JPS6337077B2 - - Google Patents

Description

[Detailed description of the invention]

Purpose of the Invention [Field of Industrial Application] The present invention relates to metal film laminated ceramics, and more specifically to metal film laminated ceramics that exhibit high durable adhesion between metal films and ceramics even when subjected to external force or thermal strain. It concerns ceramics. [Prior Art] Ceramics generally have excellent heat resistance, thermal shock strength, mechanical strength at high temperatures, abrasion resistance, or high insulation properties, and are therefore suitable as members used under severe conditions. However, in reality, ceramics are rarely used alone, and in mechanical parts using ceramics, they are used together with other materials, such as metals, to perform their functions. However, when attempting to join ceramics and metal, it is difficult to join them directly, so the method is to first metallize the surface of the ceramic using a certain method and then join the desired metal member. It's here. This method involves screen-printing a metallizing paste on the surface of the ceramic and then heating it in a non-oxidizing atmosphere, or placing highly active metals (Ti, Zr) on the surface of the ceramic in a vacuum container or in an inert atmosphere. Physical vapor deposition methods have been used, such as an activated metal method in which metal is heated in a vacuum, or a method in which metal is ignited in a vacuum and the vapor generated at that time is deposited. [Problems to be Solved by the Invention] However, simply laminating a metal layer on ceramics as described above, for example, using a high melting point metal method using molybdenum and manganese, does not allow the metal to form a layer. For example, when the ceramic is silicon nitride, this metal layer cannot obtain sufficient adhesion strength because there is very little oxide in the ceramic that forms a reactive phase with molybdenum-manganese. The active metal method also has the same drawbacks as the refractory metal method. In addition, even if a metal layer is formed by physical vapor deposition, when attaching other metal members to this vapor-deposited metal layer, if high-temperature brazing such as silver brazing is used, depending on the metal to be vapor-deposited, Heat diffusion occurred, resulting in a decrease in adhesive strength with ceramics. Furthermore, when the ceramic is zirconium oxide, its thermal expansion is larger than that of the silicon nitride material mentioned above, and since it is an oxide, it can be expected that sufficient adhesion strength can be obtained by the high melting point metal method, but the composition of the ceramic Due to the difference in the adhesive strength, some adhesives were not able to obtain sufficient adhesive strength. Even when sufficient adhesion strength was obtained, sufficient reliability in adhesion of the metal layer could not be obtained when repeated heat treatments were applied. Although it is necessary to laminate a metal film with sufficient adhesion strength on the ceramic surface in order to bond ceramic parts to metal parts by brazing etc., Due to differences in expansion rates, there was no one that could withstand all conditions. Structure and Effects of the Invention In view of the above-mentioned problems, the present inventors completed the present invention as a result of intensive research in order to realize a versatile metal film laminated ceramic that can withstand a wide range of usage conditions. [Means and effects for solving the problem] That is, the gist of the first invention is to provide a ceramic material made of one or two selected from titanium and zirconium formed on the surface of ceramics by physical vapor deposition. a second metal layer made of one or more selected from chromium, molybdenum, and tungsten formed by physical vapor deposition on the first metal layer;
having a metal layer and a third metal layer made of one or two selected from silver and copper formed by physical vapor deposition or chemical plating on the metal layer and the second metal layer; The gist of the second invention lies in the metal film laminated ceramics characterized by a first metal layer made of one or two selected from titanium and zirconium formed on the surface of the ceramic by a physical vapor deposition method; A second metal layer made of one or more selected from chromium, molybdenum, and tungsten formed on the first metal layer by physical vapor deposition, and formed on the second metal layer by physical vapor deposition. A third metal layer consisting of one or two selected from nickel and palladium, and one or two selected from silver and copper formed on the third metal layer by physical vapor deposition or chemical plating. A metal film laminated ceramic is characterized in that it has a metal film composed of a fourth metal layer made of two types. Ceramics include all known ceramics such as silicon nitride, zirconia, alumina, and silicon carbide. A general known method is used for the physical vapor deposition method,
Examples include vacuum evaporation, ion beam evaporation, sputtering, etc., and these methods have the characteristic that the material and film thickness can be selected freely.
Further, as the chemical plating method that can be used for the uppermost layer, a general known method can be used, such as an electrolytic plating method, an electroless plating method, and the like. Titanium and zirconium, which are the first layer metals in contact with the ceramics, are highly active metals and react well with nitrogen and oxygen in the ceramics to form an intermediate layer of nitride or oxide. Therefore, the first layer has the effect of strongly adhering to ceramics. The thickness of the first layer is usually set to 500 to 5000 Å, and preferably 1000 to 2000 Å from the viewpoint of thermal shock resistance. If the thickness of the first layer is less than 500 Å, the difference in thermal expansion between the ceramic and the other layer or the metal member bonded to the top layer will not be alleviated, leading to a decrease in bond strength.
If the thickness exceeds 5000 Å, the influence of the difference between the thermal expansion of the first layer itself and the ceramic will appear, resulting in a decrease in adhesive strength. The second layer metals, chromium, molybdenum, and tungsten, have thermal expansion coefficients of 5.5 to 8.4 × 10 ^-6 /°C, which are relatively close to the thermal expansion coefficients of ceramics, which are 2.9 to 12 × 10 ^-6 / °C, and buffer thermal shock. It is effective as a material and has a high degree of activity, so it also has an auxiliary effect on the adhesion of the first layer. In addition, when this metal film laminated ceramic is joined to other metal members, brazing is performed using eutectic silver solder, but at such high temperatures, the third layer metal or the top layer in the first invention In the second invention, the second layer also has the effect of preventing adhesion from decreasing due to thermal diffusion of the third layer metal reaching the first layer. The above description of the first and second layers is common to the first invention and the second invention. Next, silver and copper, which are the third layer metals of the first invention, have particularly good malleability, and when the laminated ceramics of the invention is applied, they have the effect of alleviating the difference in thermal expansion between this layer and the mating member to be joined. Therefore, the thicker this layer is, the better, but it also depends on the sample shape.
