WO2012014619A1 - Sealing glass and sealing composite material - Google Patents

Abstract

This sealing glass is for sealing a metal object to be sealed, characterized by comprising, by mol%, 15 to (but not including) 30% SnO, 20 to 40% P₂O₅, 5 (but not including 5) to 20% WO₃, and 3.4 to (but not including) 30% ZnO, as a glass composition, wherein the mol ratio SnO/ZnO is 1 to 4.5.

Description

Glass for sealing and composite material for sealing

This invention relates to the glass for sealing used in order to seal a metal to-be-sealed thing. In the following description, “sealing” includes the concept of “sealing” in which members are hermetically bonded, and “sealing glass” includes the concept of “sealing glass”.

As shown in FIG. 1, a metal double container 10 having a heat retaining function, such as an electric pot, is arranged between the outer container 1 and the inner container 2 in a state where the outer container 1 and the inner container 2 are arranged to overlap each other. The communication part between the hollow part 4 and the external atmosphere formed in this is sealed with the sealing material 3. And the hollow part 4 of the metal double container 10 sealed with the sealing material 3 in this way is maintained in the vacuum state (for example, refer patent document 1).

The hollow part 4 is kept in a vacuum state through the following steps. That is, first, as shown in FIG. 2, before sealing, the sealing material 3 is accommodated in the recessed part 5 formed in the metal double container 10. And after evacuating the hollow part 4 via the exhaust port 6 provided in the bottom part of the recessed part 5, the sealing material 3 is fuse | melted in the recessed part 5, and the exhaust port 6 is sealed. Such sealing of a metal object such as the metal double container 10 (including sealing of metal and metal, metal and ceramic, metal and glass, etc.) usually prevents oxidation of the metal. Further, it is performed in a non-oxidizing atmosphere such as a reduced pressure atmosphere or an inert atmosphere.

Here, the metal material used for the metal double container is selected according to the durability (heat resistance, acid resistance) against the heat treatment and acid treatment in the production process, the steel material value, and the like. Considering these matters comprehensively, the metal material of the metal double container is not a general austenitic (18% Cr · 8% Ni) SUS304 but a ferritic (18% Cr) SUS436. Or SUS403 may be used.

On the other hand, glass may be used for the sealing material 3 in addition to metal materials such as aluminum, tin, and nickel. When glass (hereinafter referred to as sealing glass) is used as the sealing material 3, the process temperature can be shortened by reducing the sealing temperature, and material costs can be saved by reducing the thickness of the steel material. As a result, the manufacturing cost of the metal double container can be reduced.

Specifically, PbO—B ₂ O ₃ glass containing a large amount of lead is widely used as the sealing glass (see, for example, Patent Documents 2 to 5). However, due to environmental considerations, it has also been proposed to use lead-free glass such as Bi ₂ O ₃ —B ₂ O ₃ glass or SnO—P ₂ O ₅ glass as the sealing glass. (For example, see Patent Documents 6 to 10).

JP 2000-166777 A JP 2002-345655 A Japanese Utility Model Publication No. 6-16897 JP-A-62-209712 Japanese Patent Laid-Open No. 5-47322 JP 2005-350314 A Japanese Patent No. 2628007 JP 2000-72479 A JP 2001-139344 A JP 2008-30972 A

By the way, in the case of a metal double container, for example, an electric pot, for example, sealing is performed in an intermediate temperature range of 500 to 800 ° C. The sealing glass is also used for sealing the mouth of a sheathed heater, and in this case as well, sealing is performed at the same intermediate temperature range (for example, 450 to 800 ° C.).

However, when the metal object to be sealed such as a metal double container or a sheathed heater is sealed using the above SnO—P ₂ O ₅ glass in such an intermediate temperature range, the above SnO—P ₂ Due to the fact that the O ₅ glass is a low-melting glass, bubbles are easily generated in the glass. As a result, gas leaks from the bubbles due to long-term use, and the airtightness of the sealed portion is impaired, and the possibility that the sealed portion peels increases.

On the other hand, Bi ₂ O ₃ —B ₂ O ₃ -based glass has a problem that it is difficult to ensure a stable state because a bismuth component is easily reduced in a sealing process performed in a non-oxidizing atmosphere (see, for example, Patent Document 10). ).

