JPH0624091B2 - Oxide cathode structure - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an oxide cathode assembly, and is suitable for use in a color cathode ray tube, a display tube or the like, which requires particularly stable characteristics, and is suitable for ultrafast and long-life oxidation. The present invention relates to a cathode structure.

[Technical Background of the Invention and Problems Thereof] It is desirable that a color cathode ray tube or a display tube should output a picture as quickly as possible when the switch is put in and obtain a stable screen.

Recently, fast-moving cathodes have been widely used to meet this demand. An example of this fast-moving cathode assembly is shown in FIG. Nickel-chromium alloy, for example nickel-chromium alloy containing 20% by weight of chromium, is used for the cathode sleeve (12), and a small amount of reducing agent such as 0.06% by weight of magnesium and 0.03% of silicon.
Base metal mainly composed of nickel containing 11% by weight (11)
An electron emitting material (13) composed of a ternary carbonate of barium, strontium and calcium is applied on the top. This ternary carbonate is later decomposed by heating in vacuum and converted into a ternary oxide. The cathode sleeve (12) is heated in wet hydrogen having an appropriate oxygen partial pressure during the manufacturing process of the cathode to blacken the surface by selectively oxidizing chromium, and the thermal emissivity is, for example, 0.2 of Nickel. To 0.8 to increase the heat radiation at high temperatures at steady operating temperature and to justify this increased heat loss, for example per cathode volume,
By supplying a large amount of electric power to the heater (14), which is about four times as high as that of the conventional non-fast moving cathode, it is possible to rapidly raise the temperature. Other than increasing the input power, the method of obtaining fast motion is to use the cathode sleeve (12) or the base metal.
There is a method of reducing the heat capacity by reducing the volume of (11).

If the fast-moving property of the cathode is expressed using the image output time as an index, it can be expressed by the following equation, as is clear from the above description.

The method of increasing the electric power supplied to the heater in order to improve the fast-moving property has a risk of lowering the heat utilization efficiency in the steady operation and raising the cathode temperature in the steady operation more than necessary. On the other hand, a method of reducing the heat capacity of the cathode by reducing the thickness of the cathode sleeve (12) or the base metal (11) is, for example, a manufacturing process in which welding of the cathode sleeve (12) and the base metal (11) becomes difficult. There is concern that the above problems may occur, the strength may be reduced due to thinning, and the emission may be deteriorated due to a reduction in the absolute amount of the reducing agent. Taking these various factors into consideration, the image output time that can be industrially and practically realized in the oxide cathode structure shown in FIG. 1 has been limited to about 2.5 to 3 seconds. It should be noted that the image output time of the fast-moving cathode currently commercially available is 4 to 5 seconds.

On the other hand, in the field of display tubes for on-board and on-board aircraft, such as color cathode ray tubes, there is a strong demand for higher speed, that is, one second display.

As shown in FIG. 2, the oxide cathode assembly satisfying the image output time on the order of 1 second is obtained by directly heating the base metal (21), which also functions as a filament, by heating the electron emitting material (23). Although a thermal oxide cathode assembly is known, this cathode assembly is liable to cause disconnection, and an intermediate layer material formed of a large amount of tungsten or the like added as a heating element to increase resistance causes peeling. Easy to wake up. In addition, even a slight voltage fluctuation is easily affected by it, and the peripheral circuit becomes large, so there are many problems in terms of reliability and cost. It has been desired to develop an oxide cathode assembly satisfying the above requirements.

In such a situation, as shown in FIG. 3 as an oxide cathode assembly that realizes super-high speed operation, the basic structure of the conventional oxide cathode assembly is separated and two cathode sleeves (32) are welded and joined. Then, the cap-shaped basic metal (31) is welded and joined thereto, the electron-emitting substance (33) is applied on the base metal (31), and the heater (34) is arranged in the cathode sleeve. A superfast oxide cathode structure having a structure has been proposed. In this cathode assembly, firstly the base metal (31) is the heater (34).
It is placed in the center where the temperature rises first when heated by. Secondly, the area where the heater 34 and the cathode sleeve 32 face each other is increased, so that heat transfer is enhanced. Thirdly, the cathode sleeve (32) and the base metal (31) can be easily thinned, and the constants determined by the cathode structure and the heat capacity of the cathode can be reduced without increasing the heater input power. With this, it is possible to display images for one second.

