Sealed ceramic component and method of producing the same

Abstract

To provide a sealed ceramic component of excellent cost-performance and method of producing the same.SOLUTION: In a sealed ceramic component formed by bonding a ceramic component and a metal component with an active metal brazing material according to the embodiment of the present invention, a chamfered section formed between an end face and an outer peripheral face of the ceramic component and the metal component are bonded to each other with an active metal brazing material. A method of producing a sealed ceramic component formed by bonding a ceramic component and a metal component, comprises a step of preparing the ceramic component by forming a chamfered section on an outer side of an end face thereof, a printing step of printing / drying paste of an active metal brazing material on the chamfered section to obtain a printed component, and a bonding step of bonding the metal component placed on the printed component by applying a heat treatment thereto.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments generally relate to a ceramic sealed component (hereinafter referred to as a ceramic sealed component) in which a ceramic component and a metal component are joined together, such as for use in electric power pipes. [Background technology]

[0002] Ceramic sealed components for magnetrons, power tubes, and electron tubes are typically made by forming a metallized layer primarily composed of a high-melting-point metal such as molybdenum (Mo) on a ceramic component such as alumina (aluminum oxide: Al2O3). By bonding the ceramic and metal together and sealing the interior of the component airtight, ceramic sealed components can protect the interior from the external environment and provide electrical insulation through the ceramic. For example, a cylindrical ceramic sealed component is made of sintered alumina. A metallized layer primarily composed of molybdenum is formed on the ring-shaped upper and lower end surfaces of the cylindrical ceramic component. A nickel (Ni) layer of a predetermined thickness is then formed on the surface of this metallized layer to improve bonding strength and seal with other metal components. This nickel portion is then joined to the cylindrical metal component using silver solder (e.g., BAg-8).

[0003] As a ceramic sealed component, an electron tube with a vacuum airtight structure has been disclosed in which a molybdenum metal surface is formed on a ceramic cylindrical body and an iron metal cylindrical body is joined with a brazing material (Patent Document 1). According to Patent Document 1, by replacing the metal cylinder from Kovar with iron, it is possible to manufacture a low-cost electron tube.

[0004] Also, a vacuum switch outer tube has been disclosed in which a nickel-based alloy is bonded to ceramics using an active metal, without using a high-melting-point metal such as molybdenum (Patent Document 2). According to Patent Document 2, it is possible to manufacture a vacuum switch outer tube with high bonding strength without forming intermetallic compounds that cause the bond to become unstable.

[0005] Furthermore, compression sealing has been disclosed as a manufacturing method for ceramic sealing components (Patent Document 3). According to Patent Document 3, a sealing component with high vacuum airtightness can be manufactured by fitting a metal ring and a window material together and compressively sealing them. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Application No. 1-46978 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-220253 [Patent Document 3] Patent Application No. Hei 1-206163 Summary of the Invention [Problem to be solved by the invention]

[0007] Compression sealing involves joining a metal part with large thermal expansion around a ceramic part with small thermal expansion, and as the metal part cools during joining, it contracts and acts on the ceramic part, resulting in a strong seal. However, because the metal part expands more than the ceramic part when heated during joining, the dimensional precision and tolerances of the parts and jigs become stricter, and the manufacturing method is complicated.

[0008] Furthermore, when metallizing the ceramic surface with a high-melting point metal such as molybdenum, a furnace is required to heat the surface to a high temperature of over 1400°C, and the high-temperature treatment requires high energy costs. Also, it is difficult to braze the formed high-melting point metallized layer to metal parts as is, and the surface must be plated with nickel or other metals, making the process complicated.

[0009] In contrast, joining with active metal brazing filler metal requires a heating temperature of 1000°C or less, which is advantageous in terms of energy costs. However, like metallization with high-melting-point metals, there are issues with component precision and complex manufacturing methods.

[0010] The embodiments solve these problems and relate to a highly productive ceramic sealed component and a manufacturing method thereof that do not require complicated processes when a ceramic component and a metal component are joined by a compression seal using an active metal brazing material. [Means for solving the problem]

[0011] In the ceramic sealed component according to the embodiment, in which a ceramic component and a metal component are joined with an active metal brazing material, a chamfered portion formed on the outer side of an end face of the ceramic component is joined to the metal component with the active metal brazing material. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing an example of a ceramic sealing component according to an embodiment; [Figure 2] FIG. 1 is a cross-sectional view showing an example of a ceramic sealing component according to an embodiment. [Figure 3] 1 is an enlarged cross-sectional view of a joint portion of a ceramic sealing component according to an embodiment; [Figure 4] 1 is an enlarged cross-sectional view of a joint portion of a ceramic sealing component according to an embodiment; [Figure 5] 1 is a cross-sectional view showing an example of a manufacturing process for a ceramic sealing component according to an embodiment; [Figure 6] 1 is a cross-sectional view showing an example of a printing process for a ceramic sealing component according to an embodiment; [Figure 7] FIG. 1 shows a ceramic sealing component according to a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the ceramic sealed component according to the embodiment, in which a ceramic component and a metal component are joined with an active metal brazing material, a chamfered portion formed on the outer side of an end face of the ceramic component is joined to the metal component with the active metal brazing material.