Therefore, the present invention is SnO that can satisfactorily seal a metal object to be sealed in an intermediate temperature range even in a non-oxidizing atmosphere, and can ensure hermeticity of the sealed portion over a long period of time. It is a technical object to provide a sealing glass made of -P ₂ O ₅ glass.

The present inventor conducted various experiments, and by strictly regulating the glass composition range of the SnO—P ₂ O ₅ glass, even in a non-oxidizing atmosphere, the intermediate temperature range (500 to 800 ° C. It was found that the metal object to be sealed can be satisfactorily sealed in a temperature range (preferably a temperature range of 450 to 800 ° C.), and the reaction between the glass and the metal object to be sealed can be optimized at the time of sealing. It is proposed as an invention. That is, the sealing glass of the present invention is a sealing glass for sealing a metal object, and the glass composition is SnO 15-30% (however, 30% in terms of mol%). P ₂ O ₅ 20-40%, WO ₃ 5-20% (excluding 5%), ZnO 3.4-30% (excluding 30%), The molar ratio SnO / ZnO is 1 or more and 4.5 or less.

The glass composition range of the sealing glass of the present invention is regulated as described above. If it does in this way, the situation where many bubbles generate | occur | produce in glass can be prevented, flowing appropriately in an intermediate temperature range. Moreover, the glass for sealing reacts appropriately with the metal object to be sealed, and strong adhesiveness can be ensured. Furthermore, even when sealing is performed in a non-oxidizing atmosphere, it is possible to prevent a situation where the surface of the sealing portion is devitrified and deteriorated. Therefore, since these advantages can be enjoyed, as a result, the hermeticity of the sealed portion can be secured over a long period of time, and a good sealed state can be realized even in the middle temperature range.

Second, it is preferable that the sealing glass of the present invention does not substantially contain PbO. In this way, environmental demands in recent years can be satisfied. Here, “substantially free of PbO” refers to a case where the content of PbO in the glass composition is 1000 ppm (mass) or less.

Third, the glass for sealing of the present invention preferably has a glass transition point of 350 to 500 ° C. The glass transition point can be measured with a push rod thermal dilatometer or the like.

Fourthly, the sealing glass of the present invention is preferably used for sealing in a reduced pressure atmosphere of 1.0 × 10 ⁻² Torr or less.

Fifth, the sealing glass of the present invention is preferably used for sealing in an atmosphere having an oxygen concentration of 5% by volume or less.

Sixth, the sealing glass of the present invention is particularly preferably used for sealing a metal double container.

Seventh, the sealing glass of the present invention preferably has a sealing temperature of 450 to 800 ° C.

Eighth, the sealing glass of the present invention is preferably formed by a drop forming method.

Ninth, the sealing glass of the present invention is preferably cut after being molded.

Tenth, the sealing composite material of the present invention is a sealing composite material containing glass powder and a refractory filler, wherein the glass powder is made of the above-mentioned sealing glass.

Eleventhly, it is preferable that the sealing composite material of the present invention has a glass powder content of 45 to 100% by volume and a refractory filler content of 0 to 55% by volume.

According to the present invention as described above, since the glass composition range of the sealing glass made of SnO—P ₂ O ₅ glass is strictly adjusted, even in a non-oxidizing atmosphere, the metal can be used in the middle temperature range. The product to be sealed can be satisfactorily sealed, and the hermeticity of the sealed portion can be ensured over a long period of time.

It is the cross-sectional schematic which shows the structure of metal double containers. FIG. 2 is an enlarged schematic cross-sectional view of a region indicated by X in FIG. 1 before a sealing step.

The sealing glass according to one embodiment of the present invention has SnO 15 to 30% (excluding 30%), P ₂ O ₅ 20 to 40%, WO ₃ 5 in terms of glass composition as a glass composition. -20% (excluding 5%), ZnO 3.4-30% (excluding 30%), and the molar ratio SnO / ZnO is 1 or more and 4.5 or less.

The reason why the glass composition range of the SnO—P ₂ O ₅ glass is limited as described above will be described below. In addition, in description of the containing range of each component,% display points out mol%.

