JPS63294644A - Surface treatment method for electrode parts of cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain oxidated films having desired radiation factors for both cases of Fe material and Ni-Fe material subjected to surface treatment by means of the same treatment furnace by setting the grade of replacing the oxidating environment in the case of Fe material smaller than that in the case of Ni-Fe material. CONSTITUTION:A flat mask formed with Fe material and another flat mask formed with Ni-Fe material are annealed at about 900 deg.C and about 1000 deg.C respectively and press-molded after being subjected to straightening and then, a blackening process for forming black rust is applied to the surfaces of those formed shadow masks 6. For instance, if steam is fed in a furnace 1 at about 0.14m<3>/min flow rate and maintained at about 560 deg.C for 30 minutes after the inner pressure of the furnace 1 is set to about 200mmAq, black rust with 0.75 radiation factor can be obtained in the case of Fe material. If the inner pressure inside a container 2 is set lower than that in the case of Fe material, so as to set a higher grade of replacement of the oxidating environment inside the container 2, in the case of Ni-Fe material, an oxidated film with the desired radiation factor 0.33 or more can be obtained. Thus, oxidated films having desired radiation factors can be obtained when oxidated films are formed on both Fe material and Ni-Fe material by means of the same treatment furnace.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for surface treatment of electrode parts of a cathode ray tube, and in particular, to a method for surface treatment of electrode parts of a cathode ray tube, such as a shadow mask or an electron gun. This invention relates to a surface treatment method for improving heat dissipation of electrodes, etc.

[Conventional technology] The conventional technique will be described below using a shadow mask as an example.

For details on the manufacturing method of shadow masks, please refer to Co., Ltd. [1(
7) II Ko I Gaku 1964 Vo114/NO, 9゜36
and pages 39-40, and Nikkei Electronics 1984, 1.2, pages 84-85.

By the way, as shown in FIG. 5, a cathode ray tube consists of a panel 10 that is a dish-shaped glass container, and a funnel-shaped funnel 12 that houses an electron gun 11 that emits an electron beam. A shadow mask 6 is interposed between the funnel 12 and the panel 10 and is held by a support section.

As shown in FIG. 6, this shadow mask 6 is 0.15
A round or rectangular electron beam passage hole 15 is formed in the base 14 of ~0.25 m5 pure iron plate (hereinafter referred to as "rFe material").
A flat mask with a flat shape is used as a pretreatment I! p (at 700 to 920°C in a hydrogen atmosphere), and after removing the strain, the panel 10 is pressed into a spherical shape along the inner surface. After cleaning, the surface is coated with 7% 11 (Fe
, , O, ) is subjected to a blackening process to form a coating. This blackening treatment involves first completely degreasing the oil that adhered during press working, blackening with nickel sulfide, blackening by immersing in alkaline molten salt, and using dichromate solution. Alternatively, there are methods of blackening by heating in a steam or carbon dioxide atmosphere. As shown in FIG.
It covers the surface of the shadow mask base 14 to prevent the formation of red rust due to oxidation when the shadow mask base 14 is heated at a concentration of around 400° C. in an air atmosphere during the process of manufacturing color cathode ray tubes. At the same time, it has the effect of increasing the emissivity of the surface of the shadow mask and reducing thermal deformation.Furthermore, it reduces the scattering of light by the shadow mask 6, and when forming phosphor pixels on the inner surface of the panel 10. , which has the effect of reducing the scattering of light so that the outline of the picture element is clearly formed.

Of these, the suppression of thermal deformation will be explained in detail.
During operation of the color negative Tita tube, nearly 80% of the electron beam emitted from the electron gun 11 hits the shadow mask 6, and the kinetic energy of the electron beam is converted into energy and absorbed, and the shadow mask 6 The temperature rises to well over 80° C., causing a doming phenomenon and a decrease in color purity. When black rust is formed on the surface of the shadow mask 6, the emissivity decreases to 0.
Since the shadow mask has a large diameter of 75 mm, heat dissipation from the shadow mask is improved and the temperature rise is reduced, thereby suppressing the occurrence of the doming TiA phenomenon.

By the way, if we calculate the difference in heat dissipation due to the presence or absence of black rust, the radiant heat flow rate q between infinitely wide parallel planes is q = σ.

(T, 'T2') / (1/ε, +1/ε2-
1) Here, σ. : Stefan-Boltzmann constant -4,88xlQ8
kcal/m' -h Yani'ε,: Emissivity of the surface of the shadow mask (Surface 1) ε2: Emissivity of the inner surface of the panel (Surface 2) ■,: Kelvin temperature of Surface 1 T2: Kelvin of Surface 2 It's temperature.