However, compared with the conventional oxide cathode shown in FIG. 1, although the structure is such that thermal deformation caused by thinning does not easily occur, it does not mean that deformation does not occur at all. For example, a cup-shaped base metal (31) having a plate thickness of 40 μm and a diameter of 1 mm and a height of 0.15 mm having the composition used in the description of FIG. 1 was prepared, and a cathode sleeve (32) was used in the description of FIG. The composition was made to have a thickness of 15 μm, a diameter of 1 mmφ and a length of 2.5 mm, assembled into an oxide cathode assembly, and intermittently ignited at a 25% increase in the rated voltage of the heater (34). A phenomenon that the cathode sleeve (32) and the cathode sleeve (32) are deformed was observed. In the cathode sleeve (32), a nickel-chromium-tungsten alloy, in which tungsten as shown in JP-A-53-119662 is added in place of the nickel-chromium alloy, and solid solution strengthened, for example, 20% by weight of chromium and 4% by weight By using a nickel-chromium-tungsten alloy containing 20% of tungsten, deformation can be prevented, and even if the thickness is reduced to 10 μm, no problem occurs.

Therefore, also for the base metal (31), there is a demand for the development of a base metal that is not accompanied by a reduction in emission and is excellent in strength even when it is made thin.

[Object of the Invention] The present invention has been made in view of the above-mentioned needs,
It is an object of the present invention to provide a super fast-moving type oxide cathode structure which is excellent in strength and has a long life in terms of emission.

SUMMARY OF THE INVENTION That is, according to the present invention, in an oxide cathode assembly having at least a base metal mainly made of nickel containing a trace amount of a reducing agent coated on the top surface of an electron-emitting substance, yttrium is used as the base metal. 0.05 wt% to 2.0 wt% alone, or 0.05 wt% to 2.0 wt%
It is characterized by containing wt% and other predetermined weight% elements, and other predetermined weight% elements are 0.05 wt% to 2.0 wt%.
% Lanthanum, and other specified weight% elements
At least one of 0.01% by weight to 2.0% by weight of hafnium and zirconium, and other predetermined weight% of 0.
Lanthanum from 05 wt% to 2.0 wt% and 0.01 wt% to
At least one of 2.0 wt% hafnium and zirconium, and 0.01 wt% to 1.
0% by weight silicon, other predetermined% by weight elements
0.05 wt% to 2.0 wt% lanthanum, 0.01 wt% to 1.0 wt% silicon, other predetermined wt% elements are 0.05 wt% to 2.0 wt% lanthanum and 0.01 wt%
It is an embodiment that at least one of hafnium and zirconium of 2.0 to 2.0 wt% and silicon of 0.01 to 1.0 wt% are used, and the thickness of the base metal is thinner than 100 μm.

[Examples of the Invention] Before describing the examples of the present invention, the process leading to the present invention will be described in detail.

A nickel (Ni) ribbon with a thickness of 40 μm containing various reducing agents is made in the same process by the vacuum melting → rolling method, and a 5 mm wide × 100 mm long test piece for high temperature tensile test is cut out from this nickel ribbon and used as a cathode. Assuming the maximum temperature of the base metal in the manufacturing process and cathode-ray tube manufacturing process, which is approximately 1000 ° C, after vacuum annealing at this temperature for 5 minutes, the operating temperature of the cathode
A high temperature tensile test was performed in the range of room temperature to 1000 ° C including 800 ° C. As a result, the tensile strength and elongation at 800 ° C, the operating temperature of the cathode, were as shown in the table below.

