Preparation method of aluminum nitride / metal composite structure containing graphite-like carbon nitride film intermediate layer

Abstract

The invention relates to the technical field of ceramic composite materials, in particular to a preparation method of an aluminum nitride / metal composite structure containing a graphite-phase-like carbon nitride film intermediate layer. The graphite-like g-C3N4 film with a certain thickness is generated in situ between the aluminum nitride ceramic substrate and the metal film, so that the problem of interface mismatching caused by physical attribute difference between the ceramic and the metal film is solved. Moreover, since the preparation method provided by the invention belongs to in-situ generation of the graphite-like g-C3N4 film, the interface bonding strength between the g-C3N4 film and the aluminum nitride ceramic matrix and between the g-C3N4 film and the metal film is high, and in addition, the g-C3N4 film also has excellent mechanical properties, can relieve stress concentration around the interface and improve the mechanical properties of the interface.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic composite materials, and in particular to a method for preparing an aluminum nitride / metal composite structure containing a graphite-like phase carbon nitride film intermediate layer. Background Art

[0002] Aluminum nitride (AlN) ceramics have attracted extensive attention in the fields of electronic devices, automotive industry, and aviation due to their unique physical properties such as high thermal conductivity, stable high-temperature performance, good electrical insulation, low dielectric constant, and excellent high-frequency power characteristics. In addition, AlN also has certain piezoelectric properties and is an important material for manufacturing pressure sensors, resonators, and acoustic filters. However, AlN must be surface metallized before being used in the fields of electronics and sensing. However, since AlN does not wet most metals, the interface bonding is poor, and the physical properties such as thermal expansion coefficient and elastic modulus between ceramics and metals are quite different, local stress is easily generated during electrode welding or service, and the initiation and expansion of microcracks will cause interface debonding failure. Therefore, how to improve the bonding quality between aluminum nitride ceramics and surface metals is a common main problem. At present, screen printing, electroplating, magnetron sputtering, direct copper coating and other methods are mainly used for surface metallization. However, no matter what method is used, the physical properties of aluminum nitride ceramics and surface metals cannot be changed, and it is difficult to eliminate the uneven stress around the interface. Therefore, how to further improve the bonding quality between aluminum nitride ceramics and surface metals remains a difficult problem that needs to be solved urgently. Summary of the invention

[0003] In view of this, the present invention provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer. The preparation method introduces a graphite-like carbon nitride film intermediate layer between the aluminum nitride and the metal layer. 3 N 4 and make the graphite phase gC 3 N 4 It is generated in situ between aluminum nitride ceramic and metal film, which greatly improves the interface bonding strength between ceramic and metal and significantly enhances the overall performance of aluminum nitride components.

[0004] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, the steps comprising:

[0005] S1, coating the ethanol and / or aqueous solution of carbon nitride compounds on the surface of aluminum nitride ceramics according to the spraying amount that can obtain a graphite-like carbon nitride film with a theoretical thickness of 30nm≤δ≤120nm, and calcining at 500-600°C for 4.5-5.5h after drying;

[0006] S2, drying the aluminum nitride ceramic surface composite metal slurry obtained in step S1, calcining at 500-600° C. for 0.8-1.2 h under vacuum conditions, and cooling with the furnace to obtain an aluminum nitride ceramic having an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film;

[0007] The spraying amount is calculated based on the theoretical thickness of the graphite-like carbon nitride film, the total surface area of ​​the aluminum nitride ceramic to be sprayed, the density of the graphite-like carbon nitride film, and the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of carbon and nitrogen compounds.

[0008] The present invention first coats the ethanol and / or aqueous solution of carbon and nitrogen compounds on the surface of aluminum nitride ceramics according to a theoretical thickness of 30nm≤δ≤120nm, forms a film containing carbon and nitrogen elements after drying and calcining, and then continues to metallize the film surface by compounding metal slurry on the film surface, and forms a composite structure of "aluminum nitride ceramic matrix / graphite-like carbon nitride film / metal film" from the inside to the outside after drying and calcining.

