JPH0161215B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for firing a cathode holding component hermetically sealed with crystallized glass. BACKGROUND ART Conventionally, for example, cathode holding parts for cathode ray tubes have been used which have a structure hermetically sealed with crystallized glass. In particular, in color picture tubes, a structure that uses three electron beams is common, and the cathode also has three cathodes arranged in an in-line or delta shape. By integrally holding the cathode with a hermetic seal, assembly man-hours can be reduced and reliability and quality can be improved. FIG. 1 shows a conventionally used cathode holding component of this type. In the figure, a is a partially sectional front view;
b is a plan view. In the figure, the cathode holding part 1 consists of a frame-shaped support 2 made of 42% nickel-iron (42Ni-Fe) alloy, and three iron-nickel-cobalt (Fe
-Ni-Co) alloy, and crystallized glass 4 filled between the two. The crystallized glass 4 is made of zinc oxide (ZnO) 55
-65wt%, boron oxide ( _{B2O3 )} 15-25wt%, silicon dioxide ( _SiO2 ) 10-15wt%, magnesium oxide (MgO) 3-7wt%, and has excellent heat resistance properties. It is equipped with Although omitted from the diagram,
A heater is installed inside each cylindrical body 3, and a cathode is fixed to the tip thereof. By adopting this integral configuration, it becomes easier to achieve relative positional accuracy of the three cathodes, and
Since the cylindrical body 3 is hermetically sealed by the heat-resistant crystallized glass 4, changes over time during use, such as deformation and positional displacement, are reduced, and it is expected that the life characteristics will be improved. In this case, since the cathode reaches a high temperature of about 750° C. when in use, the cathode holding part 1 needs to have sufficient heat resistance so as not to melt or deform at about 750° C. In particular, the glass 4 for hermetic sealing must be sufficiently firmly adhered to the support 2 and the cylindrical body 3 so that no peeling occurs at the adhesive interfaces 4a and 4b even during rapid heating and cooling. It must have sufficient heat resistance to prevent foaming under certain conditions. When manufacturing such a cathode holding part 1, as shown in FIG.
The support 2 and the cylindrical body 3 are arranged at predetermined positions, filled with a pellet-like or powder-like crystallized glass 4 which has been preformed and pre-sintered, and an upper die 5b made of carbon is placed thereon. Then, if necessary, a weight is added on top of the upper mold 5b, and firing is performed in an inert atmosphere such as nitrogen. However, in this case, the firing temperature and time are
It has been extremely difficult to set firing conditions that will greatly affect the quality of the manufactured cathode holding parts and will produce good cathode holding parts in terms of adhesive strength, heat resistance, appearance, etc. For example, when firing is carried out under the conditions shown in (a) of Table 1, sufficient adhesion strength between the cylindrical body 3 and the crystallized glass 4 cannot be obtained, and the crystallized glass 4
In this case, bubbles 6 as shown in FIG. 3a are generated, and sufficient heat resistance cannot be obtained. Further, under the conditions shown in Table (b), the crystallized glass 4 protrudes 7 and rises 8 as shown in FIGS. 3b and 3c, making it impossible to obtain a normal external shape. Furthermore, in the same table (c), sufficient adhesive strength between the cylindrical body 3 and the crystallized glass 4 cannot be obtained, and control of the conditions is delicate and difficult.

