Ceramic-sealed component and method for manufacturing same

Abstract

According to an embodiment of the present invention, a ceramic-sealed component in which a ceramic component and a metal component are bonded via a bonding layer is such that the bonding layer includes: one or more metals selected from silver and copper; an active metal; and a low-melting-point metal having a lower melting point than silver. In the ceramic-sealed component, when the portion of the bonding layer from the center to the ceramic component side along a direction orthogonal to the ceramic component plane is defined as a ceramic-side layer, and the portion from the center to the metal component side is defined as a metal-side layer, the mass% of the low-melting-point metal in the ceramic-side layer is greater than the mass% of the low-melting-point metal in the metal-side layer.

Description

Ceramic sealing component and method for manufacturing the same

[0001] The embodiments generally relate to ceramic sealing components (hereinafter referred to as "ceramic sealing components") in which ceramic components used in power pipes and the like are joined to metal components, and a method for manufacturing the same.

[0002] As ceramic sealing components for magnetrons, power tubes, and electron tubes, a metallized layer mainly composed of high-melting-point metals such as molybdenum (Mo) is used, along with alumina (aluminum oxide: Al). ２ O ３ Ceramic sealing components are used, which are formed on ceramic parts such as ). Ceramic sealing components bond ceramics and metal, sealing the inside of the component hermetically by blocking out the outside air, thereby protecting the inside from the external environment and providing electrical insulation through the ceramics. In ceramic sealing components, a metallized layer mainly composed of molybdenum is formed on the ring portions of the upper and lower ends of a cylindrical ceramic part made of alumina sintered body. A nickel (Ni) layer of a predetermined thickness is formed on the surface of this metallized layer to improve the bonding strength with the metal part and to perform sealing. This nickel portion and the cylindrical metal part are joined with silver brazing material (e.g., BAg-8).

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

[0004] Furthermore, a vacuum switch outer tube in which a nickel-based alloy is bonded to ceramics using an active metal without using high-melting-point metals such as molybdenum is disclosed (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 cause instability in the bond state. In addition, an active metal layer formed by adding tin to a brazing material containing an active metal (hereinafter referred to as "active metal material") is disclosed (Patent Document 3). According to Patent Document 3, the melting point of the active metal material can be lowered by adding tin.

[0005] Japanese Patent Application No. 1-46978, Japanese Unexamined Patent Publication No. 2001-220253, Japanese Patent No. 7330382

[0006] Metallizing ceramic surfaces using high-melting-point metals such as molybdenum requires a furnace to heat to temperatures above 1400°C, and the high-temperature processing incurs significant energy costs. Furthermore, it is difficult to braze the formed high-melting-point metal metallized layer to metal parts, necessitating surface plating with nickel or other metals, thus complicating the process.

[0007] In contrast, to ensure sealing (airtightness) when joining active metal materials, the joining width tends to be wider, but the thermal expansion coefficients of ceramics and metals are different (for example, the thermal expansion coefficient of alumina is 7.2 × 10⁻⁶). －６ 16.5 × 10⁻¹⁰ of copper per °C －６ / ℃, iron 11.7 × 10 －６ (At 0°C / °C), cracks and other defects are likely to occur due to the difference in thermal expansion. Brazing with active metal materials allows for joining at a lower temperature compared to metallization with high-melting-point metals, thus mitigating the difference in thermal expansion. When joining ceramic parts and metal parts using active metal materials or brazing materials that do not contain active metals (hereinafter referred to as "inert metal materials") (for example, silver brazing material), it is advantageous to join at a higher temperature to increase the joint strength. However, if the joining temperature is too high, there is a possibility of joining defects occurring where the silver and copper components in the active metal material or silver brazing material dissolve and separate, reducing the joint strength with the ceramic parts.

[0008] Furthermore, when joining ceramic and metal parts using brazing material, an active metal layer made of active metal material is first formed on the surface of the ceramic part, and then the metal part is joined by brazing using inert metal material placed on the active metal layer. For this reason, brazing of active metal material was performed at a higher temperature than brazing of inert metal material. Consequently, the melting point of active metal material was higher than that of inert metal material. In order to raise the melting point of active metal material, it is necessary to include a large amount of metals with high melting points, such as copper (Cu) and silver (Ag), which tend to melt and separate from other metal components of the brazing material during the heating process. This melting and separation can cause unevenness in the joint, potentially leading to leakage defects and crack defects. In addition, inert metal material is often processed into foil shapes, and in the case of small-batch, high-mix production, processing of numerous inert metal material parts is required, which is a source of increased costs.

[0009] Furthermore, while lowering the bonding temperature is effective in mitigating the difference in thermal expansion coefficients between ceramic and metal parts, adding low-melting-point metals such as tin tends to cause the low-melting-point metal to precipitate on the surface of the bonded layer, resulting in increased surface irregularities. These irregularities on the bonded layer surface are prone to becoming fracture initiation points due to external impacts and thermal cycling, potentially leading to poor bond strength and leakage failures.

[0010] The embodiment solves these problems and relates to a ceramic sealing part and a method for manufacturing the same, which prevents separation of silver and copper in the bonding layer when a ceramic part and a metal part are joined by brazing with an active metal material and an inert metal material, and reduces the deposition of low-melting-point metals in the active metal material component onto the surface of the bonding layer, thereby suppressing bonding defects and leakage defects.

[0011] In the embodiment, a ceramic-sealed component in which a ceramic component and a metal component are joined by a bonding layer comprises a bonding layer containing one or more metals selected from silver and copper, an active metal, and a low-melting-point metal having a lower melting point than silver. In this ceramic-sealed component, if the bonding layer is defined as a ceramic-side layer extending from the center toward the ceramic component along a direction perpendicular to the plane of the ceramic component, and a metal-side layer extending from the center toward the metal component, then the mass percentage (wt%) of the low-melting-point metal in the ceramic-side layer is greater than the mass percentage of the low-melting-point metal in the metal-side layer.

[0012] In the ceramic sealing component, when the bonding layer is divided into N layers (where N is an integer of 20 or more) along the direction, and the mass percentage of low-melting-point metal is measured in each layer, it is preferable that the mass percentage of low-melting-point metal in the ceramic side layer is the average value of the mass percentages of low-melting-point metal measured in each of the N / 2 layers constituting the ceramic side layer, and the mass percentage of low-melting-point metal in the metal side layer is the average value of the mass percentages of low-melting-point metal measured in each of the N / 2 layers constituting the metal side layer.

[0013] In the ceramic sealing component, silver and copper are molten in the bonding layer. When the bonding layer is divided into N layers along that direction, and the mass percentages of silver, copper, and active metal are measured in each layer, and the mass percentages of silver, copper, and active metal are plotted from the ceramic component side to the metal component side of the bonding layer, it is preferable that when there are maximum values ​​of Wm for the mass percentage of active metal, Wc for the mass percentage of copper, and Wa for the mass percentage of silver, the ratio of the second largest maximum value Wm2 for the mass percentage of active metal to the maximum value Wm is 0.7 or less, the ratio of the minimum value Wc1 for the mass percentage of copper to the maximum value Wc is 0.3 or more, and the ratio of the maximum value Waq for the mass percentage of silver in the 1 / 4 range on the ceramic component side to the maximum value Wa is 0.3 or more and 0.5 or less.

[0014] In the ceramic sealing component, it is preferable that in the plot of mass percent of copper, the proportion of values ​​less than or equal to 0.5Wc (half of the maximum value Wc) is 40% or less, and in the plot of mass percent of silver, the proportion of values ​​less than or equal to 0.5Wa (half of the maximum value Wa) is 50% or less.

[0015] In the ceramic sealing component, it is preferable that the bonding layer contains one or more metals selected from titanium, zirconium, and hafnium as the active metal.