The thickness is preferably 1 μm or more, and it is further preferable to increase the thickness in proportion to the difference in coefficient of thermal expansion of the metal member to be bonded to the laminated ceramic of the present invention, so that the ability to absorb strain due to the difference is improved. In addition to the physical vapor deposition method, this third layer can also be formed by chemical plating methods such as the electrolytic plating method and electroless plating method described above to produce the same effect, but from the viewpoint of adhesion strength with the second layer, Physical vapor deposition is preferred. As described above, the first invention includes, from the ceramic side, a first layer selected from titanium and zirconium, a second layer selected from chromium, molybdenum, and tungsten, and a third layer selected from silver and copper. However, the second invention has a structure in which a layer selected from nickel and palladium is provided between the second and third layers of the first invention. That is, in the second invention, from the ceramic side, the first layer is selected from titanium and zirconium, the second layer is selected from chromium, molybdenum, and tungsten, the third layer is selected from nickel and palladium, and the third layer is selected from silver and copper. The fourth layer is selected from the following. Of these four layers, the first layer, second layer, and fourth layer correspond to the first layer, second layer, and third layer of the above-mentioned first invention, and their contents are also exactly the same. Explaining the third layer selected from nickel and palladium of the second invention, this layer has the effect of improving wettability for silver soldering etc. even though it is covered with the fourth layer, and has a thick layer. Usually 500~
It is formed to a thickness of 5000 Å, but considering the decrease in adhesion strength due to the difference in thermal expansion coefficient with other layers, it is preferably 1000 to 2000 Å. If it is less than 500 Å, the wettability effect is weak;
When the thickness exceeds 5000 Å, the adhesion strength decreases rapidly.
This layer also has the effect of preventing the second layer from becoming brittle due to oxidation when the layer above it, that is, the fourth layer, is formed by chemical plating. [Effects of the Invention] With the structure as described above, the metal film laminated ceramic of the first invention has the metal film itself firmly attached to the ceramic, has durability against severe thermal shock, and furthermore Even if another metal member is attached to the ceramic member by brazing or the like, it absorbs distortion due to the difference in thermal expansion coefficient between the metal member and the ceramic and maintains high adhesion. In addition, in the second invention, in addition to producing the same effects as in the first invention, the presence of the third layer selected from nickel and palladium improves the wettability of silver brazing, etc., resulting in higher adhesion. At the same time, it prevents oxidation of the second layer during chemical plating and produces a stronger adhesion effect. The metal film laminated ceramics according to the first and second inventions can be used as parts of insulating heat dissipation fins for transformers to join the transformer body and metal fins, and can be used for automobiles as heat resistant parts. The metal film itself can be effectively used as a conductive layer, and can be used as a wear-resistant part, or as a part to make various machines lighter, more heat resistant, and more wear resistant. [Example] Next, the present invention will be specifically described based on Examples. First, the first invention will be explained using Example 1. Example 1 After pressure molding and firing ceramics, the surface on which the metal film was to be formed was polished. Thereafter, a cleaning process was carried out including washing with a neutral detergent and pure water, then replacing water with acetone, and drying with 1,1,1-trichloroethane and acetone. This cleaned ceramic was used as a substrate and placed in the vacuum chamber of a vacuum evaporation machine (EBV-6DH manufactured by Japan Vacuum Technology Co., Ltd.), and the internal pressure was reduced to 10 ^-6 Torr level to 300
℃ and melt-deposited titanium or zirconium, chromium or molybdenum or tungsten, and silver or copper in this order using an electron beam to form a three-layer metal film on the ceramic. Next, the second invention will be explained in Example 2. Example 2 A cleaning process was performed on ceramics in the same manner as in Example 1. Next, set it in a similar vacuum chamber,
Under similar conditions, titanium or zirconium, chromium or molybdenum, nickel or palladium, and copper were deposited in this order to form a four-layer metal film. Comparative Example 1 for Examples 1 and 2 above is a two-layer metal film in which the first layer is titanium and the second layer is copper, which is known as a conventional ceramic surface metallization method. formed on the surface. In Examples 1 and 2 and Comparative Example 1, the following adhesion strength test was conducted by changing the type of ceramic, the type or thickness of the metal layer. The test results using the test pieces of Example 1 and Comparative Example 1 were
Table 2 shows the test results using the test piece of Example 2. Adhesion strength test As shown in the front view of Fig. 1, the above Examples 1 and 2
Or ceramics 1 manufactured according to comparative example
A silver ingot 4 was bonded to the surface of the upper metal film 2 using a silver solder 3 to produce a test piece. However, ceramics 1
The dimensions of the silver ingot 4 were 15 mm x 15 mm x 5 mm, and the thickness of the silver solder 3 was set to 0.03 mm. After fixing the silver ingot 4 side of the thus produced test piece to a jig, force was applied from the side of the ceramic 1 to measure the adhesion shear strength of the metal film 2. or,
Separately, the adhesive shear strength of the test piece after a heat treatment test of 600°C x 2 hours → 25°C x 2 hours was similarly measured. Example 3 In the same manner as in Example 1, titanium, molybdenum, and copper were deposited in this order on the surface of alumina ceramics, and then copper was plated using a chemical plating method to form a three-layer metal film. In contrast to Example 3, as Comparative Example 2, a metal film of molybdenum-manganese was formed on the surface of alumina ceramics using a refractory metal method. A repeated heat treatment durability test was conducted for the above Example 3 and Comparative Example 2, and the results are shown in Table 3. Repeated heat treatment durability test As shown in the cross-sectional view of Figure 2, a pin 5 was bonded to the surface of the metal film 2 on the ceramic 1 manufactured in Example 3 or Comparative Example 2 using silver solder 3, and a test piece was was produced. After that, the above test piece was
5. Heating at 500℃ for 10 minutes and then cooling to room temperature.
Executed times. The pin 5 of the thus produced test piece and the ceramic 1 were fixed with a jig and a tensile load was applied to measure the adhesion tensile strength of the metal film 2.