Sample Nos. 2, 4, 6, 8 and 9 represent the amount of reducing agent added in atomic%
If adjusted to 0.20% to 0.25% by atom, it contains approximately the same amount of reducing agent, indicating a change due to the difference in the type of added reducing agent. . From the comparison of sample numbers 1, 2, 4, 6, 8 and 9, (i)
Magnesium (Mg) contributes little to improving tensile strength and elongation. (Ii) Lanthanum (La) greatly contributes to the improvement of elongation in all the test temperature regions. (Iii) Yttrium (Y) greatly improves the tensile strength in all regions of the test temperature, and has the same strength as Sample 2 even at a plate thickness half that of Sample 2 at 800 ° C. (Iv) Hafnium (H
f) and zirconium (Zr) have a great effect of improving the strength in the vicinity of room temperature, but when the test temperature rises, the effect becomes small and disappears at 1000 ° C or higher. Further, comparison of Samples 6, 7 or 10, 11 revealed that (V) silicon (Si), like Mg, hardly contributes to improvement in high temperature strength and high temperature elongation.

Furthermore, as a result of detailed investigations on the characteristics of the reducing agent added to the base metal in a trace amount and the various physical properties of the obtained base metal, the inventors have found that Mg, tungsten (W), etc. The base metal added with a reducing agent having a limit has only solid solution strength, but Mg, S with a small solid solution limit
With i, the effect is small. Also, as with almost pure Ni, crystal grains grow by heating, and improvement of mechanical properties at high temperature cannot be expected, of course. Secondly, in the case of a free Ba formation reaction such as Zr and Hf, a base metal containing a reducing agent, which is said to be a site (place) for supplying and reacting with a crystal grain boundary of the base metal, has a temperature higher than a certain temperature. Heat treatment causes crystal grain growth to abruptly, which suppresses grain boundary migration due to segregation of Zr and Hf at grain boundaries, but rapidly increases solid solubility in Ni above a certain temperature. Therefore, the effect of suppressing the grain boundary migration is lost, which is reflected in the mechanical properties. Thirdly, the base metal containing Y or La does not grow so much even if it is heat-treated at a high temperature. Does not occur, and this is because Y or La has almost no solid solution limit in Ni even at high temperature and is dispersed and precipitated in the base metal as a stable intermetallic compound with Ni. In the material, since it is a fine crystal grain, the grain boundary bond is large and it breaks. Rack-and-pinion hardly DenHata, Therefore good elongation, HanTsuta be a Y additives that increase the barrier and strength Te summer mobile fine intermetallic compounds of transition.

The crystal grain size of the above-mentioned base metal will be described below with reference to the drawings. First, FIG. 4 shows the base metal in each dry hydrogen atmosphere.
It is the figure which showed the relationship between the processing temperature at the time of heating for 10 minutes, and the average crystal grain size of the base metal calculated | required by the linear intercept method (linear intercept method). That is, the curve
(21) shows the result of heat treatment of a Ni alloy containing 0.03 wt% Si and 0.06 wt% Mg, which is widely used as a conventional base metal, and the curve (22) shows a curve containing 0.35 wt% Zr. Shows the results of heating the experimental Ni alloy of the invention, curve (23) is 0.54
The result of having heat-processed the experimental Ni alloy of this invention containing La by weight% is shown. Note that these three alloys contain 0.20 to 0.23 atom% when the amount of reducing agent added is converted to atomic%, and they contain almost the same amount of reducing agent, and show changes due to the difference in the type of additive reducing agent. Will be. As the base metal, a material which was produced by a vacuum melting rolling method and which was rolled to a plate thickness of 150 μm through the same annealing and rolling process was used.

It is clear from FIG. 4 that first, the base metal containing Mg and Si causes the growth of crystal grains at a relatively low temperature, and second, Zr alone contains the crystal grains when it contains Mg and Si. Although the growth of crystal grains is suppressed up to about 1000 ° C, where it grows, the growth of crystal grains occurs at high temperatures. Third, when La is added, the growth of crystal grains is caused by Zr addition. It is shown that the growth of crystal grains is remarkably suppressed even at the temperature at which is generated. It should be noted that almost the same results as Zr were obtained when Hf was used and La was obtained when Y was used.