[0016] In the ceramic sealing component, the thickness of the bonding layer is 70 μm or more.

[0017] In the ceramic sealing component, it is preferable that the metal component is made of one or more metals selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

[0018] In the ceramic sealing component, it is preferable that the ceramic component be made of alumina, aluminum nitride, or silicon nitride.

[0019] Furthermore, the manufacturing method for ceramic sealing parts that join ceramic parts and metal parts according to the embodiment includes the steps of: printing and drying an activated metal material paste made of an activated metal material containing one or more metals selected from silver and copper and a low melting point metal with a lower melting point than silver on the end face of a ceramic part, and heating it at a heating temperature T1 of 600°C to 850°C to form an activated metal layer; and printing and drying an inert metal material paste made of an inert metal material containing silver on the surface of the formed activated metal layer, then placing a metal part on it and heat-treating it at a heating temperature T2 to form an inert metal layer and join the metal part to the ceramic part. In this manufacturing method, the temperature difference (T2-T1) obtained by subtracting the heating temperature T1 from the heating temperature T2 is 20°C or more.

[0020] In this manufacturing method, it is preferable to include one or more metals selected from titanium, zirconium, and hafnium as the active metal.

[0021] In this manufacturing method, it is preferable that the printing thickness of the active metal paste is 20 μm or more, and the printing thickness of the inert metal paste is 50 μm or more.

[0022] A perspective view showing an example of a ceramic sealing component according to the embodiment. A longitudinal cross-sectional view showing an example of a ceramic sealing component according to the embodiment. A diagram showing an example of a cross-section of the joint of a ceramic sealing component according to the embodiment. A diagram showing an example of a manufacturing process for a ceramic sealing component according to the embodiment. An enlarged view of an example of a cross-section of the joint of a ceramic sealing component according to the embodiment. A diagram showing the mass percentage of an example of a cross-section of the joint of a ceramic sealing component according to the embodiment. A diagram showing the mass percentage of an example of a cross-section of the joint of a ceramic sealing component according to a comparative example. A diagram showing the mass percentage of an example of a cross-section of the joint of a ceramic sealing component according to a comparative example. Embodiment

[0023] In the embodiment, a ceramic-sealed component in which a ceramic component and a metal component are joined by a bonding layer comprises a bonding layer containing one or more metals selected from silver and copper, an active metal, and a low-melting-point metal having a lower melting point than silver. In this ceramic-sealed component, if the bonding layer is defined as a ceramic-side layer extending from the center toward the ceramic component along a direction perpendicular to the plane of the ceramic component, and a metal-side layer extending from the center toward the metal component, then the mass percentage of the low-melting-point metal in the ceramic-side layer is greater than the mass percentage of the low-melting-point metal in the metal-side layer.

[0024] Furthermore, the manufacturing method for ceramic sealing parts that join ceramic parts and metal parts according to the embodiment includes the steps of: printing and drying an activated metal material paste made of an activated metal material containing one or more metals selected from silver and copper and a low melting point metal with a lower melting point than silver on the end face of a ceramic part, and heating it at a heating temperature T1 of 600°C to 850°C to form an activated metal layer; and printing and drying an inert metal material paste made of an inert metal material containing silver on the surface of the formed activated metal layer, then placing a metal part on it and heat-treating it at a heating temperature T2 to form an inert metal layer and join the metal part to the ceramic part. In this manufacturing method, the temperature difference (T2-T1) obtained by subtracting the heating temperature T1 from the heating temperature T2 is 20°C or more.

[0025] Figure 1 shows an example of a perspective view of a ceramic sealing component 1 according to an embodiment. Reference numeral 2 denotes a cylindrical metal component, and reference numeral 3 denotes a cylindrical ceramic component. The metal component 2 is joined to the ceramic component 3 by two ring-shaped bottom surfaces (first bottom surface and second bottom surface) which are the joining parts. Figure 1 shows an example in which the metal component 2 is joined to the first bottom surface (e.g., the upper end surface) of the ceramic component 3 and to the second bottom surface (e.g., the lower end surface). The embodiment is not limited to this form, and may also be a form in which a metal component is joined to a rectangular tubular ceramic component, a form in which there is no metal component on one bottom surface (e.g., the lower bottom surface) and a metal component is joined only to the other bottom surface (e.g., the upper end surface), or a form in which a metal component is joined to a ceramic component that has openings in two or more places on one bottom surface (e.g., the upper bottom surface).

[0026] The ceramic sealing component 1 according to this embodiment includes, for example, a ceramic component 3 made of cylindrical alumina and a bonding layer 10 (shown in Figure 3) provided on a part of the surface of the ceramic component. The bonding layer 10 here is provided with an activated metal layer 4 (shown in Figure 3) formed from an activated metal material which is a mixture of metals such as copper (Cu) and silver (Ag) on ​​the ceramic component 3 side, activated metals such as titanium (Ti), zirconium (Zr), and hafnium (Hf), and low melting point metals such as tin (Sn) and indium (In), which have a lower melting point than silver (961°C). The metal component 2 is, for example, a cylindrical metal component made of Kovar (Fe-Ni-Co), a special alloy mainly composed of iron (Fe), nickel (Ni), and cobalt (Co), or copper (Cu).

[0027] Figure 2 shows an example of a cross-sectional view of a ceramic sealing component according to an embodiment. Reference numeral 1 denotes a ceramic sealing component, reference numeral 2 denotes a metal component, and reference numeral 3 denotes a ceramic component. The ceramic component 3 is preferably made of one of alumina, aluminum nitride, or silicon nitride. Alumina includes alumina-based ceramics obtained by adding other ceramics to alumina. For example, zirconia-added alumina (Algyl) is a sintered body obtained by mixing alumina and zirconium oxide. In addition, alumina may have sintering aids other than zirconia added to it. The added sintering aids form a grain boundary phase consisting of a glass 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 them in a total amount of 1% by mass or more and 15% by mass or less in terms of individual metal elements. Furthermore, it is preferable that the ceramic component 3 is alumina, which has good cost performance as an insulating sealing component.

[0028] The material of the metal part 2 joined to the ceramic part 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 steel such as rolled steel and alloy steels such as chromium steel. Examples of iron-nickel alloys include 42 Alloy (Ni 42 mass%, Mn 0.8 mass% or less, remainder Fe) and Kovar (Ni 29 mass%, Co 17 mass%, remainder Fe). Iron and iron alloys offer excellent cost performance, while iron-nickel alloys offer superior physical properties such as thermal expansion coefficient. Furthermore, copper and copper alloys are easily deformable to relieve stress due to differences in thermal expansion, and it is preferable to form metal parts from copper and copper alloys when heat has a significant impact. 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. Therefore, depending on the application, it is preferable to form the metal part 2 from iron and iron alloys, iron-nickel alloys, copper and copper alloys. It is also possible to use two or more types of metal in the ceramic part 3, such as using Kovar for one metal part 2 and copper for the other metal part 2. Furthermore, the metal part 2 is manufactured by processing it into a predetermined shape by pressing, cutting, bending, etc. In addition, it is possible to plate it with nickel or the like to improve corrosion resistance and wettability.

[0029] Figure 3(a) shows an example of a longitudinal cross-section of the joint of a ceramic sealing component 1 according to an embodiment, which is an enlarged view of section A in Figure 2. Reference numeral 2 denotes a metal component, reference numeral 3 denotes a ceramic component, reference numeral 10 denotes a bonding layer, reference numeral 4 denotes the active metal layer of the bonding layer 10, and reference numeral 5 denotes the inert metal layer of the bonding layer 10. In Figure 3(a), the tip of the metal component 2 on the bonding layer 10 side is bent and is joined to the ceramic component 3 in a planar manner via the bonding layer 10. Also, in Figure 3(b), which is an enlarged view of section A in the same Figure 2, the tip of the metal component 2 on the bonding layer 10 side is joined to the ceramic component 3 via the bonding layer 10.

