A method for producing a ceramic / metal composite

Abstract

The application belongs to the field of welding, and discloses a preparation method of ceramic / metal composite material. The ceramic is quickly metallized by laser scanning marking on the ceramic surface, and the metallized ceramic and copper are sintered by hot isostatic pressing to prepare the ceramic / metal composite material. The problems of poor wettability of the ceramic and the metal and high preparation cost are solved, the cost is reduced by laser metal foil pretreatment on the ceramic surface, the processing time is short, the process temperature is low, and the operation is safer. In the preferred embodiment of the application, there is a transition layer with a thickness of about 6 microns, and the existence of the transition layer can well increase the bonding force of the composite material, and the peeling strength can reach 9.94 N / mm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of welding, and relates to a preparation method of ceramic / metal composite material. BACKGROUND

[0002] The composite material formed by ceramics and copper has excellent mechanical properties of ceramic material and electrical conductivity of copper, and is widely used in power devices. However, the ceramic material is mainly composed of ionic bonds and covalent bonds, while the copper is composed of metal bonds, and there is an essential difference between the atomic structures of ceramics and copper. Therefore, it is difficult to prepare the ceramic / metal composite material due to the poor wettability of the two, and it is basically impossible to directly wet and spread the copper on the surface of the ceramic material. In view of this problem, it is extremely important to combine the ceramic and copper in a suitable way.

[0003] Nowadays, adding active metal filler or metallizing the surface of the ceramic is a common pretreatment method for preparing the ceramic / metal composite material. However, the cost of adding the active metal filler is too high, and the method of metallizing the surface of the ceramic mainly includes physical vapor deposition, chemical vapor deposition, plasma method and the like, which are time-consuming and not suitable for mass industrial production. Therefore, a rapid, efficient and low-cost method is urgently needed to prepare the ceramic / metal composite material. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application provides a preparation method of ceramic / metal composite material, which solves the problems of poor wettability of ceramic and metal and high preparation cost. The ceramic surface is pretreated by laser metal foil, the cost is reduced, the processing time is short, the process temperature is low, the operation is safer, and finally the ceramic / metal composite material with high bonding strength is prepared by hot isostatic pressing sintering.

[0005] The above object of the present application is achieved by the following technical scheme:

[0006] The preparation method of the ceramic / metal composite material comprises the following steps: the ceramic surface is quickly metallized by laser scanning marking, and the ceramic after metallization is combined with copper by hot isostatic pressing sintering to prepare the ceramic / metal composite material.

[0007] Further, the specific steps of the above method are as follows:

[0008] S1. Put the cleaned ceramic substrate on the workbench, cover a layer of metal foil on the surface, draw the pattern of the corresponding metallization area on the laser parameter control software of the optical fiber laser, set the laser parameters, start marking, and complete the metallization of the ceramic surface after marking.

[0009] S2. Put the metalized ceramic and copper into a package material for vacuum packaging. Put the vacuum packaged sample into a hot isostatic pressing sintering furnace for sintering, so that the metalized ceramic and copper are tightly combined. After sintering, take out the sample, and finally prepare a ceramic / metal composite material.

[0010] Further, the ceramic in step S1 can be any one of Si3N4, AlN or other ceramic materials, with a thickness of 0.30-1.00 mm; the metal foil can be any one of copper or nickel, with a thickness of 0.01-0.03 mm.

[0011] Further, the ceramic substrate in step S1 needs to be ultrasonically cleaned in anhydrous ethanol and acetone for 10 minutes respectively, then rinsed with deionized water, and finally dried with a hair dryer.

[0012] Further, the optical fiber laser parameter control software in step S1 is EZCad2.5.3.

[0013] Further, the pattern of the metalized area in step S1 is adjusted according to the actual size of the ceramic substrate, which can be set to a circle, a rectangle or other shapes; click the fill button to set the scanning line spacing.

[0014] Further, the laser parameters in step S1 are as follows: the power of the fiber laser is 700-900 W, the scanning speed is 50-80 mm / s, and the scanning spacing is 0.03-0.05 mm.

[0015] Further, the package material in step S2 can be any one of nickel foil, titanium foil or low-temperature steel, with a thickness of 0.1-0.15 mm; the copper thickness is 0.1-5.0 mm.

[0016] Further, the vacuum packaging in step S2 is to put the metalized ceramic and copper into the package material, and through vacuum pumping, the vacuum degree is reduced to 10 -3 Pa or below.