The curve (24) shown in FIG. 5 shows the relationship between the amount of La added and the average crystal grain size of the base metal after heat treatment for 10 minutes in a dry hydrogen atmosphere. The measurement points (31), (32) and (33) show the results when the base metal with the added amounts of La changed to 0.15 wt%, 0.26 wt% and 0.54 wt% was treated at a temperature of 1200 ° C. From the results shown in FIG. 5, it can be seen that the desired crystal grain size can be controlled by changing the amount of La added.

As described above, when Y or La does not have a solid solution limit in Ni even at high temperatures and is precipitated and dispersed as an intermetallic compound that is stable even at high temperatures, almost no crystal grain growth occurs even when subjected to high temperature treatment. It is possible to obtain a base metal that does not cause the phenomenon, and enables stable use of a base metal containing a reducing agent that mainly supplies a grain boundary and serves as a reaction site in the reaction of forming free Ba such as Zr and Hf. There is an effect that the characteristics of Zr and Hf can be utilized to the maximum.

It is considered that the base metal is deformed during use with the cathode, firstly due to thermal fatigue due to repeated intermittent ignition and secondly due to creep deformation due to its own weight during ignition. To increase the resistance to thermal fatigue and creep, (a) select a material whose tensile strength does not decrease even at high temperatures, (b) use a metal structure that does not easily propagate fatigue cracks, and (c) stably precipitate at high temperatures. Although it is possible to disperse the substance, from the above series of experimental results, it is possible to satisfy these requirements by adding Y and La at the same time, and to improve the emission by adding Hf or Zr. Therefore, the present invention has been completed.

Further, it is said that the oxides of Y and La have poor compatibility with the alkaline earth metal oxides of the electron emitting material, and Y produced as a result of activating the electron emitting material during use of the cathode.
Oxides of La and La are formed at the interface between the electron-emitting substance and the base metal, and there was concern about the phenomenon of peeling of the electron-emitting substance at this interface, so-called peeling. Therefore, several kinds of base metals with different addition amounts of Y and La were prepared and incorporated into the oxide cathode structure as shown in Fig. 1, and the triode method was used to increase the rated heater voltage by 30% and the triode every 50 hours. We performed a 300-hour intermittent test while performing a tapping test that gives an impact to. As a result, in the base metal in which the total amount of Y or La added exceeds about 1.7% by weight, it was found that the electron emitting substance peeled off from the interface with the base metal in the tapping test after 250 hours. Furthermore, the cathode was taken out from the test triode after the intermittent ignition test was completed for 300 hours in an inert atmosphere, and the electron emitting material was scratched with a tip of a needle having a constant radius of curvature, and a scratching test was performed. It was found that the base metal in which the total addition amount of the above was more than about 1.25% by weight peeled off the electron emitting material due to scratching.

On the other hand, no peeling of the electron emitting material was observed in the tapping test and the scratching test in the case where Si was ignited in addition to Y or La. When cross sections of the Si-added base metal and the non-added base metal were examined by EPMA, in the Si-added base metal, Ba, which is a constituent component of the electron-emitting substance, was observed along the grain boundaries near the base metal surface. Then, it was found that a large number of pieces penetrated into the base metal once, and the structure was as if the root had been rooted. This is because Si, which is easy to form a complex oxide with Ba, plays a role in attracting Ba into the base metal, and it is possible to form a structure in which the electron-emitting substance has many roots in the base metal. It turned out to be effective.

Next, it will be described in more detail with reference to examples.