[0030] The bonding layer 10 forms an active metal layer 4 at a low temperature using an active metal material containing a ceramic component 3 and an easily wettable active metal. To prevent a decrease in strength due to the separation of silver and copper, copper is selected as it is more cost-effective than silver, and components such as tin (Sn), which has a low melting point, are added to the active metal material to lower the melting point of copper. Furthermore, since the active metal in the active metal layer 4 reacts with hydrogen and becomes brittle, making it prone to leakage failure, an inert metal paste 6 made of an inert metal material (e.g., silver solder) is printed to cover the active metal layer 4, as described later, and the metal component 2 is joined by heating in a vacuum or a non-oxidizing atmosphere (e.g., a nitrogen-hydrogen mixed atmosphere). At this time, if the heating temperature T2 is too high, the silver in the inert metal material (e.g., silver solder) will diffuse too much into the active metal layer 4, so the heating temperature T2 is set to +50°C or less of the melting temperature T of the silver solder. Furthermore, if the heating temperature T2 is too low, the inert metal material paste 6 (for example, silver solder paste) will not wet the active metal layer 4. Therefore, it is preferable to set the heating temperature T2 to +20°C or higher of the melting temperature T of the silver solder. In other words, it is preferable that the heating temperature T2 of the silver solder be between T+20°C and T+50°C. For example, the melting temperature of silver solder (BAg-8), a typical example of an inert metal material, is approximately 780°C. Therefore, when using silver solder, the heating temperature T2 is preferably between 800°C and 830°C, and the temperature difference (T2-T1) is within the range described later.

[0031] The active metal material of the active metal layer 4 contains active metals such as Ti (titanium). Examples of active metals other than Ti include Zr (zirconium) and Hf (hafnium). As an active metal, a mixture of Ti and copper (Cu) is also possible. For example, Ti is 0.1% to 10% by mass, and Cu is the remainder. Another example of an active metal is a mixture of Ti, Ag, and Cu. Ti is 0.1% to 10% by mass, Cu is 10% to 60% by mass, and Ag is the remainder. In addition, a low-melting-point metal is added to the active metal material to lower the melting point of the active metal material during bonding. The low-melting-point metal has a lower melting point than the other elements contained in the bonding layer. Examples of low-melting-point metals are indium (157°C), tin (232°C), bismuth (271°C), antimony (630°C), and zinc (419°C). The melting points of these low-melting-point metals are lower than those of other metals in the bonding layer, such as silver (961°C), copper (1085°C), titanium (1666°C), zirconium (1852°C), and hafnium (2233°C). Therefore, adding one or more low-melting-point metals to the active metal material in an amount of 1% to 15% by mass lowers the bonding temperature.

[0032] Furthermore, to control the diffusion of silver and copper, if necessary, one or more elements selected from aluminum (Al), silicon (Si), carbon (C), and magnesium (Mg) may be added to the active metal material in an amount of 1% to 15% by mass. The active metal material is printed as a paste onto the surface of the ceramic part 3 and then dried. Subsequently, a metallized layer (active metal layer 4) is formed on the surface of the ceramic part by heating in a vacuum or in a non-oxidizing gas at a heating temperature T1 of 600°C to 850°C. Next, an inert metal material paste 6 (for example, silver brazing paste) is printed onto the surface of the formed active metal layer 4 and then dried. Subsequently, the metal part 2 is placed in contact with the printed and dried paste surface, and the ceramic part 3 and the metal part 2 are joined by heating in a vacuum or in a non-oxidizing gas at a heating temperature T2 of 620°C to 910°C, with a temperature difference (T2-T1) of 20°C to 60°C.

[0033] Figure 4 shows a process diagram of the manufacturing method of the ceramic sealing part 1 according to the embodiment shown in Figure 3(b). Figure 4(a) is a cross-sectional view of the ceramic part 3. In Figure 4(a), chamfers are formed on the outer and inner circumferences of the ceramic part 3. Although it can be used even without chamfers, the end faces of the ceramic part 3 are prone to chipping due to external impacts, and chamfers are effective in preventing chipping. Figure 4(b) shows the ceramic part 3 after the activated metal material has been printed as a paste, dried, and then heated in a vacuum or non-oxidizing gas to form the activated metal layer 4. Since the paste is printed on the flat end face of the ceramic part 3, the surface of the activated metal layer 4 before joining is substantially flat. In addition, although the activated metal material is printed as a paste only on the flat part of the end face of the ceramic part 3 in Figure 4(b), it is also possible to print the paste on the chamfered portion as well.

[0034] Figure 4(c) shows the state after printing and drying an inert metal paste 6 made of an inert metal material on the surface of the activated metal layer 4. Since the activated metal layer 4 contains an activated metal that is prone to hydrogen embrittlement, it is preferable that the inert metal paste 6 covers the entire surface of the activated metal layer 4 after bonding. When the inert metal paste 6 is printed in layers with the same printing pattern, it is possible to spread the inert metal paste 6 during printing and cover the entire surface of the activated metal layer 4 by making the viscosity of the inert metal paste 6 slightly lower than the viscosity of the activated metal paste. It is also possible to print so that the entire surface of the activated metal layer 4 is covered by a printing pattern that is larger (wider) than the printing pattern of the inert metal paste 6. If the printing pattern is made too large, the inert metal paste 6 will accumulate on the activated metal layer 4 and metal parts 2 without reacting with the ceramic parts 3 when heated, and if it exists in clumps around the activated metal layer 4 and metal parts 2 at this time, it will cause stress concentration. For this reason, when making the printing pattern of the inert metal paste 6 larger, it is preferable to make it 0.1 mm or less larger than the printing pattern of the activated metal paste made of an activated metal material.

[0035] Figure 4(d) shows a state where the metal component 2 is placed on the surface of the printed and dried inert metal material paste 6. When joining a plurality of metal components 2 as shown in Figure 2, they are placed simultaneously. With the metal component 2 placed on the surface of the inert metal material paste 6, heating is performed to join the metal component 2 to the inert metal layer 5 (ceramics component 3).

[0036] Figure 4(e) shows a state where the metal component 2 is joined to the inert metal layer 5. The inert metal layer 5 has climbed up the side surface of the metal component 2 to form a strong joining state. Thus, by covering the tip of the metal component 2 with the inert metal layer 5, sealing without leakage inside and outside the component becomes possible.

[0037] Next, a method for manufacturing the ceramics sealing component 1 according to the embodiment will be described. As long as the ceramics sealing component 1 has the above-described configuration, its manufacturing method is not particularly limited, but the following methods can be mentioned as methods for obtaining a good yield.

[0038] An example of the ceramics component 3 of the ceramics sealing component 1 according to the embodiment has a cylindrical shape. For example, the outer diameter is 50 mm, the inner diameter is 38 mm, and the height (axial length) is 50 mm. The ceramics component 3 is likely to have chips or cracks at the corners due to external impacts or the like. Therefore, it is preferable to chamfer the outer peripheral portion and the inner peripheral portion of the end face of the ceramics component 3 (shown in Figure 4(a)). The chamfer shape of the ceramics component 3 can be, for example, a C-chamfer or an R-chamfer, and the chamfer size is preferably 0.1 mm or more and 2 mm or less.

[0039] Examples of the material of the metal component 2 of the ceramics component 3 according to the embodiment include iron and iron alloys, copper and copper alloys, iron-nickel-based alloys such as 42 alloy and Kovar, tungsten, molybdenum, and the like. Kovar has excellent physical properties such as a thermal expansion coefficient, and copper and copper alloys are easy to deform in order to relieve stress due to the thermal expansion difference. Therefore, it is preferable to form the metal component 2 using Kovar or copper and copper alloys.

