JPS5914539B2 - Alloy for soft glass sealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in NiCr-Fe based soft glass sealing alloys, and particularly to sealing alloys that suppress the generation of yellow powder.

This type of 42%Ni-6%Cr-Fe alloy has been widely used for cathode ray tube anode buttons, digital display tube lead frames, etc. In this case, it is usually
After the alloy is molded into the desired shape, it is treated with an oxide film in a wet base and sealed with glass.

The properties required for this alloy are: ■ The coefficient of thermal expansion of the alloy closely matches that of glass; ■ The film formed by the oxide film treatment firmly adheres to the alloy base; ■ The absence of yellow powder ( Needle-shaped oxides (called yellow powder because they look like yellow powder) do not form on the surface after the oxide film treatment. The reason for the need for the above item is that yellow powder is the starting point for cracks after glass sealing. This is because there is a risk that this will occur, and it is also unfavorable in terms of commercial value.

As is well known, regarding ■ out of the above three points, Fe-Ni
An alloy of 40 to 48 wt%-Cr4 to 8 wt% satisfies the conditions.

Regarding improvement of the adhesion of the oxide film in (■), the above Ni
-Cr -IF e-based alloy with Al, Zr, 'ri
It is known that those to which Y or R-E are added are effective.

However, there are currently very few countermeasure proposals regarding the control of the generation of yellow powder.

The purpose of the present invention is to provide a NiCr-Fe based soft glass sealing alloy that suppresses the generation of yellow powder, which is the condition (1), as well as (1) and (2) above. , M n y S i are both 0.1
It is characterized by keeping the S content to less than 0.01 wt% and the 02+N2 content to less than 100 ppm.

According to the inventor's experimental research, the mechanism of generation of yellow powder is estimated as follows.

First, at 1250℃ for 60 minutes in wet hydrogen (dew point 30℃)
Conventional 42%Ni-6%Cr-F treated with oxide film
The yellow powder generated on the oxide film of the e-alloy is a needle-shaped oxide with a small sphere at its tip, and is mainly composed of Mn Cr 204
It consists of

The underlying oxide film from which this yellow powder has been removed mainly consists of Cr2O3, with some (Mn, Fe)Cr20
It has a structure containing 4.

Next, yellow powder begins to be generated when the coating is applied at a temperature of 1200°C or higher, and after enriching the elements normally contained in the alloy by vapor deposition or plating on the surface of the alloy before coating, the yellow powder is produced under the same conditions as above. As shown in Table 1, it was found that the Mn N811 Al-enriched specimens produced a significant amount of yellow powder, while the Cr-enriched specimens suppressed the generation of yellow powder.

Combining the above results, the following conclusions can be drawn.

■ MnO, Sio2. Portions where Al2O3 has a certain specific composition ratio react with each other to form an oxide with a low melting point (melting point: 1200° C.).

(2) A part of the Mn oxide on the surface of the oxide film is reduced to metal Mn by hydrogen in the atmosphere.

Since Mn easily evaporates, it becomes a gas relatively easily.

■ The gaseous Mn is captured by the low melting point oxide (droplet part) that has become a liquid.

(2) The captured Mn diffuses through the droplet, precipitates at the droplet/oxide film interface, and becomes MnCr2O4.

(2) In this way, needle-like oxides of MnCr2O4 grow on the oxide film of the 42%Ni-6%Cr-Fe alloy.

From the above point of view, in order to suppress the generation of cross powder, 42%N
In order to improve the composition of the i-6%Cr-Fe alloy for soft glass sealing, it is sufficient to suppress the MnySi content in the alloy as much as possible, while increasing the Cr content. Among these, Cr cannot be increased due to the need for oxide film growth and thermal expansion characteristics.

That is, as mentioned above, the present invention is applicable to the conventional N i -Cr-
In the Fe-based soft glass sealing alloy, Mn.

It is characterized by suppressing the contents of Si, S, and 020N2 as much as possible, and the reason for limiting the components is as follows.

Mn and Si: Mn is added for desulfurization and deoxidation, Si is added for deoxidation,
Usually, this type of alloy has Mn and Si in an amount of 0.1 to 1% each.
However, in order to prevent the generation of yellow powder during oxide coating treatment, this amount must be suppressed as much as possible.

However, as a result of experiments, the inventor found that Mn and Si were each 0.1
It was confirmed that yellow powder would not be generated in actual oxide film treatment if it was within a range of less than wt%.

Further, if each of Mn and Si is less than 0.005 wt%, it is not preferable in terms of hot workability.

S and 02. N2: When Mn and Si are restricted as described above, S and 02. The influence of N2 can no longer be ignored.

Therefore, by examining the raw materials used for the alloy in advance and thoroughly examining the conditions for melting and agglomeration, the S content should be 0.01 wt% or less.
2+N2 needs to be reduced to 1100 pp or less.

Next, as an example, several examples of the sealing alloy of the present invention were compared with several examples of conventional alloys, and each alloy was tested at 1250°C x 60 minutes (H
Table 2 shows the occurrence of yellow powder after the film treatment at 2D-P (30°C) along with other properties.

Claims (1)

[Claims] 1. Ni: 40-48%, Cr: 4-48% by weight
8%, 0.005%<;: Mn<0.10%, 0.
005 So<:S i <0.10%, and S:
An alloy for soft glass sealing which suppresses generation of yellow powder, characterized in that: <:0.01 So, 02+N2<100 ppm, and the remainder substantially consists of Fe. 2 Ni: 40-48%, Cr: in weight percent. 4-8%, 0.005%, Mn 0.10%, 0.00
5.0010% Si and Al, Zr, Tt, Y
, Sc. Contains 0.005 to 1.0% of one or more of R-E (atomic number 57 to 71), and S: <0.10%,
A soft glass sealing alloy which suppresses the generation of yellow powder, characterized in that the remainder is essentially bent iron.