Ceramic sealing member and method of manufacturing the same

Abstract

The ceramic sealing member of the embodiment is a ceramic sealing member in which a ceramic member and a nickel-plated metal member are joined by a joining layer containing silver, copper, an active metal, and a low-melting metal, a compound of nickel and the active metal is formed in the joining layer, and the distance from the compound to the surface of the joining layer is 10 μm or more. In addition, the manufacturing method of the ceramic sealing member of the embodiment includes the following steps: a step of printing and drying an active metal paste containing at least copper, an active metal, and a low-melting metal on a ceramic member to obtain an active metal paste printed member; a step of printing and drying a solder paste containing at least silver and copper on the surface of the active metal paste printed member to obtain a solder paste printed member; and a joining step of disposing a metal member on the solder paste printed member and performing a heat treatment.

Description

Technical Field

[0001] The implementation generally involves a ceramic sealing component (hereinafter referred to as a ceramic sealing component) formed by joining a ceramic component for power transistors and the like with a metal component. Background Technology

[0002] Ceramic sealing components used in magnetrons, power transistors, and electron tubes employ a ceramic sealing component in which a metallization layer primarily composed of high-melting-point metals such as molybdenum (Mo) is formed on a ceramic component such as alumina (Al₂O₃). This ceramic sealing component provides an airtight seal to the interior of the component by bonding the ceramic to the metal and blocking external gases, thereby protecting the interior from the influence of the external environment and providing electrical insulation using the ceramic. The ceramic sealing component has a molybdenum-based metallization layer formed on the two bottom surfaces (first and second bottom surfaces) of the annular joint of a cylindrical ceramic component formed from a sintered alumina body. On the surface of this metallization layer, a nickel (Ni) layer of a specified thickness is formed to improve the bonding strength with the cylindrical metal component to which the ceramic sealing component is to be bonded and to achieve a seal. This nickel layer and the cylindrical metal component are bonded using silver solder (e.g., BAg-8).

[0003] As a ceramic sealing component, an electron tube is disclosed having a vacuum-sealed structure in which a metal surface formed of molybdenum is formed at the joint of a cylindrical ceramic, and a cylindrical iron metal is joined by brazing filler metal (Patent Document 1). According to Patent Document 1, a low-cost electron tube can be manufactured by replacing the metal component joined with the ceramic with iron-nickel-cobalt alloy.

[0004] Furthermore, a vacuum switch outer tube is disclosed that uses an active metal to bond a nickel-based alloy to ceramic without using high-melting-point metals such as molybdenum (Patent Document 2). According to Patent Document 2, a vacuum switch outer tube with high bonding strength can be manufactured without creating intermetallic compounds that could cause instability in the bonding state. Additionally, a bonding body using nickel-free stainless steel is disclosed (Patent Document 3). According to Patent Document 3, since no compound between the active metal and nickel is formed, airtightness and bonding strength can be maintained.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 1-46978 Patent Document 2: Japanese Patent Application Publication No. 2001-220253 Patent Document 3: International Publication No. 2023 / 063396 Summary of the Invention

[0006] The problem the invention aims to solve When using high-melting-point metals such as molybdenum to metallize ceramic surfaces, furnaces heated to temperatures exceeding 1400°C are required, incurring energy costs for high-temperature processing. Furthermore, it is difficult to directly braze the resulting high-melting-point metallization layer to metal components; surface plating with materials such as nickel is necessary, making the process complex.

[0007] In contrast, when using active metal brazing filler metals, heating temperatures below 1000°C offer advantages in terms of energy costs. However, when nickel plating is applied to metal parts to improve rust resistance and wettability, there is a problem that nickel can form compounds with the active metal, leading to reduced bond strength and leakage.

[0008] The implementation addresses this problem by relating to a highly productive ceramic sealing component and a method thereof that suppresses poor bonding and leakage when joining ceramic and metal components using an active metal solder.

[0009] Methods for solving problems The ceramic sealing component involved in the embodiment is a ceramic sealing component formed by bonding a ceramic component to a nickel-plated metal component through a bonding layer containing silver, copper, active metal and low melting point metal. A compound of nickel and active metal is formed in the bonding layer, and the distance between the compound and the surface of the bonding layer is more than 10 μm. Attached Figure Description

[0010] Figure 1 This is a perspective view showing an example of a ceramic sealing component according to an embodiment.

[0011] Figure 2 This is a longitudinal sectional view showing an example of a ceramic sealing component according to an embodiment.

[0012] Figure 3 This is a diagram showing an example of a cross-section of the joint of a ceramic sealing component according to an embodiment.

[0013] Figure 4 This is an example of an enlarged view showing a cross-section of the joint of the ceramic sealing component according to an embodiment.

[0014] Figure 5 This is a figure showing an example of the mass percentage of the joint section of the ceramic sealing component in the embodiment.

[0015] Figure 6 This is a cross-sectional view illustrating an example of the manufacturing process of a ceramic sealing component according to an embodiment.

[0016] Figure 7 This is a diagram showing an example of the heating curve of the ceramic sealing component according to the embodiment. Detailed Implementation

[0017] The ceramic sealing component involved in the embodiment is a ceramic sealing component formed by bonding a ceramic component to a nickel-plated metal component through a bonding layer containing silver, copper, active metal and low melting point metal. A compound of nickel and active metal is formed in the bonding layer, and the distance between the compound and the surface of the bonding layer is more than 10 μm.

