Ceramic sealing component and method of manufacturing the same

Abstract

To provide: a ceramic component used in a ceramic sealing component having excellent airtight characteristics; the ceramic sealing component using the ceramic component; and a method of manufacturing the same.SOLUTION: In a ceramic component used in a ceramic sealing component having two metal components of different materials joined at both end surfaces, when an arithmetic average surface height at one end surface is S1 and an arithmetic average surface height at the other end surface is S2, S1 / S2≥1.2. Furthermore, a method for manufacturing the ceramic sealing component includes: a step of preparing the ceramic component; and a step of bonding the ceramic component and the metal component with one or more active metals selected from titanium, zirconium, and hafnium, and one or more solder metals selected from copper and silver.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The embodiments generally relate to a ceramic part, a ceramic sealed part in which a ceramic part and a metal part are joined together (hereinafter, abbreviated as "ceramic sealed part"), and a manufacturing method thereof. [Background technology]

[0002] As ceramic sealing parts for magnetrons, power tubes, and electron tubes, metallization layers mainly composed of high melting point metals such as molybdenum (Mo) are applied to alumina (aluminum oxide: Al 2 O 3 ) are used. Ceramic sealed parts are bonded to ceramics and metals to block the outside air and hermetically seal the inside of the part, thereby protecting the inside from the external environment and electrically insulating it with the ceramics. For example, in a ceramic sealed part as shown in Figure 1, a metallized layer mainly composed of molybdenum is formed on the ring parts on the upper and lower end surfaces of a cylindrical ceramic part made of sintered alumina. A nickel (Ni) layer of a certain thickness is formed on the surface of this metallized layer to improve the bonding strength with other metal parts and to perform sealing. This nickel part and the cylindrical metal part are bonded with silver solder (e.g. BAg-8).

[0003] As a ceramic sealed part, an electron tube having a vacuum airtight structure in which a metal surface made of molybdenum is formed on a ceramic cylinder and an iron metal cylinder is joined with a 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 cylinder with iron from Kovar.

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

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The ceramics used for ceramic sealed components have the characteristics of being hard but brittle. One of the causes of this brittleness is the influence of the surface state. If there are defects such as scratches on the surface of the ceramics, these defects will become the starting points for fractures and the like. Therefore, polishing the surface of the ceramics to remove defects and reduce the surface roughness improves the mechanical reliability of the ceramics. For example, in the case of ceramic balls for bearings, by reducing the surface roughness by polishing, mechanical performance that can withstand high speeds and high rotations is obtained.

[0007] However, in order to metallize (metalize) the surface to bond the ceramics to the metal, the surface roughness of the ceramics should be moderately rough for better bonding (metallizing) strength. This is because when the surface becomes rough, the area of bonding by chemical reaction can be increased, and the metallizing component enters the concave part, increasing the mechanical strength physically due to the anchor effect. Therefore, regarding the surface state of the ceramics, there is a trade-off relationship that in order to increase the strength of the ceramics, it is better to reduce the surface roughness, and in order to increase the bonding strength, it is better to increase the surface roughness.

[0008] On the other hand, in order to ensure the sealing property (airtightness) in the bonding between the ceramics and the metal, a strong bonding layer is required. However, since the thermal expansion coefficients of the ceramics and the metal are different (for example, the thermal expansion coefficient of alumina is 7.2×10 -6 / °C, while that of copper is 16.5×10 -6 / °C, carbon steel 11.7×10 -6 / (°C), stress is generated due to the difference in thermal expansion, and cracks are likely to occur. When joining the same type of metal, there is no difference in joining, but when joining multiple types of metals with different properties, differences in joining are likely to occur, which may impair the sealing performance.

[0009] Also, in order to increase the bonding strength between ceramics and metal without changing the state of the ceramics, for example, there is a method of increasing the amount of components contributing to the bonding during metallization and raising the bonding temperature. However, when increasing the bonding strength of the bonding part of one of the metals among multiple metals with different properties, it is necessary to use two types of pastes and two types of bonding temperatures, which complicates the manufacturing process and results in poor cost performance. Also, when increasing the bonding strength of the bonding parts of both metals, the bonding temperature will rise even for metals that do not require an increase in bonding strength, which will generate a further difference in thermal expansion and may impair the sealing performance.

[0010] The embodiment solves such problems and relates to a highly productive ceramic sealing component that suppresses bonding defects and leakage defects when a ceramic component is joined to metal components with different properties, and a manufacturing method thereof.

Means for Solving the Problems

[0011] The ceramic component according to the embodiment is a ceramic component used for a ceramic sealing component in which two metal components of different materials are joined to an end face. When the arithmetic mean surface height of one end face is S1 and the arithmetic mean surface height of the other end face is S2, S1 / S2≥1.2.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0013] The ceramic component according to the embodiment is a ceramic component used for a ceramic sealing component in which metal components of two different materials are joined to the end faces. When the arithmetic mean surface height of one end face is S1 and the arithmetic mean surface height of the other end face is S2, S1 / S2 ≥ 1.2.