[0017] Further, the hot isostatic pressing sintering in step S2 is to put the successfully packaged sample into a hot isostatic pressing sintering furnace for sintering. The sintering process is as follows: ① increase the temperature from 25℃ to 600-700℃ at a rate of 5-10℃ / min, increase the pressure to 80-100 MPa, and maintain for 20-30 min, then increase the temperature to 750-900℃ at a rate of 3-5℃ / min, and increase the pressure to 120-200 MPa; ② maintain at the highest temperature and pressure for 15-30 min; ③ decrease the temperature to 300-400℃ at a rate of 5-10℃ / min; ④ decrease to room temperature with the furnace.

[0018] Further, the furnace cover is opened, the sample is taken out, and the package is cut off to obtain a ceramic / metal composite material.

[0019] The present application has the following advantages compared with the prior art:

[0020] The present application provides a preparation method of ceramic / metal composite material, which comprises the following steps: covering a metal foil on the surface of a ceramic substrate, performing laser scanning etching to make the metal foil deposit on the surface of the ceramic to realize the metallization of the ceramic; vacuum packaging the ceramic and copper together; and putting the vacuum packaged sample into a hot isostatic pressing sintering furnace to sinter the metallized ceramic and copper to prepare the ceramic / metal composite material. The present application can apply laser to generate a large amount of energy instantaneously and quickly, the metal foil absorbs the energy, and the metal particles are deposited on the surface of the ceramic as the laser beam is deposited on the surface of the ceramic. Since the scanning speed is extremely fast, the coagulation time of the metal particles is short, which leads to the adhesion phenomenon between the particles. Therefore, the molten metal is coated on the surface of the ceramic, which effectively improves the wettability of the ceramic surface. The poor wettability of the metal and the ceramic is well relieved, and the bonding strength of the ceramic / metal composite material is significantly improved.

[0021] The preparation method of the present application realizes the metallization of the ceramic surface at room temperature, improves the surface wettability, reduces the cost, realizes the close combination of the ceramic and the copper, increases the wettability of the ceramic and the copper, and prepares the ceramic / metal composite material with high bonding strength through hot isostatic pressing sintering. In the preferred embodiment of the present application, there is a transition layer with a thickness of about 6 μm. The existence of the transition layer can well increase the bonding force of the composite material, and the peeling strength can reach 9.94 N / mm, which is much higher than that of the prior art. After 50 thermal cycles, the combination of the copper layer and the ceramic layer is still very close, which indicates that the combination of the ceramic after surface metallization and the copper can well relieve the thermal stress and prolong the service life. BRIEF DESCRIPTION OF DRAWINGS

[0022] The present application will be further described below in combination with the drawings and examples:

[0023] Figure 1 The XRD patterns of the ceramic surface before and after copper metallization according to Example 1 of the present application.

[0024] Figure 2 The SEM pattern of the ceramic surface after copper metallization according to Example 1 of the present application.

[0025] Figure 3 The SEM pattern of the ceramic / metal composite material prepared according to Example 1 of the present application.

[0026] Figure 4 The line scanning energy spectrum pattern of the ceramic / metal composite material prepared according to Example 1 of the present application; wherein Fig. (a) is the SEM pattern, and Fig. (b) is the energy spectrum pattern of the line passing through the area of Fig. (a).

[0027] Figure 5SEM image of the ceramic / metal composite material of Inventive Example 3. DETAILED DESCRIPTION

[0028] The application will be described in greater detail by specific examples, but the scope of the application is not limited by the examples. Unless otherwise specified, the experimental methods used in the application are conventional methods, and the experimental apparatus, materials, reagents, etc. used can be obtained from commercial sources.

[0029] Example 1

[0030] A method for preparing a ceramic / metal composite material, the specific steps are as follows:

[0031] S1. Select Si3N4 ceramic with a size of 10x10x0.35mm 3 , place a layer of copper foil with a size of 10x10x0.02mm 3 on the surface; open the EZCad2.5.3 software to draw the pattern of the required laser parameter marking, click the fill button, set the laser parameters, the laser power is 900W, the scanning speed is 60mm / s, and the scanning interval is 0.03mm.

[0032] S2. Turn on the power of the fiber laser, click the red light display, place the ceramic and copper foil on the workbench, align the laser focal length with the ceramic metallization area, click the marking button to start laser processing, and the marking is completed when the marking is completed.