[0018] Figure 1 This is an example of a perspective view showing a ceramic sealing component 1 according to an embodiment. Symbol 3 represents a cylindrical ceramic component, and symbol 2 represents a cylindrical metal component. The metal component 2 is joined to the ceramic component 3 via a joint, i.e., two annular bottom surfaces (a first bottom surface and a second bottom surface). Figure 1 The illustration shows an example where a metal component 2 is joined to a first bottom surface (e.g., the upper end face) and a second bottom surface (e.g., the lower end face) of a ceramic component 3. The embodiment is not limited to this shape; it may also include a cylindrical ceramic component with a metal component joined to it, a ceramic component with a metal component joined only to another bottom surface (e.g., the upper bottom surface) without a metal component on one bottom surface (e.g., the lower bottom surface), or a ceramic component with a metal component joined to it having openings at two or more locations on one bottom surface (e.g., the upper bottom surface).

[0019] Figure 2 This is an example of a longitudinal sectional view (showing a section along a central axis orthogonal to the bottom surface) of the ceramic sealing member 1 according to the embodiment. The ceramic sealing member 1 of the embodiment includes, for example, a cylindrical ceramic component 3 containing alumina and a metal component 2 bonded thereto. Furthermore, the metal component 2 is, for example, a nickel-plated metal component made of iron (Fe) or a Fe-Ni-Co alloy. A bonding layer 4 is provided between the ceramic component 3 and the metal component 2. Figure 3 (As shown in the diagram), maintain the airtightness (sealing) between the inside and outside of the component.

[0020] The ceramic component 3 is preferably composed of any one of alumina, aluminum nitride, silicon nitride, or alumina with added zirconium oxide (Alusier high-silicon heat-resistant aluminum alloy). Alumina includes alumina-based ceramics in which other ceramics are added. For example, alumina with added zirconium oxide is a sintered body formed by mixing alumina and zirconium oxide. Alternatively, sintering aids other than zirconium oxide may be added to the alumina. This is because the added sintering aids form grain boundary phases composed of a glassy phase, thereby densifying the alumina sintered body. Examples of sintering aids include compounds such as manganese (Mn), silicon (Si), magnesium (Mg), and calcium (Ca), and it is preferable to add at least one of these compounds, with a total content of 1% to 15% by mass (based on elemental conversion). Furthermore, the ceramic component 3 is preferably made of alumina, which offers good cost-effectiveness, as an insulating and sealing component.

[0021] The metal component 2, which joins with the ceramic component 3, is preferably made of iron (Fe) and iron alloys, iron-nickel alloys, copper (Cu) and copper alloys, tungsten (W), or molybdenum (Mo). Iron alloys include rolled steel and other carbon steels, chromium steels, and stainless steels. Examples of iron-nickel alloys include Alloy 42 (Ni 42% by mass, Mn 0.8% or less, remaining Fe) and Kova iron-nickel-cobalt alloy (Ni 29% by mass, Co 17% by mass, remaining Fe). Iron and iron alloys offer excellent cost-effectiveness, while iron-nickel alloys exhibit superior physical properties such as the coefficient of thermal expansion. Furthermore, copper and copper alloys are preferred to mitigate deformation caused by stress due to thermal expansion differences; therefore, copper and copper alloys are preferred for metal components in situations where the thermal effect is significant. Copper alloys include pure copper such as oxygen-free copper, tough copper, and deoxidized copper, as well as high-copper alloys such as beryllium copper and titanium copper. Therefore, depending on the application, iron and iron alloys, iron-nickel alloys, and copper and copper alloys are preferred for the metal component 2. Furthermore, one metal component 2 can be made of a Kova iron-nickel-cobalt alloy, and the other metal component 2 can be made of copper or the like, and two or more metal components 2 can be joined to the ceramic component 3. The metal components 2 are manufactured by stamping, machining, and bending to a specified shape. After the metal components 2 are machined into the component shape, nickel plating is performed to improve corrosion resistance and wettability. Additionally, when metal components 2 made of copper or copper alloys and other nickel-plated metal components 2 are joined to the ceramic component 3 simultaneously, the copper or copper alloy metal components 2 easily wet the solder even without nickel plating, so nickel plating may not be necessary.

[0022] The thickness of the nickel plating applied to metal component 2 is 0.5 μm or more and 3.0 μm or less. If the thickness of the nickel plating is less than 0.5 μm, the wetting with the solder deteriorates, potentially resulting in areas of non-wetting (solder breakage) that could lead to reduced joint strength and poor leakage. Even if the thickness of the nickel plating exceeds 3.0 μm, the improved wettability cannot be achieved. Furthermore, this is because if the nickel plating is too thick, the remaining nickel forms compounds with the active metal.

[0023] Figure 3 Indicates as Figure 2 The enlarged view of part A shows an example of a longitudinal section of the joint of the ceramic sealing component 1 according to an embodiment. Symbol 1 represents the ceramic sealing component, symbol 2 represents the metal component, symbol 3 represents the ceramic component, and symbol 4 represents the bonding layer. The bonding layer 4 on the ceramic component 3 side is formed of solder metals such as copper (Cu) and silver (Ag), active metals such as titanium (Ti), zirconium (Zr) and hafnium (Hf), and low-melting-point metals such as indium (In), tin (Sn), bismuth (Bi), antimony (Sb), and zinc (Zn).

