JP2851881B2 - Jointed body of alumina ceramics and iron-nickel alloy and joining method thereof - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a joined body of alumina ceramics and an iron / nickel-based alloy and a joining method thereof, particularly a joined body suitably used for a photomultiplier tube and the joined body. It relates to a joining method.

"Conventional technology and its problems" When electrical equipment parts that require vacuum tightness and high insulation, such as a photomultiplier tube made of a bonded body of alumina ceramic and metal, alumina ceramic and iron-nickel Generally, a joined body with an alloy is used. This is because an alloy having a similar thermal expansion coefficient to alumina ceramics can be obtained from an iron-nickel alloy, and thermal stress destruction of alumina ceramics can be avoided.

The joined body of the above combination is joined by a method generally called "Telefunken method". In this method, as shown in FIG. 2, a Mo-Mn mixed powder is applied as a paste on an alumina ceramic substrate 1 to a predetermined thickness, and is heated at a high temperature in a humidified hydrogen stream to form a metallized layer 2. In this method, a Ni plating layer 3 is formed on the surface of the metallized layer 2, and an iron / nickel-based alloy substrate 5 is placed on the Ni plating layer 3 via a brazing material 4 and joined.

However, obtaining a joined body by the above-described telefunken method has the following disadvantages due to the joining mechanism of the metallized layer 2 formed by the Mo-Mn mixed powder.

The joining mechanism by the metallized layer 2 will be described. Mo is maintained in a metallic state by high-temperature heating in a humidified steam flow, but the oxygen partial pressure is controlled by supplying an appropriate concentration of water, and the Mn surface is oxidized. To MnO.
Then, MnO, which is the main component of the alumina ceramic substrate, AlO ₃ reacts with SiO ₂ contained as an impurity in the alumina ceramic to form a MnO-Al ₂ O ₃ -SiO ₃ low melting point glass, which is By filling the gap of Mo-Mn, it is joined to the alumina ceramic substrate 1. Thus, in the above metallized layer 2 Mo-Mn-MnO-Al 2 O 3 -SiO 2
A reaction phase of the system will be formed.

However, the amount of water vapor supplied into the hydrogen stream greatly affects the composition of the MnO-Al ₂ O ₃ -SiO ₂ glass formed in relation to the oxygen partial pressure. Physical properties, such as the coefficient of thermal expansion, are greatly affected. Therefore, it is necessary to strictly control the amount of water vapor so that a minute crack does not occur between the Mo-Mn metals and impair the vacuum tightness. The method is a multi-step process in which a metallized layer 2, a plated layer 3, and a brazing material 4 are sequentially formed between an alumina ceramic and an alloy.

Further, in such a method, since SiO ₂ as an impurity contained in the alumina ceramics is involved in the bonding, alumina ceramics having a purity of 94 to 96% are generally used,
High purity alumina ceramics containing more than 99.5% Al ₂ O ₃ could not work. As a result, the use of such low-purity alumina ceramics impairs the high insulation properties obtained from high-purity alumina ceramics, and is disadvantageous for high voltages, for example, when used as a photomultiplier tube.

On the other hand, apart from the above-mentioned telefunken method, a method of joining using an active metal brazing material containing several% of titanium, for example, a system such as Ag-Cu-Ti or Cu-Ti is also known. In this joining method, the difference in thermal expansion between alumina ceramics and iron-nickel alloy in the high temperature range (generally, the thermal expansion coefficient of iron-nickel alloy at 500 ° C or higher is caused by the coexistence of soft metals such as Ag-Cu or Cu. It is known that a good joined body can be obtained by alleviating abrupt increase in the size of alumina ceramics).

However, recently, the performance requirements of photomultiplier tubes have become stricter, so when used as photomultiplier tubes, it is essential to be able to withstand use at high temperatures. When a large amount of soft metal such as is used, there is an inconvenience that high-temperature resistance performance is reduced.