[0014] FIG. 1 shows an example of a perspective view of a ceramic sealing component 1 according to an embodiment. 3 is a cylindrical ceramic component, and 2 is a roughly cylindrical metal component with a widened joint. FIG. 1 shows an example in which a metal component 2 is joined to the upper end face and the lower (opposite) end face of the ceramic component 3. The embodiment is not limited to this shape, and may also be a rectangular cylindrical ceramic component or metal component, or may be a component in which the lower bottom face is a ceramic component and only the upper side (one side) is joined to a metal component, or a ceramic component having two or more openings on one side to which a metal component is joined.

[0015] FIG. 2 shows an example of a cross-sectional view of a ceramic sealed component according to an embodiment. In the ceramic sealed component 1 according to the embodiment, for example, the ceramic component 3 is a cylindrical ceramic component made of alumina. The ceramic component 3 has a chamfered portion formed on the outer periphery of its end face. In addition, for example, the metal component 2 is a metal component made of iron (Fe) or Kovar (Fe-Ni-Co) plated with nickel. The metal component 2 has a taper (slope) formed so that it can be overlapped with the chamfered shape of the ceramic component 3. A bonding layer 4 is present between the ceramic component 3 and the metal component 2, maintaining sealing (airtightness) between the inside and outside of the component.

[0016] 3 is an enlarged view of part A in FIG. 2, showing a cross-sectional view of a joint of a ceramic sealed component according to an embodiment. 2 is a metal component, 3 is a ceramic component, and 4 is a joint layer. The joint layer 4 is formed of a brazing metal such as copper (Cu) or silver (Ag), and an active metal such as titanium (Ti), zirconium (Zr), or hafnium (Hf).

[0017] In FIG. 3, 21 of the metal part 2 is an inclined portion and 22 is a straight portion. The inclined portion 21 is formed at approximately the same angle as the inclination of the chamfered portion 31 of the ceramic part. That is, the angle θm formed by the inclined portion 21 and the straight portion 22, that is, the inclination angle of the inclined portion of the metal part (hereinafter abbreviated as "the inclination angle of the inclined portion"), is approximately the same as the angle θc formed by the chamfered portion 31 and the outer peripheral portion 30 of the ceramic part 3, that is, the inclination angle of the chamfered portion of the ceramic part (hereinafter abbreviated as "the inclination angle of the chamfered portion"). By making the inclination angle θm of the inclined portion and the inclination angle θc of the chamfered portion approximately the same, the bonding layer 4 on the surface of the chamfered portion 31 of the ceramic part 3 and the inner peripheral portion 24 of the inclined portion 21 of the metal part 2 can be bonded by being in surface contact with each other.

[0018] Because the ceramic part 3 and the metal part 2 are heated during joining, they also thermally expand in the circumferential direction when the temperature rises. At this time, the metal part 2, which has a larger thermal expansion coefficient than the ceramic part 3, expands more. Conversely, when the temperature drops, the contraction αm of the metal part 2 is greater than the contraction αc of the ceramic part 3, so joining is performed with stress applied inward to the ceramic sealed part 1, resulting in a strong joint.

[0019] 3, the length of the inner circumferential portion 24 is made longer than the length of the chamfered portion 31, thereby allowing for a margin of error in terms of positional accuracy during assembly. This allows for a margin of error in terms of dimensional accuracy and assembly accuracy compared to conventional compression seals, which will be described later.

[0020] In the ceramic sealing component according to the embodiment, the angle formed between the chamfered portion and the outer circumferential surface is equal to or greater than 135 degrees and equal to or less than 170 degrees.

[0021] By making the inclination angle of the metal part and the inclination angle of the chamfered portion closer to each other, a strong seal can be formed that utilizes the difference in thermal expansion. The inclination angle θc of the chamfered portion formed by the chamfered portion and the outer periphery is preferably 120 degrees or more and 170 degrees or less. If the inclination angle θc of the chamfered portion is smaller than 120 degrees, it will be less susceptible to stress due to the difference in thermal expansion. Furthermore, since the chamfered portion 31 becomes larger, the end face 32 becomes smaller, and the end may be more susceptible to chipping. Furthermore, if it is larger than 170 degrees, it will be difficult to perform pad printing, as described below.