[0024] The bonding layer 4 is an active metal solder layer formed by active metal solder, comprising solder metal (silver and copper), active metal, and low-melting-point metal. Copper and silver, used as solder metal in bonding layer 4, have relatively low melting points and melt easily at suitable brazing temperatures. Furthermore, alloying copper and silver further lowers their melting points. The alloyed copper and silver have lower melting points than the metal component 2 used in brazing, thus providing the advantage of joining the metal component 2 without melting. Additionally, copper and silver exhibit excellent flowability and penetration for brazing, easily penetrating between components via capillary action. Furthermore, copper and silver contribute to the strength and durability of the brazed joint. When copper and silver cool after brazing, they are less prone to generating stress between the ceramic component 3 and the metal component 2, thus reducing the likelihood of cracking or deformation at the joint. Moreover, their excellent thermal and electrical conductivity also minimizes the impact on the functionality of the brazed joint.

[0025] The active metal in bonding layer 4 reacts with the ceramic, which has poor wettability with the metal, reducing the interfacial energy and thus improving wettability. Improved wettability allows the solder to easily penetrate the gaps between components, increasing bonding strength. Furthermore, the active metal forms metallic bonds between the atoms of the base material and the solder, creating a solid solution at the bonding interface, which contributes to the strength and durability of the joint. The active metal readily reacts with nickel to form nickel-active metal compounds. Therefore, the nickel contained in metal component 2, the nickel plating formed on the surface of metal component 2, and the active metal readily react to form nickel-active metal compounds. These nickel-active metal compounds readily react with external air atmospheres such as hydrogen, becoming embrittled, which may lead to reduced bonding strength and poor leakage.

[0026] The melting point of the low-melting-point metal in bonding layer 4 is lower than that of other elements contained in bonding layer 4. The melting points of these low-melting-point metals are indium (157°C), tin (232°C), bismuth (271°C), antimony (630°C), and zinc (419°C). Their melting points are lower than those of other metals contained in the bonding layer, such as silver (961°C), copper (1085°C), titanium (1666°C), zirconium (1852°C), and hafnium (2233°C). Therefore, the low-melting-point metal diffuses faster than other metals during heat treatment. By diffusing faster than nickel or active metals, the added low-melting-point metal reacts with copper or silver to form a bonding layer, preventing nickel-active metal compounds from precipitating onto the surface of the bonding layer. Furthermore, the low-melting-point metal is added to the active metal solder paste. This is because if added to a solder paste composed of silver and copper, the melting point of the silver-copper alloy becomes lower, causing it to melt and solidify first.

[0027] The proportion of low-melting-point metal is between 5% and 15% by mass. When the amount of low-melting-point metal is less than 5% by mass, diffusion into the solder layer becomes insufficient, and the effect of preventing the precipitation of nickel-active metal compounds on the outermost surface of the bonding layer is not achieved. Conversely, if the proportion of low-melting-point metal is more than 15% by mass, the proportion of silver and copper, which are the main components of the solder, becomes less, and the mechanical properties and other functions of the bonding layer may also be reduced.

[0028] Figure 4 Indicates as Figure 3 The enlarged view of part B shows an example of a longitudinal section of the joint of the ceramic sealing component 1 according to an embodiment. Symbol 5 represents the active metal layer, primarily composed of active metal, in the bonding layer 4. The active metal layer 5 exists on the surface of the ceramic component 3, facilitating the bonding between the ceramic component 3 and the metal component 2. Symbol 6 represents the brazing filler layer (hereinafter referred to as the "brazing filler layer") in the bonding layer 4, composed of brazing filler metal (silver and copper) and a low-melting-point metal. The brazing filler layer 6 exists near the end face of the metal component 2 between the active metal layer 5 and the metal component 2, facilitating the bonding between the active metal layer 5 and the metal component 2. Furthermore, the brazing filler layer 6 forms a meniscus at the location on the side of the metal component 2 to improve the bonding strength. Therefore, the brazing filler layer 6 forming the meniscus forms the outermost surface (hereinafter referred to as the "outer surface of the brazing filler layer") 61 that is in contact with the external atmosphere. The outermost surface 61 of the brazing filler layer is composed of brazing filler metal (silver and copper) and a low-melting-point metal. This is because, as described later in the manufacturing method, the low-melting-point metal contained in the active metal solder paste printed on the ceramic component 3 is heat-treated and diffuses to the outermost surface 61 of the solder layer. Symbol 7 represents the nickel-active metal compound in the bonding layer 4. Figure 4 (Three examples are shown below). As described in the manufacturing method below, the active metal contained in the active metal solder paste printed on the ceramic component 3 reacts with the nickel plating layer formed on the surface of the metal component 2 to form a nickel-active metal compound (hereinafter referred to as "nickel-active metal compound") mainly composed of nickel and active metal. The nickel-active metal compound 7 contains more than 50% by mass of nickel and active metal. The nickel-active metal compound 7 may contain solder metal (silver and copper), low-melting-point metals, etc. As mentioned above, the added low-melting-point metal diffuses quickly and reaches the outermost surface 61 of the solder layer first. Therefore, the nickel-active metal compound 7 exists inside the solder layer, even further than the outermost surface 61.

[0029] The distance L between the outermost surface 61 of the solder layer and the nickel-active metal compound 7 is greater than 10 μm. When the distance L is less than 10 μm, the external atmosphere such as oxygen and hydrogen reacts with the nickel-active metal compound 7 and causes embrittlement, which may reduce the airtightness and bonding strength.