[0040] An example of the shape of the metal part 2 according to the embodiment is a substantially cylindrical shape. For example, the metal part 2 having a substantially cylindrical shape has a wall thickness D of 1 mm and a height (axial length) of 20 mm. In the case of FIG. 3(a), the unprocessed part of the tip of the metal part 2 having a substantially cylindrical shape has an outer diameter (the diameter formed by the outer wall) of 48 mm and an inner diameter (the diameter formed by the inner wall) of 46 mm. The tip portion of the metal part 2 has a flange shape that bends inward substantially vertically, and the length L is 3 mm. The metal part 2 having the above shape can be obtained by forming it into a cylindrical shape by pressing or the like and then forming the tip portion into a flange shape by pressing or drawing. It is also possible to obtain a bent shape by punching with a press while leaving a bent portion from a bottomed cylinder. In the case of FIG. 3(b), the metal part 2 having a substantially cylindrical shape has a wall thickness D of 1 mm, an outer diameter of 46 mm, and an inner diameter of 44 mm. These metal parts 2 can be plated with nickel or the like to improve corrosion resistance and wettability.

[0041] The form at the time of joining the active metal material and the inert metal material is a paste. For sheets or wires, after melting the active metal material and the inert metal material and processing them into sheet or wire shapes, a process for processing them into predetermined dimensions according to the product shape is required. In contrast, although there is a process for manufacturing the paste, the paste is excellent in handling, such as printing it on the necessary parts according to the product shape. Also, if the amount of the active metal material and the inert metal material is too small, gaps that are unjoined portions will occur, and if it is too large, segregation of the brazing material will occur, causing stress fracture. Therefore, it is possible to adjust the amount of the active metal material and the inert metal material used according to the brazing area.

[0042] The activated metal paste, made from activated metal materials, is prepared by mixing activated metal powder with brazing metal powder such as copper, and then adding an organic binder and an organic solvent. The organic binder is not particularly limited as long as it is burned away during the drying and joining (heating) 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 sintering processes. A preferred example is terpineol or butyl carbitol. The activated metal paste is prepared, for example, by crushing and mixing activated metal powder and brazing metal powder, and then mixing with an organic binder and an organic solvent. The ratio of activated metal contained in the activated metal material components 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.

[0043] The printing thickness of the activated metal paste is preferably between 20 μm and 100 μm. If the printing thickness is less than 20 μm, variations in the thickness of the activated metal layer 4 will occur, reducing the bonding strength. On the other hand, if it exceeds 100 μm, no further effect can be obtained. The paste is printed on the surface of the ceramic part 3 with a uniform thickness using a screen printing method or the like. If the printing thickness is uneven, there will be an excess of activated metal in the thicker areas, causing buildup of brazing material and cracks due to thermal stress. Also, in the thinner areas, leakage failures will occur due to the breakdown of the activated metal. For this reason, the difference in printing thickness between the thicker and thinner areas of the activated metal paste is preferably 15 μm or less, and more preferably 10 μm or less.

[0044] The activated metal paste printed on the ceramic part 3 is dried in an atmospheric environment. If the drying temperature is low and the drying time is short, the organic solvent components of the activated metal paste may not volatilize sufficiently, potentially causing voids during bonding. Conversely, if the drying temperature is high and the drying time is long, oxidation of the paste surface may progress, potentially changing the bonding temperature. For this reason, the drying temperature is 50°C to 100°C, preferably 60°C to 80°C. The drying time is 5 minutes to 30 minutes, preferably 10 minutes to 20 minutes.

[0045] After the activated metal paste placed on the surface of the ceramic part 3 dries, an activated metal layer 4 is formed on the ceramic part 3 by heating. The bonding temperature is 600°C to 850°C, preferably 690°C to 810°C. The bonding time is preferably in the range of 5 minutes to 60 minutes after reaching the bonding temperature. If the bonding temperature is low and the bonding time is short, the activated metal material may not melt sufficiently and bonding may not occur. Conversely, if the bonding temperature is high and the bonding time is long, the inert metal material (e.g., silver solder) may melt too much and spread, causing voids. The bonding atmosphere with the inert metal should be a vacuum or a non-oxidizing atmosphere as needed. If performed in a vacuum, 1 × 10 －２ The pressure is preferably Pa or lower. Non-oxidizing atmospheres include nitrogen, nitrogen-hydrogen, and argon atmospheres. By using a vacuum or non-oxidizing atmosphere, oxidation of the inert metal layer, which is made of inert metal material, can be suppressed. This improves the bonding strength. For brazing with inert metal material, continuous furnaces or batch furnaces are used. Continuous furnaces are superior in terms of mass production, while batch furnaces allow for easier control of temperature and atmosphere. The inert metal layer 5 is formed by heating in the above atmosphere for a predetermined time.

[0046] The inert metal material in the inert metal paste 6 is composed of the material of the metal part 2, an active metal material, and a metal with good wettability. Silver solder is commonly used for joining ceramic parts 3 and metal parts 2. Silver solder mainly consists of silver and copper, but may also contain other metal components such as zinc and nickel. A commonly used silver solder (BAg-8) is 72% silver and 28% copper. In BAg-8, as specified in "Silver Solder (JIS_Z3261:1998)", the silver (Ag) content is 71% to 73%, the copper (Cu) content is 27% to 29%, and the total content of other elements is 0.15% or less. The inert metal paste is made by adding an organic binder and an organic solvent to a mixture of metal powders. The organic binder is not particularly limited as long as it is burned off during the drying and joining (heating) processes. A preferred example is ethyl cellulose. The organic solvent is not particularly limited as long as it is burned away during the drying or sintering process. Preferred examples include terpineol and butyl carbitol. The inert metal paste 6 is prepared, for example, by crushing and mixing metal powder, and then mixing it with an organic binder and an organic solvent.

[0047] The printing thickness of the inert metal paste 6 is preferably 50 μm or more and 200 μm or less. If the printing thickness is less than 50 μm, variations in the thickness of the inert metal layer 5 will occur, reducing the bonding strength. On the other hand, if the printing thickness of the inert metal paste 6 exceeds 200 μm, no further effect can be obtained. Furthermore, the paste 6 is printed to the end face of the ceramic part with a uniform thickness by a screen printing method or the like. If the printing thickness is uneven, there will be an excess of inert metal material in the thicker parts of the paste 6, causing accumulation of inert metal material and resulting in cracks due to thermal stress. Also, in the thinner parts of the paste 6, leakage failures will occur due to the inert metal material being cut off. For this reason, the difference in printing thickness between the thicker and thinner parts of the paste 6 is preferably 20 μm or less, and more preferably 15 μm or less.

[0048] The inert metal paste 6 printed on the active metal layer 4 is dried in an atmospheric environment. If the drying temperature is low and the drying time is short, the organic solvent components of the inert metal paste 6 may not volatilize sufficiently, potentially causing voids during bonding. Conversely, if the drying temperature of the inert metal paste 6 is high and the drying time is long, oxidation of the paste surface may progress, potentially changing the bonding temperature conditions. For this reason, the drying temperature of the inert metal paste 6 is 50°C to 100°C, preferably 60°C to 80°C. The drying time of the inert metal paste 6 is 5 minutes to 30 minutes, preferably 10 minutes to 20 minutes.

[0049] The metal part 2 is joined by placing it on the dried surface of the paste after the inert metal paste 6 has dried and heating it. The joining temperature of the metal part 2, i.e., the heating temperature T2, is 620°C to 910°C, preferably 750°C to 830°C. The joining time for the metal part 2 is preferably in the range of 5 minutes to 60 minutes after reaching the joining temperature. As shown in Figures 3(a) and (b), the inert metal layer 5 melts and spreads to wet the surface of the metal part 2, enabling a bond with sealing properties. If the joining temperature of the metal part 2 is low and the joining time is short, the inert metal material (e.g., silver solder) may not melt sufficiently and the joining may not occur. Conversely, if the joining temperature is high and the joining time is long, the inert metal material may melt too much and spread, which may cause the inert metal material to break or voids to occur.