[0009] The inventors found in the research process that the film obtained after calcination in step S1 is not a graphite-like carbon nitride film (gC 3 N 4 ), the obtained film was confirmed to contain carbon and nitrogen elements by energy spectrum test, and when the surface was further compounded with metal slurry to metallize the surface and calcined, it was found that gC was formed between the aluminum nitride substrate and the metal film. 3 N 4 This indicates that the preparation method provided by the present invention can decompose the film containing carbon and nitrogen elements obtained in step S1 in situ during the solidification process of the metal slurry and generate a graphite-like carbon nitride film (gC 3 N 4 ), and because this type of graphite phase carbon nitride film is an in-situ decomposition reaction, it can more firmly combine the aluminum nitride ceramic substrate and the metal film, effectively improving the interface bonding strength between the aluminum nitride ceramic and the metal film.

[0010] Exemplarily, the spraying amount V is calculated as follows:

[0011]

[0012] In formula I: δ is the theoretical thickness of the graphite-like carbon nitride film, in nm; A is the surface area of ​​the spraying, in cm 2 ; ρ is the graphite-like carbon nitride film gC 3 N 4 Density, in g / cm 3 ; c is the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of the carbon and nitrogen compounds, in mg / L.

[0013] In combination with the first aspect, the aluminum nitride ceramic in step S1 is pre-treated as follows: the aluminum nitride ceramic is placed in an alkaline solution for ultrasonic treatment, and then washed with water and ethanol and dried to remove surface oil and impurities.

[0014] The alkaline solution may be a sodium hydroxide or potassium hydroxide aqueous solution, or may be other alkaline solutions.

[0015] In combination with the first aspect, the carbon-nitrogen compound includes at least one of melamine, dicyandiamide and urea.

[0016] In combination with the first aspect, the concentration of the carbon and nitrogen compounds in the ethanol and / or aqueous solution of the carbon and nitrogen compounds is 550-1200 mg / L.

[0017] Preferably, the concentration of the carbon and nitrogen compounds in the ethanol and / or aqueous solution of the carbon and nitrogen compounds is 576-1152 mg / L.

[0018] In combination with the first aspect, in step S1, an ethanol and / or aqueous solution of carbon nitride compounds is coated on the surface of the aluminum nitride ceramic by ultrasonic spraying.

[0019] In combination with the first aspect, the aluminum nitride ceramic surface composite metal slurry obtained in step S1 is specifically: the metal slurry is composited on the aluminum nitride ceramic surface by screen printing, chemical plating, electroplating or magnetron sputtering, preferably screen printing and chemical plating.

[0020] In combination with the first aspect, the metal liquid may be a metal liquid of gold, silver, copper or nickel.

[0021] A second aspect of the present invention provides an aluminum nitride ceramic having an aluminum nitride / metal composite structure with an intermediate layer of a graphite-like carbon nitride film, which is prepared according to the above preparation method.

[0022] The aluminum nitride ceramics provided by the present invention having an aluminum nitride / metal composite structure with an intermediate layer of a graphite-like carbon nitride film are mainly used in the fields of electronic information, sensing and new energy.

[0023] The third aspect of the present invention provides a method for preparing an aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, the steps comprising: applying an ethanol and / or aqueous solution of a carbon nitride compound to the surface of the aluminum nitride ceramic in a spraying amount that can obtain a graphite-like carbon nitride film with a theoretical thickness of 120nm≤δ≤2μm, drying, and calcining at 500-600°C for 4.5-5.5h to form a graphite-like carbon nitride film on the surface of the aluminum nitride ceramic;

[0024] The spraying amount is calculated based on the theoretical thickness of the graphite-like carbon nitride film, the total surface area of ​​the aluminum nitride ceramic to be sprayed, the density of the graphite-like carbon nitride film, and the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of carbon and nitrogen compounds.

[0025] Exemplarily, the spraying amount V is calculated as follows:

[0026]

[0027] In formula I: δ is the theoretical thickness of the graphite-like carbon nitride film, in nm; A is the surface area of ​​the spraying, in cm 2 ; ρ is the graphite-like carbon nitride film gC 3 N 4 Density, in g / cm 3 ; c is the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of the carbon and nitrogen compounds, in mg / L.

