JPH07176278A - Getter device for electron tube - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a getter device for a high-quality electron tube, which has high-temperature oxidation resistance and does not cause obstacles such as explosive scattering and floating of the getter material during use. [Composition] At least Ba-Al in the metal getter container.
A getter device for an electron tube, wherein a mixed powder containing alloy powder and Ni-Al alloy powder is filled as a getter material. By mainly using Ni-Al alloy powder instead of Ni powder, it is possible to suppress the generation of NiO during high temperature heating in the atmosphere and prevent the explosive scattering of Ba during getter flash. Becomes

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a getter device for an electron tube, and more particularly to a vaporizable getter device used for a high quality electron tube.

[0002]

2. Description of the Related Art Conventionally, a getter device has been used in an electronic tube used for a color television or the like in order to completely remove unnecessary oxidizing gas and the like in the tube after exhaustion. The getter device is, for example, a getter container made of metal such as stainless steel and filled with a predetermined amount of getter material made of a mixed powder of Ba-Al alloy powder and Ni powder,
Usually, it is placed at a predetermined position in the electron tube which is evacuated and sealed. And by external heating such as high frequency induction heating
Ba is vaporized (hereinafter referred to as getter flash) to form a getter film of Ba on the inner wall of the tube. However, such getter devices may inevitably undergo undesired heating during the electron tube assembly process.

For example, in recent large-sized electron tubes, CDTs (color display electron tubes), etc., the frequency of the deflection yoke is improved by the realization of high resolution to satisfy the demand for high quality, and thereby the getter is obtained. It is obligatory to mount the device on a mask frame or the like. That is, the getter device has conventionally been attached to the convertor part of the electron gun via a stainless steel antenna,
There is a problem that the electron beam emitted from the electron gun is affected by the slight magnetism of the antenna arranged in the deflection yoke, and the beam does not strike a predetermined position, resulting in color shift. Due to such a problem, it is inevitable to attach the getter device to a mask frame or the like other than the deflection yoke. The getter device is attached before the panel part and the funnel part of the electron tube are joined. After the getter device is attached, the getter device is installed in the atmosphere at about 450 ° C.
After heating for about 1 hour, the panel part and the funnel part are sealed with glass frit.

However, conventional Ba-Al alloys (eg BaA
l ₄ ) The getter material containing the mixed powder of powder and Ni powder (mixing weight ratio 1: 1) is about 450 ° C in the atmosphere as described above.
When heated at 1 hour, it oxidizes to form nickel oxide (NiO). When NiO is generated in the getter device, Ni
O and BaAl ₄ react rapidly at high temperature, resulting in explosive scattering of Ba during getter flash, and when the amount of NiO generated further increases, even the metal getter container melts down, It will be explosively scattered with the getter material.
Such explosive scattering of Ba is a major cause of pressure resistance failure in an electron tube for a color television, and must be absolutely avoided. For the above reasons, there is a need for a getter device that does not oxidize the getter material even when it is exposed to high temperatures in the atmosphere and does not cause any trouble.

Conventionally, for such a purpose, a getter device in which the surface of the getter material is coated with an organic silane (Japanese Patent Laid-Open No. Sho 61-96, 1988).
No. 52-84960) and a getter device coated with silicon oxide (see Japanese Patent Laid-Open No. 52-139355). For example, in JP-A-52-84960, an apparatus having a getter material coated with an organic silane such as polysiloxane containing alkyl, aryl, aralkyl, alkaryl, or hydrogen is disclosed in the air at 420 ° C. for 1 hour. It is described that Ba can be vaporized and vaporized without enduring the explosive scattering of the material.

However, the getter device thus coated with organosilane has the following drawbacks in its use. That is, this getter device mainly releases a large amount of hydrocarbon gas during getter flush, and the released gas is not easily adsorbed on the getter film, so that the pipe internal pressure is 0.
It is left in a low vacuum of about 133Pa. As is well known, a large amount of residual gas is ionized and then accelerated and collides with a cathode or an anode in a space where a high voltage is loaded such as a television electron tube. It is easily inferred that due to such a sputtering effect, a part of the electron emissive material on the cathode is deposited on other undesired locations, resulting in a significant deterioration in pressure resistance.