SnO is a component that lowers the melting point of glass, and its content is 15 to 30% (however, not including 30%), preferably 20 to 28%. When the SnO content is less than 15%, the viscosity of the glass increases, and the fluidity tends to decrease in the middle temperature range. Note that when the SnO content is 20% or more, the fluidity is improved in the middle temperature range, so that high airtightness is easily secured. On the other hand, if the SnO content is more than 30%, the glass softens at a low temperature, so that the working temperature becomes too low and it is difficult to use in the middle temperature range. That is, when used for sealing a metal double container, the glass flows too much at the time of sealing, making it difficult to seal the exhaust port of the metal double container in the middle temperature range.

P ₂ O ₅ is a glass-forming oxide, and its content is 20 to 40%, preferably 25 to 35%. If the content of P ₂ O ₅ is less than 20%, the glass becomes unstable. On the other hand, when the content of P ₂ O ₅ is more than 40%, the moisture resistance is lowered. Incidentally, when the content of P ₂ O ₅ is more than 25%, the glass is more stable, if 35% or less, it is possible to improve the weather resistance.

WO ₃ is a component that optimizes the reactivity with the metal object to be sealed and increases the adhesive strength and air tightness. Further, when WO ₃ is added, the weather resistance is improved, so that the long-term reliability of the sealed portion can be improved. The content of WO ₃ is 5 to 20% (excluding 5%), preferably 10 to 15%. When the content of WO ₃ is 5% or less, it is impossible to obtain the above effect. On the other hand, when the content of WO ₃ is more than 20%, the phase separation tendency becomes strong at the time of melting, and the glass becomes unstable. When the content of WO ₃ is 10 to 15%, the fluidity is improved in the middle temperature range. Further, when the content of WO ₃ is more than 5%, the above effect can be enjoyed. However, when sealing is performed in an air atmosphere, the glass tends to be devitrified at the time of sealing. Therefore, the sealing glass of this embodiment is preferably used for sealing in a reduced pressure atmosphere of 1.0 × 10 ⁻² Torr or lower, or sealing in an atmosphere having an oxygen concentration of 5% by volume or lower.

ZnO is an intermediate oxide and a component having a great effect of stabilizing the glass, and its content is 3.4 to 30% (excluding 30%), preferably 5 to 28%. . In consideration of overall glass stability (devitrification resistance, phase separation, etc.), the ZnO content is preferably 5% or more. However, when the ZnO content is 30% or more, the component balance of the glass composition is impaired, and devitrification is likely to occur on the glass surface during sealing. If the ZnO content is 28% or less, the stability of the glass is improved in the middle temperature range.

The molar ratio SnO / ZnO is 1 or more and 4.5 or less, preferably 1 or more and 4 or less. When the molar ratio SnO / ZnO is smaller than 1, the glass tends to be unstable. On the other hand, when the molar ratio SnO / ZnO is larger than 4.5, the glass flows too much at the time of sealing, and it becomes difficult to seal the metal object to be sealed, and bubbles are easily generated in the glass.

The following components can be added as optional components.

MgO is a network-modifying oxide and a component that stabilizes the glass. The MgO content is preferably 0 to 20%, particularly preferably 0 to 5%. When the content of MgO is more than 20%, devitrification tends to occur on the glass surface during sealing.

Al ₂ O ₃ is an intermediate oxide, a component that stabilizes the glass, and a component that further reduces the thermal expansion coefficient. The content of Al ₂ O ₃ is preferably 0 to 10%, particularly 0.5 to 5% in consideration of the stability of the glass, the thermal expansion coefficient, the fluidity, and the like. When the content of Al ₂ O ₃ is more than 10%, the softening temperature rises, the fluidity tends to decrease at medium temperature range.

SiO ₂ is a glass-forming oxide and a component that suppresses devitrification. The SiO ₂ content is preferably 0 to 15%, particularly preferably 0 to 8%. If the content of SiO ₂ is more than 15%, the softening temperature rises and the fluidity tends to decrease in the middle temperature range.

