JPH04293751A - Metallic material for sealing soft glass - Google Patents

Abstract

PURPOSE:To offer an Fe-Cr metallic material for sealing a soft glass used for a fluorescent character display tube and provided with sealability, etching properties and scale peeling properties than that of a costly Fe-42% Ni-6% Cr base alloy. CONSTITUTION:This Fe-Cr metallic material for sealing has a compsn. constituted of, by weight, 24 to 30% Cr, <=0.06% C, <=1.0% Si, <=1.0Mn, 0.03 to 0.5% Al, <= 0.06% N and the balance substantial Fe. Furthermore, nickel plating may be applied to the surface of the metallic material. Only by the addition of Al, its adhesive strength to the base metal of an oxidized film is secured. Because Ti is not added, the improvement of its etching properties, scale peeling properties or the like can furthermore be attained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal material for sealing soft glass used in fluorescent display tubes and the like.

0002

[Prior Art] Metal materials conventionally used for sealing soft glass include Fe-42%Ni-6
%Cr alloy, Fe-18%Cr alloy, Fe-28%Cr
There are alloys, etc.

Although the Fe-42%Ni-6%Cr alloy has excellent compatibility and sealing properties with soft glass, it
It is an expensive material because it contains a large amount of , and its fields of use are limited.

On the other hand, Fe-18%Cr alloy
Although it is an inexpensive material that does not contain i, its coefficient of thermal expansion is slightly higher than that of soft glass. Therefore, in the cooling stage after the soft glass is sealed, cracks are likely to occur in the soft glass. In addition, the sealing property itself is Fe-42%Ni-
It is inferior to 6% Cr alloy.

[0005] Fe-28%Cr alloys include F256-72, which is standardized by ASTM. This Fe-28
%Cr alloy has almost the same coefficient of thermal expansion as soft glass, but does not have sufficient sealing properties. Therefore, highly reliable glass sealing cannot be obtained.

[0006] For this reason, when glass sealing requires high quality and reliability, expensive Fe-42%
The use of Ni-6%Cr alloy was unavoidable. Therefore, instead of the Fe-42%Ni-6%Cr alloy, various metal materials have been proposed as being inexpensive and having excellent sealing properties. In Fe-18%Cr alloy and Fe-28%Cr alloy, which have been considered as substitute materials for Fe-42%Ni-6%Cr alloy, Ti, Al, etc. are added to improve sealing properties. Added.

For example, Japanese Patent Publication No. 50-37008 introduces a Fe-18Cr based sealing alloy to which Ti is added to prevent the precipitation of γ phase and the decrease in the coefficient of thermal expansion caused by the C content. . In addition, special public service 63-102
No. 92 discloses that Fe-18%Cr alloy or Fe-28
It has been proposed to add Ti to %Cr-based alloys. This improves sealing properties.

[0008]

By the way, with the recent technological progress, the demand for processing accuracy for sealing alloys has become extremely high. For example, alloys used in fluorescent display tubes are processed into a desired shape by etching or punching, and then heated to a temperature of 70°C in a humid hydrogen gas atmosphere.
Oxidation treatment is performed under conditions of 0 to 1100°C and heating time of about 10 minutes. As shown in FIG. 1, the sealing alloy 1 having an oxide film formed on its surface by oxidation treatment is sealed to a glass plate 3 with a low melting point glass 2 that acts as an adhesive. Next, in order to electrically connect to an external terminal, the oxide film 4 formed on the surface of the sealing alloy 1 is partially removed and solder plating is performed.

[0009] In this series of steps, etching property, which had not been considered a problem in the past other than glass sealing property, has come to be seen as a problem as demands for processing precision have become higher. Furthermore, as a pretreatment for solder plating, the sealing alloy is pickled, and good scale removability during pickling is also a necessary condition.

[0010] In this regard, the aforementioned Fe-18% Cr alloy and Fe-28% Cr alloy containing Ti, Al, etc. have poor etching properties and scale removal properties, and require a high degree of machining accuracy. It was not suitable as a sealing alloy.

The present invention was devised to solve these problems, and provides a sealing material that improves etching properties and scale removal properties by adding only Al, and has excellent sealing properties and reliability. Aims to provide wearable metal materials.

0012

[Means for Solving the Problems] In order to achieve the object, the metal material for soft glass sealing of the present invention has Cr: 24 to
30% by weight, C: 0.06% by weight or less, Si: 1.0% by weight or less, Mn: 1.0% by weight or less, Al: 0.03~
0.5% by weight, N: 0.06% by weight or less, and the remainder substantially consists of Fe.