Further, JP-A-52-139355 discloses that a getter device in which a getter material is coated with a silicon oxide layer can withstand heating at about 450 ° C. for 1 hour in the atmosphere. It has been shown that a silicon oxide layer is obtained by heating the silicate remaining after dipping the getter device in, for example, an ethyl silicate solution to 120 ° C. in vacuum. The getter device thus obtained is
As shown below, it exhibits some oxidation resistance against high temperature oxidation. In other words, when the getter material surface is coated with a silicon oxide layer and heated in the atmosphere at about 450 ° C for 1 hour and then getter flashed in vacuum, the degree of explosive scattering of Ba is considerably improved. Therefore, a small amount of the getter material is removed and the partially sintered getter material is lifted to the outside of the container.

[0008]

However, the explosive scattering of Ba and the floatation of the getter material due to the oxidation of Ni in the getter material cause the deterioration of the withstand voltage characteristics significantly, no matter how slight it is. Must be avoided. Further, such explosive scattering causes deposition of scattered particles to an undesired portion in the tube, which may not only deteriorate the pressure resistance but also cause a short circuit in the circuit. Furthermore, the lift of the getter material causes the formation of a Ba film at an undesired portion in the tube, which also causes deterioration of the withstand voltage characteristic.

The present invention has been made in order to cope with such a problem, has high temperature oxidation resistance, and is free from obstacles such as explosive scattering and floating of the getter material during use. An object is to provide a getter device for a high-quality electron tube.

[0010]

A getter device for an electron tube according to the present invention is a getter device for an electron tube, wherein a getter material is filled in a metal getter container, wherein the getter material is at least a Ba-Al alloy powder. It is characterized by containing a Ni-Al alloy powder.

The Ni-Al alloy powder used in the present invention basically depends on the composition of the Ba-Al alloy powder and the mixing ratio with the Ba-Al alloy powder, but basically it is a residue after getter-fishing. Ni-Al (including Al in Ba-Al alloy powder)
An intermetallic compound with Al, for example, having a composition ratio capable of forming Ni ₃ Al, NiAl, or the like is used. In particular,
For example, it is produced by pulverizing an alloy obtained by mixing and melting at a ratio of Ni: Al = 75 mol%: 25 mol% or Ni: Al = 50 mol%: 50 mol% by an atomizing method and then sieving. Ni and
The composition ratio with Al may be adjusted such that the amount of Al is in the range of about 25 to 50 mol%. The average particle size of the Ni-Al gold powder is preferably about 3 to 7 μm. In such a Ni-Al alloy powder, Al near the surface of the powder is oxidized by heating before the getter flash, so that further oxidation, that is, generation of NiO is suppressed.

As the Ba-Al alloy powder, it is preferable to use a Ba-Al alloy powder having an average particle size of about 210 to 50 μm, which is manufactured by a similar method. And such Ba-Al
The mixing ratio of the alloy powder and the Ni-Al alloy powder described above is
Although it should be set in consideration of the composition ratio of these alloy powders, specifically, the weight ratio is preferably in the range of about 60:40 to 40:60.

Further, in the present invention, in order to improve the flowability of the getter material and improve the filling property by pressing, Ni powder can be used in combination with the above Ni-Al alloy powder. As the Ni powder, it is preferable to use one having an average particle size of about 1 to 7 μm. Ni powder is Ni-
It is preferably used in the range of about 30% by weight or less based on the Al alloy powder. The amount of Ni powder used is 40% of that of Ni-Al alloy powder.
If it exceeds 5% by weight, the high temperature oxidation resistance becomes insufficient, which may cause explosive scattering of Ba.

The getter device for an electron tube according to the present invention comprises the above-mentioned Ba-Al alloy powder and Ni-Al alloy powder, or
Ba-Al alloy powder and Ni-Al alloy powder and Ni powder are mechanically mixed at a desired mixing ratio, the mixture is filled in a metal getter container, and pressed by a pressing device or the like. can get.

[0015]

In the electron tube getter device of the present invention, the Ni-Al alloy powder is used as the getter material together with the Ba-Al alloy powder. This Ni-Al alloy powder has a Ni oxide layer (Al ₂ O ₃ ) that has a Ni oxide layer (Al ₂ O ₃ ) even when it is heated at a high temperature in the atmosphere (for example, a heating process at the time of sealing the panel portion and the funnel portion of the electron tube).
The formation of nickel oxide (NiO) can be prevented because the oxidation of nickel is suppressed. Therefore, it is possible to prevent the explosive scattering of Ba and the floating of the getter material, and it is possible to realize a stable getter flash. Also, after getter flashing, as with the conventional getter material, Ni
And an intermetallic compound of Al to stabilize generates a (NiAl, Ni ₃ Al, etc.), nor adversely affect the operation of electronic tubes.

