JP2002126507A - Method for producing gas absorption getter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a linear getter capable of encapsulation in the space of a closed instrument having an every shape. SOLUTION: In this method for producing the gas absorption getter, gas- absorbing alloy grains are carried in the periphery of a metal wire whose cross- sectional shape is a circle. The gas-absorbing alloy grains having >=400 Vickers hardness are used and the metal wire satisfying the relation of the formula (1) is used. A load is applied to the gas-absorbing alloy grains sandwiched between a tool and the metal wire. 100<=Hv<=205-150×D...(1). Wherein, Hv represents Vickers hardness of the metal wire and D represents diameter (mm) of the metal wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container or equipment such as a thermos, a plasma display or the like, the inside of which is kept in a vacuum or an inert gas atmosphere (hereinafter, these are collectively referred to as "sealed equipment"). The present invention relates to a method for manufacturing a getter that is enclosed in a device and absorbs air or impurity gas therein.

[0002]

2. Description of the Related Art A sealed device as described above is manufactured by evacuating and sealing the inside of the device by a vacuum pump at the time of manufacturing, or by sealing and sealing with an inert gas after evacuating. For example, in a plasma display panel, after evacuation, an inert gas such as neon or xenon is sealed therein, but carbon, such as oxygen, nitrogen, water vapor, or methane that is inevitably generated in the panel manufacturing process. Impurity gas such as hydrogen gas has an adverse effect on plasma generation intensity and stability during use. In addition, the plasma display panel is generally assumed to have a product life of about 10 years. Therefore, if a small amount of the above-mentioned gas is generated from the component material during that period, the function is reduced.

[0003] Therefore, in order to prevent a decrease in the degree of vacuum during use or to absorb an impurity gas in an inert gas, a gas absorbing material (hereinafter simply referred to as "getter") is provided inside the sealed device. It is common to enclose. Further, depending on the type and manufacturing method of the sealed device, a desired degree of vacuum may be obtained only with a getter without using a vacuum pump. In such a getter, the gas absorption capability is maintained for a long period of time, that is, in addition to the long gas absorption life, the removal of the impurity gas as soon as possible after sealing, that is, the gas absorption, There is a need for a fast absorption rate.

As a substance effective for absorbing the impurity gas as described above, for example, a Zr-Fe-V system, a Zr-Al system, and a Zr-Ni system as disclosed in Japanese Patent Publication No. 5-17293 are disclosed. , Zr-Fe
Alloys (hereinafter referred to as “gas absorbing alloys”) have been developed. Since it is necessary to increase the reaction area of these alloys as much as possible, powders having an average particle diameter of 100 μm or less are usually formed into pellets by a press molding method for convenience of handling. However, the diameter of the pellet to be formed is about 1 mm, and its length is limited to about three times the diameter. That is, it is difficult to process the gas absorbing alloy itself by a press molding method to produce a linear or thin plate-like getter.

US Pat. Nos. 3,652,317 and 3,856,709
In the specification of No., a thin strip-shaped base material is sandwiched between a pair of upper and lower strip-shaped metal plates, and a granular material of the getter alloy is placed on the upper surface of the strip-shaped base material and the upper surface of the lower metal plate, and pressed using a pressing roll. A method for manufacturing a getter is disclosed. In these specifications, it is stated that a strip-shaped getter having a thickness of about 0.2 mm can be manufactured by the above-described manufacturing method, but the width of the getter is limited to about several cm to about several mm due to a problem in producing a roll. Would. Further, it is possible to cut the band-shaped getter into a narrow one, but in that case, the yield is greatly reduced due to the cutting allowance, which is not suitable for industrial production.

[0006] None of the above-mentioned getters is flexible with respect to shape change, and in a flat sealing device having a relatively large area or an elongated sealing device having a large aspect ratio, the gas absorption in the container is made uniform. Therefore, it is difficult to evenly encapsulate the getter. There are many restrictions depending on the space where the band-shaped getter is arranged. If the width of the band-shaped getter is reduced by cutting to avoid such a restriction, the gas-absorbing alloy does not exist on the cut surface. Absorption capacity is reduced.