[0030] The distance L between the outermost surface 61 of the solder layer and the nickel-active metal compound 7 is determined by observing the cross-section of the joint. Simply put, the distance is determined by the elemental distribution. Energy-dispersive X-ray fluorescence (EDX) is used for analysis. Figure 4 The cross-section of such a joint is color-mapped for nickel and active metal. Since the overlapping portion of nickel and active metal can be regarded as nickel-active metal compound 7, the distance L between the outermost surface 61 of the solder layer and nickel-active metal compound 7 can be measured.

[0031] In cases where the boundaries of nickel-active metal compound 7 are unclear, X-ray-based mass spectrometry analysis can be performed by transverse boundary analysis. Figure 5 (a) is an illustrative representation of... Figure 4 A graph showing the mass percentage of the constituent elements at a distance L from direction D1 in section C. The mass percentage was determined using energy-dispersive X-ray fluorescence (EDX) analysis. The mass percentage of the solder metals (silver and copper), active metals, low-melting-point metals, and nickel constituting solder layer 6 is shown, illustrating the distribution from the outer side (the portion of the ceramic metal circuit component exposed to atmosphere or gas) towards the inner side (the interior of the bonding layer). The minimum mass percentage (zero) represents the region where the observed element is absent; the mass percentage increases as the observed element is present. The location where any metal element exceeds 2% by mass is defined as the outermost position L1. Figure 5 (b) is to Figure 5 (a) is an enlarged view of part D. Furthermore, position L2, which serves as the boundary between the solder layer 6 and the nickel-active metal compound 7, is defined as a location where nickel content is 20% by mass or higher. Therefore, distance L is the distance between position L1 and position L2.

[0032] Figure 6 A process diagram illustrating the manufacturing method of the ceramic sealing component according to the embodiment. Figure 6 (a) is a longitudinal sectional view of ceramic component 3. Figure 6 In (a), chamfers are formed on the outer and inner periphery of the ceramic component 3. Even without chamfers, the ceramic sealing component 1 can be obtained, but ceramics are easily damaged by external impacts, etc., and chamfering is effective in preventing damage.

[0033] Figure 6 (b) shows the state of the active metal solder paste printed component 3, on which the dried active metal solder paste 8 has been printed. To print the paste on the end face of the ceramic component 3, which is a flat surface, the surface of the active metal solder paste 8 before bonding is approximately flat. Furthermore, in Figure 6 In (b), active metal solder paste 8 is printed only on the flat part at the end, but active metal solder paste 8 can also be printed on the chamfered part.

[0034] The active metal solder paste 8 is prepared by adding an organic binder and an organic solvent to a metal powder made by mixing one or more solder metals selected from copper and silver, one or more active metals selected from titanium, zirconium, and hafnium, and one or more low-melting-point metals selected from indium, tin, bismuth, antimony, and zinc. The organic binder is not particularly limited as long as it is a binder that is burned off during the drying and bonding processes. Ethyl cellulose is a preferred example of an organic binder. The organic solvent is not particularly limited as long as it is an organic solvent that is burned off during the drying and bonding processes. Terpineol and butyl carbitol are preferred examples of organic solvents. The active metal solder paste 8 is prepared by mixing active metal powder and solder metal powder, and then mixing the mixture with the organic binder and organic solvent. Furthermore, the proportion of active metal in the active metal solder component is 0.1% by mass or more and 15% by mass or less, preferably 0.5% by mass or more and 10% by mass or less.

[0035] The printing thickness of the active metal solder paste 8 is preferably 10 μm or more and 30 μm or less. If the printing thickness is less than 10 μm, the thickness of the active metal solder layer will be inconsistent, reducing the bonding strength. On the other hand, if it exceeds 30 μm, better results cannot be obtained. In addition, the paste is printed on the end face of the ceramic component with a uniform thickness by screen printing or the like. If the printing thickness is uneven, there will be excess active metal solder in the thicker parts, resulting in solder accumulation and cracks caused by thermal stress. In addition, poor leakage will occur in the thinner parts due to solder breakage. Therefore, the difference between the thick and thin parts of the printing thickness is preferably 5 μm or less.

[0036] Figure 6 (c) is in Figure 6(b) The state of a solder paste-printed component formed by printing dried solder paste 9 onto the surface of dried active metal solder paste 8. Solder paste 9 is composed of a metal that has good wettability with both the metal component 2 and the active metal solder. Silver solder is mostly used in the bonding of ceramic component 3 and metal component 2. Silver solder is mainly composed of silver and copper, but sometimes it also contains other metal components such as zinc and nickel. There is a silver solder (BAg-8) based on 72% silver and 28% copper that is frequently used in bonding ceramic component 3 and metal component 2. In BAg-8 based on "Silver Solder (JIS Z3261:1998)", silver (Ag) is 71% to 73% and copper (Cu) is 27% to 29% and other elements total 0.15% or less. Solder paste 9 is a substance in which solder metal powder is mixed and organic binder and organic solvent are added. There are no particular limitations on the organic binder as long as it is a binder that is burned off in the drying process and the bonding process. Ethyl cellulose is a preferred example of an organic adhesive. There are no particular limitations on the organic solvent, as long as it is burned off during the drying or bonding process. Preferred examples of organic solvents include terpineol and butyl carbitol. The solder paste is prepared, for example, by crushing and mixing metal powder, and then mixing it with an organic adhesive and an organic solvent.