[0022] In the ceramic sealed component according to the embodiment, the active metal brazing material is an active metal brazing material made of one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing metals selected from copper and silver.

[0023] Active metals react with ceramics that have poor wettability with metals, reducing the interfacial energy and improving wettability. Improved wettability allows the brazing filler metal to penetrate more easily into the gaps between the components, improving joint strength. Active metals also form metallic bonds between the atoms of the base metal and brazing filler metal, creating a solid solution at the joint interface, contributing to the strength and durability of the joint.

[0024] Copper and silver, used as brazing filler metals, have relatively low melting points and melt easily at temperatures suitable for brazing. Furthermore, when copper and silver are alloyed, the melting point is even lower. Because the melting point of the alloyed copper and silver is lower than that of the metal components used in brazing, it has the advantage of being able to join the metal components without melting them. Copper and silver also have excellent fluidity and permeability, which are necessary for brazing, and easily penetrate between components via capillary action. Furthermore, copper and silver contribute to the strength and durability of the brazed joint. Copper and silver are less likely to generate stress between ceramics and metal components when cooling after brazing, making the joint less likely to crack or deform. They also have excellent thermal and electrical conductivity, which does not affect the functionality of the brazed joint.

[0025] An example of an active metal brazing material is a mixture of titanium and copper (Cu). For example, the titanium content is 0.1 to 10 mass%, with the remainder being copper. Another example of an active metal brazing material is a mixture of titanium, silver, and copper. The titanium content is 0.1 to 10 mass%, the copper content is 10 to 60 mass%, and the remainder is silver. If necessary, 1 to 15 mass% of one or more elements selected from indium (In), tin (Sn), aluminum (Al), silicon (Si), carbon (C), and magnesium (Mg) may be added.

[0026] In the ceramic sealed component according to the embodiment, the metal component is one or more metal components selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

[0027] The material of the metal component 2 bonded to the ceramic component 3 is preferably iron (Fe) and iron alloys, iron-nickel alloys, copper (Cu) and copper alloys, tungsten (W), or molybdenum (Mo). Iron alloys include carbon steels such as rolled steel, and alloy steels such as chromium steel and stainless steel. Iron-nickel alloys include Alloy 42 (42% Ni by mass, 0.8% or less Mn by mass, balance Fe) and Kovar (29% Ni by mass, 17% Co by mass, balance Fe). Iron and iron alloys offer excellent cost performance, while iron-nickel alloys offer excellent physical properties, such as excellent thermal expansion coefficients. Furthermore, copper and copper alloys are easily deformed to relieve stress due to differential thermal expansion. Therefore, when the impact of heat is significant, metal components are preferably formed from copper and copper alloys. Copper alloys include pure copper such as oxygen-free copper, tough pitch copper, and deoxidized copper, as well as high-copper alloys such as beryllium copper and titanium copper. For this reason, depending on the application, it is preferable to use metal parts made of iron and iron alloys, iron-nickel alloys, copper and copper alloys. It is also possible to use two or more types of metal parts, such as Kovar on one side and copper on the other. Metal parts are manufactured by processing them into a desired shape using processes such as pressing, cutting, and bending. After processing into the part shape, metal parts can be nickel-plated to improve corrosion resistance and wettability. Furthermore, metal parts made of copper and copper alloys are easily wetted by brazing filler metal components even without nickel plating, so they can be joined without nickel plating.

[0028] Figure 4 shows an enlarged cross-section of a ceramic sealed component according to an embodiment other than that shown in Figure 3. In the configuration shown in Figure 3, the inclined portion 21 of the metal component 2 is bonded by a surface, resulting in a large bond distance (area) and a long leak distance. However, bending or other processes are required to widen the tip of the metal component. In contrast, the configuration shown in Figure 4 shortens the bond distance, but bending or other processes are not required. In Figure 4(a), the metal component 2 is straight (cylindrical) and the end portion 20 is flat. Therefore, it is bonded to the chamfered portion 31 at the end portion 20 and the inner periphery 24. The bonding layer 4 spreads over the easily wetted surface of the metal component, forming a meniscus shape between the chamfered portion 31 and the end portion 20, and between the chamfered portion 31 and the inner periphery 24, forming a strong bond. In Figures 4(b) and (c), the tip of the metal component 2 is knife-edge shaped, while in Figure 4(d), it is U-shaped. In both cases, the bonding layer spreads over the surface of the metal component 2, forming a meniscus shape, similar to Figure 4(a).

[0029] In the ceramic sealed component according to the embodiment, the ceramic component is made of alumina, aluminum nitride, silicon nitride, or zirconia-added alumina.