Therefore, the present inventors performed rolling work (hereinafter simply referred to as “rolling work”) while pressing and rotating a metal wire with a tool on which gas-absorbing alloy particles were scattered, thereby forming the metal wire. A getter in which gas-absorbing alloy particles are supported on the entire peripheral surface and a method of manufacturing the getter have been proposed (Japanese Patent Application No. Hei 10-26139).
11-180557). However, in the invention, depending on the type of the metal wire and the gas-absorbing alloy particles, the gas-absorbing ability such as the gas-absorbing speed and the gas-absorbing life was sometimes poor.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a linear getter which can be sealed in a space of a sealed device having any shape and has an excellent ability to absorb impurity gas and the like.

[0009]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies with the aim of improving the gas absorption life and the gas absorption rate of the getter. As a result, the following (A) to (F)
Was obtained. (A) The larger the amount of the gas-absorbing alloy particles supported on the metal wire per unit surface area (hereinafter, referred to as “supporting rate”), the longer the gas absorption life. However, if the gas-absorbing alloy particles bite into the metal wire too much, the gas-absorbing life will be shortened. (B) As the particle size of the gas-absorbing alloy particles supported on the metal wire is smaller, the surface area increases, so that the gas absorption speed is higher. (C) When the gas-absorbing alloy particles that have been finely divided in advance are supported on the metal wire, the number of contact points between the gas-absorbing alloy particles and the metal wire increases, and the pressure applied to the individual particles is dispersed. Can't get the rate. Therefore, it is effective to roll-process the gas absorbing alloy particles in a coarse state, and to crush the gas absorbing alloy particles into the metal wire while pulverizing the particles. (D) Gas-absorbing alloy particles are Ni or its alloy, Fe or its alloy, C
In order to dig into and carry a metal wire such as u, Ti,
The Vickers hardness must be 400 or more. (E) The hardness of the metal wire is preferably small in order to support the gas-absorbing alloy particles, and large in order to pulverize the gas-absorbing alloy particles during rolling. However, if the hardness of the metal wire is too small, the gas absorbing alloy particles will bite into the metal wire too much, and the gas absorption amount will be reduced. (F) Even if the hardness of the metal wire is constant, if the diameter is increased, the number of contact points with the gas absorbing alloy particles increases, so the pressure applied to each particle is dispersed, and the gas absorbing alloy particles are sufficiently pulverized. You will not be able to do it. Therefore, it is necessary to adjust the hardness of the metal wire according to the diameter of the metal wire.

The present invention has been made based on the above findings, and the gist of the invention resides in the following (1) and (2) methods for producing a gas absorption getter. (1) In a method of manufacturing a gas absorbing getter in which gas absorbing alloy particles are supported around a metal wire having a circular cross section, a gas absorbing alloy particle having a Vickers hardness of 400 or more is used, and Using a material that satisfies the relationship of the following equation (1), while rotating the metal wire by a tool, applying a load to the gas absorbing alloy particles sandwiched between the tool and the metal wire, Manufacturing method of a gas absorbing getter. 100 ≦ Hv ≦ 205−150 × D (1) where Hv: Vickers hardness of metal wire, D: diameter of metal wire
(2) The tool is composed of an upper tool and a lower tool, and the metal wire is sandwiched between the upper tool and the lower tool on which the gas-absorbing alloy particles have been sprayed. The method according to claim 1, wherein the upper tool and / or the lower tool are moved while applying a load with a lower tool, and the metal wire is rotated.

In the above method (2), it is desirable to use a tool having an uneven surface on the lower surface as the upper tool.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 is a diagram schematically showing the principle of the getter manufacturing method of the present invention. (A) and (b), in the getter manufacturing method of the present invention, for example,
Gas absorbing alloy particles 2 are sprayed on the lower tool 4 so as to cover almost the entire surface. The metal wire 1 is arranged on the lower tool 4 on which the gas absorbing alloy particles 2 are sprayed, and the upper tool 3 is moved. The metal wire 1 is arranged so as to sandwich the metal wire 1 together with the lower tool 4. After this arrangement is completed, the metal wire is rotated while pressing the metal wire against the gas absorbing alloy particles by moving the upper tool 3 in the direction of the arrow in the figure.

The upper tool 3 and the lower tool 4 are preferably made of a high-hardness material such as tool steel or cemented carbide. If the metal wire can be rotated while being pressed against the gas absorbing alloy particles, the lower tool 4 may be moved instead of moving the upper tool 3, or both the upper tool 3 and the lower tool 4 may be moved. .