[0037] The printing thickness of the solder paste 9 is preferably 70 μm or more and 300 μm or less. If the printing thickness is less than 70 μm, the thickness of the solder layer will be inconsistent, reducing the bonding strength. On the other hand, if it exceeds 300 μm, the above-mentioned effect cannot be obtained. In addition, the paste is printed on the end face of the ceramic component with a uniform thickness by screen printing or the like. If the printing thickness is uneven, there will be an excess of active metal solder in the thicker parts, resulting in solder accumulation and cracks caused by thermal stress. In addition, poor leakage will occur in the thinner parts due to solder breakage. Therefore, the difference in printing thickness between the thick and thin parts is preferably 20 μm or less.

[0038] The active metal solder paste 8 contains an active metal that reacts with nickel to form a brittle compound. Therefore, it is preferable that the solder paste 9 covers the entire surface of the active metal solder after bonding. When printing with the same pattern as the active metal solder paste 8, by making the viscosity of the solder paste 9 lower than that of the active metal solder paste 8, it is possible to expand and cover the entire surface during printing. Alternatively, by setting the printing pattern of the solder paste 9 to be larger (wider) than the printing pattern of the active metal solder paste 8, it is also possible to print in a way that covers the entire surface of the active metal solder layer. If the printing pattern is too large, the solder paste 9 will not react with the ceramic component 3 during heat treatment and will concentrate on the active metal solder layer or the metal component 2. However, if it forms clumps around the active metal solder layer or the metal component, it will become a cause of stress concentration. Therefore, when increasing the printing pattern of the solder paste 9, it is preferable to be within a range of 0.1 mm or less larger than the printing pattern of the active metal solder paste 8.

[0039] Figure 6 (d) is a state in which a metal component 2 is placed on the surface of the dried solder paste 9 printed on the solder paste printing component. In such a state... Figure 2 In the case of joining multiple metal parts 2, multiple metal parts 2 are set at the same time. The metal parts 2 are joined by heat treatment in the set state.

[0040] The heat treatment curve is preferably performed in two stages: a primary heating temperature and a secondary heating temperature that is higher than the primary heating temperature. Figure 7 This graph shows an example of a heat treatment curve, with temperature on the vertical axis and time on the horizontal axis. The initial heating temperature T1 needs to melt the low-melting-point metal, so it is set to a temperature higher than the melting point of the low-melting-point metal. Furthermore, to allow the low-melting-point metal to diffuse throughout the bonding layer, the holding time at the initial heating temperature T1 is preferably 10 to 30 minutes. If the holding time is less than 10 minutes, the low-melting-point metal will not diffuse throughout, and the effect of preventing the precipitation of nickel-active metal compounds at the outermost surface of the bonding layer will be lost. Moreover, even holding times exceeding 30 minutes cannot achieve the same effect.

[0041] Furthermore, the difference between the primary heating temperature T1 and the secondary heating temperature T2 (T2-T1) is less than 120°C. The secondary heating temperature T2 is performed under conditions where the metal has a lower melting point than the primary heating temperature T1, resulting in a lower melting temperature for the solder paste than usual. Therefore, if the difference between the primary heating temperature T1 and the secondary heating temperature T2 (T2-T1) is greater than 120°C and the secondary heating temperature T2 is high, the solder paste will spread on the surface of the metal component 2 without forming a meniscus. If a meniscus is not formed, the bonding strength of the metal component 2 may decrease. Additionally, the secondary heating temperature T2 is maintained for 1 to 10 minutes to melt the solder. If the maintenance time is less than 1 minute, sufficient heating to melt the solder cannot be achieved. Furthermore, even extending the time to more than 10 minutes does not achieve the same effect.

[0042] Figure 6 (e) shows the state where the metal component 2 is joined. The joining layer 4 rises to the side of the metal component 2 to form a strong joint. In this way, by covering the side of the metal component 2 with the joining layer 4, a high joint strength and a leak-free seal can be achieved inside and outside the component.

[0043] Next, the manufacturing method of the ceramic sealing member 1 according to the embodiment will be described. As long as the ceramic sealing member 1 has the above-described structure, its manufacturing method is not particularly limited, and the following methods can be cited as methods for obtaining a good yield.

[0044] One example of the ceramic component 3 in the embodiment is cylindrical, for example, with an outer diameter of 50 mm, an inner diameter of 38 mm, and a height of 50 mm. The ceramic component 3 is prone to developing chips and cracks at its corners due to external impacts, etc. Therefore, it is preferable to chamfer the outer and inner circumferences of the end face. The chamfer shape can be, for example, a C-shaped chamfer or an R-shaped chamfer, and the size of the chamfer is preferably 0.1 mm or more and 2 mm or less.

[0045] Examples of materials that can be used for the metal component 2 in this embodiment include iron and iron alloys, copper and copper alloys, iron-nickel alloys, tungsten, and molybdenum. One example of the shape of the metal component 2 in this embodiment is a generally cylindrical shape. For example, in... Figure 2 The height is 20mm, the outer diameter is 46mm, and the inner diameter is 44mm. These metal parts 2 are nickel-plated with a thickness of 0.5μm or more and 3.0μm or less to improve corrosion resistance and wettability.