[0013] Further, the surface of this metal material may be plated with Ni. In this case, the Ni plating is preferably 2
It is formed with a thickness of ~4 μm.

[0014]

[Function] In the metal material for soft glass sealing of the present invention, the etching properties, scale removal properties, and sealing properties are improved by adding only Al. Al oxide formed by oxidation treatment improves the adhesion strength between the oxide film and the base metal due to its nodule-like morphological characteristics, and the glass adhesion strength is shown in Figure 2 depending on the Al content. to improve. However, since Al oxide does not exhibit an excessive anchoring effect on the base metal, the oxide film can be easily peeled off from the base metal by pickling, etc., and it also has the effect of improving pickling properties, scale removal properties, etc. .

In this regard, in the Ti-containing sealing alloy described in Japanese Patent Publication No. 62-10292, because the Ti oxide formed by oxidation treatment has a wedge-shaped morphological feature, the adhesion between the oxide film and the base metal is difficult. Although the strength is improved, T
Since the i-oxide has a strong anchoring effect on the base metal, it is extremely difficult to peel off the oxide film from the base metal by pickling or the like, which is a factor that impedes manufacturability. In addition, the sealing alloy described in Japanese Patent Publication No. 50-37008 in which Al is added together with Ti also has similar disadvantages due to the addition of Ti.

Therefore, the present invention aims to ensure the adhesion strength of the oxide film without adding Ti and improve the etching and scale removability by balancing the other alloy components.

The composition of the present invention will be explained below. Cr: Cr, which is a basic component of the sealing alloy, is an effective element for adjusting the thermal expansion coefficient of the sealing metal material. 2
If the Cr content is less than 4% by weight, the coefficient of thermal expansion becomes too large, causing cracks in the sealed soft glass. However, a Cr content exceeding 30% by weight significantly deteriorates the workability of the sealing metal material. Therefore, Cr
The content was set at 24 to 30% by weight.

C: In order to improve corrosion resistance and prevent precipitation of γ phase, it is preferable to keep the C content as low as possible. However, excessively lowering the C content causes difficulties in smelting. Therefore, the upper limit of the C content was set at 0.06% by weight as a range that would cause no problems from a practical standpoint.

Si: An effective element for promoting internal oxidation of the metal material during oxidation treatment and improving the adhesion of the oxide film to the base metal. However, the Si content is 1
If it exceeds % by weight, a disadvantage appears in that the coefficient of thermal expansion becomes large. Therefore, the Si content was specified to be 1% by weight or less.

Al: Al is an effective element in improving the properties of the oxide film, including its adhesion to base metal. Such effects are small when the Al content is less than 0.03% by weight. However, if the Al content exceeds 0.5% by weight,
Makes the sealing metal material hard and reduces workability. Therefore, the Al content was set in the range of 0.03 to 0.5% by weight.

N: In order to suppress precipitation of the γ phase, the N content is preferably as low as possible. However, excessively reducing the N content requires sufficient denitrification reaction during smelting, which increases manufacturing costs. Therefore, the upper limit of the N content is set to 0.000000000000000000000000000000000000000000000000000000000000000000000000ssssssss.2020.0.0.0.0.0.0.0.
It was set at 0.06% by weight.

[0022] In addition, this metal material also contains P up to 0.04% by weight and 0.03% by weight as other unavoidable impurities.
It is permissible to contain up to S, up to 0.5% by weight Ni.

Furthermore, Ni plating may be applied to the surface of the sealing metal material, if necessary. Ni plating is formed by normal strike plating and main plating, and facilitates removal of the oxide film on the surface of the metal material. the result,
Solder plating after sealing soft glass is easily performed. Further, the thickness of the Ni plating is adjusted to such an extent that Ni remains uniformly on the surface layer of the metal material after the oxide film is removed.

During the oxidation treatment, Cr in the base metal diffuses into the surface layer through the Ni plating layer, and a Cr oxide film is formed on the outermost layer. Therefore, in order to obtain a thickness suitable for glass sealing of the Cr oxide film, it is preferable to perform Ni plating to a thickness of 2 to 4 μm.

[0025]

[Examples] The present invention will be specifically explained below with reference to Examples. Example 1: Six types of alloys shown in Table 1 were melted, and after hot rolling, annealing and cold rolling were repeated to obtain plates with a thickness of 0.2 mm. From this plate material, width 40mm and length 70m
A test piece for soft glass sealing was cut out.