(Example 1) Ni-based base metal containing 0.4% by weight of Y and 0.03% by weight of Si, and Ni containing 0.75% by weight of Y and 0.03% by weight of silicon.
The base metal of the base is made by the vacuum melting method, and then rolled,
After annealing and other steps, a ribbon with a thickness of 40 μm was drawn into a cap shape with an upper circle of 1.0 mmφ and a lower circle of 1.4 mmφ, and the base metal was squeezed to a thickness of 15 μmt, a diameter of 0.8 mmφ, and a length of 3.0 mm. Laser welding was performed on a twin-barrel type structure composed of a cathode sleeve, and an electron emitting substance was applied on the surface to obtain a super fast motion type oxide cathode structure as shown in FIG. This structure was incorporated into an electron gun for a display, and a forced life test by intermittent ignition was performed through the usual processes such as exhaust, carbonate decomposition, sealing, getter flashing, activation, and so on. As a comparative product, Mg
A Ni-based base metal containing 0.06% by weight and 0.03% by weight of Si was vacuum-melted, a display tube was produced through the same steps as those described above, and a forced life test by intermittent ignition was similarly performed. The output time was about 1.7 seconds in all cases.

The amount of change in the cutoff voltage in the life test is shown in FIG. Since the change in the cutoff voltage is proportional to the dimensional change between the cathode and the first grid, it is possible to know the deformation of the base metal by measuring the cutoff voltage.
In FIG. 6, curves (45) and (46) are the base metals according to the present invention, and when the base metals containing Y of 0.4 and 0.74% by weight are used, the four lines (47) show the conventional base metals. It is a variation curve of a cut-off voltage when used. This result shows that the base metal of the conventional product is remarkably deformed, whereas the base metal of the present invention can prevent the deformation of the base metal.
Moreover, it can be seen that the effect is remarkable when the content of Y is large.

Next, FIG. 7 shows the change over time of the cathode current. In FIG. 7, curves (55) and (56) are the base metals according to the present invention, the base metals containing 0.4 and 0.75 wt% of Y, respectively, and the curve (57) is the cathode current when the conventional base metals are used. It is a curve. This result shows that the base metal of the present invention is superior in emission to the conventional product. Peeling was not observed in any of the life tests.

(Example 2) Ni alloy containing 1.25 wt% Y, and 1.25 wt% Y, Si
Alloy containing 0.05% by weight of Mg, and as a comparative product, Mg of 0.
A Ni alloy round bar containing 06% by weight and 0.03% by weight of Si is put in a zirconia container (62) as shown in Fig. 8, and this is melted by high frequency induction heating from the outside to melt the molten metal into a zirconia container (62 (4) was supplied to the surface of a cooling roll (66) made of copper from a nozzle (64) provided at the bottom of the above) to obtain a thin ribbon having a thickness of 40 μm in the tangential direction. The entire apparatus was kept in a vacuum chamber to prevent oxidation during melting of the alloy and production of the ribbon.

The ribbon thus obtained was cut into a predetermined size, a base metal was prepared in the same manner as in (Example 1), and was incorporated into a display tube as a superfast moving cathode.

In this case, it was confirmed that the base metal according to the present invention has a small change in the cutoff voltage as in the case of Example 1 and is excellent in terms of emission. It should be noted that with some Si-free materials, the emission suddenly deteriorated, but this was due to peeling, and it was found that the addition of Si is desirable when the amount of Y added is increased.

In the above (Example 1) and (Example 2), the added Y is three kinds of 0.4, 0.75, and 1.25% by weight, respectively, and the amount of Y added is preferably 0.05 or more and 2.0% by weight or less. This is because if it is less than 0.05% by weight, the effect of sufficient high temperature strength up is not obtained, and if it exceeds 2.0% by weight, the effect is almost saturated and no further effect can be expected.