[0050] Furthermore, the bonding atmosphere for inert metals shall be either a vacuum or a non-oxidizing atmosphere as necessary. Examples of non-oxidizing atmospheres include a nitrogen atmosphere and a nitrogen-hydrogen mixed 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 brazing with inert metals. Continuous furnaces are superior in terms of mass production, while batch furnaces allow for easier control of temperature and atmosphere. Brazing with inert metals is performed by heating the parts for a predetermined time in the above atmosphere.

[0051] The thickness of the bonding layer 10 that joins the ceramic part 3 and the metal part 2 is preferably 70 μm or more. As mentioned above, this is because the bonding layer 10 is formed from an active metal layer 4 of 20 μm or more and an inert metal layer 5 of 50 μm or more. In this case, the thickness of the bonding layer 10 refers to the distance between the bonding surface of the metal part 2 and the ceramic part 3. For example, in Figure 3(a), the tip of the metal part 2 is bent into a flange shape and is joined to the ceramic part 3 on a flat surface. Therefore, the thickness of the bonding layer 10 is defined as the axial distance between the reference position (for example, approximately the central part) on the bent surface of the side (the bottom surface of the metal part 2 in the plane of Figure 3(a)) and the ceramic part 3. Also, in Figure 3(b), the end face of the metal part 2 is joined to the ceramic part 3. Therefore, the thickness of the bonding layer 10 is defined as the axial distance between the reference position (for example, approximately the central part) on the end face of the metal part 2 and the ceramic part 3. Furthermore, if the tip of metal part 2 is pointed, such as in a U-shape or V-shape, the pointed tip portion is used as the thickness of the bonding layer.

[0052] In the embodiment, the ceramic-sealed component 1 is bonded to a ceramic component 3 and a metal component 2 by a bonding layer 10, the bonding layer 10 containing silver, copper, an active metal, and a low-melting-point metal. In this case, if the bonding layer 10 is defined as the ceramic side layer 10C from the center toward the ceramic component 3 along the U-axis direction (shown in Figure 5) perpendicular to the plane of the ceramic component 3, and the metal side layer 10M from the center toward the metal component 3, then the mass percentage of the low-melting-point metal in the ceramic side layer 10C is greater than the mass percentage of the low-melting-point metal in the metal side layer 10M.

[0053] To determine the mass percentage of low-melting-point metal in the ceramic side layer 10C and the mass percentage of low-melting-point metal in the metal side layer 10M, first, the bonding layer 10 is divided into N layers (where N is an integer of 20 or more) along the U-axis direction (as shown in Figure 5), and the mass percentage of low-melting-point metal is measured in each layer. Then, in the bonding layer 10, the average value of the mass percentage of low-melting-point metal measured in each of the N / 2 layers constituting the ceramic side layer 10C is greater than the average value of the mass percentage of low-melting-point metal measured in each of the N / 2 layers constituting the metal side layer 10M.

[0054] Figure 5 shows an enlarged view of portion B in Figure 3(b). Figure 5 schematically shows a state in which the space between the ceramic part 3 and the metal part 2 is divided into 20 sections. N layers R1 to RN are obtained by dividing the bonding layer 10 in the U-axis direction. For example, the mass percentage of the constituent elements is measured for each of the 20 layers R1 to R20 obtained by dividing the bonding layer 10 in the U-axis direction using an energy-dispersive X-ray fluorescence analyzer (EDX). In an example of the ceramic sealing part 1 according to the embodiment, the bonding part 10 is divided to create layers R1 to RN having a rectangle with a width of 200 μm and a height (thickness) of 3.6 μm, including the central part of the bonding surface with the ceramic part 3, and the mass percentage of the elements constituting each layer is measured using an energy-dispersive X-ray fluorescence analyzer (EDX). When the integer N is 20, the ceramic side layer 10C constituting the bonding layer 10 includes layers R1 to R10, and the metal side layer 10M includes layers R11 to R20.

[0055] Figure 6 shows a plot of elemental mass % for an example of a cross-section of the bonding layer 10 of the ceramic sealing part 1 according to Example 1, which will be described later. In Figure 6, the integer N greater than or equal to 20 is 27. In Figure 6, the mass % (wt%) values ​​of each layer (distance) from the ceramic part 3 side to the metal part 2 side for (a) tin (Sn), (b) titanium (Ti), (c) copper (Cu), and (d) silver (Ag) are plotted as a broken line (or approximation curve). Also, for convenience, the values ​​on the left side of the graph, i.e., the ceramic part 3 side, for example, between 0 and 3.6 μm, are plotted at 0 μm on the horizontal axis.

[0056] When the mass percentages of elements are plotted in each layer R1-RN from the ceramic component 3 side to the metal component 2 side, a plot for the mass percentage of low-melting-point metal exists on the ceramic component 3 side in the ceramic side layer 10C, and a plot exists on the metal component 2 side in the metal side layer 10M. In this case, the average mass percentage of the ceramic side layer 10C is greater than the average mass percentage of the metal side layer 10M, indicating that the diffusion of tin to the metal component 2 side is suppressed. This makes it possible to suppress the deposition of low-melting-point metal on the surface of the inert metal layer 5. Note that if the number of divisions of the bonding layer 10, i.e., the integer N, is odd, the average value should be calculated for the layers 10C and 10M on both sides, excluding the mass percentage plot of the central layer. Alternatively, the mass percentage plot of the central layer may be added to the layers 10C and 10M on both sides, and then the average value should be calculated for the layers 10C and 10M on each side.

[0057] In Figure 6(a), the average mass percentage of the 13 plots in the ceramic side layer 10C is 17.1 mass%, which is greater than the average mass percentage of the 13 plots in the metal side layer 10M, which is 11.3 mass%, indicating that the diffusion of tin into the layer on the metal component 2 side is suppressed. This makes it possible to suppress the deposition of tin on the surface of the inert metal layer 5.

[0058] In Figure 6(b), the second largest maximum value of active metal mass%, Wm2, is 6.0 mass%, which is 0.45 times the maximum maximum value Wm13.2 mass%, and therefore less than or equal to 0.7 times. When the active metal material is heated, titanium, which is the active metal, reacts with the ceramics to form a bonding layer, so the maximum value of active metal exists on the ceramic component 3 side. When the inert metal paste 6 is printed and heated at heating temperature T2, some of the active metal in the active metal layer 4 diffuses into the inert metal layer 5. At this time, if the heating temperature T2 is low, the effect on the active metal layer 4 is small, so the effect on the magnitude of the maximum value is small. If the heating temperature T2 is high, the active metal in the active metal layer 4 diffuses greatly, so the maximum value of active metal in the inert metal layer 5 becomes larger than 0.7 times the maximum value (mass). At this time, if there is insufficient active metal necessary for bonding, the bonding strength will decrease.

[0059] In Figure 6(c), the minimum value Wc1 for copper mass% is 21.1 mass%, which is 0.37 times the maximum value Wc56.6 mass%, and therefore greater than or equal to 0.3 times. For example, if the inert metal material used is BAg-8 brazing material, the copper content is 28%. If the active metal material contains more copper than this, the maximum value of copper will be on the ceramic component 3 side. When the heating temperature T2 is low, the effect on the active metal layer 4 is small, so there is no minimum value, or the effect on the magnitude of the maximum value becomes small, resulting in a value of 0.3 times or less. When the heating temperature T2 is high, the silver and copper in the silver brazing material, which is the inert metal material, dissolve and separate, resulting in a value greater than 50%. When the metals in the silver brazing material dissolve and separate, the bonding strength decreases. If there are two or more minimum values, the smaller value is considered the minimum value.

