Direct aluminum-coated ceramic substrate and preparation method thereof

Abstract

The embodiment of the invention provides a direct aluminum-coated ceramic substrate and a preparation method thereof, and relates to the field of heat dissipation substrates. The preparation method of the direct aluminum-coated ceramic substrate comprises the following steps: forming a transition layer on the ceramic substrate, and then hot-pressing and sintering aluminum foil on the surface of the transition layer to form a first aluminum layer; the transition layer comprises a second aluminum layer, a silicon layer and a magnesium layer which are stacked in sequence, the second aluminum layer is located on the surface of the ceramic substrate, and the first aluminum layer is located on the surface of the magnesium layer. The direct aluminum-coated ceramic substrate prepared by the preparation method disclosed by the invention is relatively high in shear strength, relatively excellent in thermal shock resistance and impact resistance and relatively long in service life.

Description

Technical Field

[0001] This application relates to the field of heat dissipation substrates, and more particularly, to a direct bonded aluminum ceramic substrate and a method for preparing the same. Background Art

[0002] With the continuous progress of electronic technology, the heat dissipation problem has gradually become a bottleneck restricting the development of power electronic products towards high power and light weight. In the packaging application of power electronic components, the heat dissipation substrate not only undertakes functions such as electrical connection and mechanical support, but is also an important channel for heat transfer. Ceramic substrates are commonly used materials in power modules, with special thermal, mechanical, and electrical properties, and are ideal choices for demanding power electronic applications. For example, in a direct bonded aluminum ceramic substrate (Direct Bonded Aluminum, DBA), due to the low melting point of aluminum, relatively good wettability with the ceramic substrate, and excellent plasticity, etc., it can be used as a key component in the power control and conversion system of hybrid electric vehicles. However, the shear strength of the direct bonded aluminum ceramic substrates currently on the market is poor, and the ability to resist thermal shock is also weak, resulting in a short service life. Summary of the Invention

[0003] An object of an embodiment of this application is to provide a direct bonded aluminum ceramic substrate and a method for preparing the same. The direct bonded aluminum ceramic substrate prepared by the preparation method of this application has strong shear strength, excellent thermal shock resistance, and a long service life.

[0004] In a first aspect, an embodiment of this application provides a method for preparing a direct bonded aluminum ceramic substrate, which includes the following steps: forming a transition layer on the ceramic substrate, and then hot-pressing and sintering an aluminum foil on the surface of the transition layer to form a first aluminum layer; the transition layer includes a second aluminum layer, a silicon layer, and a magnesium layer that are sequentially stacked, the second aluminum layer is located on the surface of the ceramic substrate, and the first aluminum layer is located on the surface of the magnesium layer.

[0005] In the above technical solution, although the bonding force between silicon and the ceramic substrate is poor, the bonding force between silicon and aluminum is strong, and the bonding force between aluminum and aluminum nitride is also strong. Therefore, in the transition layer, the first aluminum layer is disposed on the surface of the ceramic substrate, and then the silicon layer is disposed, so that the interfacial bonding force between the ceramic substrate and the transition layer is also strong; moreover, the bonding force between silicon and magnesium is also strong, so the bonding force between the various layer structures in the transition layer is also strong. In addition, hot-press sinter the aluminum foil on the surface of the transition layer. On the one hand, since the magnesium layer can destroy the oxide layer on the surface of the aluminum foil during sintering, the interfacial bonding force between the second aluminum layer and the transition layer can be improved by hot-press sintering; on the other hand, during the hot-press sintering process, an Al-Si eutectic phase can be formed at the interface between the second aluminum layer and the silicon layer of the transition layer, which can further improve the strength of the transition layer. Therefore, the directly aluminum-clad ceramic substrate prepared by the preparation method of the present application has strong interfacial bonding force, so it has good shear strength and thermal shock resistance, and a long service life.