B ₂ O ₃ is a glass-forming oxide and a component that stabilizes the glass. The content of B ₂ O ₃ is 0 to 25%. When the content of B ₂ O ₃ is more than 25%, the viscosity of the glass becomes too high, and the fluidity is remarkably lowered at the time of sealing, which may impair the airtightness of the sealing part. In particular, in the glass composition system according to the present embodiment, when the content of B ₂ O ₃ is more than 25%, the glass is likely to undergo phase separation. B ₂ O ₃ tends to increase the viscosity of the glass. For this reason, when it is desired to greatly reduce the softening temperature, it is preferable that B ₂ O ₃ is not substantially contained, that is, 0.1% or less.

When R ₂ O (R is any one of Li, Na, K, and Cs) is added at least one of the R ₂ O components, the adhesion to a metal object to be sealed such as stainless steel is improved. The content of R ₂ O is preferably 0 to 20%, particularly preferably 0.1 to 10%. When the content of R ₂ O is more than 20%, the glass tends to be devitrified at the time of sealing. The contents of Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O are each preferably 0 to 12%, particularly preferably 0.1 to 10%. Of the R ₂ O components, Li ₂ O has a great effect of improving the adhesion with a metal object.

The lanthanoid oxide is a network-modified oxide, and its content is preferably 0 to 25%, 0.1 to 20%, particularly preferably 0.5 to 15%. When the content of the lanthanoid oxide is more than 25%, the sealing temperature becomes high, and the fluidity tends to decrease in the middle temperature range. As the lanthanoid oxide, La ₂ O ₃ , CeO ₂ , Nd ₂ O ₃ or the like can be used. Moreover, weather resistance can be improved if content of a lanthanoid oxide shall be 0.1% or more.

In addition to the lanthanoid oxide, the addition of other rare earth oxides such as Y ₂ O ₃ can further enhance the weather resistance. The total content of rare earth oxides excluding lanthanoid oxides is preferably 0 to 5%.

Furthermore, in order to stabilize the glass, MoO ₃ , Nb ₂ O ₅ , TiO ₂ , ZrO ₂ , CuO, MnO, In ₂ O ₃ , R′O (R ′ is any of Mg, Ca, Sr, and Ba). ) Etc. may be added up to 35% in total. In addition, when there is more content of these components than 35% in total, the component balance of a glass composition will be impaired, glass will become unstable on the contrary, and manufacture of the glass for sealing will become difficult. In addition, if content of these components is 25% or less in total, glass will not become unstable easily.

The content of MoO ₃ is preferably 0 to 20%, particularly preferably 0 to 10%. When the content of MoO ₃ is more than 20%, the viscosity of the glass becomes high and the glass hardly flows in the middle temperature range.

The contents of Nb ₂ O ₅ , TiO ₂ and ZrO ₂ are each preferably 0 to 15%, particularly preferably 0 to 10%. If these components are each more than 15%, the component balance of the glass composition is impaired, and conversely, the glass tends to be unstable.

The CuO and MnO contents are each preferably 0 to 10%, particularly preferably 0 to 5%. If each of these components is more than 10%, the component balance of the glass composition is impaired, and the glass tends to be unstable.

In ₂ O ₃ is a component that can be used for the purpose of obtaining high weather resistance when the cost is not taken into consideration. The content of In ₂ O ₃ is preferably 0 to 5%.

The total content of R′O is preferably 0 to 15%, particularly preferably 0 to 5%. When the content of R'O is more than 15% in total, the component balance of the glass composition is impaired, and conversely, the glass tends to become unstable.

In addition to the above components, other components can be added, for example, up to 5%. Moreover, as mentioned above, it is preferable that PbO is not included substantially from an environmental viewpoint.

The SnO—P ₂ O ₅ glass having the above glass composition has a glass transition point of about 350 to 500 ° C., a deformation point of about 380 to 530 ° C., and a thermal expansion coefficient of about 60 × in the temperature range of 30 to 300 ° C. 10 ⁻⁷ to 110 × 10 ⁻⁷ / ° C. Further, the glass can satisfactorily seal a metal object in a temperature range of 500 to 800 ° C. in a reduced pressure atmosphere of 1.0 × 10 ⁻² Torr or less, and further has a residual oxygen concentration of 5 volumes. %, For example, in an inert atmosphere such as nitrogen or argon, a metal object to be sealed can be satisfactorily sealed at a temperature range of 450 to 650 ° C.