(Example 3) 0.45% by weight of Y, 0.55% by weight of La and Ni-based base metal and 0.45% by weight of Y, 0.55% of La and 0.05% by weight of Si
A Ni-based base metal was produced by a vacuum melting method, and then a ribbon having a thickness of 40 μm was produced through processes such as rolling and annealing. A cap-shaped base metal is made from this ribbon in the same manner as in (Example 1), incorporated into an electron gun for a color cathode ray tube, and subjected to steps such as exhausting, decomposition of carbonate, sealing, getter flashing and activation, and then a color cathode ray tube. Was manufactured, and a forced life test by intermittent ignition was performed under the same conditions as in (Example 1). As a comparative product, 0.06 wt% Mg, Si
Is vacuum-melted into a Ni-based base metal containing 0.03% by weight, and a color cathode-ray tube is manufactured through the same steps as those described above.
Similarly, a forced life test was performed by intermittent ignition. As a result, in any of the color cathode ray tubes using any base metal, the image output time was about 1.6 to 1.7 seconds, but the base metal according to the present invention was the same as in (Example 1) and (Example 2). It was found that the change in the cut-off voltage is small and the emission is excellent, and that the base metal containing silicon is also effective for the emission. During the forced life test, peeling was not recognized by using any base metal.

Example 4 A Ni alloy containing 1.5% by weight of Y and 1.5% by weight of La and 1.
Ni alloy containing 5% by weight, 1.5% by weight of La and 0.07% by weight of Si,
And 0.06% by weight of Mg and 0.03% by weight of Si as a comparative product
Using Ni, a thin ribbon having a thickness of 40 μm and a width of 10 mm was made in the same manner as in (Example 2), and a cap-shaped base metal was made from this ribbon in the same manner as in (Example 1). Was subjected to a forced life test under the same conditions as those of the assembly (Example 1).

Also in this case, it was confirmed that the base metal according to the present embodiment hardly changes the cut-off voltage, and thus the base metal hardly deforms, and is excellent in emission as in the other embodiments. Among the base metals according to this example, the Si-free material caused peeling after long-term use, but the Si-added material showed no peeling even after long-term use, and stable use was possible. Atsuta

The above-described (Example 3) and (Example 4) are the Ni-based substrate metal containing 0.45 wt% Y and 0.55 wt% lanthanum, and the Ni-based substrate containing 1.5 wt% Y and 1.5 wt% La. Although two kinds of metals have been described, La is preferably added in an amount of 0.05% by weight or more and 2% by weight or less. This is because if it is less than 0.05% by weight, sufficient high temperature strength up and high temperature elongation up effects cannot be obtained, and if it exceeds 2% by weight, the effect is almost saturated and no further effect can be expected.

Further, (Example 1) and (Example 3) were manufactured by a vacuum melting-rolling method, and in (Example 2) and (Example 4), a ribbon for a base metal was manufactured by a molten metal quenching method.
This is because if the total amount of La and La exceeds 1% by weight, the workability, especially the hot workability, is significantly reduced. However, the present invention is not limited by the method of manufacturing the base metal.

On the other hand, the addition amount of Si is preferably 0.01% by weight or more and less than 1.0% by weight. This is because if it is less than 0.01% by weight, a sufficient effect of preventing peeling cannot be expected, and if it exceeds 1.0% by weight, Si itself has an adverse effect on peeling.

(Example 5) A Ni-based substrate metal containing 0.26% by weight of Y and 0.13% by weight of Zr was produced by a vacuum melting method, and then subjected to usual steps such as rolling and annealing, and then having a thickness of 100 µm and a diameter of 1.3 mm. It is punched into a disk, welded to the tip of the cathode sleeve shown in FIG. 1, coated with an electron-emitting substance on the surface, and then incorporated into an electron gun of a color cathode ray tube, then exhaust, decomposition of carbonate, sealing, getter flush, A forced life test was performed through a normal process such as activation. As a comparative product, Ni containing only 0.13% by weight of Zr
The base metal of the base was melted in vacuum, a color cathode ray tube was prepared through the same steps as those described above, and the forced life test was conducted in the same manner. When the variation value of the cut-off voltage in the test time of 3000 hours was measured, the comparative product was about 3% larger, and it was found that this example is superior to the deformation and the emission is also significantly superior. Ivy.

Although Zr added in this example is 0.13% by weight, a similar effect can be obtained with Hf as the element to be added.
It is desirable to contain at least one of 0.05 wt% or more and 2.0 wt% or less. This is because if it is less than 0.05% by weight, sufficient reducing power cannot be expected, and if it exceeds 2.0% by weight, further improvement of the electron emission ability cannot be expected, but rather the consumption of the electron emitting substance is accelerated. is there.