[0033] S3. Put the metallized ceramic and 10x10x0.20mm 3 copper into a circular titanium foil with a diameter of 125mm and a thickness of 0.10mm for vacuum packaging, and reduce the vacuum degree to below 10 -3 Pa.

[0034] S4. Put the vacuum packaged sample into a hot isostatic pressing sintering furnace for sintering, the sintering process is: heat from 25℃ to 600℃ at 10℃ / min, pressurize to 100MPa, keep for 20min, then heat to 750℃ at 5℃ / min, pressurize to 150MPa; keep at the highest temperature and pressure for 30min; decrease to 300℃ at 5℃ / min; finally decrease to room temperature at 10℃ / min.

[0035] S5. Open the furnace cover, take out the sample, and cut off the packaging to obtain the ceramic / metal composite material.

[0036] After the peel strength test, the peel strength is 9.94N / mm.

[0037] Comparative Example 1

[0038] Comparative Example 1 differs from Example 1 in that the copper foil used for surface metallization has a thickness of 0.001 mm, the laser power for setting the laser parameters is 600 W, the scanning speed is 100 mm / s, and the scanning pitch is 0.02 mm. The rest is the same as Example 1.

[0039] After measurement: the peel strength is 1.16 N / mm.

[0040] Comparative Example 2

[0041] Comparative Example 2 differs from Example 1 in that the hot isostatic pressing sintering process is: direct heating to 750°C, and pressurizing to 150 MPa; keeping at the highest temperature and the highest pressure for 30 min; decreasing to 300°C at a rate of 5°C / min; and finally decreasing to room temperature at a rate of 10°C / min. The rest is the same as Example 1.

[0042] After measurement: the peel strength is 2.41 N / mm.

[0043] Comparative Example 3

[0044] Comparative Example 3 differs from Example 1 in that the Si3N4 ceramic surface is not laser metallized. The rest is the same as Example 1.

[0045] The comparison between the comparative examples and the preferred embodiments of the present application is as follows:

[0046]

[0047]

[0048] The above-described embodiments are merely preferred embodiments of the present application, and are not all the embodiments that can be implemented by the present application. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present application should be considered to be within the scope of the claims of the present application.

Claims

1. A method for preparing a ceramic / metal composite material, characterized in that, The specific steps of the method are as follows: S1. Place the cleaned ceramic substrate on the worktable, cover its surface with a layer of metal foil, draw the corresponding metallization area pattern on the laser parameter control software of the fiber laser, set the laser parameters, start marking, and the metallization of the ceramic surface is completed after the marking is finished. S2. The metallized ceramic and copper are placed in a cladding material for vacuum cladding. The vacuum-clad sample is then placed in a hot isostatic pressing furnace for sintering to ensure that the metallized ceramic and copper are tightly bonded. After sintering is complete, the sample is removed, and a ceramic / metal composite material is finally prepared. The laser parameters in step S1 include a fiber laser power of 700~900W, a scanning speed of 60mm / s, and a scanning spacing of 0.03~0.05mm. The sheathing material in step S2 is selected from any one of nickel foil, titanium foil, and low-temperature steel, with a thickness of 0.1~0.15mm; the copper thickness is 0.1~5.0mm. The hot isostatic pressing sintering in step S2 involves placing the successfully encapsulated sample into a hot isostatic pressing sintering furnace for sintering. The sintering process is as follows: ① Increase the temperature from 25°C to 600-700°C at a rate of 5-10°C / min, increase the pressure to 80-100MPa, hold for 20-30 minutes, then increase the temperature to 750-900°C at a rate of 3-5°C / min, and increase the pressure to 120-200MPa; ② Hold at the highest temperature and pressure for 15-30 minutes; ③ Decrease the temperature to 300-400°C at a rate of 5-10°C / min; ④ Decrease the temperature to room temperature with the furnace.

2. The method for preparing a ceramic / metal composite material as described in claim 1, characterized in that, The ceramic in step S1 is any one of Si3N4, AlN or other ceramic materials, with a thickness of 0.30~1.00mm; the metal foil is any one of copper or nickel, with a thickness of 0.01~0.03mm.

3. The method for preparing a ceramic / metal composite material as described in claim 2, characterized in that, The ceramic substrate in step S1 needs to be ultrasonically cleaned in anhydrous ethanol and acetone for 10 minutes each, then rinsed with deionized water, and finally dried with a hair dryer.

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