JPS6396247A - Fe-ni-co sealing alloy having superior resistance to cracking by ag solder - Google Patents

Abstract

PURPOSE:To refine the grains of an Fe-Ni-Co sealing alloy having a specified compsn. and to improve the resistance to cracking by Ag solder, by incorporating a specified amount of B or Nb into the alloy. CONSTITUTION:The compsn. of an alloy for sealing hard glass or ceramics is composed of, by weight, 25-35% Ni, 13-20% Co, 0.001-0.015% B and/or 0.05-0.30% Nb and the balance Fe with inevitable impurities. The compsn. may be composed of 25-35% Ni, 13-20% Co, 0.001-0.015% B, 0.005-0.20% one or more among Ti, Zr, Nb, REM and Y and the balance Fe. By the compsn., the infiltration of molten Ag solder into the grain boundaries of the alloy under tensile stress can be inhibited and the resistance of the alloy to cracking by Ag solder is improved.

Description

[Detailed description of the invention] Industrial field of application The present invention relates to the improvement of a Fe-Ni-Co based sealing alloy that seals with hard glass or ceramics, and improves grain refinement and Ag braze cracking resistance. Measured Fe-Ni-
This invention relates to a Co-based sealing alloy.

BACKGROUND ART Fe--Ni--Co alloys have been widely used as alloys for sealing hard glass or ceramics.

This Fe--Ni--Co based sealing alloy is sealed with glass or brazed with Ag to ceramics, and then joined to various metal members by welding or brazing.

Generally, Ag brazing is performed in an H2 gas atmosphere at 800%
It is carried out at temperatures between ℃ and 900℃, but Fe-Ni-Co
When tensile stress is applied to the alloy or there is residual tensile stress in the alloy, the molten Ag solder during brazing becomes Fe-N.
Cracks may occur by penetrating the grain boundaries of the i-Co alloy.

For this reason, generally before Ag brazing, Ni plating is applied to the surface of the sealing alloy parts, and the Fe-Ni-Co alloy and A
Measures were taken to prevent direct contact with the wax.

Therefore, Ag brazing of Fe-Ni-Co based sealing alloy is a technique to prevent cracking over time, by adding rare earth elements etc. to the Fe-Ni-Co based sealing alloy to make it compositionally resistant to Ag.
Proposal to improve brazeability (Japanese Patent Application Laid-Open No. 50-123
No. 514 ff1).

The above method uses Ce and AI or Si added Fe-Ni.
-Co alloys are first subjected to oxidation treatment before Ag soldering, and then the oxide film on the surface is removed by mechanical or chemical methods to prevent Ag soldering from penetrating into the grain boundaries of the sealing alloy. It is.

In addition, in Japanese Patent Publication No. 51-2894, rare earth-added F
In the e-Ni-Co alloy, the effect of the additive is said to suppress the depth of grain boundary expansion of the Ag solder during adhesion of the Ag solder.

Purpose of the Invention The purpose of the present invention is to compositionally improve the Ag braze cracking resistance of conventional Fe-Ni-Co sealing alloys for sealing with hard glass or ceramics. The objective is to create a Fe-Ni-Co based sealing alloy that does not require any treatment.

Structure and Effects of the Invention The inventors have discovered that the A-resistant
As a result of various studies aimed at improving the brazing resistance compositionally, we found that by incorporating a specific amount of B or Nb into the Fe-Ni-Co alloy, Fe-Ni
- It is possible to suppress the penetration of molten Ag solder into the grain boundaries at high speed under the tensile stress of the Co-based alloy,
This invention was completed based on the finding that Ag braze cracking resistance was significantly improved.

That is, this invention includes Ni 25 wt% to 35 wt%, Co 13 wt%
% to 20 wt%, and further B 0.001 wt% to 0.
015wt%, Nb 0.05wt%~0.30wt
It is a Fe-Ni-Co based sealing alloy with excellent Ag wax cracking resistance, characterized by containing one type of Ni 25 wt%, and the remainder consisting of Fe and unavoidable impurities. ~35 wt%, Co13 wt
%~20wt%, B 0.001wt%~0.015w
t%, and further contains B and Ti, Zr, Nb,
At least one type of RESY from 0.005 wt%
It is a Fe-Ni-Co based sealing alloy with excellent Ag braze cracking resistance, and is characterized by containing 0.20 wt% and the remainder consisting of Fe and unavoidable impurities.

The sealing alloy according to the present invention can be obtained by adding B or Nb to the basic composition of Fe-Ni-Co, and further by adding Ti to the basic composition of Fe-Ni-Co.
, Zr, Nb, RE, and Y. In addition to the above composition, C0.
05 wt% or less, N 50 ppm or less, 0100 p
pm or less, S 0.025wt% or less, Mn 1. Ow
It is preferable that Si is 0.5wt% or less.

Reason for limiting the components In this invention, Ni 25 wt% to 35 wt%
, Co 13 wt% to 20 wt% is required as a sealing alloy to have strong bonding properties with hard glass or ceramics, etc., so the coefficient of thermal expansion should be similar or the same as that of the material to be bonded. If the composition is outside the above range, the difference in thermal expansion coefficient between the alloy and hard glass or ceramics will become too large to be practical. It is necessary to combine them appropriately.

