JPS6217079A - Method of sealing ceramic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a ceramic sealing method that achieves a good yield on the shoulder side for airtightly sealing ceramics and metals and ceramics used in electron tubes, etc. It is.

[Conventional technology]

The most commonly used method for airtightly sealing ceramics and metals is the high melting point metal preparation method, which is highly reliable;
It is an expensive method that requires a high metallization firing temperature of 400-1500°C, followed by sintering, logging, and a total of eight firing processes. Therefore, there is a demand for lowering the firing temperature as much as possible to further reduce the number of firings. As an example of such a method, ammonium molybdate “
It is known to use an aqueous solution of .

That is, ammonium molybdate and lithium hydroxide are dissolved in total ammonium hydroxide and water, and this solution is applied to a ceramic, then fired in a reducing atmosphere to form a metal lath, and then copper brazed to a mating metal.

In this method, the metallization firing temperature is at most 1
200'c, and sealing can be achieved with a total of two heating operations, which has a great economical effect.

[Problem that the invention seeks to solve]

However, the biggest drawback of this method is that it does not use a solution.
This means that it has poor applicability on ceramics. In other words, as an application method, dipping has no choice but to use brushing, but neither method can provide a uniform film thickness;
Furthermore, in the former case, it is necessary to scrape off the excess adhered portion after drying, resulting in a problem of poor yield.

This invention was made to solve these problems, and aims to provide a ceramic sealing method that allows firing at a lower temperature than the conventional method, improves reliability of sealing, and has a high yield. .

[Means for Solving the Problems] The ceramic sealing method of the present invention includes a paste-like kneaded material containing ammonium molybdate, lithium hydroxide, a solvent, and an organic binder. A step of adhering to the sealing surface of a non-metallic object to be sealed among the adherends, a firing step of firing in a 1ff1 element atmosphere, and a first step after the adhering step. By heating the second object to be sealed together with a log attaching agent in a reducing atmosphere, the first object is heated.
, a log attaching step is performed to seal the second object to be sealed.

[Effect]

The paste-like kneaded material containing ammonium molybdate, lithium hydroxide, a solvent, and an organic binder according to the present invention can be applied to a sealing surface with a uniform film thickness depending on printing conditions by, for example, screen printing. This eliminates the need for extra work steps, and improves the reliability of the fired product with the deposits.

〔Example〕

The solvent used in this invention is, for example, at least one of n-butyl carpitol acetate, methyl ethyl ketone, methyl isobutyl ketone, butanol, tricrene, terpineol, and the like.

The organic binder used in this invention is, for example, at least one of nitrocellulose, polyacrylate, polymethacrylate, polyester, polyolefin, and ethyl cellulose.

The present invention will be specifically explained below with reference to Examples.

Embodiment 1 FIG. 2 is a perspective view of an embodiment of the present invention, showing a state in which a paste-like kneaded material is adhered to an object to be sealed. In the figure, 111 is a first sealed body of an alumina ceramic cylinder, for example, and (2) an attached paste-like kneaded product patterned by RI, for example, screen printing.

That is, first, 90y of ammonium heptamolybdate and 10yfjr of lithium hydroxide were ground in a ball mill for 24 hours using acetone as a solvent, and then dried at 120°C for 2 hours. Ethyl cellulose 3.52 for this dry matter
and terpineol 32y'i1 (added and kneaded well to form a paste.

This was screen printed on the surface of the alumina ceramic cylinder 11) in a pattern as shown in FIG. 2 and dried. The film thickness of the deposit (2) after drying was l-420 microns.

FIG. 1 is a sectional view of a ceramic sealed body according to an embodiment of the present invention, in which a second sealed body (31, for example, a Kovar ring) and a log (for example, a copper log) are placed on the deposit (2). When the adhesive (4) was set and heated to 1100° C. in a reducing atmosphere such as hydrogen, held for 5 minutes, and taken out after cooling, a sealed body of ceramic and Kovar was obtained.

The tensile strength of this sealed body was measured and averaged 9.2~
It was found that the value was obtained, and it was found to be sufficient for practical use.

By forming ammonium molybdate into a paste and applying it using the printing method, it does not result in an uneven film such as breakage or thickening, which is the case when using a solution, and therefore it can be applied using a printing method. Since the particles flow uniformly, a sealed body can be formed by a single heating operation, and a highly reliable seal with practical strength can be obtained.

Example 2 In addition to using nitrocellulose 4f instead of ethylcellulose 8.52 in actual mfMJl and n-butyl carpitol acetate (n-butylcarpitol acetate) 80F7 instead of terpineol 82F, other products of the present invention were prepared in the same manner as in Example 1. When a ceramic sealed body according to the example was obtained and its strength was measured, it was found that it could be put to practical use as well as in Example 1.

Example 3 In Example 1, 8.5y of ethyl cellulose was replaced with polyacrylate 8y1, and terpineol 829 was replaced with n.
-butylcarpitol acetate-)80. A ceramic sealed body according to yet another example of the present invention was obtained in the same manner as in Example 1 except that P was used, and its strength was measured. As in Example 1, it was found to be fully usable for practical use! j! IJ revealed.

In addition, in the above example, a case was described in which the firing process and the logging process are performed at the same time, and firing only needs to be done once, but even if the logging process is performed after the firing process, the intended purpose may not be achieved. can be reached.

Note that it is also possible to use, for example, a silver log other than that used in the above embodiment as a log supplement.

In the above example, the raw materials of ammonium molybdate and aluminum hydroxide were ground and used as they were, but the same result could be obtained by converting them into a phlegm solution and then making the precipitate obtained by evaporation to dryness into a paste. be effective.

As can be seen from the above description, the method of the present invention is not limited to all fields of application, and can be applied to any technical field of sealing ceramics to ceramics or ceramics to metals.

〔Effect of the invention〕

As described above, the present invention applies a paste-like kneaded material containing ammonium molybdate, lithium hydroxide, a solvent, and an organic binder to a nonmetallic sealing material of the first and eighth objects to be sealed. A step of adhering to the sealing surface of the adherent, a firing step of firing the adhered material in a reducing atmosphere, and a first step that has undergone the adhering step. By heating the second object to be sealed in a reducing atmosphere in conjunction with a log attachment process, the first and second objects to be sealed are sealed. It is possible to obtain a ceramic sealing method that enables low-temperature firing, improves sealing reliability, and has a high yield.

As claimed in claim 2, by performing the firing process and the logging process at the same time, the heating operation can be performed only once, and firing can be performed at a lower temperature than the conventional method, resulting in reliable sealing. It is possible to obtain a ceramic sealing method with improved properties and a good yield.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sealed body according to an embodiment of the invention, and FIG. 2 is a perspective view of an embodiment of the invention. In the figure, +11 is the first sealed object, (2) is the deposit,
(31 is the second sealed body, +411r10 additional rules.

Claims (4)

[Claims] (1) A paste-like kneaded product containing ammonium molybdate, lithium hydroxide, a solvent and an organic binder,
A step of adhering to the sealing surface of a non-metallic object among the first and second objects to be sealed, a firing step of baking the above-mentioned adhered material in a reducing atmosphere, and a second 1. A ceramic sealing method that performs a logging step of sealing the first and second objects to be sealed by heating the second object in a reducing atmosphere together with a logging rule. (2) The ceramic sealing method according to claim 1, wherein the firing step and the logging step are performed simultaneously. (3) A method for sealing ceramics according to claim 1 or 2, wherein the first and second objects to be sealed are ceramics. (4) The method for sealing ceramics according to claim 1 or 2, wherein the first and second objects to be sealed are ceramic and metal, respectively.