[0006] In a possible implementation manner, in the step of hot-press sintering the aluminum foil on the surface of the transition layer, the hot-press sintering temperature is 550 °C to 650 °C, and the hot-press sintering pressure is 1 MPa to 10 MPa.

[0007] In the above technical solution, due to the presence of the magnesium layer in the transition layer, the melting point of the transition layer is relatively low. Therefore, sintering at a temperature of 550 °C to 650 °C can form a good eutectic phase at the interface between the second aluminum layer and the silicon layer, and the preparation difficulty is relatively low.

[0008] In a possible implementation manner, the thickness of the second aluminum layer is less than the thickness of the first aluminum layer.

[0009] In a possible implementation manner, the thickness of the second aluminum layer is 1 μm to 10 μm, and the thickness of the silicon layer is 1 μm to 10 μm.

[0010] In the above technical solution, when the above conditions are met, there will be no excessive diffusion between the silicon layer and the second aluminum layer, thus affecting the heat dissipation performance of the directly aluminum-clad ceramic substrate. At the same time, a sufficient amount of Al-Si eutectic phase can be formed to improve the interfacial bonding force of the directly aluminum-clad ceramic substrate.

[0011] In a possible implementation manner, the thickness of the first aluminum layer is 0.1 mm to 0.3 mm.

[0012] In the above technical solution, various patterns can be etched on the first aluminum layer that meets the above conditions, and it can be used as the final circuit.

[0013] In a possible implementation manner, a physical vapor deposition method is used to form a transition layer on the ceramic substrate; optionally, the physical vapor deposition method includes any one of sputter deposition method and evaporation method.

[0014] In the above technical solution, the thickness of the transition layer formed by physical vapor deposition is appropriate, which can well meet the usage requirements of the directly aluminum-clad ceramic substrate.

[0015] In a possible implementation, the preparation steps of the transition layer include: forming a second aluminum layer on the surface of the ceramic substrate, then forming a silicon layer on the surface of the second aluminum layer, and then forming a magnesium layer on the surface of the silicon layer.

[0016] In a possible implementation, the ceramic substrate is AlN; and / or, the thickness of the ceramic substrate is 0.5 mm to 1 mm.

[0017] In a second aspect, an embodiment of the present application provides a directly aluminum-clad ceramic substrate, which includes a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer that are sequentially stacked.

[0018] In the above technical solution, due to the good interfacial bonding force between the layer structures of the directly aluminum-clad ceramic substrate, the shear strength and thermal shock resistance of the directly aluminum-clad ceramic substrate are improved. The directly aluminum-clad ceramic substrate of the present application can be directly prepared by the above preparation method. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of the directly aluminum-clad ceramic substrate provided by the embodiment of the present application. Detailed Embodiments

[0021] The following will describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0024] In the description of this application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present application, it should also be noted that, unless otherwise clearly specified and limited, the term "setting" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood by specific circumstances. In addition, if the specific conditions are not indicated in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] The current DBA has good wettability and excellent plasticity, and can be used as a key component of the power control and conversion system of hybrid vehicles. However, the current DBA has poor shear strength and weak thermal shock resistance, resulting in a short service life, which is also a technical problem that needs to be solved urgently.

[0027] In order to solve the above technical problems, the present application provides a direct aluminum-coated ceramic substrate and a preparation method thereof. The direct aluminum-coated ceramic substrate and the preparation method thereof according to the embodiment of the present application are specifically described below.

[0028] In a first aspect, the present application provides a method for preparing a direct aluminum-clad ceramic substrate, which comprises the following steps:

[0029] S100, forming a transition layer on a ceramic substrate, wherein the transition layer comprises a second aluminum layer, a silicon layer, and a magnesium layer which are stacked in sequence.