[0060] Furthermore, in Figure 6(d), the maximum value Waq of silver mass% in the 1 / 4 range F1 on the ceramic component 3 side is 28.7 mass%, which is 0.46 times the maximum value Wa 63.0 mass%, and is within the range of 0.3 times to 0.5 times. This indicates that the inert metal material containing silver is moderately diffused into the active metal layer 4. When the inert metal material is moderately diffused into the active metal layer 4, the active metal layer 4 and the inert metal layer 5 are firmly bonded.

[0061] Furthermore, in Figure 6(c), in the plot of copper mass %, out of 27 points in the U-axis direction, 6 points are 0.5Wc or less, which is half the maximum value Wc. The proportion of points 0.5Wc or less is 22.2%, which is within the range of 40% or less. Note that the proportion of points 0.5Wc or less may be determined not by the proportion of the number of plots, but by an approximation curve based on multiple plots. In that case, the proportion of points 0.5Wc or less is the proportion of the range of points 0.5Wc or less to the entire range of the bonding layer 10 in the U-axis direction. If the proportion of points 0.5Wc or less is 40% or less, there is sufficient copper to contribute to bonding and sealing. If the proportion of points 0.5Wc or less exceeds 40%, there will be areas where non-copper constituent elements are excessive, which can cause bonding failures and leakage failures.

[0062] Furthermore, in Figure 6(d), in the plot of silver mass %, 13 out of 27 points in the U-axis direction are 0.5 Wa or less, which is half the maximum value Wa. The proportion of points 0.5 Wa or less is 48.1%, which is within the range of 50% or less. Note that the proportion of points 0.5 Wa or less may be determined not by the proportion of the number of plots, but by the range of the approximation curve based on multiple plots. In that case, the proportion of points 0.5 Wa or less is the proportion of the range of points 0.5 Wa or less to the entire range of the bonding layer 10 in the U-axis direction. If the proportion of points 0.5 Wa or less is 50% or less, there is sufficient silver to contribute to bonding and sealing. If the proportion of points 0.5 Wa or less exceeds 50%, there will be areas where non-silver constituent elements are excessive, which can cause bonding failures and leakage failures.

[0063] Figure 7 shows a plot of elemental mass % for an example of a cross-section of the bonding layer of a ceramic sealing component according to Comparative Example 3 described later. This is the case when the heating temperature T2 is relatively low and the temperature difference (T2-T1) is 15°C, which is less than 20°C. In Figure 7, the integer N greater than or equal to 20 is 24. In the mass % of tin in Figure 7(a), the average mass % of the 12 plots on the ceramic side layer (corresponding to the ceramic side layer 10C of this embodiment shown in Figure 5) is 11.4 mass%, which is smaller than the average mass of the 12 plots on the metal side layer 10M (corresponding to the metal side layer 10M of this embodiment shown in Figure 5), which is 14.5 mass%, indicating that tin diffusion into the metal side layer 10M is occurring. Even at a low heating temperature T2, the temperature is maintained at the melting point of the low-melting-point metal, and diffusion is progressing. In this state, there is a high possibility that tin will precipitate onto the surface 51 of the inert metal layer 5. This precipitate causes irregularities on the surface of the inert metal layer 5, which then trigger fracture, leading to poor bonding and ultimately causing leakage problems.

[0064] Furthermore, in Figure 7(b), the second largest maximum value Wm2 for the mass percent of titanium, an active metal, is 4.9 mass%, which is 0.52 times the largest maximum value Wm9.4 mass%, and therefore less than or equal to 0.7 times. Also, in Figure 7(c), the minimum value Wc1 for the mass percent of copper is 19.3 mass%, which is 0.34 times the maximum value Wc57.3 mass%, and therefore greater than or equal to 0.3 times.

[0065] On the other hand, in the 1 / 4 range F2 on the ceramic component side of Figure 7(d), the maximum value Waq of silver mass percent is 20.3 mass percent, which is 0.27 times the maximum value Wa 75.0 mass percent and less than 0.3 times. This is because the inert metal material containing silver has not sufficiently diffused into the active metal layer 4. If the inert metal material has not sufficiently diffused into the active metal layer 4, the bonding between the active metal layer 4 and the inert metal layer 5 will weaken, leading to bonding failures and leakage failures.

[0066] Furthermore, in Figure 7(c), in the plot of copper mass%, 10 out of 24 points along the U-axis are 0.5 Wc or less, and the proportion of 0.5 Wc or less is 41.1%, which is outside the range of 40% or less. If the proportion of 0.5 Wc or less exceeds 40%, areas with an excess of constituent elements other than copper will occur, causing bonding failures and leakage failures. Also, in the plot of silver mass%, in Figure 7(d), 12 out of 24 points along the U-axis are 0.5 Wa or less, and the proportion of 0.5 Wa or less is 50.0%, which is within the range of 50% or less. If the proportion of 0.5 Wa or less is 50% or less, there is sufficient silver to contribute to bonding and sealing. If the proportion of 0.5 Wa or less exceeds 50%, areas with an excess of constituent elements other than silver will occur, causing bonding failures and leakage failures.

[0067] Figure 8 shows a plot of elemental mass % for an example of a cross-section of the bonding layer of a ceramic sealing component according to Comparative Example 2, which will be described later. This is the case when the heating temperature T2 is relatively high and the temperature difference (T2-T1) is 70°C, which is above 60°C. In Figure 8, the integer N greater than or equal to 20 is 22. In the mass % of tin in Figure 8(a), the average mass % of the 11 plots on the ceramic side layer (corresponding to the ceramic side layer 10C of this embodiment shown in Figure 5) is 10.3 mass%, which is smaller than the average mass of the 11 plots on the metal side layer (corresponding to the metal side layer 10M of this embodiment shown in Figure 5), which is 15.8 mass%, indicating that tin diffusion into the metal side layer 10M is occurring. The heating temperature T2 is high and the temperature is maintained at the melting point of the low-melting-point metal, allowing diffusion to proceed. In this state, there is a high possibility that tin will precipitate onto the surface 51 of the inert metal layer 5. This precipitate causes irregularities on the surface of the inert metal layer 5, which then trigger fracture, leading to poor bonding and ultimately causing leakage problems.

[0068] Furthermore, in Figure 8(b), the second largest maximum value Wm2 for the mass percent of titanium, the active metal, is 12.0 mass%, which is 0.85 times the largest maximum value Wm14.1 mass%, and more than 0.7 times. This indicates that a sufficient bonding layer of active metal cannot be formed near the surface of the ceramic component. If the presence of active metal, which contributes to the bonding of ceramic components, is low, it can cause bonding defects and leakage defects near the ceramic component.

[0069] Furthermore, in Figure 8(c), the minimum local minimum Wc1 of copper mass% is 3.6 mass%, which is 0.05 times the maximum local maximum Wc79.2 mass% and less than 0.3 times. This indicates that there are areas in the bonding layer where there is insufficient copper, which can cause bonding failures and leakage failures. Also, in Figure 8(d), the maximum value Waq of silver mass% in the 1 / 4 range F3 on the ceramic component side is 0.6 mass%, which is 0.01 times the maximum local maximum Wa86.9 mass% and less than 0.3 times. This is because the inert metal material containing silver has not sufficiently diffused into the active metal layer 4. If the inert metal material has not sufficiently diffused into the active metal layer 4, the bonding between the active metal layer 4 and the inert metal layer 5 will be weak, causing bonding failures and leakage failures.