[0028] The inventors found in the research process that when the thickness of the graphite-like carbon nitride film generated on the surface of aluminum nitride ceramic is 120nm≤δ≤2μm, after drying and calcining, a graphite-like carbon nitride film (gC 3 N 4 ), indicating that when the coated carbonitride compound is greater than a certain amount, after drying and calcination, the carbonitride compound can directly decompose in situ on the surface of the aluminum nitride ceramic and generate a composite structure of "aluminum nitride ceramic matrix / graphite-like carbon nitride film" with the aluminum nitride ceramic.

[0029] In combination with the third aspect, the carbon-nitrogen compound includes at least one of melamine, dicyandiamide and urea, and the concentration of the carbon-nitrogen compound in the ethanol and / or aqueous solution of the carbon-nitrogen compound is 550-1200 mg / L.

[0030] Preferably, the concentration of the carbon and nitrogen compounds in the ethanol and / or aqueous solution of the carbon and nitrogen compounds is 576-1152 mg / L.

[0031] A fourth aspect of the present invention provides an aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, which is prepared according to the above-mentioned method for preparing the aluminum nitride ceramic having a graphite-like carbon nitride film on its surface.

[0032] The present invention generates a graphite-like phase gC with a certain thickness in situ between the aluminum nitride ceramic substrate and the metal film. 3 N 4The film solves the problem of interface mismatch between ceramic and metal films due to differences in physical properties. Moreover, since the preparation method provided by the present invention can generate graphite-like phase gC in situ 3 N 4 Film, gC 3 N 4 The film has a high interface bonding strength with the aluminum nitride ceramic substrate and the metal film. In addition, gC 3 N 4 The film itself also has excellent mechanical properties, which can relieve stress concentration around the interface and improve the interface mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figures are scanning electron microscope images and Raman spectra of an aluminum nitride ceramic substrate and an aluminum nitride ceramic substrate treated in Comparative Example 1, wherein (a) is a scanning electron microscope image of the aluminum nitride ceramic substrate, (b) and (c) are scanning electron microscope images of the aluminum nitride ceramic surface obtained in Comparative Example 1 at different proportions, and (d) is a Raman spectra of the aluminum nitride ceramic surface obtained in Comparative Example 1;

[0034] Figure 2 The figures are scanning electron microscope photographs and electron energy spectra of the aluminum nitride ceramic substrate and the aluminum nitride ceramic substrate treated in Comparative Example 2, wherein (a) is a scanning electron microscope photograph of the aluminum nitride ceramic substrate, (b) is a scanning electron microscope photograph of the surface of the aluminum nitride ceramic obtained in Comparative Example 2, and (c) and (d) are electron energy spectra of the surface of the aluminum nitride ceramic obtained in Comparative Example 2;

[0035] Figure 3 Scanning electron microscope photographs and Raman spectra corresponding to Example 1, wherein (a) is a scanning electron microscope photograph of the aluminum nitride surface in contact with the carbon nitride film containing a graphite-like phase, (b) is a scanning electron microscope photograph of the metal film surface in contact with the carbon nitride film containing a graphite-like phase, and (c) is a Raman spectra of the aluminum nitride surface and the metal film surface in contact with the graphite-like carbon nitride film;

[0036] Figure 4 The Raman spectra of the aluminum nitride ceramics with composite structures obtained in Comparative Examples 1 and Comparative Examples 3 to 4 are shown;

[0037] Figure 5 The mechanical property test curves of the aluminum nitride ceramic samples with composite structures obtained in Comparative Example 5 and Examples 1 to 3 are shown. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0040] A large number of studies have shown that introducing an intermediate buffer layer between aluminum nitride and the surface metal film is an effective method to improve the bonding quality between ceramics and metals. For example, studies have shown that screen printing porous copper between aluminum nitride and copper film can improve the bonding strength of the interface, mainly because it can relieve the local stress of the interface to a certain extent. In addition, electroplating a Ni-P intermediate layer on the surface of aluminum nitride by chemical plating can enhance the interfacial bonding strength between W-Cu alloy and aluminum nitride. However, none of the above combines aluminum nitride with the metal film through chemical bonds, and there is still room for improvement in the bonding strength between aluminum nitride and the metal layer.