[0016]

EXAMPLES Examples of the getter device for an electron tube of the present invention will be described below.

Example 1 First, an alloy obtained by mixing and melting at a ratio of Ni: Al = 75 mol%: 25 mol% was pulverized by an atomizing method and then sieved to produce a Ni-Al alloy powder having an average particle size of 7 μm. did. Next, this Ni-Al alloy powder and Ba- with an average particle size of 100 μm were used.
Al alloy powder (composition ratio; Ba: Al = 55: 45 (weight ratio))
The mixture was mixed at a weight ratio of 1: 1.

Next, several percent iron nitride powder was added as a nitrogen supply / release source to a mixed powder of Ni-Al alloy powder and Ba-Al alloy powder to obtain a getter material. This getter material has an outer diameter of 20 m
An exothermic Ba getter device having a target nitrogen emission source was manufactured by filling an annular getter container made of stainless and having a U-shaped cross section with m, an inner diameter of 10 mm, and a height of 2.0 mm, and pressurizing it with a pressing device.

The getter device thus obtained was heated in air at 450 ° C. for 2 hours, and the amount of nickel oxide (NiO) produced was measured. As a result, it was confirmed that almost no NiO was produced. . Further, the getter device after heating in the atmosphere was installed in a vacuum container that was evacuated, and induction heating was performed by a high frequency from the outside to perform getter flash. Then, when the amount of scattered Ba and the amount of released gas at this time were measured, when the flash start time was 13 seconds,
Good results were obtained, with a scattered amount of 120 mg and an emitted gas amount of 10.6 Pa · l. These values are similar to those obtained when the getter flash is used without heating in the atmosphere in the getter device using the mixed powder of the conventional Ba—Al alloy powder and Ni powder. Moreover, when the distribution of the formed Ba film was examined, it was confirmed that Ba was uniformly dispersed.

As a comparison with the present invention, a getter device using a mixed powder of Ba—Al alloy powder and Ni powder (weight ratio = 1: 1) is heated at 450 ° C. in the atmosphere for 2 hours, When the amount of nickel oxide (NiO) produced was measured by increasing the amount of oxidation,
NiO was produced in a large amount of 7.0% by weight. In addition, when this getter device was installed in a vacuum container that was evacuated, and induction heating was performed from the outside with high frequency to perform getter flash, explosive scattering of Ba occurred and flash start time was 13 seconds, Ba scattering amount 50 mg, emission gas amount 23.2 Pa ・ l
The result was obtained.

Example 2 An alloy obtained by mixing and melting at a ratio of Ni: Al = 50 mol%: 50 mol% was pulverized by an atomizing method and then sieved to produce a Ni-Al alloy powder having an average particle size of 7 μm. Next, the Ni-Al alloy powder and the Ba-Al alloy powder having an average particle size of 100 μm were mixed in a weight ratio of 1: 1.

Next, several percent iron nitride powder as a nitrogen supply / release source was added to a mixed powder of Ni-Al alloy powder and Ba-Al alloy powder to obtain a getter material. This getter material has an outer diameter of 20 m
An exothermic Ba getter device having a target nitrogen emission source was manufactured by filling an annular getter container made of stainless and having a U-shaped cross section with m, an inner diameter of 10 mm, and a height of 2.0 mm, and pressurizing it with a pressing device.

The getter device thus obtained was heated in air at 450 ° C. for 2 hours, and the amount of nickel oxide (NiO) produced was measured. As a result, it was confirmed that almost no NiO was produced. . Further, the getter device after heating in the atmosphere was installed in a vacuum container that was evacuated, and induction heating was performed by a high frequency from the outside to perform getter flash. Then, when the amount of scattered Ba and the amount of released gas at this time were measured, when the flash start time was 13 seconds,
The amount of scattering was 100 mg, and the amount of released gas was 9.8 Pa · l. Although the amount of scattering was slightly reduced, it was within the usable range.

[0024]

As described above, according to the getter device for an electron tube of the present invention, nickel oxide is scarcely generated even when it is heated at a high temperature in the atmosphere. Oxidation is not caused, and thus a stable and uniform getter flash can be generated. Therefore, the getter device of the present invention exerts a particularly excellent effect on a high-quality electron tube and greatly contributes to the improvement of the quality and reliability of the electron tube.

[0025]

Claims (1)

[Claims] 1. A getter device for an electron tube, comprising a metal getter container filled with a getter material, wherein the getter material contains at least Ba—Al alloy powder and Ni—Al alloy powder. Getter device for electron tubes.