[0030] In this step, the preparation steps of the transition layer are as follows: First, a second aluminum layer is formed on the surface of the ceramic substrate, then a silicon layer is formed on the surface of the second aluminum layer, and then a magnesium layer is formed on the surface of the silicon layer. In the obtained transition layer, the second aluminum layer is located on the surface of the ceramic substrate, and the magnesium layer is far from the ceramic substrate. Since the bonding force between aluminum and aluminum nitride is also strong, the transition layer in this step has a good interfacial bonding force with the ceramic substrate; moreover, since the bonding force between silicon and aluminum and magnesium is strong, the bonding force between the various layer structures in the transition layer of the present application is also strong.

[0031] In this step, the transition layer can be prepared by Physical Vapor Deposition (PVD); Physical Vapor Deposition is a technology that physically vaporizes the material source (solid or liquid) surface into gaseous atoms or molecules, or partially ionizes them into ions under vacuum conditions, and deposits a thin film with a certain special function on the substrate surface through a low-pressure gas (or plasma) process. Therefore, the layer structure deposited by Physical Vapor Deposition has a thinner thickness, higher crystal quality, and fewer defects, which can better improve the performance of the obtained directly aluminum-clad ceramic substrate. Specifically, Physical Vapor Deposition includes, but is not limited to, any one of sputtering deposition and evaporation deposition. Of course, in some other embodiments, other methods can also be used to prepare the various layer structures in the transition layer, as long as the purpose of the present application can be met.

[0032] In addition, when using Physical Vapor Deposition to prepare different layer structures in the transition layer, the preparation parameters can be specifically adjusted according to actual needs, and Physical Vapor Deposition can well control the thickness of each layer structure formed by deposition in the transition layer. Since the process of preparing layer structures by Physical Vapor Deposition is relatively mature, it will not be elaborated in this application.

[0033] In this step, the thickness of the obtained second aluminum layer is 1 μm to 10 μm, and the thickness of the silicon layer is 1 μm to 10 μm. In this way, the silicon layer and the second aluminum layer will not diffuse excessively, thus affecting the heat dissipation performance of the directly aluminum-clad ceramic substrate, and at the same time, a sufficient amount of Al-Si eutectic phase can be formed in the subsequent steps to improve the interfacial bonding force of the directly aluminum-clad ceramic substrate.

[0034] In addition, in this step, the thickness of the obtained magnesium layer is generally 0.1 μm to 1 μm, which can not only remove the oxide layer and reduce the sintering temperature in the subsequent steps, but also is not likely to have an adverse effect on the heat dissipation performance of the directly aluminum-clad ceramic substrate.

[0035] In this step, the material of the used ceramic substrate is generally AlN, and the thickness can be 0.5 mm to 1 mm. In this way, various patterns can be etched on the first aluminum layer, which can be used as the final circuit.

[0036] S200. Hot press and sinter an aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer.

[0037] In this step, the first aluminum layer is formed by hot pressing and sintering the aluminum foil. On the one hand, during hot pressing and sintering, the magnesium layer can break the oxide layer on the surface of the aluminum foil, resulting in good interfacial bonding force between the formed first aluminum layer and the magnesium layer. On the other hand, during the hot pressing and sintering process, an Al-Si eutectic phase can be formed at the interface between the second aluminum layer and the silicon layer of the transition layer, which can further improve the interfacial bonding force between the various layer structures in the transition layer. Moreover, due to the presence of the magnesium layer, the melting point of the transition layer is relatively low. Therefore, the temperature of hot pressing and sintering can make the interface between the second aluminum layer and the silicon layer form an Al-Si eutectic phase within a relatively low range. Specifically, in this step, the temperature of hot pressing and sintering is usually 550°C to 650°C, preferably 550°C to 600°C, such as 550°C, 560°C, 580°C, 600°C, 620°C, 650°C, etc. or within the range composed of any two of the above values; the pressure of hot pressing and sintering is 1 MPa to 10 Mpa, such as 1 MPa, 3 MPa, 5 MPa, 8 MPa, 10 MPa, etc. or within the range composed of any two of the above values.

[0038] In some embodiments of the present application, the thickness of the first aluminum layer formed in this step is generally 0.1 mm to 0.3 mm, which is convenient for etching the circuit.