[0014] FIG. 1 shows a perspective view of an example of a ceramic sealing component 1 according to the embodiment. 2 is a cylindrical ceramic component, and 3 and 4 are metal components of different materials having a cylindrical shape. The metal components 3 and 4 are joined by the end faces of the ceramic component 2. In FIG. 1, an example is shown in which the metal component 3 is joined to the upper end face of the ceramic component 2 and the metal component 4 is joined to the lower (opposite) end face. The embodiment is not limited to such a form, and a rectangular prism-shaped ceramic component or metal component may be used. A form in which the lower bottom surface is a ceramic component and only the upper side (one side) is joined to a metal component, or a ceramic component having two or more openings on one side surface may be joined to a metal component.

[0015] FIG. 2 shows an example of a cross-sectional view of the ceramic component according to the embodiment. The upper (one side) end face of the cylindrical ceramic component 2 is 21, and the lower (opposite) end face is 22. When the arithmetic mean surface height of the end face 21 is S1 and the arithmetic mean surface height of the end face 22 is S2, S1 / S2 ≥ 1.2. Hereinafter, in FIG. 2 and subsequent figures, the end face 21 is shown in a black layer shape in order to distinguish it from the end face 22.

[0016] Fig. 3 shows a cross-sectional view of the ceramic sealing component 1 according to the embodiment. 3 is a component made of metal A (hereinafter abbreviated as "metal A component"), and 4 is a component made of metal B (hereinafter abbreviated as "metal B component"). At this time, the metal A component 3 and the metal B component 4 are made of different materials. For example, the metal A component 3 is stainless steel, and the metal B component 4 is a cylindrical metal component made of copper (Cu). At this time, the metal A component 3 is joined to the end face 21 with an arithmetic mean surface height of S1 via the joining layer 5. Also, the metal B component 4 is joined to the end face 22 with an arithmetic mean surface height of S2 via the joining layer 5. For example, the ceramic component 2 is a ceramic component made of cylindrical aluminum oxide (alumina), and the joining layer 5 is configured to be joined with an active metal brazing material layer.

[0017] The ceramic component 2 is preferably any one of alumina, alumina added with zirconia (aluzir), silicon nitride, and aluminum nitride. Alumina includes alumina-based ceramics obtained by adding other ceramics or the like to alumina. For example, alumina added with zirconia is a sintered body obtained by mixing alumina and zirconium oxide. Further, a sintering aid other than zirconia may be added to alumina. This is because the added sintering aid forms a grain boundary phase composed of a glass phase to densify the alumina sintered body. Examples of the sintering aid include compounds such as manganese (Mn), silicon (Si), magnesium (Mg), and calcium (Ca). It is preferable to add at least one or more of these sintering aids in a total amount of 1 to 15% by mass in terms of oxide. Also, silicon nitride and aluminum nitride may also be added with a sintering aid for densification. Examples of the sintering aid include oxides such as rare earth elements, Mg, Ca, aluminum (Al), titanium (Ti), and hafnium (Hf). It is preferable to add at least one or more of these in an amount of 1 to 15% by mass or less in terms of oxide. Among these ceramic components, alumina is excellent in cost performance.

[0018] The ceramic component 2 has two end faces for joining metal components. When one end face of the ceramic component 2 is designated as 21, the other end face is 22. When the arithmetic mean surface height of the end face 21 is S1 and the arithmetic mean surface height of the end face 22 is S2, S1 / S2 ≥ 1.2. To adjust the surface roughness of the ceramic component 2 within the range of S1 / S2 ≥ 1.2, there are a method of adjustment in the process before firing and a method of adjustment in the process after firing. In the method of adjustment in the process before firing, for example, there are methods of mechanically roughening or mechanically refining one end face of the molded body formed by pressing. To roughen the surface roughness of the molded body, the surface is polished with a coarse buff or a substance having a surface equivalent to that of a buff (such as resin or ceramics). To refine it, it can be adjusted by polishing the surface with a fine buff or a substance having a surface equivalent to that of a buff. Also, in the production line, it is possible to roughen the surface roughness of the end face of the molded body on the installed side by placing the molded body on a setter with a rough surface and applying vibration.

[0019] The method of adjustment in the process after sintering can change the surface roughness by performing rough honing or fine honing by honing (blasting) treatment in addition to polishing with the above-mentioned buff. Also, the surface roughness can be adjusted by polishing with grindstones having different roughnesses.

[0020] Note that the surface roughness is defined as the arithmetic mean height of the surface (Sa). The arithmetic mean height of the surface is measured in accordance with "Geometrical Product Specifications (GPS) - Surface texture: Areal - Part 6: Classification of surface texture measuring methods (JIS B0681-6:2014)". The measurement location and measurement area are measured at a location approximately in the center of the end face portion, which is the joint portion, with a diameter equal to half the width of the end face. For example, when joining the entire end face portion of a cylindrical shape, if the width of the end face (the difference between the outer diameter and the inner diameter) is 10 mm, the measurement is taken with a diameter of 5 mm. Also, if there is a chamfer, it is taken as half the width excluding the chamfer portion. At this time, if the width to be measured is not uniform, the largest (widest) portion shall be measured. Also, if the maximum widths of the two end faces are different, it shall be adjusted to the diameter of the measurement area of the smaller end face. The measurement can be performed using a non-contact surface roughness meter and a laser microscope (e.g., VK-X series manufactured by Keyence Corporation).