[0046] The active metal solder and its form are paste. Sheets and wires are used in processes where the active metal solder is melted and processed into sheet or wire shapes, and then shaped into specified dimensions according to the product shape. In contrast, although paste has a paste manufacturing process, it is superior for printing and other processing at necessary locations according to the product shape. Furthermore, if the amount of active metal solder is too small, unbonded areas will occur, resulting in solder breakage; if it is too large, solder accumulation will cause stress failure. Therefore, the amount of paste used can be adjusted according to the bonding area.

[0047] Activated metal solder paste 8 is a paste made by adding an organic binder and an organic solvent to a substance containing active metal powder and solder metal powder. The organic binder is not particularly limited as long as it is an adhesive that is burned off during a drying process and a bonding process. Ethyl cellulose is a preferred example of an organic binder. The organic solvent is not particularly limited as long as it is an organic solvent that is burned off during a drying process and a bonding process. Terpineol and butyl carbitol are preferred examples of organic solvents. The activated metal solder paste is prepared, for example, by pulverizing and mixing active metal powder and solder metal powder, and then mixing it with an organic binder and an organic solvent. Furthermore, the proportion of active metal contained in the activated metal solder component is 0.1% by mass or more and 15% by mass or less, preferably 0.5% by mass or more and 10% by mass or less.

[0048] The printing thickness of the active metal solder paste 8 is preferably 10 μm or more and 30 μm or less. If the printing thickness is less than 10 μm, the thickness of the active metal solder layer will be inconsistent, reducing the bonding strength. On the other hand, if it exceeds 30 μm, better results cannot be obtained. In addition, the paste is printed on the end face of the ceramic component 3 with a uniform thickness by screen printing or the like. If the printing thickness is uneven, there will be excess active metal solder in the thicker parts, resulting in solder accumulation and cracks caused by thermal stress. In addition, poor leakage will occur in the thinner parts due to solder breakage. Therefore, the difference in printing thickness between the thick and thin parts is preferably 5 μm or less.

[0049] The paste printed on ceramic component 3 is dried in atmospheric conditions. If the drying temperature is low and the drying time is short, the solution components of the paste cannot evaporate sufficiently, and residual solution may evaporate during bonding, creating voids. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface will progress, and the bonding temperature may change. Therefore, the drying temperature is 50°C or higher and 100°C or lower, preferably 60°C or higher and 80°C or lower. The drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0050] The solder paste 9 is composed of a metal that has good wettability with the metal component 2 and the active metal solder. Silver solder is mostly used in the bonding of the ceramic component 3 and the metal component 2. Silver solder is mainly composed of silver and copper, but sometimes also contains other metals such as zinc and nickel. There is a silver solder (BAg-8) based on 72% silver and 28% copper, which is frequently used in bonding the ceramic component 3 and the metal component 2. In BAg-8 based on "Silver Solder (JIS Z3261:1998)", silver (Ag) is 71% to 73% or less, copper (Cu) is 27% to 29% or less, and other elements total 0.15% or less. The solder paste 9 is a substance in which solder metal powder is mixed and an organic binder and an organic solvent are added. The organic binder is not particularly limited as long as it is a binder that is burned off during the drying and bonding processes. Ethyl cellulose is a preferred example of an organic binder. There are no particular limitations on the organic solvent, as long as it is burned off during the drying or bonding process. Preferred examples of organic solvents include terpineol and butylcarbidol. Solder paste is prepared, for example, by crushing and mixing metal powder, and then mixing it with an organic binder and an organic solvent.

[0051] The printing thickness of the solder paste 9 is preferably 70 μm or more and 300 μm or less. If the printing thickness is less than 70 μm, the thickness of the solder layer will be inconsistent, reducing the bonding strength. On the other hand, if it exceeds 300 μm, the above-mentioned effect cannot be obtained. In addition, the paste is printed on the end face of the ceramic component 3 with a uniform thickness by screen printing or the like. If the printing thickness is uneven, there will be excess solder in the thicker parts, resulting in solder accumulation and cracks caused by thermal stress. In addition, leakage will occur in the thinner parts due to the breakage of the metal solder. Therefore, the difference in printing thickness between the thick and thin parts is preferably 20 μm or less, and more preferably 15 μm or less.

[0052] The solder paste 9 printed on the active metal solder layer formed by the active metal solder paste 8 is dried in atmospheric air. If the drying temperature is low and the drying time is short, the solution components of the paste cannot evaporate sufficiently, and the residual solution may evaporate during bonding, creating voids. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface will progress, and the bonding temperature conditions may change. Therefore, the drying temperature is 50°C or higher and 100°C or lower, preferably 60°C or higher and 80°C or lower. Furthermore, the drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0053] After the solder paste 9 is dried, the metal part 2 is placed on the dried paste surface and heated for bonding. The heating process preferably has two stages: a first heating and a second heating at a higher temperature. The first heating temperature T1 is 650°C or higher and 850°C or lower, preferably 700°C or higher and 800°C or lower. The bonding time for the first heating is preferably in the range of 10 to 30 minutes when the first heating temperature is reached. Furthermore, the difference between the second heating temperature T2 and the first heating temperature T1 (T2-T1) is preferably 120°C or lower. The bonding time for the second heating is preferably between 1 and 10 minutes when the second heating temperature T2 is reached. Figure 6 As shown in (e), the bonding layer 4 melts and wets and expands on the surface of the metal component 2, thus achieving a sealable bond. If the bonding temperature is low and the bonding time is short, the active metal solder may not melt sufficiently and fail to bond. Conversely, if the bonding temperature is high and the bonding time is long, the solder may melt excessively and wet expand, resulting in solder breakage and voids.