FIG. 2 is a view of the apparatus of FIG. 1 as viewed from above an upper tool. In this case, as shown in FIG.
Move the upper tool diagonally. The moving direction of the upper tool 3 (the direction of the arrow A in the figure) is 60 to 90 with respect to the axial direction of the metal wire 1 (the angle between the arrows A and B in the figure).
° should be within the range. If the moving direction is set to an angle of less than 90 °, the metal wire can be sent out in the axial direction (the direction of arrow B in the figure) together with the compaction, so that the getter can be manufactured without a feed mechanism. it can. However, if this angle is less than 60 °, the driving force in the axial direction of the metal wire is too strong, and there is a possibility that the metal wire may be broken depending on the material. Therefore, the angle is preferably 60 ° or more.

Here, from the viewpoint of preventing slipping between the upper tool 3 and a metal wire, the upper tool 3 has an uneven surface 5 as shown in FIG.
It is desirable to have The shape of the unevenness 5 is not particularly limited. However, in order to increase the chance of contacting the metal wire at many places and pressing the gas-absorbing alloy particles 2, and to prevent clogging by the gas-absorbing alloy particles 2, the pitch between adjacent convex portions is set. May be 0.2 to 2 mm, and the elevation difference of the unevenness may be 0.05 to 1.5 mm from the viewpoint of prevention of clogging by the gas absorbing alloy particles 2 and ease of processing the upper tool 3. When the above-mentioned unevenness 5 is formed on the upper tool 3, the unevenness 5
It is necessary that the direction of the groove is not parallel to the axial direction of the metal wire 1 so that the metal wire 1 does not enter the unevenness 5 and hinder the rotation. In particular, the angle between the axial direction of the metal wire 1 and the direction of the groove of the unevenness 5 is preferably in the range of 30 to 60 °.

The apparatus for implementing the method of the present invention is not limited to the apparatus shown in FIG. That is, the upper tool 3
Alternatively, as an alternative to the lower tool 4, any device having a tool that can dig into the metal wire 1 while crushing the gas absorbing alloy particles 2 may be used. For example, a tool in which a metal wire is sandwiched between a curved upper tool and a lower tool, or a drum-shaped tool in which upper and lower tools rotate, and the gas-absorbing alloy particles are sandwiched by the drum-shaped tool while sandwiching the metal wire. This is a device that can pour gas-absorbing alloy particles into a metal wire while pulverizing the gas-absorbing alloy particles. Alternatively, a device may be provided in which the above-described tools are installed on the left and right rather than vertically, and the gas absorbing alloy particles are supplied from above the tools.

Even when a getter is manufactured by using the above-described apparatus, the Vickers hardness of the gas-absorbing alloy particles is reduced.
If it is less than 400, the metal wire will not sufficiently penetrate and the carrying amount will be small, so that the gas absorption life as a getter will be short. Therefore, the Vickers hardness of the gas absorbing alloy particles needs to be 400 or more. For example,
As gas absorbing alloy particles with Vickers hardness of 400 or more, Zr-V-Fe alloy, Zr-V alloy, Zr-Fe alloy, Zr-N alloy, Zr-Al alloy and two or more of these There are mixtures and the like. In particular, a Zr-V-Fe alloy is preferable in terms of gas absorption characteristics. The particle size of the gas absorbing alloy particles before rolling is 63 μm at the maximum and 50 μm on average from the viewpoint of grinding and adhesion.
Something is good.

On the other hand, when the Vickers hardness of the metal wire is less than 100, the gas-absorbing alloy particles are too deep and the portion where the gas-absorbing alloy particles are exposed is reduced, so that the gas absorption amount is reduced and the gas-absorbing alloy particles are reduced. Becomes insufficient, and the gas absorption rate decreases. Also,
When the diameter of the metal wire is D, if the Vickers hardness of the metal wire is larger than “205-150 × D”, the gas-absorbing alloy particles are easily crushed, but the gas-absorbing alloy particles do not bite into the metal wire. And the amount of gas-absorbing alloy particles carried,
Both gas absorption decreases. Metal wires satisfying the above hardness include Ni-Cr alloy, Ni-Fe alloy, Ni-Co alloy, stainless steel, Ti, Ti alloy, work hardened copper alloy and the like. Also, the present invention is directed to a metal wire having a diameter of 0.7 mm or less. If the diameter of the metal wire exceeds 0.7 mm, the number of contact points between the metal wire and the gas-absorbing alloy particles increases, and the gas-absorbing alloy particles cannot be crushed and cut into the metal wire.

