JPH0475871B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for joining ceramics to ceramics or ceramics to metal by brazing. [Prior Art] Recently, ceramic materials have begun to be used in a wide range of fields as structural materials due to their excellent properties. In most cases, ceramics are used alone, but due to the brittleness of ceramics, it is sometimes necessary to combine them with tough metals. Furthermore, in order to make ceramics with complex shapes, a brazing material is needed to join the ceramics together. By the way, the following method has been known as a method for joining ceramics. Powder mainly composed of Mo and W is applied to the surface of the ceramic base material and heated to 1400 to 1700 in a reducing atmosphere.
A method in which a metallized layer is formed on a ceramic base material by heating to ℃, and then Ni plating is applied, and then metal and ceramic are joined using silver solder, or ceramics that have been similarly metallized and Ni-plated are joined together. A method of joining metals and ceramics that are joined via Pt, Au, etc. placed on the surface of the ceramic base material, facing each other, and then applying pressure from one side to join them at an appropriate high temperature. Ceramic is coated with a mixed powder of copper sulfate and kaolin, heated and baked at 900-1300℃ in an oxidizing atmosphere, the baked layer is reduced, and silver solder etc. applied on the reduced layer is used to coat other metal parts. How to join with. A method in which a combination of copper foil and titanium foil is placed between ceramics or ceramics and metals for bonding, and soldered at eutectic temperature in a vacuum atmosphere (see US Pat. No. 2,857,663). A method of bonding ceramics metallized with a foil of 30 μm or less thick consisting of a transition metal consisting of at least one of Cu, Fe, and Ni and at least one of Ti, Zr, Y, and Hf (Unexamined Japanese Patent Publication No.
60-32648). The reason why the thickness was kept below 30 μm using this method is that cracks would occur in the ceramic after metallizing. However, in the case of this method, there are disadvantages in that the working steps are as long as four and complicated, and in addition, there is a disadvantage in that the heating temperature is high. In the case of method 2, it is possible to join by a simple method called pressure welding, but it is not economical because it requires intervening an expensive precious metal between the parts to be joined, and it is difficult to ensure sufficient contact between the metal base material and the ceramic base material. The drawback is that high pressure is required for the process, making it difficult to join the complex shapes. The advantage of this method is that the pretreatment is simple because it can be carried out in the atmosphere. However, stress occurs between the ceramic and the objects to be joined due to subsequent silver brazing, etc. Although the apparent shear strength exceeds 5 kg/mm ² , minute cracks have occurred in the joint, and the airtightness has deteriorated. There are no drawbacks. This method is called active metal brazing and is known as a method that facilitates the joining of ceramics. However, in the case of ceramics called fine ceramics such as silicon nitride, this method was effective for oxide ceramics. Even if this method is used, it is difficult to obtain high bonding strength. In the case of the method,
The process becomes longer because a metallizing process is required. [Problems to be Solved by the Invention] In the above-mentioned conventional method, a brazing material is used in the method, but the joining of ceramics is not performed only with a brazing material. The method of , does not involve joining using brazing metal. , is a soldering method. However, as seen in the disclosure of 2007, when joining metal and ceramic or ceramic to ceramic, cracks were generated in the ceramic part due to thermal stress at the soldering interface, which was a problem. The method of solving this problem assumes metallization in a vacuum or an inert atmosphere. The present inventor investigated various factors that influence the bonding strength of ceramics bonded using foil manufactured by the liquid quenching method, and found that a direct brazing filler metal (i.e., a metallization process) using thick foil as a brazing filler metal was used. We have found that high bonding strength can be obtained by the omitted brazing method. Therefore, it is an object of the present invention to solve the above-mentioned problems by changing the metal structure of the brazing material and the thickness of the foil, and to provide a brazing joining method suitable for joining ceramics to ceramics and ceramics to metals. [Means for solving the problem] The present invention provides Cu40 to 70 atom%, Ti30 to 60 atom%,
At least one of Ni, Co, and Fe is 0.5 to 15 atomic%
The present invention provides a method for joining ceramics, which is characterized in that ceramics are joined without metallization using an amorphous or microcrystalline alloy foil strip having a thickness of 40 μm or more as a brazing material. The constituent elements of the present invention will first be explained with respect to the composition of the alloy foil. Ti is an element that has a high affinity with oxygen, nitrogen, etc., and reacts with O, N, etc. of ceramics to form a bonding layer. If Ti is less than 30 atomic% (24.4% by weight), it will be difficult to manufacture an amorphous amorphous foil strip, and if it exceeds 60 atomic% (53.1% by weight), TiN etc. will form at the joint.
After the Ti compound is formed, the amount of Ti remaining in the solder joint increases. In this case, a stress load remains in the ceramic after soldering, which may cause cracks, which is not preferable. The optimal Ti content is
It is 30-45 atom%. Ti, an active metal, has a high melting point (1720°C) and is unsatisfactory as a normal brazing material as it is, but when alloyed with Cu, it is lowered by several hundred degrees Celsius in its eutectic composition region, and Ti ₂₃ Cu At ₇₇ it will be about 880℃. Utilizing this fact, TiCu alloy can be used as a soldering material that can be used to interpose active metals between ceramics or to join ceramics and metals. To bring about this effect, 40 to 70 atom% (46.9 to 75.6
