JPS5866235A - Cathode substrate of thermal electron emission type cathode - Google Patents

Abstract

PURPOSE:To obtain a cathode substrate capable of producing a thermal electron emission type cathode with a low cost and the excellent characteristics and reliability by adhering metallic powders around a heater wire formed in a desired cathode shape substrate by electrodeposition or spraying so that an electron radioactive material can be retained in gaps formed by metallic powders. CONSTITUTION:As electrodeposition is continued, tungsten powders 7 are adhered in protrusions and recesses around a heater wire 1. When a necessary quantity is adhered to form a powder layer, it is heat treated and sintered in a hydrogen or vacuum atmosphere at 1,000-2,000 deg.C for about 20min, then the metallic powders are solidified. An oxide material 9 is coated or filled by spraying in the recesses 8 formed with solidified nickel powders, then an oxide cathode with the excellent characteristics and reliability is obtained even if the cathode shape is complicated such as a coil-like shape.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention (1) is a thermoelectron emission type cathode such as an oxide cathode, an impregnated cathode, or a cermet cathode, which has a particularly complicated cathode shape and is suitable for an interlocking type that operates immediately after the heater is turned on. 'Relating to the cathode substrate of an electron-emitting cathode.

Conventional 1 For example, as shown in Fig. 1, a coiled cathode is made of gold, and a thermionic emission type cathode that requires an interlocking type is used.As an oxide cathode, a part of the coil of a double coil as shown in Fig. 1 is used as an oxide cathode. It is thought that an oxide substance is filled and fixed inside.

In addition, in the case of an impregnated cathode, a spiral groove is formed on the outer periphery of a round rod of high melting point powder sintered body, and then the central part is cut out using a drill or the like, leaving a spiral coil portion. However, with the above-mentioned cathode, some of the oxide filled in the coil cracks and falls off during repeated operations with the oxide cathode, or many cracks cause the electron emission characteristics to deteriorate and the oxide that falls off. There is a major drawback in terms of reliability and lifespan due to the adverse effects on the tube due to the substance.

In addition, with the impregnated cathode, more than 90% of the material of the round bar high melting point metal powder sintered body must be discarded, and the manufacturing technology is difficult, making the cathode very expensive9. As such, it is not in a usable condition.

The present invention has been made in view of these points.

Thermionic emission type cathodes, such as oxide outer electrodes and impregnated cathodes, which have complex cathode shapes such as the coil shape shown in Figure 1 and are interlocked, are inexpensive, have good characteristics, and are reliable. The purpose is to provide a cathode substrate that can be achieved. Specifically, metal powder is layered around a heater wire formed into a base shape of a desired cathode shape by electrodeposition or spraying. FIG. 3 is a schematic cross-sectional view of a device configured to hold a formed gap and an electron emissive substance.

In Fig. 2, 1 is a heater wire made of, for example, tungsten and formed into a cathode-shaped base, 2 is an electrode wire of 100 ml, and 3 is the other electrode, which is a metal cylinder. 4 is an electrodeposition liquid, such as glycerin 350. .9. Water 350.!9. Nitrate 15g, diameter 2μ
300.m of tungsten powder. ! i" (r mixed, 5 containers, 6 is a power source. When the electrodeposition liquid 4 is stirred well with this device and the power supply 6 is applied so that the heater wire 1 side is negative, the electrodeposition liquid 4 The tungsten powder inside is attracted to the heater wire layer 1 and tightly adheres around the heater wire layer 1.

At this time, the area around the heater wire 1 where the tungsten powder first adhered.

The distance between the electrodes in the 9-particle diameter spectrometer that has adhered is narrower than that in other parts, making it easier for the next powder to adhere to the vicinity of the powder that adhered first.