Therefore, in the method of manufacturing the getter by the above-mentioned rolling treatment, the Vickers hardness of the gas absorbing alloy particles is set to 400 or more, and the hardness of the metal wire is set as follows.
By limiting so as to satisfy (1), the amount of the gas-absorbing alloy particles carried on the metal wire, the gas absorption speed, and the gas absorption amount become extremely good. 100 ≦ Hv ≦ 205−150 × D (1) where Hv: Vickers hardness of metal wire, D: diameter of metal wire
(mm) FIG. 3 is a diagram schematically showing a cross section of a getter manufactured by the method of the present invention. As shown in the figure, the getter manufactured according to the present invention is a linear body in which the gas absorbing alloy particles bite around the metal wire and the gas absorbing alloy particles are carried around the metal wire. Further, since the gas-absorbing alloy particles that have been cut into the getter metal wire manufactured by the method of the present invention are ground by rolling,
% Or more has a particle size of 25 μm or less, and the average particle size is 10 μm or less.

[0021] Only the gas-absorbing alloy particles may be carried around the metal wire. However, the gas-absorbing alloy particles themselves emit a small amount of gas and are softer than the gas-absorbing alloy particles. Cu, Ni, etc.) can be mixed.
When the soft metal particles are mixed, the metal particles are fluidly interposed between the gas-absorbing alloy particles by rolling processing to prevent the gas-absorbing alloy particles from falling off the metal wire.

When the above metal particles are mixed, the mixing ratio is not particularly limited, but it is not preferable to use a large amount of the metal particles because they do not have a gas absorbing function. Therefore, 2 metal particles per 100 parts by volume of gas absorbing alloy particles
It is desirably 0 volume parts or less. The average particle size of the metal particles may be substantially the same as that of the gas absorbing alloy particles.

[0023]

EXAMPLES In order to confirm the effects of the present invention, various tests were carried out by supporting gas absorbing alloy particles on metal wires shown in Table 1 below by rolling.

[0024]

[Table 1] The gas absorbing alloy particles were produced by the following method. A raw material containing 19.3% by mass of V, 3.7% by mass of Fe, and 1.5% by mass of Ni and adjusted so that the balance was Zr was melted in a high-frequency vacuum melting furnace, and then an ingot was produced. After the ingot was pulverized, it was pulverized in an Ar gas atmosphere using a jaw crusher and a disc mill, and classified by passing through a 63 μm mesh sieve to obtain gas-absorbing alloy particles used in the present example. The hardness of the gas absorbing alloy particles is 4
At 69, the average particle size was 52 μm.

Rolling was performed by the following method. The apparatus shown in FIG. 1 was used as an apparatus for rolling compaction. The upper and lower pair of tools 3 and 4 are made of stainless steel plate with a side length of 150 mm and a thickness of 10 mm (the surface is smooth), the surface of the upper tool 3 is provided with irregularities of 0.5 mm pitch, and the surface of the lower tool 4 is It was smooth. Further, the gas absorbing alloy particles 2 were sprayed on the surface of the lower tool 4 so as to cover the entire surface. At this time, the density of the gas absorbing alloy particles was about 6 × 10 ⁵ particles / cm ² . The metal wire 1 having a length of 100 mm shown in Table 1 above is placed thereon, and the upper tool 3 is sandwiched from above by applying a force of 245 to 343 N, and the upper tool 3 is moved by hand to move the metal wire 1 by 200 mm. Rotated.
At this time, the moving direction of the upper tool 3 was set at an angle of 75 ° with respect to the axial direction of the metal wire 1.

