JPS6110082A - 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, it relates to improvements in sealing compositions used at both ends of metal ride 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. When trying to obtain higher efficiency and color rendering properties, this operating temperature limit has become a stumbling block. In metal halide lamps, higher efficiency and color rendering can be obtained by increasing the operating temperature by increasing the wall load of the arc tube, but since quartz cannot withstand such high temperatures for long periods of time, This resulted in a shortened 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 area, and any vapor pressure can be obtained depending on the size of the heat insulating plate at the end of the arc tube. It is configured so that it can be used. Therefore, in order to raise the operating temperature of metal halide lamps and obtain higher efficiency and color rendering, various attempts have been made to use alumina ceramic tubes, etc., which have higher heat resistance and chemical stability than quartz, instead of quartz arc tubes. It is being

In this metal halide lamp using a ceramic arc tube, as a sealing material for the end of the arc tube, for example, 5102-At2 described in British Patent No. 8,010,906 is used.
0. - MgO-based sealing materials, BeO-AA2C)5-5i02-based sealing materials described in Japanese Patent Publication No. 49-32301, and the like are known. When using these sealing materials, one end of the arc tube is first sealed, the filler gas and additives are sealed, and then the other end is sealed. and time are selected to minimize losses due to volatilization of additives or loss of purity of the fill 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 column after melting and solidification, and in many cases, these cracks expanded when the arc tube was turned on, leading to leakage. In addition, with the latter composition, the viscosity of the molten sealing material during sealing is high, and after solidification, the gap between the ceramic cap and the nozzle tube becomes large, making it easy for leaks to occur. I took it in,
Seal failure was likely to occur. In addition, there was a practical problem in the adhesive strength with alumina. Furthermore, it is necessary to consider the halogen resistance of such a sealing material to high-temperature halogen 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 At20, Y2O, L&205.
By selecting a predetermined composition ratio (wt%) of 5102 and BeO, a sealing material with high corrosion resistance, no generation of microcracks or bubbles after melting and solidification, and high adhesive strength can be obtained. The purpose of the present invention is to provide a ceramic metal halide lamp that has a long life, high efficiency, and high color rendering properties.

Means for Solving the Problems As a result of many experiments with such sealing materials, the inventors found that ht2o, (aluminum oxide), Y2O5 (
Yttrium oxide), La2C15 (U/Li/)
, 5io2 (silicon dioxide) and Beo (silicon dioxide)
A component with high halogen resistance, such as 71 Jum), was selected. Here, it was discovered that by adding an appropriate amount of beryllium oxide, an interfacial reaction occurs between the beryllium oxide and the alumina substrate, resulting in high adhesive strength and a reduction in viscosity when melted, and it was confirmed that a good sealing material can be obtained.

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

At205: 5-30% by weight Y2O5: 10-40% by weight La2()5: 30-70% by weight 5102: 5-
30% by weight 8eO: 2-15% by weight Function The reason for the above compositional limitation is as follows.

If the amount of At205 is 30% by weight or more, there will be many bubbles in the sealing material, crystal precipitation will be large, and cracks will occur frequently, and if the amount of 5IO2 is 30% by weight or more, the melting point will be severely lowered, making it practically problem, and the coefficient of thermal expansion is ht2o
If it becomes too small than that of No. 3, cracks will occur. Y2
If the O3 concentration is 40% by weight or more, the melting point is 1500℃.
This caused a practical problem, and the amount of BeO was reduced to 15% by weight.
If it is more than that, the crystallinity becomes too large and bubbles and cranks are generated.

If the amount of L & 203 is 70% by weight or more, bubbles and cracks will occur frequently and leakage will occur easily. Next, to explain the reason for the lower limit, 5102, Be01At205, Y2
O.

If the amount is less than the limited value, the melting point will increase significantly, which is a practical problem. If LJO5 is less than 30% by weight, the precipitation of crystals will become too large, resulting in frequent cracks between crystals, making it easy to leak.

Therefore, by adjusting each component within the above component ratio, halogen resistance is high, the coefficient of thermal expansion with alumina ceramic is within the permissible limit, and the melting point is 1200 to 14.
It was found that a sealing material having a temperature of 50° C. or less without any practical problems could be obtained.

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 part is sealed by heating to 1,400 to 1,600°C in the inside. Examples N11l to N in Table 1
[The only difference in characteristics in L4 is that the melting point at the time of sealing is slightly different, and the ratio between the crystal phase and the glass phase is slightly different; there are almost no bubbles, no cracks, and the airtightness is good. Ta.

In this way, by combining the above examples and various experimental results, the composition of the sealing material is At205: 5-30% by weight Y2O5: 10-40% by weight La2O3: 30-70% by weight 5IO2: 5-30% by weight BeO: It has become clear that a sufficiently satisfactory sealing state can be obtained with a sealing material in the range of 2-15% by weight.

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 time. No leaks were observed.

Effects of the Invention As is clear from the above explanation, when the sealing composition according to the present invention seals ceramics to ceramics or ceramics to metals, fine racks and air bubbles are not generated inside the bonded area. Since it has high adhesive strength and excellent halogen resistance, it can prevent lamp malfunctions due to cracking.

Further, since the melting point of the sealing material can be selected within an appropriate range, there are advantages such as good workability.

Claims (1)

[Claims] 5-30% by weight Al_2O_3, 10-40% by weight Y_2O_3, 30-70% by weight La_2O_3, 5
~30 wt% SiO_2 and 2-15 wt% BeO
A sealing composition for sealing a ceramic and a ceramic or a ceramic and a metal.