【table】

【table】

【table】

[Table] Written.
As shown in the results shown in Table 1, the test pieces of samples No. 1 to 7, 9, 10, 12, and 13 of the example of the first invention had a metal film on the ceramic to a greater extent than the other samples. It was found that it adhered firmly and showed high durability against heat treatment. Further, as shown in the results shown in Table 2, in the test pieces of samples Nos. 21 to 28 of the example of the second invention, the metal film was very firmly adhered to the ceramic. Furthermore, it can be seen that the durability against heat treatment is even higher than that of Example 1, as the difference between the shear strength at room temperature and the shear strength after heat treatment is small. Furthermore, as shown in the results shown in Table 3, the test piece of sample No. 29 of the example of the first invention had very excellent adhesive strength even when subjected to repeated heat treatments.
The tensile strength was 5.8 times higher than that of the comparative example using the high melting point metal method.

[Brief explanation of the drawing]

FIG. 1 shows a front view of a test piece for a shear strength test, and FIG. 2 shows a cross-sectional view of a test piece for a tensile strength test. 1... Ceramics, 2... Metal film, 3... Brazed part, 4... Silver ingot, 5... Pin.

Claims (1)

[Scope of Claims] 1. A first metal layer made of one or two selected from titanium and zirconium formed on the surface of ceramics by physical vapor deposition, and formed on the first metal layer by physical vapor deposition. a second metal layer made of one or more selected from chromium, molybdenum, and tungsten; and a second metal layer selected from silver and copper formed on the second metal layer by physical vapor deposition or chemical plating. A metal film laminated ceramic characterized by having a metal film composed of a third metal layer made of one or two types. 2. A first metal layer made of one or two selected from titanium and zirconium formed on the surface of the ceramic by physical vapor deposition, chromium and molybdenum formed on the first metal layer by physical vapor deposition, A second metal layer made of one or more selected from tungsten, and a third metal layer made of one or more selected from nickel and palladium formed on the second metal layer by physical vapor deposition. layer and a fourth metal layer made of one or two selected from silver and copper formed by physical vapor deposition or chemical plating on the third metal layer. Metal film laminated ceramics.