[0039] The directly aluminum-clad ceramic substrate prepared by the preparation method of the present application has a structure as Figure 1 shown, including a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer stacked in sequence. For the directly aluminum-clad ceramic substrate of the present application, due to its strong interfacial bonding force, its shear strength is strong, and its thermal shock resistance is also relatively excellent, and its service life is long.

[0040] The features and properties of the present application will be further described in detail below in conjunction with embodiments.

[0041] Example 1

[0042] This example provides a directly aluminum-clad ceramic substrate, and its preparation steps are as follows:

[0043] (1) Take an AlN with a thickness of 0.5 mm as the ceramic substrate, and use the PVD method to sequentially deposit a second aluminum layer, a silicon layer, and a magnesium layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 1 μm, 1 μm, and 0.1 μm in sequence.

[0044] (2) Hot press and sinter aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer. The temperature of hot press sintering is 550 °C, and the pressure of hot press sintering is 1 MPa. The thickness of the first aluminum layer obtained by hot press sintering is 0.1 mm.

[0045] For the directly aluminum-clad ceramic substrate of this embodiment, its structure includes a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer that are sequentially stacked, and the thicknesses of each layer structure are 0.5 mm, 1 μm, 1 μm, 0.1 μm, and 0.1 mm respectively.

[0046] Example 2

[0047] This embodiment provides a directly aluminum-clad ceramic substrate, and its preparation steps are as follows:

[0048] (1) Take an AlN with a thickness of 1 mm as the ceramic substrate, and use PVD method to sequentially deposit and form a second aluminum layer, a silicon layer, and a magnesium layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 10 μm, 10 μm, and 0.1 μm in sequence.

[0049] (2) Hot press and sinter aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer. The temperature of hot press sintering is 650 °C, and the pressure of hot press sintering is 10 MPa. The thickness of the first aluminum layer obtained by hot press sintering is 0.3 mm.

[0050] For the directly aluminum-clad ceramic substrate of this embodiment, its structure includes a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer that are sequentially stacked, and the thicknesses of each layer structure are 1 mm, 10 μm, 10 μm, 0.1 μm, and 0.3 mm respectively.

[0051] Example 3

[0052] This embodiment provides a directly aluminum-clad ceramic substrate, and its preparation steps are as follows:

[0053] (1) Take an AlN with a thickness of 0.8 mm as the ceramic substrate, and use PVD method to sequentially deposit and form a second aluminum layer, a silicon layer, and a magnesium layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 5 μm, 5 μm, and 0.5 μm in sequence.

[0054] (2) Hot press and sinter aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer. The temperature of hot press sintering is 610 °C, and the pressure of hot press sintering is 6 MPa. The thickness of the first aluminum layer obtained by hot press sintering is 0.3 mm.

[0055] The direct aluminum-bonded ceramic substrate of this embodiment has a structure including a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer stacked in sequence. The thicknesses of each layer structure are 0.8 mm, 5 μm, 5 μm, 0.5 μm, and 0.3 mm respectively.

[0056] Example 4

[0057] This embodiment provides a direct aluminum-bonded ceramic substrate, and its preparation steps are as follows:

[0058] (1) Take an AlN with a thickness of 0.8 mm as the ceramic substrate, and use the PVD method to sequentially deposit a second aluminum layer, a silicon layer, and a magnesium layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 5 μm, 11 μm, and 0.5 μm respectively.

[0059] (2) Hot press and sinter aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer. The temperature of hot press sintering is 610 °C, and the pressure of hot press sintering is 6 MPa. The thickness of the first aluminum layer obtained by hot press sintering is 0.3 mm.

[0060] The direct aluminum-bonded ceramic substrate of this embodiment has a structure including a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer stacked in sequence. The thicknesses of each layer structure are 0.8 mm, 5 μm, 11 μm, 0.5 μm, and 0.3 mm respectively.