The present invention has been made in view of the above circumstances, and its purpose is to maintain sufficient bonding strength and sealing performance even at high temperatures, and to maintain vacuum tightness even when used as an electron tube. The point is to obtain a bonded body that can be sufficiently held, has good bonding properties with high-purity alumina ceramics, and can maintain excellent performance with respect to withstand voltage by simple means.

[Means for Solving the Problems] In the bonded body of the alumina ceramics and the iron-nickel alloy according to the present invention, a high titanium content between the alumina ceramics and the iron-nickel alloy is higher than the interface side with the alumina ceramics. A bonding layer, a first alloy layer mainly composed of iron, nickel, manganese and titanium, a silver alloy layer composed mainly of iron, nickel, manganese and titanium, and a second alloy layer mainly composed of iron, nickel, manganese and titanium The first and second alloy layers mainly composed of iron, nickel, manganese, and titanium, the silver, manganese, copper, and titanium alloy layers and the iron, nickel, The total thickness of the second alloy layer containing manganese / titanium as a main component is 1 to 100 μm
Having the bonded portion of m was the means for solving the above problem.

In addition, in the joining method of the alumina ceramic and the iron-nickel alloy, a titanium thin film or a titanium thin plate is provided on the alumina ceramic side, and 60 to 95% by weight of silver, 3 to 20% by weight of manganese, and 3 to 30% by weight of the iron / nickel alloy. 30% by weight of alloy powder or mixed powder, or alloy thin plates of 60 to 95% by weight of silver, 3 to 20% by weight of manganese and 3 to 30% by weight of copper are arranged respectively, and alumina ceramic and iron / nickel based A titanium thin film or titanium thin plate and the above-mentioned silver / manganese / copper alloy powder or mixed powder, or an alloy thin plate are interposed between the alloy and the alloy, and then heat diffusion is performed to join the alumina ceramic and the iron / nickel alloy. Is a means for solving the above-mentioned problem.

 Hereinafter, the present invention will be described in detail.

FIG. 1 is a view showing an example of the present invention. In FIG. 1, reference numeral 10 denotes an alumina ceramic plate (hereinafter abbreviated as a ceramic plate), and 11 denotes an iron-nickel alloy plate (hereinafter abbreviated as an alloy plate). Do). The ceramic plate 10 and the alloy plate 11 form a joined body 13 by having the matching portion 12 between them.

The bonding portion 12 includes a bonding layer 14 containing a high titanium content from the ceramic plate 10 side, a first alloy layer 15 mainly composed of iron, nickel, manganese, and titanium, and a silver, manganese, copper, and titanium alloy layer.
16. A second alloy layer 17 mainly composed of iron, nickel, manganese, and titanium is sequentially formed. The thickness of the bonding layer 14 is 0.1 to 5 μm, and the thickness of the alloy layers 15, 16 and 17 is The total thickness was adjusted to 1 to 100 μm or less.

Next, a method for manufacturing the joined body 13 will be described based on the joining method according to claims 2 to 4.

First, a ceramic plate 10 and an alloy plate 11 are prepared, and a titanium thin film or a titanium thin plate is provided on the ceramic plate 10 side, and 60 to 95% by weight of silver and manganese 3 to 20 are provided on the iron / nickel alloy side.
Alloy powder or mixed powder of 3 to 30% by weight of copper, or 60 to 95% by weight of silver, 3 to 20% by weight of manganese, 3 to copper
A 30% by weight alloy thin plate (hereinafter referred to as a silver / manganese / copper alloy thin plate) is arranged so that a titanium thin film or a titanium thin plate and the silver / manganese / copper are placed between the ceramics 10 and the alloy 11. An alloy powder, a mixed powder, or a thin alloy plate thereof is interposed. Here, when a thin film is used as titanium, a physical vapor deposition method (PVD method) such as a high vacuum evaporation method or a sputtering method using titanium as a target is suitably adopted as the thin film formation method. That is, a ceramic plate is formed by high vacuum evaporation or sputtering.
A titanium thin film having a thickness of 1 to 20 μm is formed on 10 and a silver / manganese / copper alloy thin plate having a thickness of 3 to 100 μm is further placed thereon. Then, an alloy plate is placed on the silver / manganese / copper alloy thin plate.
Place 11 Here, the lower limit of the thickness of the titanium thin film is 1 μm.
The reason for setting m is to secure the amount of reaction melt required for joining.

