JP2002241858A - Method for suppressing precipitation of compound in molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for realizing the suppression of precipitation of compounds in molten metal by a simple method. SOLUTION: Molten metal substantially consisting of the three components of Sn, Zn and Ti, and in which Ti in the ratio of, by weight, 0.001 to 0.2% to the total content and Zn in the ratio of 8 to 10% to the total content of Sn and Zn are contained is held at a temperature higher than the liquidus temperature as a limit temperature in which a ZnTi based compound in the molten metal and a liquid phase are coexistent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for suppressing the precipitation of a compound in a molten metal.

[0002]

2. Description of the Related Art Conventionally, various articles utilizing a molten metal as a constituent material have been known. For example, International Publication W
Japanese Patent Publication No. O00 / 58234 relates to a glass panel, and discloses a glass panel in which opposing surfaces of a pair of plate glasses are bonded and joined with a sealing material over the entire outer periphery thereof, and a gap portion is sealed in a reduced pressure state. In the panel, it is disclosed that a metal material (molten metal) in a molten state is used as the sealing material. The publication also discloses a facility device including a storage container for storing the molten metal, and a flow path extending from a lower portion of the storage container and supplying the molten metal to the sheet glass.

As a metal material suitable for bonding oxide materials such as sheet glass, Japanese Patent Application Laid-Open No. 2000-326088 is known.
The gazette discloses a lead-free solder substantially containing Sn, Zn and Ti.

[0004]

The temperature of the molten metal in the storage container gradually decreases due to heat radiation from the surface of the storage container and the surface of the molten metal while the molten metal is continuously supplied to the outer edge between the glass sheets. It is possible. However, WO00 / 58234 does not disclose anything to be noted when maintaining the temperature of the molten metal or a problem when the temperature is lowered.

[0005] When maintaining the temperature of the molten metal, a relatively high temperature region and a relatively low temperature region are generated in the molten metal depending on the arrangement of the heater for keeping heat. Therefore, particularly in the low-temperature region, the metal components constituting the molten metal react with each other, and the compound precipitates and deposits on the flow path and the discharge port of the molten metal, which may be a factor that hinders the flow of the molten metal. There is.

[0006] Also, Japanese Patent Application Laid-Open No. 2000-326088 does not particularly disclose any points or problems to be noted in keeping the lead-free solder containing Sn, Zn and Ti in a molten state.

To date, there has been no report on the thermodynamic relationship between the composition and temperature in the ternary system and the coexisting phase, and thus no phase diagram of this composition system is shown. For this reason, when using the ternary molten metal having a specific composition, almost no coexisting phases may exist at a certain holding temperature.

[0008] Deposits may be formed depending on the temperature at which the molten metal is used, which may cause problems in the molten metal discharger. However, a guideline has been obtained as a basis for setting the temperature range for holding the molten metal. Did not. For this reason, no condition for suppressing the precipitation of the compound has been grasped.

The inventors of the present application have conducted detailed studies on the precipitation of compounds when a molten metal substantially consisting of three components of Sn, Zn and Ti is maintained in a molten state. It was found that a systemic compound was precipitated, and furthermore, a melt temperature range effective for suppressing the precipitation of the ZnTi-based compound was found.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for suppressing precipitation of a compound in a molten metal by a simple method.

[0011]

SUMMARY OF THE INVENTION The present invention provides a method for substantially storing S
This is a method for suppressing precipitation of a compound in a molten metal comprising three components of n, Zn and Ti, wherein Ti and Sn and Zn are present in a ratio of 0.001 to 0.2% with respect to the total amount, expressed in terms of% by weight.
Is maintained at a temperature higher than the liquidus temperature, which is the limit temperature at which the ZnTi-based compound and the liquid phase in the molten metal coexist in the molten metal containing 8 to 10% of Zn with respect to the total amount of This is a method for suppressing precipitation of a compound in a molten metal.

According to the present invention, the temperature of the entire region of the molten metal in the above composition range is set to ZnT in the molten metal.
In order to maintain the temperature higher than the liquidus temperature, which is the temperature at which the i-based compound can be generated thermodynamically, the ZnTi
Since it was clarified that the system-based compound did not precipitate and that the solid phase precipitated in the above composition range was only a ZnTi-based compound, the method of the present invention can reliably suppress the precipitation of compounds. .

Therefore, when the molten metal is stored in the storage container, problems such as accumulation of the compound in the flow path and the discharge port and obstruction of the flow of the molten metal in the flow path and the discharge port do not occur.