With respect to the test material thus manufactured,
The results of the gas absorption test are also shown in Table 1 above. The gas absorption test was performed as follows. The test material is sealed in a stainless steel container having a capacity of 300 cm ³ and hermetically sealed. After sealing, the chamber is evacuated to 10 ^-4 Pa or less, and then Ar with a purity of 99.9995% is introduced. This is repeated twice. After that, the sealed container is heated to 450 ° C. in Ar and kept for 1 hour to activate. After activation, evacuate to 10 ^-4 Pa or less, keep the sealed container at 450 ° C, and purify 99.995
% CO ₂ gas is introduced. After introducing CO ₂ gas, the gas absorption amount and gas absorption rate were determined from the pressure change.

The gas absorption amount is the total absorption amount (Pa · L / g) until there is almost no change in pressure per 1 g of the alloy.
The gas absorption rate is defined as 1 after the start of gas absorption per gram of alloy.
It is a gas absorption amount (L / g / min) per minute in time. In addition, the gas absorption rate was measured only for some of them.

As shown in Table 1 above, Comparative Examples 1, 2,
In Nos. 5, 7, and 9, the amount of the gas-absorbing alloy particles carried is sufficient because the hardness of the metal wire is too low, but the gas absorption amount is low because the pulverization is insufficient. In Comparative Examples 3, 4, 6, and 8, the gas absorption was at a high level, but the hardness of the metal wire was too high, so the loading rate of the gas-absorbing alloy particles was low, and the gas absorption life was estimated to be poor. Is done. On the other hand, in each of the examples of the present invention, since the hardness of the metal wire was within an appropriate range, it was possible to secure a sufficient amount of loaded gas absorbing alloy particles and a sufficient amount of absorbed gas.

Next, the gas absorption rates of Examples 1 to 3 of the present invention and Comparative Examples 1 and 2 were measured. Invention Example 1
In Comparative Examples 1 and 2, the gas absorption rate was 1.97 to 2.23 L / g / min, whereas in Comparative Examples 1 and 2, the gas absorption rate was 0.41 to 0.78 L / g / min despite the high loading of the gas absorbing alloy particles. And stays at a low value. This is because, in Comparative Examples 1 and 2, the hardness of the metal wire was too low, and the pulverization of the gas absorbing alloy particles was insufficient, and the gas absorbing alloy particles were too deep into the metal wire. This is due to the reduced number of exposed surfaces.

[0030]

The getter manufactured by the method of the present invention is cut into a desired length because the gas-absorbing alloy particles have a linear shape in which the metal wire bites around the metal wire, and the getter is enclosed in the space of a closed device of any shape. can do. Since the getter limits the metal wire and the gas-absorbing alloy particles to a predetermined hardness, and crushes the gas-absorbing alloy particles by rolling to cause the metal wire to bite into the metal wire and carry it, the gas-absorbing alloy The exposed surface area is large, and the gas absorption performance, particularly the gas absorption speed and the gas absorption life, is excellent.

[Brief description of the drawings]

FIG. 1 is a view schematically showing the principle of a getter manufacturing method of the present invention. (a) is a diagram showing a case where the upper tool 3 has no irregularities, and (b) is a diagram showing a case where the upper tool 3 has irregularities.

FIG. 2 is a view of the apparatus of FIG. 1 as viewed from above the upper tool.

FIG. 3 is a diagram schematically showing a cross section of a getter manufactured by the method of the present invention.

[Explanation of symbols]

1. Metal wire, 2. 2. gas absorbing alloy particles; Upper tool,
4. Lower tool, 5. Unevenness

Claims (3)

[Claims] 1. A method for producing a gas-absorbing getter for supporting gas-absorbing alloy particles around a metal wire having a circular cross section, wherein the gas-absorbing alloy particles have a Vickers hardness of 400.
Using the above, and using a metal wire that satisfies the relationship of the following formula (1), while rotating the metal wire with a tool, the gas sandwiched between the tool and the metal wire A method for producing a gas absorption getter, comprising applying a load to absorption alloy particles. 100 ≦ Hv ≦ 205−150 × D (1) where Hv: Vickers hardness of metal wire D: diameter of metal wire (mm) 2. The upper tool and the lower tool, wherein the tool comprises an upper tool and a lower tool, and the metal wire is sandwiched between the upper tool and the lower tool on which the gas absorbing alloy particles are dispersed. The method of claim 1, wherein the upper tool and / or the lower tool are moved while applying a load with a tool to rotate the metal wire. 3. The method according to claim 2, wherein the upper tool is a tool having an uneven surface on its lower surface.