[0021] The material of the metal A component 3 joined to the end face 21 of the ceramic component 2 is preferably iron (Fe) and iron alloys, iron-nickel-based alloys (hereinafter abbreviated as "iron and iron alloys, etc."). Iron alloys are carbon steels such as rolled steel, alloy steels such as chromium steel and stainless steel. Examples of iron-nickel-based alloys include 42 alloy (Ni 42 mass%, Mn 0.8 mass% or less, balance Fe), Kovar (Ni 29 mass%, Co 17 mass%, balance Fe), etc. Iron and iron alloys are excellent in cost performance, and iron-nickel-based alloys are excellent in physical properties such as the coefficient of thermal expansion. Also, iron and iron alloys, and iron-nickel-based alloys are preferably plated to improve wettability during joining and to prevent rust. Nickel plating is preferably used for plating. This is because nickel plating is excellent in heat resistance and prevents molecular diffusion between the plating and the material.

[0022] The material of the metal B component 4 joined to the end face 22 of the ceramic component 2 is preferably copper and copper alloys. Copper alloys include pure copper such as oxygen-free copper, tough pitch copper, deoxidized copper, and high copper alloys such as beryllium copper and titanium copper. Also, the metal component is manufactured by processing into a predetermined shape by press working, cutting, bending, etc.

[0023] The ceramic component 2 and the metal component are joined by a joining layer 5. Typical methods for forming the joining layer are the active metal method and the high melting point metal method. The active metal method uses an active metal such as titanium (Ti). Other active metals besides titanium include zirconium (Zr) and hafnium (Hf). Examples of active metal soldering materials include a mixture of titanium and copper (Cu). For example, titanium is 0.1 to 10% by mass and copper is the balance. Also, as another active metal soldering material, a mixture of titanium, silver, and copper can be mentioned. Titanium is 0.1 to 10% by mass, copper is 10 to 60% by mass, and silver is the balance. Also, when controlling the diffusion of the active metal soldering material during joining, one or more selected from indium (In), tin (Sn), aluminum (Al), silicon (Si), carbon (C), and magnesium (Mg) may be added in an amount of 1 to 15% by mass as needed. An active metal soldering material paste is printed on the surface of the ceramic component and then dried. Thereafter, the metal component is placed in contact with the surface of the printed and dried paste, and the ceramic component and the metal component are joined by heating at 780 to 820°C in a vacuum or a non-oxidizing gas.

[0024] The high melting point metal method is a method in which a paste composed of powders of high melting point metals such as molybdenum (Mo) and tungsten (W) is printed on the surface of the ceramic and heated at a high temperature. A typical high melting point metal method is the molybdenum-manganese (Mn) method. In the molybdenum-manganese method, for example, 5 to 15% by mass of manganese powder is added to molybdenum powder to form a paste. A high melting point metal paste is printed on the surface of the ceramic component and then dried. Thereafter, a metallized layer of high melting point metal is formed on the surface of the ceramic component by heating at 1400 to 1500°C in a wet nitrogen-hydrogen atmosphere gas. Since the layer of high melting point metal formed on the surface of the ceramic has poor wettability, plating such as nickel (Ni) is performed. A silver soldering foil or the like is placed between this nickel plating and the metal component, and brazing joining is performed by heating at 780 to 820°C.

[0025] Both the active metal bonding and the brazing bonding after the high melting point metal are heated to a bonding temperature of about 800°C. Due to the thermal expansion coefficient and elongation (hardness) of the metal parts, there is a difference in the bonding state between the metal A parts 3 such as iron and iron alloys and the metal B parts 4 such as copper and copper alloys. The thermal expansion coefficients of iron, iron alloys, etc. and copper and copper alloys are larger than those of ceramics. When both are heated, they expand and contract after bonding to the ceramics and cooling. At this time, due to the difference in the thermal expansion coefficients between the metal and the ceramics, the metal parts contract more than the ceramic parts, so stress is generated. For example, the thermal expansion coefficient of austenitic stainless steel SUS304 is 17.3×10 ―6 / °C, and the thermal expansion coefficient of copper is approximated to 17.7×10 ―6 / °C. However, the Vickers hardness of SUS304 is 150, which is harder than that of copper at 50. Therefore, SUS304 does not deform during cooling more than copper. Thus, for bonding with ceramics, stress is more likely to occur in iron, iron alloys, etc. than in copper and copper alloys. For this reason, even if no fracture occurs in the bonding between ceramics and copper and copper alloys, fracture may occur in the bonding between iron, iron alloys, etc. and ceramics.

[0026] To increase the bonding strength on the side where a large amount of stress is generated, there are methods such as increasing the proportion of the reaction components in the paste and raising the bonding temperature, but the damage to the whole including the side where no stress is applied also increases. On the other hand, in the ceramic part according to the embodiment, the surface roughness of the surface that bonds to the metal that is likely to be stressed and break is increased. Thereby, it is possible to produce a ceramic part that bonds to two or more metal parts relatively simply.

[0027] For the bonding layer formed by the active metal method, the high melting point metal method, etc., the bonding strength increases as the surface roughness of the ceramic part is rougher. This is because the area of reaction becomes wider as the surface roughness increases. Also, the bonding layer penetrates into the ceramic part, and the bonding strength increases physically due to the anchor effect.

[0028] In the above-described example, examples include copper and copper alloys, and iron and iron alloys, etc., but combinations with other metals having different linear expansion coefficients and hardnesses are also possible. Furthermore, even for the same type of metal, combinations of easily deformable shapes and difficult-to-deform shapes are also applicable. For example, even for cylindrical metal parts of the same type, if they are thin, they are easily deformed, and if they are thick, they are difficult to deform.