In the sealing glass of this embodiment, the glass transition point is preferably 350 to 500 ° C., particularly preferably 400 to 450 ° C. When the glass transition point is lower than 350 ° C., the glass flows too much in the middle temperature range, and it becomes difficult to seal the metal object to be sealed, and bubbles are easily generated in the glass. On the other hand, when the glass transition point is higher than 500 ° C., the softening temperature increases, and the fluidity tends to decrease in the middle temperature range.

In the sealing glass of this embodiment, the yield point is preferably 380 to 530 ° C., particularly 440 to 480 ° C. When the yield point is lower than 380 ° C., the glass flows too much in the middle temperature range, and it becomes difficult to seal the metal object to be sealed, and bubbles are easily generated in the glass. On the other hand, if the yield point is higher than 530 ° C., the softening temperature rises and it becomes difficult to seal in the middle temperature range. The yield point can be measured with a push rod thermal dilatometer or the like.

In the sealing glass of this embodiment, the thermal expansion coefficient in the temperature range of 30 to 300 ° C. is 60 × 10 ⁻⁷ to 110 × 10 ⁻⁷ / ° C., particularly 70 × 10 ⁻⁷ to 85 × 10 ⁻⁷ / ° C. Is preferred. If it does in this way, since it becomes easy to match the thermal expansion coefficient of a metal to-be-sealed thing, the stress concerning a sealing part can be reduced. The thermal expansion coefficient in the temperature range of 30 to 300 ° C. can be measured with a push rod type thermal dilatometer.

The sealing glass of the present embodiment can be satisfactorily sealed against various metal objects to be sealed. Further, the sealing glass of the present embodiment is sealed in a reduced pressure atmosphere of 1.0 × 10 ⁻² Torr or lower, or in an atmosphere having an oxygen concentration of 5% by volume or lower in order to prevent metal oxidation during sealing. It is preferable to use for.

The sealing glass of this embodiment may be combined and used by adding a refractory filler in order to adjust the thermal expansion coefficient. When the refractory filler is mixed, the mixing amount is preferably 45 to 100% by volume of sealing glass (glass powder) and 0 to 55% by volume of the refractory filler. When there is more content of a refractory filler than 55 volume%, the ratio of glass powder will decrease relatively and it will become difficult to ensure required fluidity | liquidity.

Various materials can be used as the refractory filler, such as quartz, cordierite, zircon, tin oxide, niobium oxide, zirconium phosphate, zirconium tungstate phosphate, willemite, mullite and the like. The NbZr (PO ₄ ) ₃ ceramic powder has good compatibility with SnO—P ₂ O ₅ glass because it contains phosphoric acid in its components. The NbZr (PO ₄ ) ₃ series ceramic powder preferably has a small amount (for example, 0.1 to 2% by mass) of MgO added as a sintering aid.

Hereinafter, the manufacturing method of the glass for sealing of this embodiment is explained in full detail.

In the production of the sealing glass of this embodiment and the composite material using the same, first, glass raw materials are prepared so as to have the above glass composition, and then melted at 850 to 1000 ° C. to produce a molten glass. To do. In the case of the glass composition range according to the present embodiment, there is no problem even if it is melted in the atmosphere, but it is necessary to pay attention so that SnO in the glass composition is not oxidized to SnO ₂ at the time of melting. Since the SnO in the glass composition is prevented from oxidizing to SnO _2, or melted in N _2, etc. to N ₂ bubbling in the molten glass, we are preferable to perform the melt in a non-oxidizing atmosphere. Further, in the case of melting at the laboratory level, it is preferable from the viewpoint of workability that the melting crucible is covered and melted.

When the object to be sealed is a metal, it is often used alone without mixing a refractory filler. In this case, (1) the molten glass is drawn into a rod shape and cut into a predetermined length, (2) the molten glass is dropped and formed into a chip shape having a predetermined size, or (3) is formed into a lump shape. Then, the glass for sealing can be produced by solidifying. In addition, the lump-like sealing glass is used after being cut into a predetermined size. When the glass for sealing of this embodiment is used alone, a shape such as a rectangular parallelepiped, a cylinder, a sphere, an elliptical sphere, a hemisphere, an egg shape, and a repellent shape is preferable. Further, in this case, the debinding described later is unnecessary, and the sealing process can be simplified. However, since it cannot be made into a paste, it is necessary to seal the portion to be sealed of the metal object to be sealed. It is preferable to provide a recess for installing glass. Specifically, in the case of a metal double container, it is preferable to provide a recess in the exhaust port.