[0041] On this basis, the inventors conducted a large number of experiments and found that if the aluminum nitride and the metal layer can form a chemical bond through a chemical reaction, the interface bonding strength will be further improved. 3 N 4 It has high stability, unique layered structure and good piezoelectric performance, and has attracted wide attention in the fields of energy storage and conversion. The present invention introduces a graphite phase gC between the aluminum nitride and the metal layer. 3 N 4 and make the graphite phase gC 3 N 4 The in-situ generation between ceramics and metals greatly improves the interface bonding strength between ceramics and metals, and enhances the overall performance of aluminum nitride components, which has important research value and application prospects.

[0042] The technical solution of the present invention is described in more detail below through specific embodiments to make the purpose, technical solution and advantages of the present invention clearer.

[0043] In the following embodiments, the aluminum nitride ceramics used are pre-treated as follows: the aluminum nitride ceramics are placed in a 10% NaOH aqueous solution and ultrasonically treated for 20 minutes for degreasing and roughening treatment, and then repeatedly washed with deionized water and anhydrous ethanol and dried to obtain pre-treated aluminum nitride ceramics.

[0044] In the following embodiments, gC is controlled by spraying amount. 3 N 4 Theoretical thickness, taking melamine in Example 1 as an example: when gC is pre-obtained 3 N 4 When a composite structure with a theoretical thickness of 90 nm is sprayed on an aluminum nitride ceramic surface with a surface area of ​​6.25 square centimeters using an anhydrous ethanol solution of melamine with a concentration of 1152 mg / L, the spraying amount V is calculated as follows:

[0045]

[0046] Where: δ is the theoretical thickness of the graphite-like carbon nitride film, 90 nm; A is the total surface area of ​​the spraying, 6.25 cm 2 ρ is gC 3 N 4 Density 2.2g / cm 3 ; c is the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of the carbon-nitrogen compound (1152×120.12 / 126.12=1097.2) mg / L, wherein 120.12 / 126.12 is the mass ratio of carbon atoms and nitrogen atoms in melamine.

[0047] Example 1

[0048] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0049] Prepare an anhydrous ethanol solution of melamine with a concentration of 1152 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 90nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, a conductive silver paste with a thickness of 20μm is printed on the surface of aluminum nitride ceramic by screen printing. After drying, it is heat treated at 500℃ for 1 hour in a vacuum environment, and then cooled with the furnace to obtain AlN / gC 3 N 4 / Ag composite structure aluminum nitride ceramics.

[0050] Example 2

[0051] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0052] Prepare an anhydrous ethanol solution of melamine with a concentration of 1152 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 120nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, a conductive silver paste with a thickness of 20μm is printed on the surface of aluminum nitride ceramic by screen printing. After drying, it is heat treated at 500℃ for 1 hour in a vacuum environment, and then cooled with the furnace to obtain AlN / gC 3 N 4 / Ag composite structure aluminum nitride ceramics.

[0053] Example 3

[0054] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0055] A melamine aqueous solution with a concentration of 576 mg / L was prepared and sprayed on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount was controlled to gC 3 N 4 The theoretical thickness is 30nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, a conductive silver paste with a thickness of 30μm is printed on the surface of aluminum nitride ceramic by screen printing. After drying, it is heat treated at 500℃ for 1 hour in a vacuum environment, and then cooled with the furnace to obtain AlN / gC 3 N 4 / Ag composite structure aluminum nitride ceramics.

[0056] Example 4

[0057] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0058] Prepare an anhydrous ethanol solution of melamine with a concentration of 576 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 90nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, a conductive copper paste with a thickness of 30μm is printed on the surface of aluminum nitride ceramic by screen printing. After drying, it is heat treated at 500℃ for 1 hour in a vacuum environment, and then cooled with the furnace to obtain AlN / gC 3 N 4 / Cu composite structure of aluminum nitride ceramics.