Now, ε2 is aluminum and 0. O5, the surface is iron (Fe
), black rust (Fe s as ), nickel oxide (NiO
), then ε is εl (Fe )−0,3,ε
1 (Fe $ 04 ) −0,75, ε, (Ni
0) -0,90, T, -273+80-353 (K
) When T2-2 black rust is provided on the surface (surface 1) of the shadow mask, heat dissipation is improved by 10 to 11% compared to the case where no black rust is formed, and the disturbance of the shadow mask 6 is kept low. effective.

Although the above explanation has been given using a shadow mask as an example, other electrode parts, such as the m-pole of an electron gun, are also subjected to blackening treatment because it is necessary to suppress the temperature rise due to the impact of the electron beam.

[Problems to be Solved by the Invention] In recent years, cathode ray tubes have been used as displays, and there is a demand for easy-to-see, bright, and clear images.

For this reason, the display surface of cathode ray tubes must be made flatter to prevent reflected external light from entering the eyes of the display operator, and the screen mask material and electrode materials must have a low coefficient of thermal expansion. Attempts have been made to reduce thermal deformation using Invar material (hereinafter referred to as rNi-Fe material).

However, in the "blackening treatment" of Fe material, black rust (Fe@04) is stable within the range shown in Figure 7, so by heating it to 580°C in a steam atmosphere,
In addition, black rust with an emissivity of about 0.75 can be formed by heating to 630°C in a CO2 gas atmosphere, whereas N1-Fe material is difficult to oxidize, so it is almost impossible to form black rust under the above treatment conditions. No black rust is formed. In order to improve the difficulty of such blackening treatment, attempts have been made to add a pond element to the Ni-Fe material, but a Ni-1-e material suitable for practical use has not yet been realized.

Furthermore, with the flattening of the display surface, the spherical radius of the shadow mask also becomes larger, and Nl-
For a shadow mask using an Fe material, the maximum temperature for the "blackening treatment" is 800° C., which is the limit at which the spherical surface of the shadow mask is not deformed.

However, in the conventional "blackening treatment" performed by heating in a CO2 gas atmosphere, in order to increase the emissivity of N1-f-etl to 0.33 or higher, which can contribute to improving the performance of cathode ray tubes, it is necessary to
It is necessary to heat the shadow mask to a temperature of 30° C. or higher, and a shadow mask with a spherical radius of curvature of 170 CIl causes deformation of the spherical surface, so there was an illumination point.

In addition, when surface-treating Fe material and Ni-Fe material using the same processing furnace and under the same processing conditions, it is difficult to form an oxide film with a desired emissivity on the surface of the Ni-Fe material. Fe materials have a problem in that the oxide film becomes thick and easily peels off.

Therefore, this invention was made to solve these problems, and even if the fe material and the Ni-Fe material are surface-treated using the same processing furnace, the desired emissivity can be achieved for both. It is an object of the present invention to provide a surface treatment method for electrode parts of a cathode ray tube, which can obtain an oxide film having the following properties.

[Means for Solving the Problems] A method for surface treatment of cathode ray tube electrode parts according to the present invention is applicable to cathode ray tube electrode parts made of Fe material and cathode ray tube electrode parts made of N1-Fe material. In a treatment method in which the electrode parts of the tube are treated separately using the same treatment furnace and an oxide film is formed on the surface in an oxidizing atmosphere,
It is characterized in that the displacement of the oxidizing atmosphere is smaller in the case of Fe material than in the case of Ni--Fe material.

[Function] In a processing method in which an electrode part made of Fe material and an electrode part made of N1-Fe material are separately used in the same processing furnace to form oxide films in an oxidizing atmosphere, both of them have a predetermined l1lfI4 rate. In order to obtain an oxide film having
This is because if an oxide film is formed separately on the l -Fe material under the same oxidizing atmosphere conditions, the oxide film is more easily formed on the Fe material.

Therefore, in the case of the )-e material, if the displacement of the oxidizing atmosphere is made smaller than in the case of the Ni--Fe material, the supply of unreacted oxidizing gas can be suppressed. On the other hand, in the case of a Ni--Fe material, if the replacement of the oxidizing atmosphere is made larger than in the case of a Fe material, the unreacted oxidizing gas can be sufficiently supplied and the oxidation reaction can be promoted. Therefore, Fe material and Ni-1:e
When performing surface treatment on Fe materials in the same processing furnace, if the displacement of the oxidizing atmosphere is reduced in the case of Fe materials, the oxide film will become thicker and will not peel off.