[0029] FIG. 4 shows a process diagram (cross-sectional view) of a method for manufacturing a ceramic-sealed component by the reactive metal method according to an embodiment. The method for manufacturing a ceramic-sealed component according to the embodiment is a method for manufacturing a ceramic-sealed component in which metal components of two different materials are joined to an end face. First, a ceramic component with S1 / S2 ≧ 1.2 is prepared, where S1 is the arithmetic mean surface height of one end face and S2 is the arithmetic mean surface height of the other end face. Next, the ceramic component and the metal component are joined with one or more reactive metals selected from titanium, zirconium, and hafnium, and one or more brazing metal selected from copper and silver.

[0030] FIG. 4(a) is a cross-sectional view of the ceramic component 2. When S21 is the arithmetic mean surface height of the end face 21 and S22 is the arithmetic mean surface height of the end face 22, S21 / S22 ≧ 1.2. In FIG. 4(b), after printing and drying a reactive metal brazing paste on the ceramic component 2, it is heated in a vacuum or non-oxidizing gas to form a reactive metal brazing layer 6. Since the paste is printed on the flat end face of the ceramic component to form it, the surface of the reactive metal brazing layer 6 before joining is substantially flat. Also, in FIG. 4(b), the reactive metal brazing paste is printed only on the flat part at the end, but it is also possible to chamfer and print the reactive metal brazing material. FIG. 5(c) shows a state in which the metal component is joined by installing the metal component on the surface of the reactive metal brazing layer and heating. Although it is possible to join the plurality of metal components separately, it is preferable to install and join them simultaneously because stress generated by the previously joined metal component will occur again. Note that it is also possible to join the ceramic component and the metal component by installing the metal component on the printed and dried reactive metal brazing surface and heating, rather than heating the reactive metal brazing layer once and then installing and heating the metal component.

[0031] FIG. 5 shows a process diagram (cross-sectional view) of a method for manufacturing a ceramic sealing component by a high melting point metal method according to an embodiment. The method for manufacturing a ceramic sealing component according to the embodiment is a method for manufacturing a ceramic sealing component in which metal components of two different materials are joined to end faces. First, a ceramic component is prepared such that S1 / S2 ≥ 1.2 when the arithmetic mean surface height of one end face is S1 and the arithmetic mean surface height of the other end face is S2. Next, a metallized layer made of a high melting point metal is formed on the end face of the ceramic component. Next, a nickel plating is formed on the surface of the metallized layer. Next, the nickel plating and the metal component are joined by a brazing material containing copper and silver.

[0032] FIG. 5(a) is a cross-sectional view of the ceramic component 2. When the arithmetic mean surface height of the end face 21 is S21 and the arithmetic mean surface height of the end face 22 is S22, S21 / S22 ≥ 1.2. In FIG. 5(b), metallized layers 7 are formed on both end faces of the ceramic component 2. The metallized layer 7 is obtained by printing and drying a high melting point metal paste and heating it at a high temperature. FIG. 5(c) shows a state in which a plating layer 8 is formed on the surface of the metallized layer. The plating layer is formed by electroplating or electroless plating. FIG. 5(d) shows a state in which a brazing material layer 9 is formed between the plating layer and the metal component, and the ceramic component 2 and the metal component are joined. The formation of the brazing material layer is achieved by installing a brazing material sheet or the like between the metal component and the plated surface and heating it.

[0033] In the method for manufacturing a ceramic sealing component according to the embodiment, a metal component such as iron or an iron alloy is joined via a joining layer to the end face of the ceramic component having an arithmetic mean surface height of S1, and a metal component of copper or a copper alloy is joined via a joining layer to the end face having an arithmetic mean surface height of S2.

[0034] Next, a method for manufacturing the ceramic component and the ceramic sealing component according to the embodiment will be described. The manufacturing method of the ceramic component and the ceramic sealing component is not particularly limited as long as they have the above-described configuration, but the following methods can be mentioned as methods for obtaining a good yield.

[0035] An example of the ceramic component according to the embodiment has a cylindrical shape, for example, an outer diameter of 50 mm, an inner diameter of 38 mm, and a height of 50 mm. The ceramic component 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. The chamfered shape includes C-chamfering and R-chamfering, and the size of the chamfering is preferably 0.1 to 2 mm.

[0036] Examples of the material of the metal component according to the embodiment include iron and iron alloys, copper and copper alloys, iron-nickel alloys such as 42 alloy and Kovar, tungsten, molybdenum, and the like. Iron and iron alloys are excellent in cost performance, and copper and copper alloys are easily deformed to relieve stress due to the difference in thermal expansion. Therefore, it is preferable to form metal components using iron and iron alloys or copper and copper alloys.

[0037] An example of the shape of the metal component is a substantially cylindrical shape. The tip of the joining side of the metal component may remain in a straight shape so as to be joined perpendicularly to the ceramic end face, or may have a shape bent at a substantially right angle inward or outward so as to be joined horizontally to the ceramic end face. For example, the height is 20 mm. In the straight shape, the outer diameter is 46 m and the inner diameter is 44 mm. In the bent shape, the outer diameter is 48 mm, the inner diameter is 46 mm, and the inner diameter of the bent tip is 40 mm. The joining with the straight-shaped metal component is an edge seal and is joined by a line, so stress is less likely to be applied. The joining with the bent-shaped metal component is a butt seal and is joined by a surface, so leakage failure is less likely to occur. These metal components can be plated with nickel or the like to improve corrosion resistance and wettability.