Further, since the molten metal has a fine structure without containing any compound in the solidified structure, when used as a sealing material for the glass panel, an external force is applied when the glass panel is used. Even if it does, the tissue will not be broken due to its excellent mechanical strength.

Further, in the present invention, the molten metal is preferably maintained at a temperature higher than 250 ° C., whereby the precipitation of the ZnTi-based compound can be suppressed more reliably.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

(Embodiment) As a molten metal, substantially S
Lead-free solder consisting of three components of n, Zn and Ti was used. The composition of the lead-free solder is expressed in terms of% by weight, Sn
90.91%, Zn 8.99% and Ti 0.1%. From the composition of the lead-free solder, the composition of Sn 91% and Zn 9% excluding a trace amount of Ti was a Sn-Zn binary eutectic point composition, and the eutectic temperature was 198 ° C.

The molten metal in the storage container kept at 300 ° C. by the heat source was cooled to the temperature shown in Table 1, and kept as it was for 24 hours.

A sample of a small amount of the retained molten metal was used as a sample of this example, and was rapidly solidified to observe the cross-sectional structure of the sample. In Table 1, “No” indicates that no precipitate other than the eutectic structure of Sn—Zn was observed in the sample, and “Yes” indicates that the precipitate was observed. The observed precipitates were all ZnT
It was found that the compound was an i-type compound by mapping analysis for each component separately performed.

[0020]

[Table 1]

As is clear from Table 1, in the molten metal used in this example, compound precipitation was observed in the structure in the range of eutectic temperature of Sn-Zn eutectic composition to eutectic temperature + 50 ° C. Was done.

The molten metal is soldered by using a solder melting tank disclosed in WO 00/58234 and a filling jig having a relatively narrow flow path for discharging the molten metal from the solder melting tank. Supplied from the melting tank,
A glass panel was prepared by filling the periphery of the gap between two sheet glasses and bonding the entire periphery along the edge between the sheet glasses. The molten metal was kept at a temperature higher than 250 ° C. at all points from the solder melting tank to the tip of the filling jig.

Even after the peripheral portion of the gap between the two glass sheets is filled a plurality of times, the state of the molten metal discharged from the filling jig is good, and clogging occurs in a narrow flow path due to compound precipitation. And the discharge of the molten metal was not hindered.

(Comparative Example) A molten metal having the same composition as
Using a filling jig different from the filling jig described in the example in the form of the molten metal discharge flow path, the molten metal was similarly filled into the periphery of the gap between the two sheet glasses.

After filling the gap between the sheet glasses a plurality of times, the discharge of the molten metal was gradually hindered, and clogging occurred in the flow path of the filling jig. As a result of investigating the clogged part, Z
It was found that the nTi-based compound was precipitated. When the temperature distribution of the molten metal in the filling jig was examined, it was found that the temperature of the molten metal was about 210 to 230 ° C. in the portion where the compound was precipitated and clogged.

[0026]

As described in detail above, according to the method for suppressing the precipitation of a compound in a molten metal of the present invention, the method substantially comprises three components of Sn, Zn and Ti, and is expressed in terms of% by weight with respect to the total amount. 0.001 to 0.2% of Ti, Sn and Zn
Is maintained at a temperature higher than the liquidus temperature, which is the critical temperature at which the ZnTi-based compound and the liquid phase in the molten metal coexist, in a proportion of 8 to 10% of Zn with respect to the total amount of Thereby, precipitation of the ZnTi-based compound in the molten metal can be suppressed.

By maintaining the temperature of the molten metal at a temperature higher than 250 ° C., the precipitation of the ZnTi-based compound can be suppressed more reliably.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toru Futami 4-28 Kitahama, Chuo-ku, Osaka-shi, Osaka F-term in Nippon Sheet Glass Co., Ltd. 4G061 AA02 AA18 CB07 CB14 CD02 CD25 DA26 DA29 4K001 AA27 AA30 BA24 DA14

Claims (2)

[Claims] 1. A method for suppressing the precipitation of a compound in a molten metal substantially consisting of three components of Sn, Zn and Ti, wherein the amount is 0.001 to 0.
8% to the total amount of 2% Ti and Sn and Zn
Maintaining the molten metal containing 10% of Zn at a temperature higher than a liquidus temperature which is a limit temperature at which a ZnTi-based compound and a liquid phase in the molten metal coexist. Method for suppressing compound precipitation. 2. The method according to claim 1, wherein the molten metal is kept at a temperature higher than 250 ° C.