[0030] The ceramic part 3 is preferably one of alumina, aluminum nitride, silicon nitride, and zirconia-added alumina (Alzir). Alumina includes alumina-based ceramics in which other ceramics are added to alumina. For example, zirconia-added alumina is a sintered body made by mixing alumina and zirconium oxide. A sintering aid other than zirconia may also be added to alumina. This is because the added sintering aid forms a grain boundary phase consisting of a glass phase, thereby densifying the alumina sintered body. Examples of sintering aids include compounds of manganese (Mn), silicon (Si), magnesium (Mg), calcium (Ca), etc., and it is preferable to add at least one of them in a total amount of 1 to 15 mass% in terms of simple metal elements. These ceramics have heat resistance that can withstand the bonding temperature described below and a 10 14They have high insulation properties of over Ω·cm. In addition, the three-point bending strength is high, at 350 MPa for alumina, 300 MPa for aluminum nitride, 800 MPa for silicon nitride, and 600 MPa for alusil. Therefore, they combine electrical insulation and thermal mechanical properties, making them ideal for sealing ceramic parts. Of these ceramics, alumina has the best cost performance and is therefore preferred for sealing ceramic parts.

[0031] A manufacturing method of a ceramic sealed component for joining a ceramic component and a metal component according to an embodiment includes a step of preparing a ceramic component by forming a chamfered portion on the outside of the end face; a printing step of printing and drying an active metal brazing paste on the chamfered portion to obtain a printed component; and a joining step of placing a metal component on the printed component and performing a heat treatment to join them.

[0032] FIG. 5 shows cross-sectional views of steps in a manufacturing method for a ceramic sealed component according to an embodiment. FIG. 5(a) is a cross-sectional view of a cylindrical ceramic component 3. A chamfered portion 31 is formed on the outer periphery of the end face of the ceramic component 3. Methods for forming the chamfered portion 31 include forming it according to the mold shape during press molding, forming it by green processing a green compact, or forming it by polishing a sintered compact. These methods can be used to form a chamfered portion on the outside of the end face to prepare a ceramic component. In FIG. 5(a), 311 is the chamfer width (the distance from the outer periphery to the end of the chamfered portion), and 312 is the chamfer length (the distance from the top surface (end face) to the end of the chamfered portion).

[0033] 5(b) shows the state of an active metal paste-printed part after the active metal brazing paste 5 has been printed and dried on the chamfered portion 31 of the ceramic part 3. Since the paste is printed on the flat chamfered portion 31 of the ceramic part, the surface of the active metal brazing paste 8 before joining is approximately flat.

[0034] Figure 5(c) shows the state in which metal parts are placed on the printed surfaces of both chamfered portions of the printed part and then heated and bonded. Figure 5(c) shows the state in which the metal parts 2 are bonded simultaneously, but they can also be bonded separately in two separate steps. Joining them separately simplifies assembly, but there is a risk that the bonded areas will be heated again and the active metal brazing material will wet and spread too much.

[0035] In the method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component according to the embodiment, the printing of the active metal brazing paste is pad printing.

[0036] FIG. 6 shows a cross-sectional view of an example of a printing process for a ceramic sealed component according to an embodiment. FIG. 6 illustrates an example of pad printing. In FIG. 6(a), 6 is a pad, 7 is a printing plate, and 71 is a printing plate surface. Active metal paste 5 is filled on printing plate surface 71. In FIG. 6(b), pad 6 descends and is pressed against printing plate 7, transferring the active metal paste 5 onto pad 6. In FIG. 6(c), pad 6 with the transferred active metal paste 5 moves above ceramic component 3. In FIG. 6(d), pad 6 descends and is pressed against the edge face and chamfered portion 31 of ceramic component 3. At this time, the active metal paste 5 on pad 6 is transferred to chamfered portion 31. In FIG. 6(e), pad 6 ascends, and active metal paste 5 is printed on chamfered portion 31.

[0037] By printing the chamfered portion by pad printing, the active metal paste can be printed uniformly on an inclined surface such as the chamfered portion.

[0038] In the method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component according to the embodiment, the angle formed between the chamfered portion and the end face is 135 degrees or more and 170 degrees or less.

[0039] When pad printing is performed on the chamfered portion, it is preferable that the angle between the chamfered portion and the outer peripheral surface is 170 degrees or less. This is because if the angle exceeds 170 degrees, it is difficult to achieve a uniform printed surface by pad printing. Also, as mentioned above, if the inclination angle θc of the chamfered portion is less than 120 degrees, it is less susceptible to stress due to differences in thermal expansion.