On the other hand, when a thin plate is used as titanium and silver / manganese / copper alloy, for example, a thickness of 3 to
A titanium thin plate having a thickness of 20 μm and a silver / manganese alloy thin plate having a thickness of 3 to 100 μm similarly prepared by a multi-stage rolling method are prepared in advance. The reason why the lower limit of the thickness of the thin plate is set to 3 μm is that if the thickness is less than 3 μm, the handling operation becomes extremely difficult. These are sandwiched between the ceramic plate 10 and the alloy plate 11, and a titanium thin plate is arranged on the ceramic plate 10 side, and a silver / manganese / copper alloy thin plate is arranged on the alloy plate 11 side.

After interposing titanium and silver / manganese / copper alloy powder or mixed powder, or silver / manganese / copper alloy thin plate in this way, the whole is about 950 to 1250 ° C. in a vacuum or in an inert gas. Heat treatment is performed at the above temperature for about 5 to 30 minutes to obtain a joined body 13 shown in FIG.

Here, due to such thermal diffusion treatment, the titanium thin film or the titanium thin plate and the alloy powder or the mixed powder or the alloy thin plate of silver / manganese / copper react with the alloy plate 11 (iron / nickel alloy) at a high temperature. A melt mainly composed of Fe-Ni-Mn-Ti is formed at the interface with the ceramic plate 10 (alumina ceramics). Then, since the melt has good reactivity and wettability with the ceramic plate 10, a solid and highly airtight bond with the ceramic plate 10 is formed in one step when cooled. At this time, the alloy powder of silver, manganese, and copper, or the mixed powder or alloy thin plate,
By forming a melt of silver / manganese / copper / titanium, it contributes to stress relaxation between the alloy plate 11 and the ceramic plate 10 and improvement in heat resistance.

The bonding mechanism of the thus obtained bonded body 13 will be described in more detail. The bonding layer between the ceramic plate 10 and the alloy 11 is formed by the bonding layer 14 containing high titanium. This bonding layer 14 slightly oxygenates the ceramic plate 10
Formed by reacting with the alloy plate 11 while taking in from the side,
It has a structure similar to (Fe-Ni) ₂ Ti ₄ O. The thickness of the bonding layer 14 is 2 μm or less, preferably about 0.1 to 0.6 μm.

On the other hand, the first alloy layer 15 and the second alloy layer 17 containing iron, nickel, manganese, and titanium as main components are capable of diffusing the melt and titanium formed at the time of the heat bonding into the alloy plate 11, During the cooling of the melt, the silver, manganese, copper and titanium alloy layers 16
This is inevitably formed by exsolution and precipitation of an alloy containing titanium as a main component. And these alloy layers
In Nos. 15 and 17, the coefficient of thermal expansion is larger than that of the alloy plate 11 (iron-nickel alloy), and the ductility is reduced by including titanium. Therefore, the formation of the alloy layers 15 and 17 is not preferable because it causes thermal stress destruction in the joined body 13; however, in the thermal diffusion joining accompanied by the formation of the reaction melt, the alloy layers 15 and 17 having a constant thickness are formed. It is impossible to avoid the formation. The thickness of the alloy layers 15, 17 is
It depends on the thickness when the bonding layer 14 is formed. Therefore, in the present invention, in order to form the alloy layers 15 and 17 as thin as possible, the thickness of the alloy layers 15 and 17 is reduced by forming the bonding layer 14 using a titanium thin film or a titanium thin plate and optimizing the heat treatment conditions. I am holding it down.