B is a characteristic of the sealing alloy according to the present invention, and has the effect of suppressing the penetration of molten Ag solder that progresses at high speed into the grain boundaries, but if it is less than 0.001 wt%, the above effect is small, and If it exceeds 0.015 wt%, this effect will be saturated and the hot workability of the alloy will also deteriorate;
The content is set to be 0.01 wt% to 0.015 wt%.

Nb has the effect of refining crystals and suppressing the penetration of Ag solder into grain boundaries, and is effective in improving Ag solder cracking resistance, but this effect is small when the content is 0.05 wt%. Moreover, if it exceeds 0.30 wt%, this effect will be saturated and the workability of the alloy will also deteriorate, so 0.05 wt%
The content is t% to 0.30 wt%.

In this invention, a specific amount of B is contained, and further Ti,
It contains at least one of Zr, Nb, RE (rare earth element), and Y, and all of the above element groups have the effect of refining the crystal grains of the alloy and preventing the diffusion and invasion of Ag solder. At least 0.005 to be effective
wt% addition is required.

Moreover, the reason for the upper limit of addition of the above Ti, Zr, Nb, RE, and Y element groups is as follows.

If Ti exceeds 0.20 wt%, the properties of the oxide film will change and this will cause problems during glass sealing, which is undesirable.
If it exceeds 0.20 wt%, it is undesirable because it deteriorates hot workability. If RE, Y exceeds 0.20 wt%, it is unfavorable because it deteriorates hot workability, and desirably 0.10 wt%.
% or less.

Therefore, Ti, Zr, Nb, RE (rare earth element)
, Y are 0.005 wt% to 0.20 wt%, respectively.
The content shall be within the range of .

In addition, C is generated as a gas from the surface during the heating process during sealing with glass or ceramics, is included in the sealing interface, and reduces the sealing strength, so 0.05
It is preferable to set it to less than wt%.

N is desirably contained in an amount of ippm or more in order to combine with the additive elements Hf and Zr and exhibit its effect.
Further, since nitrides are generated in the alloy and deteriorate hot workability and cold workability, the content is preferably 50 ppm or less.

0 deteriorates the hot workability and cold workability of the alloy, and the added elements Hf and Zr are stabilized and no longer contained, so the content is preferably 100 ppm or less.

When S exceeds 0.025 wt%, hot workability deteriorates due to the presence of S that does not combine with Mn, and the additive elements Hf and Zr are no longer stably contained.
．． The content is preferably 0.025 wt% or less.

Mn is added to improve hot workability, but 1.0
If it exceeds wt%, the required thermal expansion coefficient cannot be obtained, so the content is preferably 1.0 wt% or less.

Si is a deoxidizing element that prevents the generation of bubbles in the steel ingot,
It is added because it has the effect of improving the adhesion of the surface oxide film, which is important for glass sealing, but if it exceeds 0.50 wt%,
0.50 because the material hardens and cold workability deteriorates.
The content is preferably less than wt%.

Fe forms the main alloy with Ni and Co, and is the remainder of the various contained elements mentioned above.

Implementation Example A 5 kg ingot was produced in an induction melting furnace with the composition shown in Table 1, and the ingot was hot rolled and softened at 800°C.
A Fe-Ni-Co alloy plate having a thickness of 0.25 mm was produced by cold rolling.

Furthermore, test pieces measuring 0.25 mm in thickness, 5 plates in width, and 100 plates in length were cut out from the various alloy plates described above.

Next, a Ag72%-Cu28% system A having dimensions of 0.05 mm thickness x width plate x length 20 mm was placed in the center of the test piece.
G A brazing alloy plate was wrapped around the test piece, one end of the test piece was fixed in a hydrogen furnace maintained at 840°C, a tensile force was applied to the other end with a weight, and the weight load was varied to cause the test piece to break. .

In the rupture test, the load corresponding to the time to rupture of 1 minute and 60 minutes (σ1 kgf/mm2) (σ60 kgf/
The Ag braze cracking resistance was evaluated using mm2), and the results are shown in Table 2.

Further, the average crystal grain size was measured when the sample was held at 850° C. for 30 minutes in a hydrogen atmosphere, and the results are shown in Table 2.

As is clear from the results in Table 2, Fe
It can be seen that the -Ni-Co based sealing alloy has a finer average grain size and significantly improved Ag braze cracking resistance.

Margin below

Claims (1)

[Claims] 1 Ni 25wt% to 35wt%, Co13wt% to 20w
t%, and further B0.001wt% to 0.015wt%
, 0.05wt% to 0.30wt% of Nb, and the remainder is Fe and unavoidable impurities. . 2 Ni25wt%~35wt%, Co13wt%~20w
t%, B0.001wt% to 0.015wt%, and further contains 0.005wt% to 0.20wt% of at least one of Ti, Zr, Nb, RE, and Y, with the remainder being Fe and unavoidable elements. A Fe-Ni-Co based sealing alloy with excellent Ag braze cracking resistance, characterized by comprising a certain amount of impurities.