[0040] In the embodiment of the method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component, the active metal brazing material is an active metal brazing material composed of one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing metals selected from copper and silver.

[0041] The active metal brazing paste is prepared by adding an organic binder and an organic solvent to a metal powder mixture of one or more active metals selected from titanium, zirconium, and hafnium and one or more brazing metals selected from copper and silver. If necessary, 1 to 15 mass% of one or more elements selected from indium (In), tin (Sn), aluminum (Al), silicon (Si), carbon (C), and magnesium (Mg) may be added. The organic binder is not particularly limited as long as it is burned away during the drying and joining processes. A preferred example is ethyl cellulose. The organic solvent is not particularly limited as long as it is burned away during the drying and firing processes. Preferred examples include terpineol and butyl carbitol. The active metal brazing paste is prepared by mixing the active metal powder and brazing metal powder, followed by mixing with an organic binder and an organic solvent. The ratio of the active metal contained in the active metal brazing material components is 0.1 to 15 mass %, preferably 0.5 to 10 mass %.

[0042] The printing thickness of the active metal brazing paste is preferably 30 to 300 μm. If the printing thickness is less than 10 μm, the thickness of the active metal brazing layer will vary, reducing the bonding strength. On the other hand, if it exceeds 30 μm, no further effect will be obtained. The paste is printed to a uniform thickness on the chamfered surface of the ceramic part using a method such as pad printing. If the printing thickness is uneven, the active metal brazing material will be excessive in thicker areas, causing brazing material pools and cracks due to thermal stress. Furthermore, in thinner areas, brazing material will run out, resulting in leakage defects. For this reason, it is preferable that the difference in printing thickness between thick and thin areas be 10 μm or less.

[0043] In the method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component according to the embodiment, the metal component is one or more metal components selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

[0044] As mentioned above, the material of the metal part 2 is preferably iron and iron alloys, iron-nickel alloys, copper and copper alloys. Iron and iron alloys offer excellent cost performance, while iron-nickel alloys have excellent physical properties such as thermal expansion coefficients. Copper and copper alloys are also easily deformed to relieve stress caused by differences in thermal expansion, and it is preferable to form metal parts from copper and copper alloys when the impact of heat is significant. For this reason, it is preferable to use metal parts made from iron and iron alloys, iron-nickel alloys, copper and copper alloys depending on the application.

[0045] In the method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component according to the embodiment, the ceramic component is made of alumina, aluminum nitride, silicon nitride, or zirconia-added alumina.

[0046] As mentioned above, the ceramic part 3 is preferably one of alumina, aluminum nitride, silicon nitride, and zirconia-added alumina (Aldzire). These ceramics have both electrical insulation and thermal and mechanical properties, making them suitable for sealing ceramic parts.

[0047] Next, a method for manufacturing a ceramic seal component according to an embodiment will be specifically described. The ceramic seal component and the manufacturing method are not particularly limited as long as they have the above-described configuration, but the following methods can be used to obtain a high yield.

[0048] An example of a ceramic part according to the embodiment has a cylindrical shape. For example, in FIG. 2, the outer diameter is 50 mm, the inner diameter is 38 mm, and the height is 50 mm. The chamfered portion has a shape similar to the side of a truncated cone with a chamfer width of 2 mm (the outer diameter of the end face is 46 mm) and a chamfer length of 5 mm (the distance from the end face to the chamfered end is 5 mm). Methods for manufacturing ceramic parts with chamfered portions include molding using a mold, green-processing a cylindrical shape, and polishing a cylindrical sintered body to form the chamfer. Mold-processing is advantageous for mass production, but green-processing, which does not require a mold, can be used for small-lot production. Ceramic parts are prone to chipping and cracking at their corners due to external impacts. For this reason, it is preferable to also chamfer the periphery of the end face. The chamfer shape can be, for example, a C-chamfer or an R-chamfer, and the chamfer size is preferably 0.1 to 0.5 mm.

[0049] An example of a metal part according to the embodiment has a cylindrical shape with one end tapered and wider. For example, in the case of FIG. 2, the height is 25 mm, the height of the straight portion is 17 mm, the outer diameter is 44 mm, and the inner diameter is 42 mm. The height of the tapered portion is 8 mm, and the outer diameter of the tapered tip is 50 mm and the inner diameter is 48 mm. Forming using a mold is highly suitable for mass production, and small quantities can be manufactured by drawing. These metal parts can be nickel-plated to a thickness of 0.5 to 3.0 μm to improve corrosion resistance and wettability.