[Example] An embodiment of this invention will be described below.

A flat mask made of Fe material and a flat mask made of Ni-Fe material were heated at about 900°C for about 10
It is annealed at 00°C and press-formed into a predetermined shape with strain relief. After cleaning and removing dirt such as oil adhering to the surface of this molded shadow mask, a blackening treatment is performed to form black rust on the surface. In this example, the flow velocity is 0
．． 141”/sin (5ft”/sin)t
'By supplying steam into the furnace and increasing the furnace pressure to approximately 200 mmAa, the Fe
In the case of wood, black rust with an emissivity of 0.75 is obtained.

FIG. 1 is a diagram schematically explaining the configuration of a furnace for processing a shadow mask according to the present invention. 1 is a processing furnace, and 2 is a container having a heated atmosphere therein. 3 is a pipe that introduces water vapor into the furnace to form an oxidizing atmosphere for blackening treatment, and the temperature is approximately 100°C from the bottom of the container part 2.
of water vapor is released into the interior of the container section 2. 4 is a pressure reduction control valve that controls the amount of water vapor supplied, and 5 is a pressure reduction I control valve 4.
This is an instrument that shows the pressure value controlled by 6 is a shadow mask which is the object to be processed, 7 is a processing jig, 8 is a lid,
A fan 9 for diffusing the inside of the container portion 2 is attached to II8, and 19 is a motor that is the power source thereof. Reference numeral 20 denotes an internal pressure meter that indicates the internal pressure value within the container section 2. Reference numeral 21 denotes an exhaust control valve that controls the exhaust of atmospheric gas within the container section 2. Note that 22 is a backing that is inserted between the container part 2 and the lid 8 for sealing. The amount of water vapor supplied is set by adjusting the pressure reduction control valve 4. Although not shown in the figure, when the temperature inside the container section 2 reaches 375°C or higher during processing, a valve for supplying water vapor opens, and then the temperature reaches 575°C.
When the heat treatment for 30 minutes at °C is completed, the valve is closed, the supply of steam is stopped, and the heater as the heat source is stopped.

When the object to be processed is a shadow mask made of Fe material, the internal pressure in the container section 2 indicates approximately 20011AQ on the internal pressure gauge 20, and the discharge control valve 21 is in the intermediate state of processing. The emissivity of the Fe material shadow mask processed under these conditions is 0.75, as indicated by the 0 mark in FIG. 2, which shows the relationship between the internal pressure in the container 2 and the emissivity. Here, the total surface area (-2) of the shadow mask, which is the object to be processed, placed in the container section 2 is indicated by the numerical value in parentheses.

When a shadow mask made of Nl--Fe material is processed under the same conditions as above, the emissivity is 0.3, as indicated by the * mark in FIG. At this time, Ni which is the object to be treated
-The total surface area of the shadow mask made of Fe material is 10-2.

Next, the total surface area of the Ni-Fe shadow mask, that is, the loading amount, was made the same, the amount of water vapor supplied was kept constant, and during the oxidation treatment (375 to 575°C), Fe5O4 was The opening amount of the discharge control valve 21 is adjusted within a stable range, and the internal pressure at the internal pressure meter 20 is set to 120 Aq. When processed under these conditions, Ni-
The emissivity of the Fe material is 0.4 as shown in FIG.

Furthermore, when the total surface area of the Ni--Fe shadow mask is doubled under the condition of an internal pressure of 1201@AQ (20-2), an emissivity of 0.3 is obtained. These relationships are shown in FIGS. 3 and 4.

Figure 3 shows the relationship between the emissivity and the total surface area (12) of the shadow mask when Ni-1:e material is treated at an internal pressure of 12011AQ, and Figure 4 shows the total surface area (12) of the shadow mask of l -Fe material. Emissivity and internal pressure when the surface area is 10-2 (
It is a figure showing the relationship with aaAQ). Referring to FIG. 3, when the internal pressure is 12C)esAq, the emissivity can be increased by reducing the total surface area of the shadow masks, that is, by reducing the number of shadow masks loaded in the container. Further, referring to FIG. 4, when the total surface area of the shadow mask is kept constant at 10.times.2, the radiation rate tends to increase as the internal pressure is lowered.