[0054] Furthermore, the bonding atmosphere is selected as needed and is a non-oxidizing atmosphere. Examples of non-oxidizing atmospheres include nitrogen atmospheres and nitrogen-hydrogen atmospheres. By setting the atmosphere to non-oxidizing, oxidation of the bonding layer 4 can be suppressed. This improves the bonding strength. The furnace used in the bonding process can be a continuous furnace or a batch furnace. Continuous furnaces offer excellent mass production capabilities, while batch furnaces facilitate temperature and atmosphere control. Bonding is performed by heating the components in the aforementioned atmosphere for a specified time.

[0055] The thickness of the bonding layer 4, which joins the ceramic component 3 and the metal component 2, is preferably 80 μm or more. This is because, as described above, the bonding layer 4 is formed of active metal solder paste 8 with a thickness of 10 μm or more and solder paste 9 with a thickness of 70 μm or more. Furthermore, the thickness of the bonding layer 4 at this point represents the distance between the bonding surface of the metal component 2 and the ceramic component 3. For example, in… Figure 6 In (e), the front end (end face) of the metal component 2 is flat. In this case, the thickness of the bonding layer 4 represents the distance between the flat portion approximately at the center of the metal component 2 and the flat portion of the ceramic component 3. Furthermore, when the front end of the metal component 2 is bent into a flange shape and joined to the ceramic component 3, the thickness of the bonding layer 4 is defined as the approximately central portion of the bent flange. Moreover, when the front end of the metal component 2 is sharp, such as in a U-shape or V-shape, the thickness of the bonding layer 4 is defined as the distance between the sharp front end portion and the ceramic surface.

[0056] The above describes the manufacturing method of the ceramic sealing component 1 according to the embodiments of the present invention, which can obtain a ceramic sealing component with excellent cost performance while maintaining the airtight performance as a sealing component.

[0057] (Examples 1-6, Comparative Examples 1-6) Granulated powder with a composition of 92% by mass alumina was prepared by adding manganese oxide (MnO2), silicon dioxide (SiO2), and magnesium oxide (MgO) as additives to alumina. The granulated powder was molded and sintered at 1500°C in atmospheric atmosphere to obtain a cylindrical ceramic part with an outer diameter of 50 mm, an inner diameter of 40 mm, a height of 50 mm, and chamfers of both the outer and inner diameters (C-angle and C-angle). Separately, aluminum nitride (AlN) granulated powder was prepared by adding 3% by mass yttrium oxide (Y2O3) as an additive. The granulated powder was molded and sintered at 1800°C in nitrogen atmosphere to obtain a cylindrical ceramic part of the same dimensions as the alumina part.

[0058] The metal parts are made by stamping iron, stainless steel (SUS304), and Kova iron-nickel-cobalt alloy into cylindrical shapes with an outer diameter of 46 mm, an inner diameter of 44 mm, and a height of 20 mm, as shown in Table 1. Furthermore, nickel plating with the thicknesses shown in Table 1 is applied to the surface of the machined metal parts.

[0059] Next, with Figure 1 The mass percentage of the mixed metal powders shown represents silver powder, copper powder, low-melting-point metal powder, and active metal powder. In Example 1, the proportions are 30% by mass of copper powder, 10% by mass of indium powder, 2% by mass of titanium, and the remainder being silver powder. It should be noted that in Example 1, this is labeled "Ag-30Cu-10In-2Ti" in Table 1, and is similarly labeled in other examples and comparative examples. The mixed metal powders were combined with ethyl cellulose and terpineol, and then pasted using a mixer to prepare an active metal solder paste. A 30 μm thick active metal paste was screen-printed onto the upper and lower ends (ring portion) of the ceramic component using a 100-mesh screen with an outer diameter of 48 mm and an inner diameter of 42 mm, and dried at 100°C in the atmosphere. The active metal solder paste was then dried.

[0060] Next, silver powder and copper powder were mixed to a metal powder ratio of 72:28 by mass, and paste-formed using the same method as for active metal solder paste to prepare silver solder paste. At the upper and lower ends (ring portions) of the ceramic component with the active metal solder layer, a 100μm thick solder paste was screen-printed using a 100-mesh screen (48mm outer diameter × 42mm inner diameter) and dried at 100°C in the atmosphere. Then, the components were arranged in a fixture in the order of metal component, ceramic component, and metal component again, and dried in a vacuum furnace (1×10⁻⁶) under vacuum. -2 (Pa or below) is heated for 20 minutes at the primary heating temperature T1 recorded in Table 2, and then heated for 5 minutes at the secondary heating temperature, thereby joining the metal part and the ceramic part to produce a ceramic sealing part.

[0061] As shown in Tables 1 and 2, in the embodiments, the values ​​of nickel plating thickness, active metal solder paste ratio, and heating temperature difference (T2-T1) are within the preferred range. On the other hand, in the comparative examples, they are outside the preferred range.

[0062] Next, as Figure 2 Cut the ceramic sealing component in the middle, such as Figure 3 The joint area was then ground. Next, the periphery of the joint area was subjected to surface analysis of the constituent elements using energy-dispersive X-ray fluorescence (EDX). The determination of the composition was based on the results of the surface analysis. Figure 4 At position D1, perform a mass percentage analysis. Calculate the mass percentage analysis value. Figure 5 The engagement distance L was such. The results are shown in Table 3.