[0050] Active metal brazing filler metal is in the form of a paste. Sheets and wires require a process in which the active metal brazing filler metal is melted and processed into a sheet or wire shape, and then cut to the required dimensions to match the product shape. In contrast, pastes require a paste manufacturing process, but are easy to handle; for example, they can be printed in the required locations to match the product shape. In addition, if the amount of active metal brazing filler metal is too small, unbonded areas will occur, resulting in braze breaks, and if too much, braze pools will occur, causing stress fractures. Therefore, the amount of paste used can be adjusted to match the bonding area.

[0051] The active metal brazing paste is prepared by adding an organic binder and an organic solvent to a mixture of active metal powder and brazing metal powder. The organic binder is not particularly limited as long as it is burned away during the drying and joining processes. A preferred example is ethyl cellulose. The organic solvent is not particularly limited as long as it is burned away during the drying and firing processes. Preferred examples include terpineol and butyl carbitol. The active metal brazing paste is prepared, for example, by crushing and mixing active metal powder and brazing metal powder, and then mixing them with an organic binder and an organic solvent. The ratio of the active metal contained in the active metal brazing material components is 0.1 to 15 mass %, preferably 0.5 to 10 mass %.

[0052] The printing thickness of the active metal brazing paste is preferably 30 to 300 μm. If the printing thickness is less than 30 μm, the thickness of the active metal brazing layer will vary, reducing the bonding strength. On the other hand, if it exceeds 300 μm, no further effect will be obtained. The paste is printed to a uniform thickness on the end surface of the ceramic component using a method such as pad printing. If the printing thickness is uneven, the active metal brazing material will be excessive in thicker areas, causing brazing material pools and cracks due to thermal stress. Furthermore, in thinner areas, the active metal brazing material will run out, resulting in leak defects. For this reason, it is preferable that the difference in printing thickness between thick and thin areas be 10 μm or less.

[0053] The paste printed on the ceramic parts is dried in the atmosphere. If the drying temperature is low and the drying time is short, the solution components of the paste are not sufficiently volatilized, and the remaining solution may volatilize during bonding, resulting in the formation of voids. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface may progress, causing changes in the bonding temperature. For this reason, the drying temperature is 50 to 100°C, preferably 60 to 80°C. The drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0054] The brazing paste printed on the active metal brazing layer is dried in the atmosphere. If the drying temperature is low and the drying time is short, the solution components of the paste are not sufficiently volatilized, and the remaining solution may volatilize during bonding, resulting in the formation of voids. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface may progress, which may change the bonding temperature conditions. For this reason, the drying temperature is 50 to 100°C, preferably 60 to 80°C. The drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0055] After the brazing filler metal paste is dried, the metal part is placed on the dried paste surface and heated to bond it. The heating temperature is 650 to 900°C, preferably 700 to 850°C. The bonding time is preferably 10 to 30 minutes after the heating temperature is reached. As shown in Figure 3, the bonding layer 4 melts and wets and spreads over the surface of the metal part 2, resulting in a bond with a seal. If the bonding temperature is low and the bonding time is short, the active metal brazing filler metal may not melt sufficiently, resulting in a bond. Conversely, if the bonding temperature is high and the bonding time is long, the brazing filler metal may melt too much, wet and spread, resulting in brazing failure and voids.

[0056] Furthermore, the bonding atmosphere should be a non-oxidizing atmosphere as needed. Examples of non-oxidizing atmospheres include a nitrogen atmosphere and a hydrogen nitrogen atmosphere. By using a non-oxidizing atmosphere, oxidation of the bonding layer can be suppressed, thereby improving the bonding strength. Continuous furnaces and batch furnaces are used for the bonding process. Continuous furnaces are superior in terms of mass production, while batch furnaces allow for easy control of the temperature and atmosphere. Bonding is achieved by heat-treating the parts in the above atmosphere for a specified period of time.

[0057] As described above, according to the method for manufacturing a ceramic seal component in the embodiment of the present invention, a ceramic seal component that is excellent in cost performance can be obtained while maintaining the airtightness performance of the seal component.

[0058] (Examples 1 to 3, Comparative Examples, Conventional Examples) Example 1 Alumina was mixed with the additives manganese dioxide (MnO2), silicon oxide (silica: SiO2), and magnesium oxide (magnesia: MgO) to prepare granulated powder with a composition of 92 mass% alumina. The granulated powder was molded using a die press and sintered in air at 1500°C to obtain a roughly cylindrical alumina part with an outer diameter of 50 mm, an inner diameter of 38 mm, a height of 50 mm, an outer chamfer length of 1 mm, and a chamfer height of 5 mm, as shown in Figure 2. The angle between the chamfer and the end face is 169 degrees.