[0070] Furthermore, in Figure 8(c), in the plot of copper mass%, 10 out of 22 points along the U-axis are 0.5 Wc or less, and the proportion of 0.5 Wc or less is 45.5%, which is outside the range of 40% or less. If the proportion of 0.5 Wc or less exceeds 40%, areas with an excess of constituent elements other than copper will occur, causing bonding failures and leakage failures. Also, in Figure 8(d), in the plot of silver mass%, 15 out of 22 points along the U-axis are 0.5 Wa or less, and the proportion of 0.5 Wa or less is 68.2%, which is outside the range of 50% or less. If the proportion of 0.5 Wa or less exceeds 50%, areas with an excess of constituent elements other than silver will occur, causing bonding failures and leakage failures.

[0071] As described above, according to the ceramic sealing component 1 and its manufacturing method in the embodiments of the present invention, a cost-effective ceramic sealing component 1 can be obtained while maintaining the airtight performance as a sealing component.

[0072] (Examples 1-6, Comparative Examples 1-6) Manganese dioxide (MnO ２ ), silicon dioxide (silica: SiO ２ ), and magnesium oxide (magnesia: MgO) sintering aids were added to alumina to prepare granulated powder having a composition of 92% by mass alumina. The granulated powder was molded by die pressing and sintered in air at 1500 °C to obtain ceramic parts 3 according to Examples 1-5 having a cylindrical shape with an outer diameter of 50 mm, an inner diameter of 40 mm, a height of 50 mm, a chamfer of 0.5 mm on the outer diameter side, and a chamfer of 0.5 mm on the inner diameter side (the ceramic parts according to Comparative Examples 1-5 are the same). Also, 3% by mass of yttria (yttrium oxide: Y ２ O ３ ) was added as an aid to aluminum nitride (AlN) to prepare aluminum nitride granulated powder. By molding the granulated powder by die pressing and sintering in nitrogen at 1800 °C, ceramic parts 3 according to Example 6 having the same shape and dimensions as the alumina parts were obtained (the ceramic parts according to Comparative Example 6 are the same).

[0073] Copper, kovar, and iron were press-processed into a cylindrical shape with an outer diameter of 46 mm, an inner diameter of 44 mm, and a height of 20 mm to obtain metal parts II according to Examples 1-6 as shown in Table 1 (the metal parts according to Comparative Examples 1-6 are the same). A 2-μm nickel plating was applied to the surface of the processed iron parts.

[0074] Next, copper powder, tin powder, and titanium hydride (TiH ２ ) powder were blended so that the metal powder blending ratio was 60:30:10 by weight, and ethyl cellulose and terpineol were mixed and kneaded in a kneader to form a paste to produce an active metal material paste. An active metal material paste with a thickness of 30 μm was printed on the upper and lower ends (ring portions) of the ceramic parts 3 by screen printing using a 100-mesh screen with an outer diameter of \\(48\\) mm × an inner diameter of 42 mm, and dried in air at 100 °C. The dried ceramic parts 3 with the active metal material paste were heated in a continuous furnace under a nitrogen atmosphere at the heating temperature T1 shown in Table 1 for 10 minutes to form an active metal layer 4 on the surface of the ceramic parts 3 (the active metal layer on the end face of the ceramic parts according to the comparative examples is the same).[[ID=,18]]

[0075] Next, an inert metal material was prepared by mixing silver powder and copper powder in a weight percentage ratio of 72:28. This inert metal material was then pasteurized in the same manner as the activated metal material paste to produce a silver brazing paste, known as inert metal material paste 6. A 100 μm thick silver brazing paste was printed onto the upper and lower ends (ring portion) of the ceramic part 3, which had an activated metal layer formed on it, using a 100-mesh screen with an outer diameter of 48 mm and an inner diameter of 42 mm by screen printing, and dried in air at 100°C. Next, the metal part 2 on the surface, the ceramic part 3, and the metal part 2 on the back were set in a jig in that order, and the metal part 2 and the ceramic part 3 were joined together by heating in a continuous furnace in a nitrogen-hydrogen mixed atmosphere at the heating temperature T2 shown in Table 1 for 10 minutes to produce a ceramic sealed part 1 (the same applies to the ceramic sealed part in the comparative example).

[0076] Furthermore, instead of metal part 2, a 10 mm x 100 mm x 0.1 mm metal plate was used for measuring joint strength. The metal plate, ceramic part, and metal plate were set in the jig in that order, heated, and joined to create a test sample for joint strength.

[0077] Next, the ceramic sealing component 1 was cut in the central part as shown in Figure 2, the joint area was polished, and the joint area was divided into 20 sections in the U-axis direction as shown in Figure 5 to obtain layers R1 to RN. For example, each layer R1 to RN has a rectangle with a width of 200 μm and a height (thickness) of 3.6 μm, including the central part of the joint surface with the ceramic component 3. For each layer R1 to RN, the mass percentage of the constituent elements was measured using an energy-dispersive X-ray fluorescence spectrometer (EDX). For the element tin, it was plotted on graphs as shown in Figures 7(a) and 8(a), and the average value of low-melting-point metal (tin) in the ceramic side layer 10C and the average value of the mass percentage of low-melting-point metal (tin) in the metal side layer 10M were determined. The obtained results are shown in Table 2.

[0078]

[0079]

[0080] As can be seen from Tables 1 and 2, in the examples, the values ​​of heating temperature T1, heating temperature T2, and temperature difference (T2-T1) were within the preferred range. In particular, the preferred range is when heating temperature T1 is 600°C or higher and 850°C or lower, heating temperature T2 is 620°C or higher and 910°C or lower, and temperature difference (T2-T1) is 20°C or higher and 60°C or lower. On the other hand, in the comparative example, heating temperature T1, heating temperature T2, or temperature difference (T2-T1) were outside the preferred range. Also, in the examples, the difference obtained by subtracting the average mass percentage of tin in the metal side layer 10M from the average mass percentage of tin in the ceramic side layer 10C was a positive value and was within the preferred range. On the other hand, in the comparative example, this difference was outside the preferred range.

[0081] Next, the mass percentages of the constituent elements, titanium, copper, and silver, which were measured as described above, were plotted on graphs as shown in Figures 7(b) to (d) and Figures 8(b) to (d). The maximum mass percentage of titanium, which is an active metal, Wm, the second maximum mass percentage of titanium, Wm2, the maximum mass percentage of copper, Wc, the minimum mass percentage of copper, Wc1, the maximum mass percentage of silver, Wa, the maximum mass percentage of silver in the 1 / 4 range on the ceramic component 3 side, Waq, the percentage of copper mass percentages less than or equal to 0.5Wc, and the percentage of silver mass percentages less than or equal to 0.5Wa were determined. From the obtained values, we calculated the ratio of the second maximum value Wm² to the maximum value Wm of titanium's mass percent (Wm² / Wm), the ratio of the minimum value Wc1 to the maximum value Wc of copper's mass percent (Wc1 / Wc), the ratio of the maximum value Waq of silver's mass percent in the 1 / 4 range on the ceramic component side to the maximum value Wa (Waq / Wa), the percentage of copper's mass percent that is 0.5Wc or less, and the percentage of silver's mass percent that is 0.5Wa or less. The obtained results are shown in Tables 3 and 4.

[0082]

[0083]

[0084] As can be seen from Tables 3 and 4, in the examples, the ratio of the second maximum mass value Wm2 to the maximum mass value Wm of titanium as the active metal (Wm2 / Wm), the ratio of the minimum mass value Wc1 to the maximum mass value Wc of copper (Wc1 / Wc), the ratio of the maximum mass value Waq in the 1 / 4 range on the ceramic component 3 side to the maximum mass value Wa of silver (Waq / Wa), the ratio of 0.5Wc or less (half the maximum mass value Wc of copper), and 0.5Wa or less (half the maximum mass value Wa of silver) were all within the preferred range. On the other hand, in the comparative examples, all of these values ​​were outside the preferred range, and in particular, Comparative Example 2 was outside all of the preferred ranges. The preferred ranges are as follows. For titanium as an active metal, Wm² / Wm is 0.7 or less. For copper, Wc¹ / Wc is 0.3 or more. For silver, Waq / Wa is 0.3 or more and 0.5 or less. For copper, the proportion of 0.5Wc or less in the U-axis direction is 40% or less. For silver, the proportion of 0.5Wc or less in the U-axis direction is 50% or less.

