium atoms in the second precursor solution is 1:1; The pressure of the second vacuum impregnation is -0.1 MPa; The second vacuum impregnation time is 30 minutes; The second drying temperature is 80°C; The second drying time is 2 hours; The temperature of the second heat treatment is 1300℃; The second heat treatment lasted for 2 hours.

6. The method for preparing the SiC / Al composite material as described in claim 1, characterized in that: The process includes the step of aluminizing the porous SiC matrix in a protective atmosphere.

7. The method for preparing the SiC / Al composite material as described in claim 6, characterized in that: The raw materials used in the aluminizing process include aluminum or aluminum alloys; The aluminum alloy includes ZL109 aluminum alloy.

8. The method for preparing the SiC / Al composite material as described in claim 6, characterized in that: The protective atmosphere includes argon; The aluminizing temperature is 800℃; The aluminizing time is 2 hours.

9. The application of the SiC / Al composite material as described in claim 1, characterized in that: Used in the fabrication of IGBT modules; or Applications include the fabrication of laser diodes; or Applications include heat sinks and packaging substrates for phased array radar; or Used in the manufacture of precision optical platforms; or Applications include the fabrication of space mirrors; or It is used in the manufacture of brake discs.

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