[0059] The metal part was obtained by pressing and drawing iron into a cylindrical shape, resulting in a cylindrical metal part with a height of 25 mm and a tapered shape on one side, as shown in Figure 2. The dimensions of each part are an outer diameter of 44 mm, an inner diameter of 42 mm, and a height of 17 mm at the straight part, and an outer diameter of 50 mm and an inner diameter of 48 mm at the tip of the tapered part. The angle (included angle) between the straight part and the tapered part is approximately 160 degrees. The surface of the processed iron part was then plated with nickel to a thickness of 1 μm.

[0060] Next, a metal powder with a powder composition ratio of 3% titanium, 10% tin, 30% copper, and residual silver was prepared. The prepared metal powder was mixed with ethyl cellulose and terpineol and made into a paste using a kneader to produce an active metal brazing paste. The active metal brazing paste was then printed onto the top and bottom chamfered portions of the alumina part by pad printing. The printing width was 3 mm. The printing time was 10 seconds. After printing, the active metal paste was dried in air at 100°C. After drying, the thickness of the active metal paste was measured and found to be 40 μm.

[0061] Next, the metal parts, ceramic parts, and metal parts are placed on a jig in that order, and then placed in a vacuum furnace (1 x 10 -2 The metal and ceramic parts were joined by heating at 850°C for 20 minutes at a pressure of 1000 kJ / cm2 or less (less than 1000 kJ / cm2).

[0062] (Examples 2 to 3, Comparative Example) Examples 2 and 3 and the comparative example were produced in the same manner as in Example 1, except that the following ceramic and metal parts were used.

[0063] Example 2 For the ceramic parts, aluminum nitride granulated powder was prepared by adding 3 mass% of yttria (yttrium oxide: YO) additive to aluminum nitride. The granulated powder was molded in a die press and sintered in nitrogen at 1800°C to obtain cylindrical ceramic parts with the same dimensions as the alumina parts. The chamfered portion had an outer diameter of 3 mm, a chamfered length of 3 mm, and a chamfered height of 3 mm, with an angle of approximately 110 degrees between the chamfered portion and the end face.

[0064] The metal part is made of oxygen-free copper and pressed into a cylindrical shape with a height of 20 mm, an outer diameter of 48 mm, and an inner diameter of 46 mm. The tip on the joining side is machined into a spherical shape as shown in Figure 4.

[0065] Example 3 For the ceramic parts, aluminum nitride granulated powder was prepared by adding 3 mass% of yttria (yttrium oxide: YO) additive to silicon nitride. The granulated powder was molded in a die press and sintered in nitrogen at 1800°C to obtain cylindrical ceramic parts with the same dimensions as the alumina parts. The chamfered portion had an outer diameter of 3 mm, a chamfered length of 3 mm, and a chamfered height of 3 mm, with an angle of approximately 110 degrees between the chamfered portion and the end face.

[0066] The metal part is made of oxygen-free copper and pressed into a cylindrical shape with a height of 20 mm, an outer diameter of 48 mm, and an inner diameter of 46 mm. The tip on the joining side is machined into a spherical shape as shown in Figure 4.

[0067] (Comparative Example) The manufacturing conditions were the same as those of the alumina part in Example 1, and the shape of the chamfered portion was an outer diameter chamfer length of 3 mm, a chamfer height of 1 mm, and the angle between the chamfered portion and the end face was approximately 108 degrees.

[0068] The manufacturing conditions were the same as those for the iron part in Example 1, with the straight part having an outer diameter of 42 mm, an inner diameter of 40 mm, and a height of 18 mm, and the tapered part having an outer diameter of 50 mm and an inner diameter of 49 mm at the tip. The angle (included angle) between the straight part and the tapered part was 108 degrees. The surface of the processed iron part was plated with nickel to a thickness of 1 μm.

[0069] (Conventional example) Next, a ceramic sealed component using a conventional compression seal was fabricated as a conventional example. Figure 7 shows a ceramic sealed component according to a comparative example. Figure 7(a) is a perspective view, and Figure 7(b) is a cross-sectional view. In the comparative example, the outer peripheral surface near the end face of the ceramic component is machined to achieve dimensional accuracy. An active metal brazing paste is printed on the outer peripheral surface near the end face, which is the joining surface. The printing method is performed by rotating the ceramic component 3 in the circumferential direction while repeatedly applying the active metal paste with a brush or the like. The inner periphery of the metal component 2 is machined so that it can be installed in close contact with the joining layer 4.

[0070] The granulated powder of Example 1 was molded using a die press and sintered at 1500°C in air to obtain a cylindrical alumina sintered body having an outer diameter of 50 mm, an inner diameter of 38 mm, and a height of 50 mm. The outer periphery of the alumina sintered body was ground to obtain an outer diameter of 49 mm, and an alumina part was obtained.