[Table] FIG. 4 shows the temperature profiles in the firing methods (a), (b), and (c) above. The present invention was made in view of the above circumstances, and its purpose is to manufacture a cathode holding part that allows easy control of firing conditions and has good quality such as adhesive strength, heat resistance, and external shape. The object of the present invention is to provide a firing method that obtains the desired results. In order to achieve this purpose, the method of firing a cathode holding part according to the present invention involves performing a first stage of firing at a relatively low temperature, and then a second stage of firing at a higher temperature for a short time. It is used for firing. FIG. 5 shows the temperature profile in the firing method according to the invention. Note that figure a shows the case where the first and second stage firings are performed consecutively, and figure b shows the case where the second stage is fired after an interval after the first stage firing. This is the case when firing is performed. The holding temperature T ₁ of the first stage firing is 770-800℃, and if it is higher than this, problems will occur in the external shape.
If it is too low, the crystallized glass will foam, resulting in poor heat resistance and insufficient adhesive strength. The holding time _t1 at this time is 30 to 60 minutes, and if it is too short, sufficient heat resistance cannot be obtained, and if it is too long, the furnace will be occupied for a long time, resulting in poor productivity. In addition, the holding temperature for the second stage of firing is T ₂
is 795 to 830°C; if it is higher than this, the appearance and shape may deteriorate, and if it is lower than this, the heat resistance and adhesive strength may become insufficient. Also, the retention time at this time
A suitable time for _t2 is 5 to 15 minutes; if it is shorter than this, problems will arise in heat resistance, and if it is too long, productivity will decrease. The reason why good quality can be obtained by such two-stage firing is understood from the results of crystal phase measurements by X-ray diffraction as follows. That is, first, the relatively low holding temperature T ₁ (°C) and holding time t ₁ of the first stage
(minutes), while suppressing the protrusion 7 and rise 8 as shown in Fig. 3 b and c,
Crystallization is performed while leaving a small amount of glassy material that contributes to adhesive strength. This makes it possible to satisfy heat resistance and appearance shape. Then, the second stage relatively high holding temperature
By firing at T ₂ (°C) and holding time t ₂ (minutes), the glassy substance is exposed to the interface between the support 2 and the cylindrical body 3, thereby increasing the adhesive strength sufficiently and at the same time further improving heat resistance. strengthens and performs complete crystallization. Hereinafter, the method for firing a cathode holding part according to the present invention will be explained in detail using Examples. The support 2 and the cylindrical body 3 are arranged at predetermined positions of the lower die 5a made of carbon as shown in FIG.
Pre-molded and pre-sintered pellet or powder
ZnO 60wt% − B ₂ O ₃ 21wt% − SiO ₂ 13wt% −
Filled with crystallized glass 4 consisting of MgO6wt%,
Place the upper die 5b made of carbon. A weight was further added on top of this upper mold 5b, and in a nitrogen atmosphere, the following table 2 (d)
Firing was performed under the firing conditions shown in (E) and (F).
As a result, as shown in the same table, good quality was obtained in terms of adhesive strength, heat resistance, and external shape under all firing conditions. Note that the evaluation of each characteristic was performed as follows. First, the adhesive strength is determined by applying a load from above by applying a pin to the cylindrical body 3, and when the cylindrical body 3 bends without peeling from the crystallized glass 4, the adhesive strength is considered to be good. Those in which 3 was peeled off from crystallized glass 4 before bending, and those in which 3 was peeled off at the same time as bending were judged as defective. Further, heat resistance was evaluated by performing a heat treatment at 750° C. for 1 hour in a vacuum of 10 ^-6 Torr, and then observing with a microscope to determine whether or not the crystallized glass 4 was foamed. Furthermore, the appearance and shape were evaluated by microscopic observation and the presence or absence of protrusion 7 and rise 8. For comparison, the quality of the cathode holding parts manufactured by the conventional firing method shown in Table 1 was evaluated using the same method as described above. The results are also shown. Further, in the two-stage firing according to the present invention, the first stage and second stage firing may be performed successively as shown in Figure 5a, or the first stage firing can be performed as shown in Figure 5b. After firing, the firing may be interrupted and the second stage firing may be performed again, and the firing conditions can be easily controlled.

[Table] As explained above, according to the method of manufacturing a cathode holding part according to the present invention, the
By holding the product for 5 to 15 minutes at 795 to 850°C and performing two-stage firing, a cathode holding part with good adhesive strength, heat resistance, external shape, etc. can be manufactured. Therefore, it is possible to improve the performance of electron tube equipment and the like using the cathode holding component. In addition, it has an excellent effect in that the firing conditions can be easily controlled.

[Brief explanation of drawings]

Figures 1a and b are a partially sectional front view and a plan view showing an example of a cathode holding component, and Figure 2 is a
A cross-sectional view showing the cathode holding part in Fig. 1 during the manufacturing process, Figs. FIG. 5 shows a temperature profile in the method of firing a cathode holding component according to the present invention. 1... Cathode holding part, 4... Crystallized glass.

Claims (1)

[Claims] 1 Zinc oxide 55-65wt%, boron oxide 15-25wt%
%, silicon dioxide 10 to 15 wt%, and magnesium oxide 3 to 7 wt%. After performing the first stage firing by holding at 770 to 800°C for 30 to 60 minutes, the second firing is performed at a temperature higher than the first stage and held at 795 to 830°C for 5 to 15 minutes.
A method for firing a cathode holding part, characterized by performing stage firing.