[Advantages of the Invention] As described above, in the electron tube in which the electron gun provided with the base metal according to the present invention is arranged, particularly in the display tube in which stable characteristics are required, the base metal is not deformed and stable life characteristics are obtained. In addition, it is possible to obtain extremely good-quality pipe characteristics having outstanding super-high-speed dynamics.

[Brief description of drawings]

FIGS. 1 to 3 are views showing different fast-moving oxide cathode assemblies provided with a base metal according to the related art and the present invention. FIG. 1 (a) is a front view of the fast-moving oxide cathode assembly. Fig. 1 (b) is a cross-sectional view of the main part of Fig. 1 (a), Fig. 2 (a) is a front view of a direct heating oxide cathode assembly, and Fig. 2 (b) is Fig. 2 ( FIG. 3 (a) is a partial cutaway top view of the super fast-moving oxide cathode assembly, FIG. 3 (b) is a cross-sectional view of the main part of FIG. 3 (a), and FIG. Figure is a graph showing the relationship between processing temperature and crystal grain size. Figure 5 is La
FIG. 6 is a graph showing the relationship between the amount added and the crystal grain size, FIGS. 6 and 7 are graphs showing the results of different forced life tests of the present invention and the conventional one, and FIG. 8 is an explanatory view of the melt quenching method. 11,21,31 …… Base metal, 12,32 …… Cathode sleeve 13,23,33 …… Electron emitting material, 14,34 …… Heater 61 …… Molten metal, 62 …… Ceramic container 63 …… High frequency coil, 64 …… Nozzle 67 …… Ribbon, 68 …… Cooling roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Eiji Yamamoto Eiji Yamamoto 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Stock Company, Toshiba Yokohama Metal Works (72) Inventor Hisashi Yoshino 1 Komukai-Toshiba, Kawasaki-shi, Kanagawa Incorporated Toshiba Research Institute (72) Inventor Masakatsu Haga 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research Institute (56) Reference JP-A-58-225528 (JP, A) JP-A 58-42134 (JP, A) JP-A-58-185741 (JP, A) JP-B-56-13783 (JP, B2)

Claims (8)

[Claims] 1. An oxide cathode assembly comprising at least a base metal consisting mainly of nickel containing a trace amount of a reducing agent coated on the top surface of an electron-emitting substance, wherein the base metal contains 0.05% by weight of yttrium. 2.0 wt% alone or 0.05 wt% or more of the ytnium
An oxide cathode assembly comprising 2.0% by weight and other predetermined weight% of elements. 2. Other predetermined weight% element is 0.05 weight% to
The oxide cathode assembly according to claim 1, characterized in that it is 2.0% by weight of lanthanum. 3. Another predetermined weight% element is 0.01 weight% to
An oxide cathode assembly according to claim 1, characterized in that it is at least one of 2.0% by weight of hafnium and zirconium. 4. Another predetermined weight% element is 0.05 weight% to
2. An oxide cathode assembly according to claim 1, characterized in that it is at least one of 2.0% by weight lanthanum and 0.01% to 2.0% by weight hafnium, zirconium. 5. Another predetermined weight% element is 0.01 weight% to
The oxide cathode assembly according to claim 1, characterized in that it is 1.0% by weight of silicon. 6. Other predetermined weight% element is 0.05 weight% to
The oxide cathode assembly according to claim 1, characterized in that it is 2.0% by weight lanthanum and 0.01% to 1.0% by weight silicon. 7. Another predetermined weight% element is from 0.05 weight% to
2. Oxide according to claim 1, characterized in that it is 2.0% by weight of lanthanum, 0.01% by weight to 2.0% by weight of at least one of hafnium and zirconium, and 0.01% by weight to 1.0% by weight of silicon. Cathode structure. 8. The oxide cathode assembly according to any one of claims 1 to 7, wherein the base metal has a thickness of less than 100 μm.