Therefore, if the electric current is continued as it is, the tungsten powder 7 will be deposited in an uneven shape around the heater IW1, as shown in an enlarged cross-sectional view in FIG. Now, if you use a mixture of nickel powder instead of all the metal powder tungsten powder in this electrodeposition solution 4, you can heat one layer of tungsten heater wire at 1000℃ to 200℃ in a hydrogen or vacuum atmosphere.
When heat treated at 0'0 for about 20 minutes, the metal powder is sintered and solidified. Even if the recess 8 formed by the fixed nickel powder has a complicated cathode shape such as a fourth shape, an oxide cathode with excellent 9% performance and reliability can be formed.

On the other hand, if an impregnated cathode having a similarly complicated shape is desired, it is desirable to apply a high melting point metal powder such as 1-batangesten powder in close contact with the cathode so as to minimize unevenness.

In this case, the powder on one side of the heater wire is dissociated for several tens of seconds using the electrodeposition device shown in FIG. The metal powder is deposited in the form of a carrier. If the solution 4 is constantly stirred during electrodeposition, it can be deposited with good uniformity.

Is there electron radiation on top of this 7 layer of metal powder? Apply an impregnating agent prepared with + quality to create a reducing atmosphere! 15 in a vacuum atmosphere
If the temperature is raised to about 00 to 1700°C, the impregnating agent will turn into metal powder 7
It is possible to easily obtain an impregnated cathode having a double H shape by penetrating into the gap between the electrodes. Moreover, since the entire heater wire 1 of the impregnated cathode obtained in this way penetrates through the center of the active melting point metal powder molten body, it becomes a direct heating type, and the entire heater ignites, which is a drawback of the impregnated cathode. The time it takes to start operating can be greatly reduced. In addition, since the metal powder layered around the heater wire 1 is powder and closely adheres to each other with gaps, the desired cathode can be obtained by designing the heater wire 1 so that it has the desired heater resistance without having much effect on the heater resistance. There is also the advantage of being able to

In the above-mentioned embodiments, it is easier to attach metal powder than electric MVC because it can be done in many pieces at once and at a low cost. Even with a structure in which the melting point metal powder is completely solidified, if all other parts are masked, a large number of pieces can be manufactured at a time and at low cost. However, it is not limited to this electrodeposition method, and other methods such as a normal spraying method can also be used. In addition, the type of metal powder depends on the purpose of the cathode used, such as metal powder such as nickel for negative electrodes, or metal powder such as molybdenum instead of tungsten, which can be used as an impregnated cathode. It is also possible to freely adjust the porosity by appropriately selecting the particle size of the powder.

As explained above, according to the present invention, cathodes of thermionic emission type such as OXA9F'' cathodes and impregnated cathodes can be easily manufactured even with cathodes having complex shapes, and are inexpensive and have good characteristics and reliability. Thermionic emission type cathodes can be borrowed, and even impregnated cathodes can be made into interlocking types, making it highly useful for cathode ray tubes, discharge tubes, etc., and greatly contributing to the development of the electronic industry. There is.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional coiled oxide shader;
The figure shows an example of the apparatus for producing the cathode substrate of the present invention, and is a schematic cross-sectional view of the KameN device. Figure 3 is a partially enlarged cross-sectional view of the metal powder fully electrodeposited around the heater wire. Figure 4 is the inventive device. Figure 5 is a partially enlarged cross-sectional view of a cathode base with metal powder attached for an impregnated cathode, and Figure 6 is a cutout of a conventional metal strip. FIG. 2 is a plan view and a WTlli diagram of an impregnated cathode in which a porous body is formed. 1... Heater wire, 4... Electrodeposition liquid, 7 River metal powder. 9...Oxide substance. Patent sponsorship Shin Nippon Mugumi Co., Ltd. Figure 1\, - Atsushi 3 Figure Atsushi 4 Figure 5 Figure 6

Claims (1)

[Claims] A thermionic emission type, characterized in that metal powder is coated on at least a part of a heater material formed into a desired one-pole-shaped base, and an electron-emitting substance can be held in the gaps between the metal powders. Cathode substrate of cathode.