[0059] Example 5

[0060] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0061] A 576 mg / L melamine aqueous solution was prepared and sprayed on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount was controlled to gC 3 N 4 The theoretical thickness is 30nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, a conductive silver paste with a thickness of 20μm is printed on the surface of aluminum nitride ceramic by screen printing. After drying, it is heat treated at 500℃ for 1 hour in a vacuum environment, and then cooled with the furnace to obtain AlN / gC 3 N 4 / Ag composite structure aluminum nitride ceramics.

[0062] Example 6

[0063] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0064] Prepare an anhydrous ethanol solution of urea with a concentration of 576 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 120nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, 2μm thick copper is plated on the surface of aluminum nitride ceramic by chemical copper plating method. After drying, heat treatment is performed at 500℃ for 1 hour in a vacuum environment, and then the temperature is lowered with the furnace to obtain AlN / gC 3 N 4 / Cu composite structure of aluminum nitride ceramics.

[0065] Example 7

[0066] This embodiment provides a method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, and the specific steps include:

[0067] Prepare an aqueous solution of urea with a concentration of 576 mg / L and spray it on the pretreated aluminum nitride ceramic surface using ultrasonic spraying. The spraying amount is controlled to gC 3 N 4The theoretical thickness is 50nm. After the solution on the surface of aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours. Then, 5μm thick copper is plated on the surface of aluminum nitride ceramic by chemical copper plating method. After drying, heat treatment is performed at 600℃ for 1 hour in a vacuum environment, and then the temperature is lowered with the furnace to obtain AlN / gC 3 N 4 / Cu composite structure of aluminum nitride ceramics.

[0068] Example 8

[0069] This embodiment provides a method for preparing an aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, and the specific steps include:

[0070] Prepare an anhydrous ethanol solution of melamine with a concentration of 1152 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 2 μm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550° C. for 5 hours, and then cooled with the furnace to obtain an aluminum nitride ceramic with a graphite-like carbon nitride film on the surface.

[0071] Example 9

[0072] This embodiment provides a method for preparing an aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, and the specific steps include:

[0073] Prepare an ethanol aqueous solution of melamine with a concentration of 576 mg / L (the volume ratio of ethanol to water is 1:1), and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 500nm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550°C for 5 hours, and then cooled with the furnace to obtain an aluminum nitride ceramic with a graphite-like carbon nitride film on the surface.

[0074] Example 10

[0075] This embodiment provides a method for preparing an aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, and the specific steps include:

[0076] Prepare an ethanol aqueous solution of melamine with a concentration of 576 mg / L (the volume ratio of ethanol to water is 1:1), and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4The theoretical thickness is 1 μm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550° C. for 5 hours, and then cooled with the furnace to obtain an aluminum nitride ceramic with a graphite-like carbon nitride film on the surface.

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing an aluminum nitride composite structure containing a graphite-like carbon nitride film, and the specific steps include:

[0079] A 576 mg / L melamine anhydrous ethanol solution was prepared and sprayed on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount was controlled to gC 3 N 4 The theoretical thickness is 90nm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550°C for 5 hours.

[0080] Comparative Example 2

[0081] This comparative example provides a method for preparing an aluminum nitride composite structure containing a graphite-like carbon nitride film, and the specific steps include:

[0082] Prepare an anhydrous ethanol solution of melamine with a concentration of 576 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 90nm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550°C for 5 hours.

[0083] Comparative Example 3

[0084] This comparative example provides a method for preparing an aluminum nitride composite structure containing a graphite-like carbon nitride film, and the specific steps include:

[0085] Prepare an anhydrous ethanol solution of melamine with a concentration of 1152 mg / L and spray it on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount is controlled to gC 3 N 4 The theoretical thickness is 120nm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550°C for 5 hours.

[0086] Comparative Example 4

[0087] This comparative example provides a method for preparing an aluminum nitride composite structure containing a graphite-like carbon nitride film, and the specific steps include:

[0088] A melamine aqueous solution with a concentration of 576 mg / L was prepared and sprayed on the pretreated aluminum nitride ceramic surface by ultrasonic spraying. The spraying amount was controlled to gC3 N 4 The theoretical thickness is 30nm. After the solution on the surface of the aluminum nitride ceramic is dried, it is moved into a tube furnace and calcined at 550℃ for 5 hours.