[0038] The component form of joining with an active metal brazing material is preferably a paste. The active metal brazing material paste is prepared by adding an organic binder and an organic solvent to a mixture of active metal powder and brazing metal powder. The organic binder is not particularly limited as long as it burns out during the drying process or the joining (heating) process. A preferred example is ethyl cellulose. The organic solvent is not particularly limited as long as it burns out during the drying process or the firing process. Preferred examples include terpineol and butyl carbitol. The active metal brazing material paste is prepared by pulverizing and mixing the active metal powder and the brazing metal powder, and then mixing them with the organic binder and the organic solvent. The ratio of the active metal contained in the active metal brazing material component is 0.1 to 15% by mass, preferably 0.5 to 10% by mass.

[0039] The printing thickness of the active metal brazing material paste is preferably 30 to 150 μm. If the printing thickness is less than 20 μm, the thickness of the active metal brazing material layer may vary, reducing the joining strength. On the other hand, if it exceeds 150 μm, no further effect can be obtained. Also, the paste is printed on the end face of the ceramic component with a uniform thickness by a screen printing method or the like. If the printing thickness is non-uniform, the active metal brazing material will be excessive in the thick part, forming a brazing material accumulation and generating cracks due to thermal stress. Also, in the thin part, leakage defects will occur due to the lack of the active metal brazing material. Therefore, the difference in the printing thickness between the thick part and the thin part is preferably 15 μm or less, and more preferably 10 μm or less.

[0040] The paste printed on the ceramic component is dried in an air atmosphere or the like. If the drying temperature is low and the drying time is short, the solution components of the paste may not be sufficiently volatilized, and voids may occur during joining. Conversely, if the drying temperature is high and the drying time is long, the oxidation of the surface of the paste may progress, and the joining temperature may change. Therefore, the drying temperature is 50 to 100 °C, preferably 60 to 80 °C. Also, the drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0041] After the paste is dried, the metal parts are placed on the dried paste surface and heated to perform bonding. The bonding temperature is 600 to 850 °C, preferably 700 to 800 °C. Also, the bonding time is preferably in the range of 5 to 60 minutes in a state where the bonding temperature has been reached. If the bonding temperature is low and the bonding time is short, the active metal brazing material may not melt sufficiently and may not bond. Conversely, if the bonding temperature is high and the bonding time is long, the active metal brazing material may melt too much and spread, resulting in the occurrence of voids or brazing failure. Also, the active metal bonding atmosphere is to be carried out in a vacuum or a non-oxidizing atmosphere as required. When carried out in a vacuum, it is preferably 1×10-2 Pa or less. Also, examples of the non-oxidizing atmosphere include a nitrogen atmosphere and an argon atmosphere. By setting it to a vacuum or a non-oxidizing atmosphere, oxidation of the active metal brazing material layer can be suppressed. Thereby, an improvement in bonding strength can be achieved. As the furnace used for brazing, a continuous furnace or a batch furnace is used. The continuous furnace is excellent in mass productivity, and the batch furnace is easy to control the temperature and atmosphere. By heating for a predetermined time in the above-described atmosphere, an active metal brazing material layer is formed.

[0042] On the other hand, the component form of the metallization with the high melting point metal is a paste. The high melting point metal paste is obtained by adding an organic binder and an organic solvent to a mixture of high melting point metal powders such as molybdenum and tungsten and additive powders. For example, in the case of a molybdenum-manganese paste, 10% by mass of manganese powder is added to the molybdenum powder. The organic binder is not particularly limited as long as it is burned out by a drying process or a bonding (heating) process. A preferable example is ethyl cellulose. The organic solvent is not particularly limited as long as it is burned out by a drying process or a firing process. A preferable example is terpineol or butyl carbitol. The high melting point metal paste is prepared by pulverizing and mixing the high melting point metal powder and the additive powder, and then mixing them with the organic binder and the organic solvent.

[0043] The printing thickness of the high melting point metal paste is preferably 10 to 30 μm. If the printing thickness is less than 10 μm, the thickness of the active metal brazing material layer may vary, reducing the bonding strength. On the other hand, if it exceeds 30 μm, no further effect can be obtained. Also, the high melting point metal paste is printed on the end face of the ceramic component with a uniform thickness by a screen printing method or the like. If the printing thickness is non-uniform, a difference in bonding strength will occur between the thick and thin parts. Therefore, the difference in printing thickness between the thick and thin parts is preferably 5 μm or less.

[0044] The high melting point metal paste printed on the ceramic component is dried in an air atmosphere or the like. If the drying temperature is low and the drying time is short, the solution component of the paste may not be sufficiently volatilized, and voids may occur during bonding. Conversely, if the drying temperature is high and the drying time is long, oxidation of the surface of the high melting point metal paste may progress, and the bonding temperature may change. Therefore, the drying temperature is 50 to 100 °C, preferably 60 to 80 °C. Also, the drying time is 5 to 30 minutes, preferably 10 to 20 minutes.

