JPH0466650A - Sealing alloy for hard glass - Google Patents

Abstract

PURPOSE:To obtain a sealed part having good conformity with hard glass and excellent in airtightness by balancing the content of each component in an Fe-Ni-Co ternary system, and furthermore reducing the Co content. CONSTITUTION:The compsn. of a sealing alloy for hard glass is formed of, by weight, 31 to 42% Ni, 1 to 15% Co as well as 38 to 46% Ni+Co and the balance Fe with inevitable impurities. In this ternary system alloy, the average thermal expansion coefficient at 30 to 400 deg.C is regulated to 4.5X10<-6> to 6.0X10<-6>/ deg.C. This value is equal to that of hard glass. At the time of melting and refining this alloy, according to necessary, desulfurizing and deoxidizing elements such as Si, Mn and Al are added. In this way, the sealing alloy for hard glass excellent in airtightness and sealability can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sealing alloy for hard glass that has excellent hermetic sealing properties.

[Prior Art 1] Hard glass has a temperature at which the viscosity is 4×10”, that is, a strain point is about 430° C.

Hard glass maintained below this strain point will not undergo viscous flow and will not retain any permanent deformation even after rapid cooling. The average coefficient of thermal expansion in the temperature range from room temperature to the strain point is approximately 5.3X10-'/'C.

Hard glass is heated to a temperature higher than its strain point and sealed with a sealing alloy. In the cooling process after sealing, stress due to thermal expansion between the hard glass and the sealing alloy is alleviated by the viscous flow of the glass in a temperature range equal to or higher than the strain point. However, in the temperature range below the strain point, stress due to the difference in thermal expansion is not relaxed, and if this stress difference is large, the hard glass may break or peeling may occur at the interface between the hard glass and the sealing alloy, resulting in airtightness. It will no longer be maintained. Therefore, the metal material sealed to hard glass is required to have a coefficient of thermal expansion almost equivalent to that of hard glass in the temperature range from room temperature to 430°C in order to have consistent thermal expansion characteristics with hard glass. be done. In this respect, Fe-29Ni-1
7Co alloy has traditionally been used as a typical sealing alloy.

However, Fe-29Ni-17Co alloy contains a large amount of Co.
It is an expensive material because it contains Therefore, it is limited in its uses and has not been widely used. Therefore, inexpensive sealing alloys have been substituted for the Fe-29Ni-17Co alloy.

Fe-42Ni alloy is known as such an inexpensive sealing alloy. Since this alloy does not contain expensive Co, it is treated as a relatively inexpensive material. Moreover, the thermal expansion coefficient at 30 to 300°C is approximately 5xiO-
'/'C, which is close to the coefficient of thermal expansion of hard glass.

[Problems to be Solved by the Invention] However, the Fe-42Ni alloy has a low transition point of 330°C. At this temperature of 330° C., the amount of change in the coefficient of thermal expansion changes rapidly per unit temperature, and a bending point is seen in the thermal expansion curve. Moreover, the coefficient of thermal expansion of 30 to 400'C (7) is relatively large at 6', 4 x 10-'/'C. Therefore, when hard glass is sealed using the Fe-42Ni alloy, a sealed portion having lower airtightness than the Fe-29Ni-17co alloy is obtained.

This airtightness is one of the most important properties required of a sealing alloy. Therefore, Fe-42Ni alloy has poor airtightness. Currently, it is not used in parts that require reliability.

The present invention has been devised to solve these problems, and is an inexpensive material that has a lower Co content than the Fe-29Ni-17Co alloy and has thermal expansion characteristics equivalent to the Fe-29Ni-1000 alloy. The purpose of the present invention is to provide a sealing alloy for hard glass.

[Means for Solving the Problems] In order to achieve the object, the sealing alloy of the present invention has Ni
:31 to 42% by weight, Coal to 15% by weight, and Ni
The amount of +Co is 38 to 46% by weight, the balance is Fe and unavoidable impurities, and the average coefficient of thermal expansion at 30 to 400°C is 4.5X10-'/°C to 6. OX 10-5/℃
It is characterized by

[Function] In order to solve the problems of sealing alloys, the present inventors have developed F
The thermal expansion characteristics of the e-Ni-Co alloy were investigated in detail. As a result, Ni was 31 to 42% by weight.