[0089] Comparative Example 5

[0090] This comparative example provides a method for preparing an aluminum nitride ceramic-metal composite structure, and the specific steps include:

[0091] Conductive silver paste was printed on the surface of AlN ceramic by screen printing. After the paste on the surface of aluminum nitride ceramic was dried, it was moved into a vacuum tube furnace and calcined at 500° C. for 1 hour to obtain aluminum nitride ceramic with AlN / Ag composite structure.

[0092] In summary, in practical applications, when the theoretical spraying thickness is ≥120nm, it can be determined whether to continue surface metallization after calcination according to actual needs.

[0093] Test Example 1

[0094] The scanning electron microscope photos of the aluminum nitride ceramic matrix are shown in Figure 2. Figure 1 The surface of the aluminum nitride ceramic obtained in Comparative Example 1 was subjected to microscopic morphology observation and Raman testing, and the results were as follows: Figure 1 (b) Figure 1 (c) and Figure 1 (d) as shown.

[0095] Depend on Figure 1 It can be seen that after the surface of aluminum nitride ceramics is coated with a solution containing carbon and nitrogen compounds and calcined, the surface of aluminum nitride ceramics is obviously covered with a layer of new substances, but no gC is found after Raman spectroscopy testing. 3 N 4 The characteristic peak (1348cm -1 and 1585cm -1 ), indicating that when the spraying amount is controlled within gC 3 N 4 The theoretical thickness is 90nm and no further metallization is performed on the surface. No graphite-like carbon nitride film gC is formed on the surface of aluminum nitride ceramics. 3 N 4 .

[0096] Test Example 2

[0097] The scanning electron microscope photos of the aluminum nitride ceramic matrix are shown in Figure 2. Figure 2 The surface of the aluminum nitride ceramic obtained in Comparative Example 2 was subjected to microscopic morphology observation and energy spectrum test, and the results were as follows: Figure 2 (b) Figure 2 (c) and Figure 2(d) as shown.

[0098] Depend on Figure 2 It can be seen that after the surface of aluminum nitride ceramics is coated with a solution containing carbon and nitrogen compounds and calcined, the surface of aluminum nitride ceramics is obviously covered with a layer of new substances. The energy spectrum results show that it is a substance containing carbon and nitrogen elements, but it is not gC 3 N 4 .

[0099] Test Example 3

[0100] The aluminum nitride ceramic with a composite structure obtained in Example 1 was subjected to a four-point bending test, and the microscopic morphologies of the aluminum nitride surface and the metal film surface in contact with the graphite-like carbon nitride film were observed. The scanning electron microscope photos are shown in FIG. Figure 3 (a) and Figure 3 (b) At the same time, Raman tests were performed on the aluminum nitride surface and the metal film surface in contact with the graphite-like carbon nitride film, and the results are shown in Figure 3 (c) as shown.

[0101] Depend on Figure 3 (c) It can be seen that gC was found on the aluminum nitride surface and the metal film surface in contact with the graphite-like carbon nitride film. 3 N 4 The characteristic peak (position is 1348cm -1 and 1585cm -1 ), indicating that gC was generated during the vacuum heat treatment of the silver paste 3 N 4 That is, the intermediate layer containing the graphite-like carbon nitride film obtained in this embodiment is in-situ generated between the contact surfaces of the aluminum nitride ceramic and the metal film.

[0102] Test Example 4

[0103] Raman spectroscopy tests were performed on the aluminum nitride ceramics with composite structures obtained in Comparative Examples 1 and Comparative Examples 3 to 4, and the results are as follows: Figure 4 As shown. It can be seen that when a carbonitride compound with a theoretical thickness of less than 120nm is coated on the surface of the aluminum nitride ceramic substrate, a graphite-like carbon nitride film will not be directly generated on the surface of the aluminum nitride ceramic substrate without further metallization and vacuum calcination of the surface; and when a carbonitride compound with a theoretical thickness of 120nm is coated, a graphite-like carbon nitride film can be directly generated on the surface of the aluminum nitride ceramic substrate without further metallization and vacuum calcination of the surface.

[0104] Test Example 5

[0105] The interface mechanical properties (critical fracture energy G IC , maximum interface peeling normal stress σ max and shear stress τ max ), the results are shown in Table 1 and Figure 5 shown.

