JPS6110081A - Sealing composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sealing material for translucent alumina ceramic.
In particular, the present invention relates to improvements in sealing compositions used at both ends of metal halide lamps using alumina ceramic tubes.

BACKGROUND OF THE INVENTION In recent years, metal halide lamps have been widely used in various fields of lighting as lamps with high efficiency and excellent color rendering properties and high practical value. However, since metal halide lamps use quartz as the arc tube material, the operating temperature limit is lower than that of highly heat-resistant ceramics such as alumina, which are used as the arc tube material of high-pressure sodium lamps. This usage temperature limit has been an obstacle when trying to obtain higher efficiency and color rendering properties. In metal/S Ride lamps, higher efficiency and color rendering can be obtained by increasing the operating temperature by increasing the wall load of the arc tube, but quartz cannot withstand such high temperatures for long periods of time. This resulted in a short lamp life.

The maximum temperature of the arc tube during operation of the metal halide lamp is at the center of the arc tube body, and the operating temperature is regulated by the temperature of this part, and the vapor pressure can be adjusted to any desired value depending on the size of the heat insulating plate at the end of the arc tube. It is structured in such a way that it can be obtained. Therefore, in order to raise the operating temperature of metal noride lamps and obtain higher efficiency and color rendering properties, it is recommended to use alumina ceramic tubes, which have higher heat resistance and chemical stability than quartz, instead of quartz arc tubes. Various attempts have been made.

In this metal ride lamp using a ceramic arc tube, as a sealing material for the end of the arc tube, for example, 5i02-At described in British Patent No. 8,010,906 is used.
20. - MgO-based sealing materials, BeO-At203-5i02-based sealing materials described in Japanese Patent Publication No. 49-32301, and the like are known. When using these arriving materials, first one end of the arc tube is sealed and filled with filler gas and additives.
The other end is sealed, and the sealing conditions, ie, temperature and time, are selected to minimize losses due to volatilization of additives or loss of purity of the filling gas.

In other words, the temperature during sealing must be relatively low and the seal must be completed in a short time, but among the sealing compositions mentioned above, the former has a rapid thermal shock during sealing and a small expansion coefficient with alumina ceramic. Due to this difference, many fine cracks were generated inside the sealing material after it was melted and solidified, and in many cases, these cracks expanded as soon as the arc tube was turned on, leading to leaks.

In addition, with the latter composition, the viscosity of the molten sealing material during sealing is high;
After solidification, the gap between the ceramic cap and the pipe becomes large, making it easy for leaks to occur, and the high viscosity tends to trap air bubbles, causing seal failure. or,
There was a practical problem with the adhesive strength with alumina. Furthermore, in such a sealing material, it is necessary to consider the halogen resistance against high-temperature I/logen vapor during lighting and the melting temperature during sealing work.

Problems to be Solved by the Invention The present invention has been made in view of the above points, and uses ht2o5, sio, , B20, as a sealing composition for sealing ceramics to ceramics or ceramics to metals.
By selecting Bso and ZrO2 at a predetermined composition ratio (weight ratio), it is possible to obtain a sealing material that has high corrosion resistance and does not produce fine racks or bubbles after melting and solidification. The purpose of the present invention is to provide a ceramic metalnoride lamp that has a long life, high efficiency, and high color rendering properties.

Means to Solve the Problems As a result of many experiments with such sealing materials, the inventors found that Az2o5 (aluminum oxide), 5iO2 (silicon dioxide), B20, (boron trioxide), BeO (oxidized Components with high halogen resistance such as beryllium) and Zr02 (zirconium oxide) were selected. Here, it was discovered that by adding an appropriate amount of zirconium oxide, there were no bubbles, the adhesive strength increased, and the viscosity could be reduced, and it was confirmed that a good sealing material could be obtained.

The present invention was completed based on the above experimental results, and its components have the following composition.

At205: 15-35% by weight 5102: 15-37% by weight B20: 20-35% by weight BeO:
5-25% by weight ZrO2: 60% by weight or less of 5i02 content Effect Here, the reason why the amount of ZrO2 in the sealing material was set to be 60% by weight or less of 5io2 content is that if it is more than this, the melting point will be abnormally high, making it difficult to put into practical use. However, Z, which has high corrosion resistance and
This is because, in addition to r S t O11, a single phase of ZrO2 is generated, which causes minute cracks in the sealing material after melting and solidification, causing leakage. Further, other reasons for limiting the composition are as follows. The amount of At205 is 35% by weight or more, B
If e0i is 25 weight% or more, the melting point becomes too high and becomes a practical problem.
5 If the weight of the fish is 35 - or more, A which is also the arc tube body
t20. If the coefficient of thermal expansion exceeds the allowable limit and cracks occur in the sealing material or in the At20 cavity, and even if cracks do not occur, the glass phase component in the mixed crystal of the seal after melting and solidification increases, resulting in failure resistance.・Logenability decreases, making it easier to leak. Also, if the amount of Be01s, o5 is reduced, the melting point will rise, which will pose a practical problem, and At20. If the amount is less than 15% by weight, the coefficient of thermal expansion will be too small than that of the At205 substrate, resulting in cranking during sealing. Furthermore, 5102i
If it is less than 15% by weight, the melting point will rise and more bubbles will be generated, which poses a practical problem. Therefore, by adjusting each component within the above-mentioned ratio, we can create a sealing material that has high... I found out that I can get it.

EXAMPLES Next, examples according to the present invention will be described together with a method of preparing a sealing material.

After pulverizing and mixing the raw materials for preparation as shown in Table 1, the mixture is compression-molded into the desired shape and placed in the sealing area between the end of the ceramic tube and the end cap, and the sealing area is vacuumed or inert gas The round portion is sealed by heating to 1,400 to 1,600° C. inside. Examples I@1 to 4 in Table 1
The only difference in characteristics is that the melting point at the time of sealing is slightly different, and the ratio of the crystal phase to the glass phase is slightly different; there are almost no bubbles, no cracks, and good airtightness. Ta.

In this way, by combining the above examples and various experimental results, the sealing material composition is At20: 15-35% by weight, 5IO2: 15-37% by weight, B2O5: 20-35% by weight, BeO: 5-25% by weight, ZrO2. : It has been revealed that a sufficiently satisfactory sealing state can be obtained with a sealing material having a 5I02 content of 60% by weight or less.

In this way, we created a metal halide lamp using a translucent alumina ceramic arc tube with predetermined amounts of thallium iodide and dysprosium iodide sealed inside the tube, and conducted lighting tests for a long period of time, but leaks from the sealing part occurred. was not seen at all.

Table 1 Effects of the Invention As is clear from the above explanation, when the sealing composition according to the present invention seals ceramics and ceramics or ceramics and metals, fine racks are not generated inside the sealing area. Furthermore, since no air bubbles are generated within the sealing column and the halogen resistance is excellent, it is possible to prevent lamp malfunctions. Further, since the melting point of the sealing material can be selected within an appropriate range, it has advantages such as good productivity.

Claims (1)

[Claims] 15-35% by weight Al_2O_3, 15-37% by weight
of SiO_2, 20-35 wt% B_2O_3, 5-
A sealing composition for sealing a ceramic and a ceramic or a ceramic and a metal, which contains 25% by weight of BeO and 60% by weight or less of ZrO_2 of the SiO_2 content.