001 to 15% by weight, and the amount of Ni + Co is 38 to 46% by weight, with the balance consisting of Fe and inevitable impurities,
The average coefficient of thermal expansion from 30 to 400°C is 4.5xlO-6/°C to 6.0, which is equivalent to hard glass. It was discovered that an alloy having OX 10-5/°C can be obtained, leading to the present invention.

As seen in FIG. 1, the Fe-Ni alloy has a smaller coefficient of thermal expansion as the amount of Ni increases.

However, there is a tendency for the coefficient of thermal expansion to increase when Ni reaches around 38% by weight. For this reason, in the Fe-Ni binary system, the thermal expansion coefficient cannot be lower than 6.0 x 10-5/°C.

When Co is added to this Fe--Ni binary alloy, the coefficient of thermal expansion decreases rapidly as shown in FIG. However, with the addition of Co, a large amount of Co
Contrary to this, the content tends to increase the coefficient of thermal expansion.

That is, the thermal expansion characteristics are determined depending on the balance between Ni content and Co content. As shown in Figure 2, in the Fe-32%Ni system, Co7-15%, Fe-35
The coefficient of thermal expansion of the Fe-Ni-Co alloy is the smallest in the range of 001 to 8% for the %Ni system and 001 to 8% for the Fe-38%Ni system. 4.5xlO-5/℃~6. equivalent to the thermal expansion coefficient.
OX I Q-'/'C, and if the amount of co falls outside of these values, the coefficient of thermal expansion becomes too large.

Therefore, in the present invention, on the condition that a value equivalent to the coefficient of thermal expansion of hard glass be obtained, the component range was selected as shown in FIG. 3, and the amount of Ni + Co was set to 38 to 46%.

Note that when melting and refining Fe-Ni-Co alloy, Si
, Mn, Aβ, and other desulfurizing and deoxidizing elements may be added. It goes without saying that the sealing alloy of the present invention may contain some amount of these elements.

(Example〕 Hereinafter, the present invention will be specifically explained with reference to Examples.

In a vacuum induction melting furnace, 12 kg of 22 types of alloys whose components and compositions are shown in Table 1 are melted, forged and hot rolled to a thickness of 3.
Finished in a plate material of mm. A test piece was cut out from this plate material,
After annealing at 850°C for 5 minutes, the coefficient of thermal expansion was measured in a temperature range of 30 to 400°C. The results are also shown in Table 1.

As is clear from Table 1, the alloy of the present invention has a coefficient of thermal expansion equivalent to that of the conventional alloy Fe-29Ni-17Co. Therefore, when hard glass was sealed using this alloy, a sealed portion with good compatibility with the hard glass and excellent airtightness was obtained.

(Hereinafter, the margins of this page) [Effects of the invention] As explained above, the present invention has the advantage of balancing the content of each component in the Fe-N1-C〇 ternary system. We have obtained an alloy whose average coefficient of thermal expansion in the temperature range is equivalent to that of hard glass. Due to its thermal expansion properties, this alloy exhibits good compatibility with hard glass and can provide a hermetic seal. Furthermore, since the Co content is low, it is used as a relatively inexpensive sealing material.

[Brief explanation of drawings]

Figure 1 shows the relationship between Ni content and thermal expansion coefficient at 30 to 40°C for Fe-Nf binary alloy, and Figure 2 shows the relationship between the Ni content and the thermal expansion coefficient at 30 to 40°C.
Effect of Ni content and Co on thermal expansion coefficient from 0 to 400°C
The influence of the content is shown in FIG. 3, which shows the Fe-Ni-Co ternary diagram in which the thermal expansion coefficients from 30 to 400°C are arranged.

Claims (1)

[Claims] (1) Ni: 31 to 42% by weight, Co: 1 to 15% by weight, and the amount of Ni+Co is 38 to 46% by weight, with the balance consisting of Fe and inevitable impurities, and the temperature is 30 to 400°C.
The average coefficient of thermal expansion is 4.5 x 10^-^6/℃~
A sealing alloy for hard glass characterized by a temperature of 6.0×10^-^5/°C.