Further, the silver / manganese / copper / titanium alloy layer 16 is also inevitably formed by diffusing the melt and titanium formed during the heat bonding into silver / manganese.
Due to its excellent ductility compared to iron / nickel / manganese / titanium (alloy layers 15 and 17) and iron / nickel-based alloy (alloy plate 11), it is generated between ceramic plate 10 and alloy plate 11. This reduces the thermal stress.

In addition, the thickness of each layer obtained by the thermal diffusion treatment can be sufficiently suppressed by the condition of the thermal diffusion treatment in addition to the previously adjusted thickness of the thin film or thin plate. Then, the thickness of the high titanium-containing bonding layer 14 resulting from the heat diffusion treatment at this time is 0.1 to 5 μm, and the first alloy layer 15 mainly composed of iron, nickel, manganese, and titanium is combined with silver, manganese, and copper. When the total thickness of the titanium alloy layer 16 and the second alloy layer is 1 to 100 μm, stable high bonding strength and high airtightness can be obtained. There is an inconvenience that the withstand voltage decreases due to the outflow of the melt.

On the other hand, the thin film or thin plate of titanium and the thin alloy plate of silver, manganese, and copper only involve the vicinity of the interface in the reaction or diffusion with the alloy layer 11 and the ceramic plate 10 that are in contact with each other during the thermal diffusion treatment. Therefore, the thickness and the thickness of each layer obtained after diffusion are not necessarily directly proportional, but especially when a thin plate is used as titanium, the thickness of the titanium thin plate is 20 μm, and the thickness of the silver / manganese / copper alloy thin plate is 100 μm. If it exceeds, the amount of reaction melt generated in each layer increases, which tends to flow out to the outside, and there is a possibility that the dielectric strength of the obtained joined body 13 against a high voltage is significantly reduced.

"Example" Hereinafter, the present invention will be specifically described with reference to examples.

(Example 1) Vacuum baking test Titanium and silver, manganese, and copper alloys having different thicknesses as shown in Table 1 were interposed between alumina ceramics and an iron / nickel alloy, and were placed in a vacuum (5 × 10 ⁽⁵ Torr) at 950 to 1150 ° C. for 10 minutes to obtain several kinds of joined bodies. Further, these were vacuum baked at 800 ° C. for 4 hours, and then leak resistance was examined using a He leak detector. The results are shown in Table 1.

Table 1 shows the thicknesses of the titanium and silver / manganese / copper alloy sheets used for the joining.

(Example 2) Compressive shear strength test As a material for forming a joint, a titanium thin plate and silver / manganese /
Using a copper alloy thin plate or a titanium thin film formed by a sputtering method and a silver / manganese / copper alloy thin plate, we examined how the difference in the thickness of the joint affected the compressive shear strength. . Table 2 shows the obtained results.

The test method was a compression shear strength test (normal temperature) at a crosshead speed of 0.5 mm / min.

Also, as a comparison, the strength in the case of joining by using a titanium alloy having a large thickness and a silver-manganese-copper alloy thickness is examined, and the results are also shown in Table 2.

(Example 3)-Withstand voltage test It was examined how a difference in thickness between a titanium thin plate and a silver / manganese / copper alloy thin plate affects the withstand voltage. The test method was measured at room temperature in a vacuum of 1 × 10 ⁻⁶ Torr or less. Table 3 shows the obtained results.

As a comparison, those having a large titanium thickness and a large silver-manganese-copper alloy thickness were used, and the influence on the withstand voltage was similarly examined. The results are also shown in Table 3.