[0061] Example 5

[0062] This embodiment provides a direct aluminum-bonded ceramic substrate, and its preparation steps are as follows:

[0063] (1) Take an AlN with a thickness of 0.8 mm as the ceramic substrate, and use the PVD method to sequentially deposit a second aluminum layer, a silicon layer, and a magnesium layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 11 μm, 5 μm, and 0.5 μm respectively.

[0064] (2) Hot press and sinter aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the magnesium layer. The temperature of hot press sintering is 610 °C, and the pressure of hot press sintering is 6 MPa. The thickness of the first aluminum layer obtained by hot press sintering is 0.3 mm.

[0065] The direct aluminum-bonded ceramic substrate of this embodiment has a structure including a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer stacked in sequence. The thicknesses of each layer structure are 0.8 mm, 11 μm, 5 μm, 0.5 μm, and 0.3 mm respectively.

[0066] Example 6

[0067] This embodiment provides a direct aluminum-bonded ceramic substrate. The main difference in its preparation steps compared to Embodiment 1 is that in step (1), the thickness of the formed silicon layer is 0.8 μm, and the thickness of the magnesium layer is 1 μm.

[0068] Embodiment 7

[0069] This embodiment provides a direct aluminum-bonded ceramic substrate. The main difference in its preparation steps compared to Embodiment 1 is that in step (1), the thickness of the formed silicon layer is 8 μm, and the thickness of the magnesium layer is 1 μm.

[0070] Embodiment 8

[0071] This embodiment provides a direct aluminum-bonded ceramic substrate. The main difference in its preparation steps compared to Embodiment 1 is that in step (1), the thickness of the formed second aluminum layer is 0.8 μm, and the thickness of the magnesium layer is 1 μm.

[0072] Embodiment 9

[0073] This embodiment provides a direct aluminum-bonded ceramic substrate. The main difference in its preparation steps compared to Embodiment 1 is that in step (1), the thickness of the formed second aluminum layer is 8 μm, and the thickness of the magnesium layer is 1 μm.

[0074] Comparative Example 1

[0075] This comparative example provides a direct aluminum-bonded ceramic substrate, and its preparation steps are as follows:

[0076] (1) Take an AlN with a thickness of 0.5 mm as the ceramic substrate, and use PVD method to sequentially deposit a second aluminum layer and a silicon layer on the surface of the AlN. The thicknesses of the deposited second aluminum layer, silicon layer, and magnesium layer are 1 μm, 1 μm, and 1 μm in sequence.

[0077] (2) Hot-press and sinter an aluminum foil on the surface of the transition layer to form a first aluminum layer, and the formed first aluminum layer is located on the surface of the silicon layer. The temperature of hot-press sintering is 550 °C, and the pressure of hot-press sintering is 1 MPa. The thickness of the first aluminum layer obtained by hot-press sintering is 0.1 mm.

[0078] For the direct aluminum-bonded ceramic substrate of this embodiment, its structure includes a ceramic substrate, a second aluminum layer, a silicon layer, and a first aluminum layer that are sequentially stacked, and the thicknesses of each layer structure are 0.5 mm, 1 μm, 1 μm, and 0.1 mm respectively.

[0079] Comparative Example 2

[0080] This comparative example provides a direct aluminum-bonded ceramic substrate, and its preparation steps are as follows:

[0081] (1) Take an AlN with a thickness of 0.5 mm as a ceramic substrate, and use the PVD method to deposit a silicon layer and a magnesium layer on the surface of the AlN in sequence. The thicknesses of the deposited second aluminum layer, silicon layer and magnesium layer are 1 μm and 0.1 μm respectively.

[0082] (2) Hot pressing and sintering aluminum foil on the surface of the transition layer to form a first aluminum layer, the formed first aluminum layer is located on the surface of the magnesium layer. The hot pressing and sintering temperature is 550°C, the hot pressing and sintering pressure is 1 MPa. The thickness of the first aluminum layer obtained by hot pressing and sintering is 0.1 mm.