Therefore, in the case of Ni-Fe material, the internal pressure inside the container is controlled to be lower than that in the case of Fe material. If the displacement of the oxidizing atmosphere in one part is increased,
An oxide film having a predetermined emissivity of 0.33 or more can be obtained. In this example, by keeping the supply amount of water vapor, which is an oxidizing gas, constant and discharging the gas in the oxidizing atmosphere to the outside of the furnace, the internal pressure is lower in the case of Ni-Fe material than in the case of Fe material. The displacement of the oxidizing atmosphere is increased. However, the amount of oxidizing gas supplied is
In the case of -Fe material, the amount may be increased more than in the case of fe material, and the displacement of the oxidizing atmosphere may be increased so that the internal pressure is lowered.

In addition, adjust the discharge 11J control valve 21 to adjust the internal pressure to 12011
When an Fe material is processed under AQ conditions, the oxide film becomes thick, and some peeling may occur depending on the surface condition before processing. This is because the Fe material is more easily oxidized and an oxide film is easily formed between the Fe material and the Ni--Fe material. On the other hand, the N1-Fe material is oxidized, 3Fe +4@2
It is thought that this is because the generation of H2 in the reaction of 0-Fe s 04+4H2 acts as a reducing effect on the production of fe@04. Therefore, it is thought that if the replacement of the oxidizing atmosphere is increased and fresh unreacted water vapor is supplied sufficiently, the formation of Fe5O4 by the oxidation reaction will be promoted despite the generation of H2 as described above. It will be done.

It should be noted that it is preferable to perform the blackening treatment on an electrode component that has been processed into the final shape of the electrode component, rather than processing the plate material into an electrode component using the blackening treatment. This is because the oxide film, which is black rust, may peel off during processing, or it may peel off easily and fall off during the imitation process.

[Effects of the Invention] As described above, according to the present invention, when forming an oxide film on the surfaces of materials that are easily oxidized and materials that are difficult to oxidize, such as Fe material and Ni-Fe material, in the same processing furnace, By adjusting the R exchange of the oxidizing atmosphere in which the oxidation reaction is carried out, it is possible to obtain an oxide film having a predetermined emissivity.

4. Drawing ll! JIIN explanation Figure 1 is an explanatory diagram showing the outline of the processing furnace used in the present invention and its processing, Figure 2 is a diagram showing the relationship between internal pressure and emissivity, and Figure 3 is a shadow when the internal pressure is kept constant. Figure 4 shows the relationship between the total surface area of the mask and the emissivity. Figure 4 shows the relationship between the internal pressure and the emissivity when the total surface area of the shadow mask is held constant. Figure 5 shows the structure of the color cathode capillary. 6 is a partially enlarged sectional view of the shadow mask, and FIG. 7 is an equilibrium state of Fe-0 system! This is a diagram g.

In the figure, 1 is a processing furnace, 2 is a container part, 3 is a vibrator, and 4
5 is a pressure reduction control valve, 5 is an instrument, 6 is a shadow mask which is an electrode part of a cathode ray tube, and 16 is an IA coating 20 which is an oxide film.
2 is an internal pressure gauge, and 21 is a discharge control valve.

Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) The cathode and tube electrode parts made of Fe material, and the cathode ray tube electrode parts made of Ni-Fe material are each treated separately in the same processing furnace and placed in an oxidizing atmosphere. In the treatment method for forming an oxide film on the surface of the Fe material, the oxidizing atmosphere is replaced with Ni-Fe.
A method for surface treatment of electrode parts of cathode ray tubes, which is characterized by making the electrode parts smaller than that of materials. (2) The replacement of the oxidizing atmosphere involves keeping the amount of oxidizing gas supplied into the processing furnace constant to form the oxidizing atmosphere, and removing the gas in the oxidizing atmosphere from outside the processing furnace. By discharging to F, the internal pressure in the processing furnace becomes F.
2. The method for surface treatment of electrode parts of a cathode ray tube according to claim 1, wherein the surface treatment is carried out in a controlled manner so that the surface treatment is higher in the case of e-material than in the case of Ni--Fe material. (3) The replacement of the oxidizing atmosphere involves reducing the amount of oxidizing gas supplied into the processing furnace for forming the oxidizing atmosphere in the case of Fe material than in the case of Ni-Fe material;
2. The method for surface treatment of electrode parts of a cathode ray tube according to claim 1, wherein the internal pressure in the treatment furnace is controlled to be higher in the case of Fe material than in the case of Ni-Fe material.