[0026]

[Table 1]

Next, the test piece was placed in a humid hydrogen gas atmosphere with a dew point of 25°C, and heated at a heating temperature of 950°C and a heating time of 10°C.
Oxidation treatment was performed under conditions of 10 minutes to form an oxide film on the surface of the test piece. Then, low melting point glass was welded to the surface of this oxide film. Note that welding is carried out in the air at a heating temperature of 4.
The test was carried out under the conditions of 50° C. and a heating time of 10 minutes.

Bending stress was applied to the test piece to which the low melting point glass was welded, and the low melting point glass or oxide film was forcibly peeled off from the test piece. The sealing property was evaluated based on the peeled location at this time. In addition, the evaluation was expressed by the test results of 50 test pieces for each test piece. In addition, after the oxidation treatment, each test piece was immersed in a mixed solution of nitric acid and mixed acid, and the scale removability was evaluated based on the time it took for the scale to completely peel off. These evaluation results are shown in Table 2.

Peeling A in Table 2 indicates that the glass was broken during the peeling test, Peeling B indicates that the glass peeled off at the interface between the glass and the oxide film, and Peeling C indicates that the glass peeled off at the interface between the oxide film and the base metal. represent. In addition, as for the sealing property, peeling A is the best, and peeling becomes worse in the order of B and C. Moreover, the scale removability was expressed as ○ if the scale was completely peeled off within 5 minutes, and × if it was not completely peeled off within 5 minutes.

[0030]

[Table 2]

As is clear from Table 2, the sealing metal material of the present invention is a Ti-added Fe-28%Cr alloy (
Test number 2) is of course Fe-42 containing a large amount of Ni.
%Ni-6%Cr light alloy (Test No. 1), exhibiting excellent sealing properties. Further, in Test No. 2, the peelability of the scale was poor, whereas in the examples of the present invention, the scale was completely peeled off within 5 minutes in all test pieces. This is considered to be due to the fact that the test piece of the present invention example does not contain Ti.

Example 2: Ni plating of various thicknesses was applied to the test piece of sample number 5 by strike plating and main plating. Then, oxidation treatment was performed in a moist hydrogen gas atmosphere with a dew point of 25° C. at a heating temperature of 950° C. and a heating time of 10 minutes to form an oxide film with a thickness of 0.3 μm. After the surface of the oxidized test piece was polished with sandpaper to remove the oxide film, flux was immediately applied and the sample was immersed in a 250° C. solder bath to perform solder plating. Further, after the oxidized test piece was sealed with glass, the test piece was subjected to a tensile test to measure the glass sealing strength.

When the area ratio and glass sealing strength of the solder plating layer formed on the surface of the test piece were measured, they changed as shown in Table 4 depending on the thickness of the Ni plating. That is, even if the test piece without Ni plating is immersed in a solder bath immediately after removing the oxide film, a solder plating layer with a sufficient area ratio is not obtained. On the other hand, in all of the Ni-plated test pieces, a solder plating layer with a sufficient area ratio was formed. On the other hand, the glass sealing strength tends to gradually decrease as the Ni plating thickness increases.

[0034]

[Table 3]

[0035]

Effects of the Invention As explained above, the sealing metal material of the present invention is suitable for use with Fe-42%Ni-6, which is used for sealing soft glass used in fluorescent display tubes, etc.
%Cr-based alloy. Furthermore, since it does not contain expensive Ni, it can be provided at a relatively low cost, and a sealed portion exhibiting high reliability and excellent sealing properties can be obtained. Further, in the case of Ni plating, a solder plating layer with good adhesion can be easily formed, so that electrical connection with external terminals can be reliably established.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional structure of a sealed portion between a sealing alloy, low melting point glass, and plate glass.

FIG. 2 shows the influence of Al on the sealing strength of the sealing metal material to low-melting glass.

[Explanation of symbols]

1 Sealing alloy, 2 Low melting point glass, 3
Plate glass, 4 oxide film

Claims (2)

[Claims] [Claim 1] Cr: 24-30% by weight, C: 0.0
6% by weight or less, Si: 1.0% by weight or less, Mn: 1.0
Weight% or less, Al: 0.03 to 0.5% by weight, N: 0.
A soft glass sealing metal material consisting of 0.6% by weight or less, the remainder substantially Fe. 2. The metal material for soft glass sealing according to claim 1, wherein the surface is plated with Ni.