(wt%) of Cu is required. Further, in order to make a Cu-Ti binary amorphous or microcrystalline alloy, a Cu content of 40 to 70 atomic % is required. At least one of Fe, Ni, and Co is a nitride reaction layer formed at the ceramic interface during brazing,
It is an element that contributes to improving the bonding strength by controlling the development of the silicide reaction layer and the oxide reaction layer. In the inventor's experiments, in the case of joining Al ₂ O ₃ and Al ₂ O ₃ , the shear strength was 10 Kg/mm ² for the Cu ₅₀ Ti ₅₀ brazing filler metal, but the shear strength was 10 Kg/mm 2 for the Cu ₄₅ Ti ₄₅ Ni ₁₀ . Stage strength 15
Kg/mm ² was obtained, and the remarkable effect of Ni on improving shear strength became clear. By the way, it is known that Cu-Ti binary alloy becomes amorphous near the eutectic composition, but the inventor's experiments revealed that a fairly large amount of
It was found that even when Fe, Ni, and Co were added, an amorphous or nearly amorphous microcrystalline structure could be obtained. Therefore, if the amount of Ni, Co, or Fe added is less than 0.5 atom%, there is no effect of improving the bonding strength, while if it exceeds 15 atom%, a normal crystal structure will result. did. In addition, when two or more types of Ni, Co, and Fe are added, the amount is the total amount added. Next, the foil dimensions and metal structure, which are other constituent elements of the present invention, will be explained. The shape of the brazing material in the prior art was the same foil shape as in the present invention, but it was a combination of copper foil and titanium foil, so it was difficult to melt each metal component quickly and uniformly. Since the brazing material of the present invention is an alloy foil, each component can be melted quickly and uniformly. The foil of the prior art has a thickness of 30 μm or less and cannot prevent the occurrence of cracks, but in the present invention, the structure of the alloy foil is amorphous or microcrystalline, so it is uniform, and therefore no cracks occur. A condition is established that makes it possible to manufacture bonded ceramics with high bonding strength. Here, the term "microcrystal" refers to a crystal structure obtained by ultra-quenching with a grain size of .mu.m or less on the order of angstroms. foil thickness
The reason why the thickness is set to 40 μm or more is that if the thickness is less than 40 μm, the bonding strength tends to decrease and cracks may occur. That is, a foil thickness of 40 μm or more is a condition for obtaining ceramics with high bonding strength. The preferred upper limit of the thickness is 80 μm. Such a foil is obtained by ultra-quenching a molten alloy having a predetermined composition by a single roll method or a twin roll method. Next, the constituent elements of the joining operation in the present invention will be explained. The alloy foil as described above is sandwiched between the members to be joined, and the alloy foil is melted and brazed. Heating at this time must be done in a vacuum or in an activated gas atmosphere. In the present invention, since the alloy foil is amorphous or microcrystalline, melting progresses uniformly, and because the foil is thick, the brazing alloy remaining between the parts to be joined is able to absorb stress during solidification of the brazing filler metal. Unconventional brazing development, which is probably due to improved wettability with ceramic, has made it possible to perform direct brazing without causing defects such as cracks in the ceramic even after bonding. [Example] The present invention will be further described below with reference to Examples. Example 1 An alloy consisting of 45% Cu, 45% Ti, and 10% Ni (atomic %) was melted in an arc furnace to form an ingot. The ingot was loaded into a #30 transparent quartz tube to a height of 60 mm. The quartz tube is compressed flat at the lower end and has a width of 20 mm.
mm and had a slit-like opening with an inner diameter of 0.5 m/m. An amorphous production device called a single roll,
The quartz tube was set on top of a cooling roll with a roll diameter of 500 mm and a roll width of 50 mm, and after melting to a temperature 100°C higher than the melting point, the molten metal was sprayed onto a cooling roll rotating at a circumferential speed of 30 m/sec to a thickness of 50 μm. Width 20mm
A foil strip with a length of 10 m was obtained. This foil strip is 10mm in diameter.
A disk-shaped Al ₂ O ₃ with a thickness of 5 mm, a diameter of 20 mm, and a thickness of 5 mm.
was sandwiched between disk-shaped Al ₂ O ₃ and charged into a heating furnace. The bonding conditions are vacuum (10 ^-4 Torr)
It was soaked at 1050°C for 30 minutes and no pressure was applied. The shear strength of the brazed member was measured by the method shown in FIG. In the figure, 1 is a pressure jig, 2 is a setting jig, 3, 4
is a ceramic conjugate. The shear strength of the bonded Al ₂ O ₃ was 15 Kg/mm ² . Example 2 Using the same treatment as in Example 1, tests were conducted to determine whether or not a foil strip having the composition shown in Table 1 could be produced and to test its bonding. In addition, compositions for which it was impossible to produce foil strips were tested as powdered brazing filler metals.

【table】

[Table] From Table 1, it is composed of 30-60% Ti, 0.5-15 atomic% of one or more of Ni, Co, and Fe, and the balance Cu, and the thickness is 40μ.
High bonding strength can be achieved by using liquid quenched foil of m or more.
It can be seen that a Si ₃ N ₄ , Al ₂ O ₃ , SiC bonded body is obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a shear strength test method. 1... Pressure jig, 3, 4... Ceramic bonded body.

Claims (1)

[Claims] 1 Cu40~70 at%, Ti30~60 at%, Ni・
It is characterized by using an amorphous or microcrystalline alloy foil containing 0.5 to 15 atomic percent of at least one of Co and Fe and having a thickness of 40 μm or more as a brazing material to join ceramics without metallization. A method for joining ceramics.