[0063] Next, to confirm the brittleness from the external atmosphere, a hydrogen heating test was conducted. In the hydrogen heating test, the heating treatment was performed in a belt furnace with a 20% hydrogen nitrogen-hydrogen atmosphere at 400°C or higher for 10 minutes as one heating treatment, and the ceramic sealing component underwent five heating treatments. The joint after the heating treatment was visually observed; cases without surface color change (discoloration) were evaluated as acceptable (○), while cases with discoloration (including partial discoloration such as spots) were evaluated as unacceptable (×).

[0064] Next, the upper and lower metal parts of the ceramic sealing component after hydrogen heating were stretched using an Instron tensile testing machine to determine the joint strength.

[0065] In addition, the upper part of the hydrogen-heat-treated ceramic sealing component was coated with silicone and pressed using a circular clamp made of Bioton Gome. The lower part was fixed to a helium leak detector for suction to conduct a helium leak test. The helium leak test was conducted according to the vacuum blowing method (spray method) of "Helium Leak Test Method" (JIS Z2331:2006), and no 1×10⁻⁶ leak occurred under a vacuum of 1.3 μPa. -9 Pa·m 3 Leakage of 1 / s or more is considered acceptable (○), while leakage is considered unacceptable (×).

[0066] As shown in Table 3, the preferred range for the bonding distance L in the embodiments is 10 μm or more. This is because, under the bonding conditions of the embodiments, the precipitation of nickel-active metal compounds on the surface of the bonding layer due to diffusion of low-melting-point metals is prevented. On the other hand, in some of the comparative examples, the preferred range is not met. This is because a barrier to prevent the precipitation of nickel-active metal compounds is not formed.

[0067] Furthermore, as shown in Table 3, no discoloration was observed in the examples regarding the hydrogen heating test. This is because the bonding distance L was sufficiently large, thus preventing hydrogen-induced embrittlement. On the other hand, discoloration was observed in the comparative examples. This is because the bonding distance L was insufficient, resulting in hydrogen-induced embrittlement.

[0068] Furthermore, as shown in Table 3, the bonding strength of the embodiments is a good value of 40 MPa or more. This is because, under the bonding conditions of the embodiments, a strong bonding layer is formed, and no embrittlement occurs during the hydrogen heating test. In contrast, in the comparative examples, the strength is 25 MPa or less. This is because embrittlement progresses during the hydrogen heating test, resulting in a decrease in bonding strength.

[0069] Furthermore, the ceramic sealing component of the embodiment did not exhibit leakage problems in the helium leak test. This is because it did not become embrittled in the hydrogen heating test. In contrast, leakage problems occurred in the comparative example. This is because embrittlement progressed in the hydrogen heating test, thus compromising hermeticity due to reduced bond strength.

[0070] As can be seen from the results shown above, the embodiments demonstrate improved tolerance to external atmospheres compared to the comparative examples.

[0071] The above embodiments of the present invention have been illustrated, but these embodiments are merely examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments or variations thereof are included within the scope or spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents. Furthermore, the above-described embodiments can be combined with each other.

Claims

1. A ceramic sealing component, characterized in that, It is a ceramic sealing component formed by bonding a ceramic component to a nickel-plated metal component through a bonding layer containing silver, copper, active metals, and low-melting-point metals. A compound of nickel and the active metal is formed in the bonding layer. The distance between the compound and the outermost surface of the solder layer in contact with the external atmosphere is greater than 10 μm.

2. The ceramic sealing component according to claim 1, characterized in that, The active metal is selected from one or more metals chosen from titanium, zirconium, and hafnium, and the low melting point metal is selected from one or more metals chosen from indium, tin, bismuth, antimony, and zinc.

3. The ceramic sealing component according to claim 1 or 2, characterized in that, The metal component is selected from one or more metal components selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

4. The ceramic sealing component according to claim 1 or 2, characterized in that, The thickness of the nickel plating is 0.5 μm or more.

5. The ceramic sealing component according to claim 1 or 2, characterized in that, The ceramic components are made of alumina, aluminum nitride, silicon nitride, or alumina with added zirconium oxide.

6. A method for manufacturing a ceramic sealing component, characterized in that, It is a method for manufacturing a ceramic sealing component by joining a ceramic component with a nickel-plated metal component, comprising the following steps: The process of printing and drying an active metal paste containing at least copper, an active metal, and a low-melting-point metal on the ceramic component to obtain an active metal paste printed component; The process of printing and drying solder paste containing at least silver and copper to obtain a solder paste printed component, in a manner that covers the entire surface of the active metal paste printed component; and The metal component is placed on the solder paste printing component, and a bonding process is performed in which the difference between the primary heating temperature T1 and the secondary heating temperature T2 (which is higher than the primary heating temperature) is less than 120°C.

7. The method for manufacturing a ceramic sealing component according to claim 6, characterized in that, The active metal paste has a printing thickness of less than 30 μm and a difference in printing thickness of less than 5 μm, while the solder paste has a thickness of more than 70 μm and a difference in printing thickness of less than 20 μm.

8. The method for manufacturing a ceramic sealing component according to claim 6 or 7, characterized in that, The holding time for the primary heating temperature is more than 10 minutes and less than 30 minutes, and the holding time for the secondary heating temperature is more than 1 minute and less than 10 minutes.

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