[0045] A metallized layer is formed by heating the dried high melting point metal paste in a wet nitrogen-hydrogen atmosphere. The heating temperature is 1350 to 1550 °C. In the high melting point metal method, a glass phase diffuses from the ceramic component to form a strong bonding layer. If the heating temperature is lower than 1350 °C, the diffusion of the glass phase may not be sufficient, and the bonding strength may decrease. Conversely, if the heating temperature is higher than 1550 °C, the glass phase may reach the surface of the metallized layer, reducing the adhesion strength to the plating described later. A continuous furnace or a batch furnace is used for heating. The continuous furnace is excellent in mass productivity.

[0046] The metallized layer formed of the high melting point metal is plated to improve the bondability with the brazing material. Types of plating include nickel plating and gold plating, etc. Among them, nickel plating has excellent corrosion resistance and cost performance. Nickel plating includes electrolytic nickel plating performed by passing an electric current and electroless nickel plating not performed by passing an electric current. Electrolytic nickel plating has a lower chemical solution cost and better cost performance than electroless nickel plating. It is preferable to perform electrolytic nickel plating with a thickness of 1 to 3 μm on the metallized layer. If the thickness is less than 1 μm, the wettability of the brazing material described later may decrease. If the thickness is more than 3 μm, it is excessive to ensure the wettability of the brazing material, and there may be a possibility of bulge failure due to being too thick.

[0047] The formed plating is joined to the metal part. A brazing material is used for joining. Among brazing materials, silver brazing that is easily wetted by nickel plating and firmly joined to the metal part is preferable. There is silver brazing (BAg-8) made of 72% silver - 28% copper, which is often used in joining ceramics and metal parts. In BAg-8 according to "Silver Brazing (JIS Z3261:1998)", silver (Ag) is 71 to 73%, copper (Cu) is 27 to 29%, and the total of other elements is 0.15% or less. Since BAg-8 does not contain evaporation metals, it is suitable for brazing of electron tubes and vacuum tubes. Because of its high silver content, it has excellent electrical conductivity and can be used for parts that can withstand high temperatures due to its high melting temperature, so it is preferable. The silver brazing is processed into a sheet shape or a wire ring shape and installed between the plated surface and the metal part, or made into a paste and printed on the plated surface or the metal part surface for use. The joining temperature of the silver brazing is 650 to 900 °C, preferably 750 to 820 °C. If the joining temperature is low, the silver brazing material may not melt sufficiently and may not join. On the contrary, if the joining temperature is high, the silver brazing material may melt too much and spread by wetting, and there may be brazing breakage or voids.

[0048] Also, the silver brazing joining atmosphere shall be performed in a non-oxidizing atmosphere as required. Examples of the non-oxidizing atmosphere include a nitrogen atmosphere and a nitrogen-hydrogen atmosphere. By using a non-oxidizing atmosphere, oxidation of the joining layer can be suppressed, and an improvement in joining strength can be achieved. As the furnace used for silver brazing, a continuous furnace or a batch furnace is used. The continuous furnace is excellent in mass productivity, and the batch furnace is easy to control the temperature and atmosphere. Silver brazing is performed by heating the parts in the above atmosphere for a predetermined time.

[0049] According to the manufacturing method of the ceramic sealing component in the embodiment of the present invention as described above, it is possible to obtain a ceramic sealing component with excellent cost performance while maintaining the airtight performance as a sealing component.

[0050] (Examples 1 to 12, Comparative Examples 1 to 7) Manganese oxide (MnO 2 ), silicon oxide (silica: SiO 2 ), and magnesium oxide (magnesia: MgO) were added as auxiliaries 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 a cylindrical ceramic component with an outer diameter of 50 mm, an inner diameter of 38 mm, a height of 50 mm, an outer diameter chamfer of 0.5 mm, and an inner diameter chamfer of 0.5 mm. Also, Aldil (alumina added with zirconia) was prepared by adding zirconia to alumina to make it 80% by mass alumina, and molded in the same manner as alumina and sintered in air at 1500 °C to obtain a cylindrical component having the same dimensions as the alumina component. Further, 1% by mass of silica (Si 2 O 3 ), 3% by mass of yttria (yttrium oxide: Y 2 O 3 ), and 1% by mass of alumina were added as auxiliaries to silicon nitride, and molded and sintered in nitrogen at 1800 °C in the same manner to obtain a cylindrical silicon nitride component having the same dimensions as the alumina component. Also, 3% by mass of yttria was added as an auxiliary to aluminum nitride (AlN), and molded and sintered in nitrogen at 1800 °C in the same manner to obtain a cylindrical aluminum nitride component having the same dimensions as the alumina component.

[0051] The ceramic parts obtained by sintering were deburred by barrel polishing, and then the surface of one end face was roughened by blasting. After that, the arithmetic mean surface height (Sa) of both end faces of the ceramic parts was measured using a Keyence laser microscope (VK-X3000). The measurement conditions were as follows: with the midpoint (diameter 44 mm) of the width of the ceramic part as the center, a range with a diameter of 2.5 mm was measured. The number of measurements was 3 times, and the measured value was the average value of the 3 times. The measurement results of the arithmetic mean surface height of the surface are shown in Table 1. In the examples, the end face with the increased arithmetic mean surface height of the surface was designated as S1, and the unprocessed end face was designated as S2. On the other hand, in Comparative Examples 1 and 6, neither end face was processed by blasting. In the other comparative examples, the end face with the increased arithmetic mean surface height of the surface in the examples was designated as S2, and the unprocessed end face in the examples was designated as S1. In Table 1, the ceramics with the same processing were configured as the same lot. For example, Examples 1 to 6, 10 to 12 and Comparative Examples 2 to 3, 6 to 7 were lots composed of ceramic parts that were manufactured and processed in the same way and the arithmetic mean surface height was measured. Also, in Table 1, the aluminum nitride parts were denoted as AlN.