[0083] The direct aluminum-clad ceramic substrate of this embodiment comprises a ceramic substrate, a silicon layer, a magnesium layer and a first aluminum layer stacked in sequence, and the thickness of each layer structure is 0.5 mm, 1 μm, 0.1 μm and 0.1 mm respectively.

[0084] The comparison of parameters in the embodiments and comparative examples can be seen in Table 1.

[0085] Application Examples

[0086] Shear strength test

[0087] The shear strength of the direct-coated aluminum ceramic substrates in various embodiments and comparative examples was tested using a tensile tester.

[0088] Thermal shock resistance test

[0089] The directly aluminum-coated ceramic substrates in the embodiments and comparative examples were placed at -40°C to 200°C and cycled for 2000 times, and the interfaces and surfaces were observed using a two-dimensional microscope to see if there were any cracks.

[0090] The test results are shown in Table 1:

[0091] Table 1

[0092]

[0093]

[0094] It can be seen from Table 1 that the directly-aluminum-coated ceramic substrate prepared by the preparation method of the present application has good shear strength and good thermal shock resistance, and no cracks are generated on the surface after multiple hot and cold cycles; and it can be seen from Examples 4 to 5 and Examples 6 and 8 that when the thickness of the second aluminum layer or silicon layer is outside the range of 1μm to 10μm, the shear strength of the directly-aluminum-coated ceramic substrate is slightly reduced.

[0095] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A preparation method of a directly aluminized ceramic substrate, characterized in that It includes the following steps: A transition layer is formed on a ceramic substrate, and then aluminum foil is hot-pressed and sintered on the surface of the transition layer to form a first aluminum layer; the transition layer includes a second aluminum layer, a silicon layer, and a magnesium layer that are sequentially stacked, the second aluminum layer is located on the surface of the ceramic substrate, and the first aluminum layer is located on the surface of the magnesium layer.

2. The preparation method of the directly aluminized ceramic substrate according to claim 1, wherein In the step of hot-pressing and sintering aluminum foil on the surface of the transition layer, the hot-pressing and sintering temperature is 550°C to 650°C, and the hot-pressing and sintering pressure is 1 MPa to 10 MPa.

3. The preparation method of the directly aluminized ceramic substrate according to claim 1, characterized in that The thickness of the second aluminum layer is less than the thickness of the first aluminum layer.

4. The preparation method of the directly aluminized ceramic substrate according to claim 1 or 3, characterized in that, The thickness of the second aluminum layer is 1 μm to 10 μm, and the thickness of the silicon layer is 1 μm to 10 μm.

5. The preparation method of the directly aluminized ceramic substrate according to claim 1 or 3, characterized in that, The thickness of the first aluminum layer is 0.1 mm to 0.3 mm.

6. The preparation method of the directly aluminized ceramic substrate according to claim 1, wherein, The transition layer is formed on the ceramic substrate by physical vapor deposition; optionally, the physical vapor deposition includes any one of sputtering deposition and evaporation coating.

7. The preparation method of the directly aluminized ceramic substrate according to any one of claims 1 to 6, characterized in that, The preparation steps of the transition layer include: forming the second aluminum layer on the surface of the ceramic substrate, then forming the silicon layer on the surface of the second aluminum layer, and then forming the magnesium layer on the surface of the silicon layer.

8. The preparation method of the directly aluminized ceramic substrate according to claim 1, characterized in that, The ceramic substrate is AlN; and / or The thickness of the ceramic substrate is 0.5 mm to 1 mm.

9. A direct aluminum-clad ceramic substrate, characterized in that, It includes a ceramic substrate, a second aluminum layer, a silicon layer, a magnesium layer, and a first aluminum layer that are sequentially stacked.

10. A directly aluminum-coated ceramic substrate, characterized in that, It is obtained by the preparation method of the directly aluminum-clad ceramic substrate according to any one of claims 1 to 8.

Images