[Effects of the Invention] As described above, the joined body of the alumina ceramic and the iron-nickel alloy according to the present invention is higher than the interface between the alumina ceramic and the iron-nickel alloy between the alumina ceramic and the iron-nickel alloy. Titanium-containing bonding layer, iron
A first alloy layer containing nickel, manganese, and titanium as main components, a silver, manganese, copper, and titanium alloy layer;
Since it has a joining portion formed by sequentially forming a second alloy layer containing manganese / titanium as a main component, it has excellent joining strength at a high temperature use, and can be applied to a vacuum sealed tube such as an electron tube. Thus, an effect excellent in withstand voltage and airtightness is exhibited.

Also, according to the joining method of the alumina ceramic and the iron / nickel alloy, the joining method is extremely simple as compared with the conventional joining method, and the obtained joined body has excellent joining strength at a high temperature as described above. Becomes

[Brief description of the drawings]

FIG. 1 is a sectional view showing a joint structure of a joined body according to the present invention, and FIG. 2 is a view showing an example of a conventional joint structure. 10 ... Alumina ceramic plate, 11 ... Iron / nickel alloy plate, 12 ... Joint, 13 ... Joint body, 14 ... Joint layer containing high titanium, 15 ... Iron, nickel, manganese, titanium A first alloy layer composed mainly of 16; an alloy layer composed of silver, manganese, copper, and titanium; 17 a second alloy layer composed mainly of iron, nickel, manganese, and titanium;

Claims (4)

(57) [Claims] 1. A joined body comprising an alumina ceramic, an iron-nickel alloy, and a joint formed therebetween, wherein the joint comprises a high titanium-containing joining layer, By forming a first alloy layer mainly composed of nickel, manganese and titanium, a silver-manganese-copper-titanium alloy layer, and a second alloy layer mainly composed of iron, nickel, manganese and titanium A first alloy layer mainly composed of iron, nickel, manganese, and titanium, and a silver, manganese, copper, and titanium alloy, which is joined to an iron-nickel alloy and has a thickness of 0.1 to 5 μm in a bonding layer containing high titanium. The total thickness of the layer and the second alloy layer containing iron, nickel, manganese, and titanium as main components is 1 to 100 μm, and the bonding between the alumina ceramic and the iron-nickel alloy is performed. . 2. An alloy powder or mixed powder of 60 to 95% by weight of silver, 3 to 20% by weight of manganese and 3 to 30% by weight of copper on the side of iron / nickel alloy, Or 60-95% by weight of silver, manganese 3
Alloy thin plates of up to 20% by weight and 3 to 30% by weight of copper, respectively, and a titanium thin film or a titanium thin plate and an alloy of silver, manganese and copper are interposed between the alumina ceramic and the iron-nickel alloy. A method of joining alumina ceramics and an iron-nickel alloy, comprising interposing a powder or a mixed powder, or a thin alloy plate thereof, and then performing thermal diffusion treatment to join the alumina ceramic and the iron-nickel alloy. 3. A method for bonding an alumina ceramic and an iron-nickel alloy according to claim 2, wherein a titanium thin film having a thickness of 1 to 20 μm is formed on the alumina ceramic by physical vapor deposition or sputtering.
Next, an alloy thin plate of 5 to 100 μm in thickness of 60 to 95% by weight of silver, 3 to 20% by weight of manganese and 3 to 30% by weight of copper is placed thereon,
A method of joining an alumina ceramic and an iron-nickel alloy, comprising placing an iron-nickel alloy on the thin alloy plate and subjecting the iron-nickel alloy to heat diffusion in a vacuum or an inert gas stream. 4. The method of joining alumina ceramics to an iron-nickel alloy according to claim 2, wherein a titanium thin plate is provided on the alumina ceramics side, and 60 to 95% by weight of silver and manganese 3 to 20 is provided on the iron-nickel alloy side. 3% to 30% by weight of an alloy thin plate, and a titanium thin plate having a thickness of 3 to 20 μm and an alloy thin plate having a thickness of 5 to 100 μm between the alumina ceramic and the iron-nickel alloy. And then performing a thermal diffusion treatment in a vacuum or in an inert gas phase.