[0052] Next, the bonding method between the ceramic part and the metal part was selected from the active metal bonding method and the high melting point metal method. In the examples and comparative examples where the active metal bonding method was selected, the metal powder mixing ratio was adjusted so that the copper powder, tin powder, and titanium hydride (TiH) powder were 60:30:10 by weight%. Ethyl cellulose and terpineol were added and kneaded in a kneader to form a paste to prepare an active metal solder paste. An active metal paste with a thickness of 60 μm was printed on the upper and lower end parts (ring parts) of the ceramic part by screen printing using a 100-mesh screen with an outer diameter of 48 mm and an inner diameter of 40 mm, and dried at 100 °C in the air. Next, using the metal parts described later, the metal parts, ceramic parts, and metal parts were set in the jig in this order, and heated in a vacuum atmosphere at 820 °C or higher for 10 minutes to bond the metal part and the ceramic part to produce a ceramic sealed part.

[0053] In the examples and comparative examples where the high melting point metal method was selected, the metal powder mixing ratio was adjusted so that the molybdenum (Mo) powder and manganese (Mn) powder were 90:10 by weight%. Ethyl cellulose and terpineol were added and kneaded in a kneader to form a paste to produce a high melting point metal paste. A 100-mesh screen with an outer diameter of 48 mm and an inner diameter of 40 mm was used to screen-print a 25-μm-thick high melting point metal paste on the upper and lower ends (ring parts) of the ceramic component, and dried in air at 100 °C. Next, a metallized layer of high melting point metal was formed on the surface of the ceramic component by heating in a wet hydrogen-nitrogen atmosphere at 1450 °C or higher for 30 minutes. Next, a 2-μm-thick nickel layer was formed on the surface of the metallized layer by electrolytic nickel plating. Next, using a 0.1-mm-thick silver solder (BAg-8), the metal component, silver solder, ceramic component, silver solder, and metal component were set on the jig in this order, and heated in a hydrogen-nitrogen atmosphere continuous furnace at 820 °C or higher for 10 minutes to join the metal component and the ceramic component to produce a ceramic sealed component.

[0054] (Table 1) TIFF2025083143000002.tif8180

[0055] Also, for measuring the bonding strength, instead of the metal component, a copper plate of 10 mm × 100 mm × 0.5 mm was prepared. In the active metal method, a test sample for bonding strength was produced by setting a copper plate and a ceramic component printed with an active metal layer on a jig in this order and heating to join them. In the high melting point metal method, a test sample for bonding strength was produced by setting a copper flat plate, silver solder, and a ceramic component with a plated layer formed on the surface of the metallized layer in this order and heating. The ceramic component was fixed to a tensile strength tester, and the copper flat plate bent vertically was pulled upward at 5 mm / min to measure the bonding strength (peel strength).

[0056] Table 2 shows the measurement results of the peel strength. In Table 2, Examples 1 and 7 to 10 are described as representatives of the same lot. Also, the peel strengths of the S1 surface and the S2 surface were measured using another ceramic component of the same manufacturing lot, but are described in the same row for convenience in Table 2.

[0057] (Table 2) TIFF2025083143000003.tif36116

[0058] As can be seen from Table 2, the peel strength of the surface with the increased arithmetic mean surface height of the surface (surface height S1) was greater than that of the surface without the increase (surface height S2). This is because increasing the arithmetic mean surface height of the surface increased the bonding area and physically bonded such as the anchor effect, resulting in an increase in the bonding strength.

[0059] Table 3 shows the metal A components and metal B components used in the examples and comparative examples. The materials of the metal A components are iron and iron alloys, etc., and are pure iron (Fe), carbon steel (S45C), stainless steel (SUS304, SUS430), kovar, and 42 alloy. The materials of the metal B components are copper and copper alloys, and are oxygen-free copper and phosphorus-deoxidized copper. These metal components were processed into a cylindrical shape with a height of 20 mm, an outer diameter of 48 mm, an inner diameter of 46 mm, and the tip portion on the bonding side processed inward at a substantially right angle to make the inner diameter 40 mm. In the examples and comparative examples, combinations of metal components as shown in Table 3 were used. In addition, a 2-μm nickel plating was applied to the surfaces of the processed parts of iron and iron alloys, etc.

[0060] Next, the upper part of the ceramic-sealed component was suppressed by applying silicone with a circular jig made of biton rubber, and the lower part was fixed to a helium leak detector and sucked to conduct a helium leak test. The helium leak test was conducted in accordance with the vacuum spraying method (spray method) of the "Helium Leak Test Method" (JIS Z2331:2006). When no leak of 1×10 -9 Pa·m 3 / s or more occurred at a vacuum of 1.3 μPa, it was considered qualified, and when a leak occurred, it was considered unqualified, and the number of defective products was determined.