[0071] The iron of Example 1 was pressed into a cylindrical shape and the inner surface was ground to obtain a metal part with an outer diameter of 51 mm and an inner diameter of 49 mm. The surface of the processed iron part was plated with nickel to a thickness of 1 μm.

[0072] Next, while rotating the alumina part in the circumferential direction, the active metal paste was applied with a brush to a width of approximately 5 mm from the edge. The printing thickness was determined to be approximately 40 μm by measuring the print weight. The printing time was 10 minutes.

[0073] Next, the metal part and the ceramic part were brought into close contact with the surface printed with the active metal paste, and then external force was applied to prevent the metal part from separating from the ceramic part. The metal part, ceramic part, metal part were set in the jig in this order, and the metal part and ceramic part were joined under the same conditions as in Example 1 to produce a ceramic sealed part.

[0074] Next, for Examples 1 to 3 and the conventional example, a helium leak test was performed by applying silicone to the upper part of the ceramic sealed part after hydrogen heat treatment with a circular jig made of Viton rubber and holding it down, and then fixing the lower part to a helium leak detector and sucking it in. The helium leak test was performed in accordance with the vacuum spray method (spray method) of the "Helium Leak Test Method" (JIS Z2331:2006), and the helium leak rate was 1×10-9 Pa m at a vacuum level of 1.3 μPa. 3 It was confirmed that no leaks of more than / s occurred.

[0075] Next, for Examples 1 to 3 and the conventional example, a tensile strength of 980 N was applied in the vertical direction using an Instron tensile tester to two locations, top and bottom, on the same side of the upper and lower metal parts of the ceramic sealing component to confirm that no breakage occurred.

[0076] In Examples 1 to 3, the conventional example, and the comparative example, no leak defects occurred in the helium leak test, and sufficient bonding strength was also obtained. In the Examples, the time required to print the active metal paste was significantly reduced compared to the conventional example. Furthermore, the Examples did not require the dimensional precision required in the conventional example, and therefore the processing was simple. Furthermore, the Examples were easy to assemble, enabling a reduction in assembly time.

[0077] As is clear from the results shown above, the Examples showed improved cost performance compared to the Comparative Examples.

[0078] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0079] 1...Ceramic sealing parts 2...Metal parts 20...tip portion, 21...inclined portion, 22...straight portion, 23...outer periphery portion, 24...inner periphery portion 3...Ceramic parts 30... outer periphery, 31... chamfered portion, 32... end face, 33... inner periphery 311... chamfer width, 312... chamfer length 4...Joining layer 5...Active metal brazing paste 6...Pad 7...Print plate, 71...Print plate

Claims

1. A ceramic sealed component in which a ceramic component and a metal component are joined using an active metal brazing material, characterized in that a chamfered portion formed between the end face and outer peripheral surface of the ceramic component and the metal component are joined using the active metal brazing material.

2. 2. The ceramic sealing component according to claim 1, wherein the angle between the chamfered portion and the outer peripheral surface is 135 degrees or more and 170 degrees or less.

3. 3. The ceramic sealed component according to claim 1, wherein the active metal brazing filler metal is an active metal brazing filler metal comprising one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing filler metals selected from copper and silver.

4. 3. The ceramic sealed component according to claim 1, wherein the metal component is one or more metal components selected from the group consisting of iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

5. 3. The ceramic sealing part according to claim 1, wherein the ceramic part is made of alumina, aluminum nitride, silicon nitride, or zirconia-added alumina.

6. A method for manufacturing a ceramic sealed component for joining a ceramic component and a metal component, comprising: preparing a ceramic component by forming a chamfer on an outer side of an end face; a printing step of printing and drying an active metal brazing paste on the chamfered portion to obtain a printed part; and a bonding step of placing a metal part on the printed part and bonding them by heat treatment.

7. 7. The method for manufacturing a ceramic sealed component according to claim 6, wherein the printing of the active metal brazing paste is performed by pad printing.

8. 8. The method for manufacturing a ceramic sealed component according to claim 6, wherein the angle formed by the chamfered portion and the outer circumferential surface is 135 degrees or more and 170 degrees or less.

9. 8. The ceramic sealed component according to claim 6, wherein the active metal brazing filler metal is an active metal brazing filler metal comprising one or more active metals selected from titanium, zirconium, and hafnium, and one or more brazing filler metals selected from copper and silver.

10. 8. The method for producing a ceramic sealed component according to claim 6, wherein the metal component is one or more metal components selected from the group consisting of iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

11. 8. The method for producing a ceramic sealed part according to claim 6 or 7, wherein the ceramic part is made of alumina, aluminum nitride, silicon nitride, or zirconia-added alumina.

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