[0106] Table 1

[0107]

[0108] It can be seen from Table 1 that, compared with Comparative Example 5, the comprehensive mechanical properties of the aluminum nitride ceramic with a composite structure prepared according to the preparation method provided by the present invention are significantly improved. Figure 5 It can be seen that gC 3 N 4 The in-situ formation of the layer significantly increases the interfacial mechanical properties of the metallized aluminum nitride ceramics, and the maximum interfacial fracture critical value can be increased from 13.0N to 30.33N, an increase of 133%.

[0109] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer, characterized in that the steps include: S1, coating the ethanol and / or aqueous solution of carbon nitride compounds on the surface of aluminum nitride ceramics according to the spraying amount that can obtain a graphite-like carbon nitride film with a theoretical thickness of 30nm≤δ≤120nm, and calcining at 500-600°C for 4.5-5.5h after drying; S2, drying the aluminum nitride ceramic surface composite metal slurry obtained in step S1, calcining at 500-600° C. for 0.8-1.2 h under vacuum conditions, and cooling with the furnace to obtain an aluminum nitride ceramic having an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film; The spraying amount is calculated based on the theoretical thickness of the graphite-like carbon nitride film, the total surface area of ​​the aluminum nitride ceramic to be sprayed, the density of the graphite-like carbon nitride film, and the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of carbon and nitrogen compounds.

2. The method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer according to claim 1, characterized in that: The aluminum nitride ceramic in step S1 is pre-treated as follows: the aluminum nitride ceramic is placed in an alkaline solution for ultrasonic treatment, and then washed with water and ethanol and dried to remove surface oil and impurities.

3. The method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer according to claim 1, characterized in that: The carbon-nitrogen compound includes at least one of melamine, dicyandiamide and urea.

4. The method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer according to claim 1 or 3, characterized in that: The concentration of the carbon and nitrogen compounds in the ethanol and / or aqueous solution of the carbon and nitrogen compounds is 550-1200 mg / L.

5. The method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer according to claim 1, characterized in that: In step S1, an ethanol and / or aqueous solution of carbonitride is coated on the surface of aluminum nitride ceramic by ultrasonic spraying.

6. The method for preparing an aluminum nitride / metal composite structure containing a graphite-like carbon nitride film intermediate layer according to claim 1, characterized in that: The aluminum nitride ceramic surface composite metal slurry obtained in step S1 is specifically prepared by compounding the metal slurry on the aluminum nitride ceramic surface by screen printing, chemical plating, electroplating or magnetron sputtering.

7. An aluminum nitride ceramic having an aluminum nitride / metal composite structure with an intermediate layer of a graphite-like carbon nitride film, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.

8. A method for preparing aluminum nitride ceramics having a graphite-like carbon nitride film on the surface, characterized in that the steps include: Spraying an ethanol and / or aqueous solution of a carbon nitride compound on the surface of an aluminum nitride ceramic in an amount sufficient to obtain a graphite-like carbon nitride film having a theoretical thickness of 120 nm ≤ δ ≤ 2 μm, drying the film and calcining the film at 500 to 600° C. for 4.5 to 5.5 hours to form a graphite-like carbon nitride film on the surface of the aluminum nitride ceramic; The spraying amount is calculated based on the theoretical thickness of the graphite-like carbon nitride film, the total surface area of ​​the aluminum nitride ceramic to be sprayed, the density of the graphite-like carbon nitride film, and the mass concentration of carbon and nitrogen in the ethanol and / or aqueous solution of carbon and nitrogen compounds.

9. The method for preparing the aluminum nitride ceramic with a graphite-like carbon nitride film on the surface as claimed in claim 8, characterized in that: The carbon-nitrogen compound comprises at least one of melamine, dicyandiamide and urea, and the concentration of the carbon-nitrogen compound in the ethanol and / or aqueous solution of the carbon-nitrogen compound is 550-1200 mg / L.

10. An aluminum nitride ceramic having a graphite-like carbon nitride film on its surface, characterized in that: Prepared according to the preparation method according to any one of claims 8 to 9.

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