[0061] Furthermore, a thermal shock test (TST) was conducted on the ceramic sealed parts that passed the helium leak test. The test conditions were a test cycle of low temperature condition -40°C × 30 minutes, high temperature condition 125°C × 30 minutes, and transfer time of 10 seconds or less for 20 cycles. After the thermal shock test, a helium leak test similar to that before the test was conducted. The case where no leak occurred was considered a pass, and the case where a leak occurred was considered a fail, and the number of defective parts was determined. The test results of each of the examples and comparative examples are shown in Table 3.

[0062] (Table 3) TIFF2025083143000004.tif9195

[0063] For the ceramic sealed parts according to the examples and Comparative Example 2, the number of leak defective parts in the helium leak test was within a preferable range. This is because the bonding strength obtained by the combination of the ceramic part and the metal part was appropriate, and it was a bonding structure that was not broken by the stress generated by the difference in thermal expansion during bonding. In contrast, in the comparative examples, a large number of leak defective parts occurred. This is because the bonding strength was not sufficiently high, and due to the difference in thermal expansion between the ceramic part and the metal part, the bonding part was damaged and airtightness could not be maintained.

[0064] Also, for the ceramic sealed parts according to the examples, the range was such that no or few leak defects occurred in the helium leak test after TST. This is because the bonding strength obtained by the combination of the ceramic part and the metal part was appropriate, and it was a bonding structure that was not broken by the stress generated by the difference in thermal expansion under the test conditions of TST. In contrast, in the comparative examples, helium leak defects occurred after TST. This is because the bonding strength obtained by the combination of the ceramic part and the metal part was not sufficient. Also, even when the bonding strength was sufficient, damage due to increasing the surface roughness of the ceramic part was large, leading to the breakage of the ceramic part and the occurrence of a leak path.

[0065] As is clear from the results shown above, in the examples, improvement in leak characteristics and reliability in TST was recognized as compared with the comparative examples.

[0066] As described above, some embodiments of the present invention have been illustrated. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof. Further, the above embodiments can be implemented in combination with each other.

Explanation of Reference Numerals

[0067] 1...Ceramic Sealing Component 2...Ceramic Component 21, 22...End Faces 3...Metal A Component 4...Metal B Component 5...Bonding Layer 6...Active Metal Brazing Material Layer 7...Metallized Layer 8...Plated Layer 9...Brazing Material Layer

Claims

1. In a ceramic component used for a ceramic sealed component in which two metal components of different materials are joined to an end face, when the arithmetic mean surface height of one end face is S1 and the arithmetic mean surface height of the other end face is S2, a ceramic component characterized in that S1 / S2 ≥ 1.

2.

2. Regarding the ceramic component according to Claim 1, an iron or iron alloy is joined via a bonding layer to the end face having an arithmetic mean surface height of S1, and a copper or copper alloy is joined via a bonding layer to the end face having an arithmetic mean surface height of S2, a ceramic sealed component characterized by this.

3. Regarding the bonding layer of the ceramic sealed component according to Claim 2, a metallized layer made of one or more refractory metals selected from tungsten and molybdenum is formed on the surface of the ceramic component, a nickel plating layer is formed on the surface of the metallized layer, and the bonding layer is a bonding layer made of a brazing material containing copper and silver on the surface of the nickel plating layer, the ceramic sealed component according to Claim 2 characterized by this.

4. Regarding the ceramic component of the ceramic sealed component according to Claim 3, the ceramic component is aluminum oxide, the ceramic sealed component according to Claim 3 characterized by this.

5. Regarding the bonding layer of the ceramic sealed component according to Claim 2, the bonding layer is made of one or more reactive metals selected from titanium, zirconium, and hafnium and one or more brazing material metals selected from copper and silver, the ceramic sealed component according to Claim 2 characterized by this.

6. Regarding the ceramic component of the ceramic sealed component according to Claim 5, the ceramic component is one selected from aluminum oxide, silicon nitride, and aluminum nitride, the ceramic sealed component according to Claim 5 characterized by this.

7. In a method for manufacturing a ceramic sealed component in which two metal components of different materials are joined to both end faces, a step of preparing the ceramic component according to Claim 1, and a step of joining the ceramic component and the metal component with one or more reactive metals selected from titanium, zirconium, and hafnium and one or more brazing material metals selected from copper and silver, a method for manufacturing a ceramic sealed component characterized by including these.

8. In a method for manufacturing a ceramic sealed component in which two metal components of different materials are joined to both end faces, a step of preparing the ceramic component according to Claim 1, and a step of forming a metallized layer made of a refractory metal on the end face of the ceramic component A step of forming nickel plating on the surface of the metallized layer; A step of joining the nickel plating and the metal part with a brazing material containing copper and silver; A method for manufacturing a ceramic sealing component, characterized by comprising the above steps.

9. In a method for manufacturing a ceramic sealing component in which metal parts of two different materials are joined to both end faces, Iron or an iron alloy is joined via a joining layer to an end face having an arithmetic mean surface height S1 of the ceramic component according to claim 1, and copper or a copper alloy is joined via a joining layer to an end face having an arithmetic mean surface height S2. The method for manufacturing a ceramic sealing component according to claim 7 or claim 8, characterized in that

10. In a method for manufacturing a ceramic sealing component in which metal parts of two different materials are joined to both end faces, The method for manufacturing a ceramic sealing component according to claim 9, characterized in that the ceramic component according to claim 1 is one selected from aluminum oxide, silicon nitride, and aluminum nitride.

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