JPS59219850A - Fusing material - Google Patents

Abstract

PURPOSE:To obtain a fusing material having a thermal expansion coefficient approximate to that of alumina ceramic as well as heat resistance and airtightness by selecting the composition of a glass principally consisting of MgO, Al2O3 and SiO2 to be within a specified range. CONSTITUTION:A glass-like substance containing 27-43wt% MgO, 5-50wt% Al2O3 and 25-55wt% SiO2 as main components is used. In addition, the glass- like substance may contain 10wt% or less of at least one of Y2O3, Sc2O3 and ZrO2. When the amount of Mg is not within the above range, a thermal expansion coefficient approximate to that of alumina ceramic can not be obtained. This composition has a thermal expansion coefficient appropriate for fusing, has no problems in its heat resistance and airtightness and does not react with a metal halide used as an additive for members charged in a lamp. Therefore, it is suitable as a fusing material 5 for a long-life metal halide lamp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing material, particularly to a sealing material suitable for sealing the ends of metal halide lamps using translucent alumina tubes.

Fig. 1 is a partial vertical cross-sectional view showing the structure of a metal halide lamp. an end cap, (3) a lamp electrode provided on the end cap (2), and (4) a lamp electrode provided on the end cap (2);
), and (5) is a sealing material that hermetically seals the arc tube (1) and the end cap (2).

In a lamp having the above configuration, an arc tube (
1) When an appropriate additive is sealed in the inside and power is supplied from the outside through the electrode lead terminal (4) between the opposing electrodes (3), a discharge is sustained between the electrodes (3) and the It emits light and functions as a lamp. Here, the electrode lead terminal (4) and the electrode (3) need to be in a conductive state, so the end cap (2) is a conductive part, but the thermal expansion characteristics of the conductive part are different from the arc tube ( 1) is approximated. Furthermore, the sealing material (5) that connects the arc tube (1) and the end cap (2) does not react with the sealing materials, and not only maintains airtightness but also does not generate excessive stress. Arc tube (11 and end cap (2)
) should be approximated to the thermal expansion characteristics of In addition, this sealing material (5) compensates for the temperature rise during lamp operation, so
It must have heat resistance of approximately 700°C or higher.

Conventionally, ridge glass and sintered bodies of fire-resistant oxides have been used as such sealing materials, but no material has been available that completely satisfies the above requirements for a sealing material. . In other words, sintered bodies of refractory oxides have poor reliability and have poor reactivity with metal halides.
Alumina borosilicate glass, which is an excellent material, has an extremely small coefficient of thermal expansion, and other glasses have drawbacks such as being susceptible to reactions with additives and not having sufficient heat resistance.

This invention was made in order to eliminate the drawbacks of the conventional sealing materials as mentioned above.
By selecting an appropriate composition range for the glass containing i02 as the main component, it is possible to create a sealing material that has a thermal expansion coefficient similar to that of alumina ceramic, has low reactivity with the encapsulated material, and has heat resistance and airtightness. is intended to provide.

The sealing material of this invention has Mg027-43%, A4
0s 5-50 weight%%, Oyobi5i0225-55
It is a glassy substance containing 1t as a main component and 1t selected from Y2O3, 5c203 and ZrO2.
i or more may be contained in a range of 10% by weight or less.

The range of components of the composition is determined based on the coefficient of thermal expansion and the ease of glass melting.

JiA3 (t
cannot obtain a thermal expansion coefficient close to that of alumina ceramic. In other words, the coefficient of thermal expansion of the Bo.
Pupils exceeding 3% by weight, larger in circumference, 27% by weight
If it is less than that, there is a tendency to deviate from the applicable range of translucent alumina in the smaller direction. Furthermore, if the weight exceeds 43%, the vitrification of this system becomes extremely conical.

When the amount of Al2O3 is less than 5% or more than 50% by weight, or when the amount of 5i02 is less than 25% by weight, it is also undesirable because the glass melting temperature becomes high. If the amount of 5102 exceeds 55°%, the coefficient of thermal expansion becomes too small, which is not preferable. The coefficient of thermal expansion closest to that of alumina ceramic is likely to be obtained when the ratio of MgO to 5i02 is approximately 1:1. The appropriate composition range of the present invention is illustrated in a three-component composition diagram as shown in FIG.

The above qt('i, with the composition within the circle, Y203 + S c
Any 14 of 203 + and ZrO2! i or 2
Even if more than one species is contained in the H11 range of 10% by weight or less, a sealing material with virtually no change in properties can be obtained.

The sealing material configured as shown in the above I-Pi is made by blending oxides corresponding to each composition, or substances that generate oxides when heated, and melting them in a heating bath in the N part of the seal to vitrify them. I do.

Next, embodiments of this invention will be congratulated. Table 1 shows examples of the main compositions and their properties.

The thermal expansion coefficient and heat resistance were measured using block test pieces produced by heat treatment after glass melting.
Airtightness is achieved by finely pulverizing molten glass and applying the powder to the sealing material (5) shown in Figure 1 at a temperature of 1350° to 160°.
After heating to 0°C, it was examined using a helium leak detector. In glass sealing, the allowable difference in thermal expansion coefficient between the sealing material and the parts to be sealed is generally 10 x
However, in the case of the structure shown in Figure 1, it is preferable that the coefficient of thermal expansion of the sealing material be larger than that of the parts to be sealed, close to the above 111. "This is not desirable. In Table 1, the compositions of 163 to 14 are suitable for sealing. , the sealing material with such a composition is NaI, InI, + ScI, ,
Cel3yz does not react with the metal halide that is the filler material in the lamp, and is used as a sealing material for metal halide lamps with a long life.

In the above description, the composition may include components other than those exemplified above, and the blending ratio can also be freely changed within the above range. Furthermore, in the above embodiments, the case of a metallolide lamp has been explained, but it can also be applied to sealing of other applications such as alumina ceramics or ceramics or metals having thermal expansion characteristics similar to those of alumina ceramics. .

As described above, according to the present invention, Mg is used as the sealing material.
Since it is composed of a glassy substance whose main components are O, Al2O5, and 5in2, it has a thermal expansion coefficient close to that of alumina ceramic, and has low reactivity with encapsulated substances such as various metal halogenides. It also has the effect of maintaining sufficient heat resistance and airtightness.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a part of a metal halide lamp using a translucent alumina tube, and FIG. 2 is a three-component composition diagram showing appropriate composition ranges of the present invention in weight percentages. In the figure, (1) is a transparent aluminum arc tube, (2) is an end cap, (3) is a lamp electrode, (4) is an electrode lead terminal for power supply, and (5) is a sealing material. . Agent Masuo Oiwa

Claims (1)

[Claims] (1127-43% by weight of Mg0, 5-50% by weight of A
A sealing material characterized in that it contains 12O3 and 25 to 55% by weight of 5i02. (2) The sealing material according to claim 1, which contains at least 10% by weight of one or more selected from Y2O2, 5c203, and ZrO2. (3) Claim 1 or 2, characterized in that the sealing substance seals an alumina ceramic.
Sealing substance as described in section.