[0085] Next, the joint strength was determined by bending a metal plate test sample at a right angle and pulling it upward using an Instron tensile testing machine. Furthermore, silicone was applied to the upper parts of the ceramic sealing part 1 according to the example and the ceramic sealing part 1 according to the comparative example using a circular jig made of Viton rubber. The upper part was held down, and the lower part was fixed to a helium leak detector and suction was applied to perform a helium leak test. The helium leak test was performed in accordance with the vacuum spray method (spray method) of the "Helium Leakage Test Method" (JIS Z2331:2006). At a vacuum of 1.3 μPa, 1 × 10⁻⁶ leaks were detected. －9 Pa・m 3 If no leakage of / s or more occurred, the test was considered a pass (A); if leakage occurred, it was considered a fail (B).

[0086] Furthermore, a thermal cycle test (TCT) was performed on ceramic sealing component 1 according to the example and the ceramic sealing component according to the comparative example, both of which passed the helium leak test. This test involved 80 cycles under low-temperature conditions of -40°C for 30 minutes and high-temperature conditions of 150°C for 30 minutes, followed by a helium leak test. A pass (A) was defined as no leak occurring, and a fail (B) was defined as a leak occurring. The test results for the example and comparative example are shown in Table 5.

[0087]

[0088] As can be seen from Table 5, the bonding strength of the example was a good value of 60 MPa or more. In contrast, the comparative example was 55 MPa or less. Under the bonding conditions of the example, the ceramic part 3 and the active metal material, the active metal material and the inert metal material, and the inert metal material and the metal part 2 each reacted to form a strong bonding layer, suppressing the diffusion of low-melting-point metal to the surface of the bonding layer 10 and resulting in a smooth surface. In contrast, under the bonding conditions of the comparative example, the reaction did not proceed as well as in the example, and the diffusion of low-melting-point metal to the surface of the bonding layer could not be suppressed, leading to a decrease in bonding strength.

[0089] Furthermore, the ceramic-sealed component in the example did not exhibit any leak failures in the helium leak test. This is because sufficient bonding distance was ensured between the ceramic component and the metal component, and bonding strength was ensured and thermal expansion differences were reduced by the bonding layer 10 consisting of an active metal layer 4 and an inert metal layer 5. In contrast, leak failures occurred in the comparative example. This is because the bonding strength was not sufficiently high, and damage occurred at the joint due to the thermal expansion difference between the ceramic component and the metal component, preventing airtightness from being maintained.

[0090] Furthermore, the ceramic sealed component 1 according to the example did not exhibit any leakage defects in the helium leak test after TCT. This is because, in addition to having a sufficient bonding distance between the ceramic component 3 and the metal component 2, bonding strength was ensured by the bonding layer 10 consisting of an active metal layer 4 and an inert metal layer 5, and the low bonding temperature reduced damage to the bonding layer due to thermal stress from heating and cooling. In contrast, the comparative example exhibited helium leak defects after TCT. This is because, in addition to insufficient bonding strength being ensured by the bonding layer consisting of an active metal layer and an inert metal layer, the mitigation of the difference in thermal expansion was insufficient, resulting in damage to the bonding layer due to thermal stress from heating and cooling and the formation of a leak path.

[0091] As is clear from the results shown above, the examples showed improved leak characteristics and reliability in TCT compared to the comparative examples.

[0092] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other.

Claims

1. A ceramic-sealed component comprising a ceramic component and a metal component joined by a bonding layer, wherein the bonding layer comprises one or more metals selected from silver and copper, an active metal, and a low-melting-point metal with a lower melting point than silver, and wherein, in the bonding layer, the portion of the layer extending from the center toward the ceramic component is designated as the ceramic-side layer, while the portion extending from the center toward the metal component is designated as the metal-side layer, the mass percentage of the low-melting-point metal in the ceramic-side layer is greater than the mass percentage of the low-melting-point metal in the metal-side layer.

2. The ceramic sealing component according to claim 1, characterized in that, when the bonding layer is divided into N (N is an integer of 20 or more) layers along the aforementioned direction and the mass % of the low-melting point metal is measured in each layer, the mass % of the low-melting point metal in the ceramic side layer is the average value of the mass % of the low-melting point metal measured in each of the N / 2 layers constituting the ceramic side layer, and the mass % of the low-melting point metal in the metal side layer is the average value of the mass % of the low-melting point metal measured in each of the N / 2 layers constituting the metal side layer.

3. The bonding layer contains molten silver and copper, and when the bonding layer is divided into N layers along the direction and the mass percentages of silver, copper, and active metal are measured in each layer, when the mass percentages of silver, copper, and active metal are plotted from the ceramic component side to the metal component side of the bonding layer, there are maximum values ​​Wm for the mass percentage of the active metal, Wc for the mass percentage of copper, and Wa for the mass percentage of silver, and the ratio of the second largest maximum value Wm2 for the mass percentage of the active metal to the maximum value Wm is 0.7 or less, the ratio of the minimum value Wc1 for the mass percentage of copper to the maximum value Wc is 0.3 or more, and the ratio of the maximum value Waq for the mass percentage of silver in a quarter range on the ceramic component side to the maximum value Wa is 0.3 or more and 0.5 or less, as described in claim 1 or 2.

4. The ceramic sealing component according to claim 3, characterized in that, in the plot of mass percent of copper, the proportion of values ​​less than or equal to half the maximum value Wc, which is 0.5Wc, is 40% or less, and in the plot of mass percent of silver, the proportion of values ​​less than or equal to half the maximum value Wa, which is 0.5Wa, is 50% or less.

5. The ceramic sealing component according to any one of claims 1 to 4, characterized in that the bonding layer contains one or more metals selected from titanium, zirconium, and hafnium as the active metal.

6. The ceramic sealing component according to any one of claims 1 to 5, characterized in that the thickness of the bonding layer is 70 μm or more.

7. The ceramic sealing component according to any one of claims 1 to 6, characterized in that the metal component is made of one or more metals selected from iron, iron alloys, iron-nickel alloys, copper, and copper alloys.

8. The ceramic sealing component according to any one of claims 1 to 7, characterized in that the ceramic component is made of alumina, aluminum nitride, or silicon nitride.

9. A method for manufacturing a ceramic sealing component for joining a ceramic component and a metal component, comprising the steps of: printing and drying an activated metal material paste made of an activated metal material containing one or more metals selected from silver and copper and a low-melting-point metal with a lower melting point than silver on the end face of the ceramic component and heating at a heating temperature T1 of 600°C to 850°C to form an activated metal layer; and printing and drying an inert metal material paste made of an inert metal material containing silver on the surface of the formed activated metal layer, then placing a metal component on it and heat-treating it at a heating temperature T2 to form an inert metal layer and joining the metal component to the ceramic component, wherein the temperature difference (T2-T1) obtained by subtracting the heating temperature T1 from the heating temperature T2 is 20°C or more.

10. The method for manufacturing ceramic sealing parts according to claim 9, characterized in that the active metal material includes one or more metals selected from titanium, zirconium, and hafnium.

11. The method for manufacturing ceramic sealing components according to claim 9 or 10, characterized in that the printing thickness of the active metal paste is 20 μm or more, and the printing thickness of the inert metal paste is 50 μm or more.

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