It is preferable that the sealing glass of the present embodiment is molded by a drop molding method (the method (2) above). When this method is used, machining such as cutting can be omitted or simplified, so that the sealing glass can be manufactured at low cost. In addition, if molten glass is pressurized with a shaping | molding die etc. after dripping of molten glass, the height etc. of sealing glass can be adjusted to a desired range.

In the case of the drop molding method, a nozzle for dropping is required, and it is necessary to weld the melting furnace and the nozzle. Considering the weldability between the melting furnace and the nozzle, platinum and its alloy, zirconium and its alloy, etc. are suitable as the melting furnace material and nozzle material.

In the case of the drop molding method, the volume of the sealing glass can be controlled by adjusting the nozzle outer diameter and the viscosity of the molten glass. When sealing the exhaust port of the metal double container, the volume of the sealing glass is preferably equal to or less than the volume of the recess formed around the exhaust port. If the volume of the sealing glass is too larger than the volume of the recess, the glass part is easily cracked due to the difference in expansion between the sealing glass and the metal (for example, SUS430 series), and the airtightness of the hollow part is increased. It becomes difficult to maintain. Moreover, when the volume of the glass for sealing is the minimum volume which reaches | attains an exhaust port, there exists a possibility that an exhaust port cannot be sealed reliably. Considering the above points, the volume of the sealing glass is preferably 50 to 120% of the volume of the recess formed around the exhaust port.

When sealing a metal double container, the sealing glass of the present embodiment is preferably used in a sealing step after being accommodated in a recess formed in the metal double container. If it does in this way, while being able to mount sealing glass stably, an exhaust port can be sealed efficiently.

The sealing glass of the present embodiment is preferably used for sealing an electric pot, a lunch jar, and a warm cooking pot, and particularly preferably used for sealing an electric pot. Since these metal double containers are sealed at an intermediate temperature range of 500 to 700 ° C., the sealing glass of this embodiment is suitable.

The sealing glass of the present embodiment is preferably used for a metal double container in which the metal material is SUS430 of ferrite type (18% Cr), or SUS436 or SUS403 of martensite type (12 to 14% Cr). Since these metal materials are often sealed at an intermediate temperature range of 500 to 700 ° C., the sealing glass of this embodiment is suitable.

Also, after forming the molten glass into a film shape, it can be processed into a powder shape by pulverization and classification. When the obtained glass powder is mixed with a refractory filler, a composite powder can be produced. Next, when the obtained glass powder or composite powder (which often contains a colorant) and a vehicle are kneaded, a paste material can be produced.

As the resin in the vehicle, aliphatic polyolefin carbonates, particularly polyethylene carbonate and polypropylene carbonate are preferred. These resins have properties that make it difficult to alter the SnO—P ₂ O ₅ glass during sealing. On the other hand, when general-purpose ethyl cellulose is used as the resin, there is a high possibility that the SnO—P ₂ O ₅ glass will be altered. The solvent in the vehicle is preferably one or more selected from N, N′-dimethylformamide, ethylene glycol, dimethyl sulfoxide, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, and N-methyl-2-pyrrolidone. These solvents have properties that make it difficult to alter the SnO—P ₂ O ₅ glass during sealing.

Subsequently, a paste material is applied to the surface of the metal object to be sealed and dried. The paste material may be applied using a dispenser, a screen printer, or the like. Next, if necessary, after firing (primary firing) for debinding, firing (secondary firing) while contacting the other object to be sealed to seal the objects to be sealed To do. It is necessary to perform secondary firing under conditions sufficient for the glass powder or the composite material to wet the adhesion surface of the object to be sealed.

The primary firing is preferably performed in an inert atmosphere such as nitrogen or argon, particularly in a nitrogen atmosphere, in order to prevent the quality change of the SnO—P ₂ O ₅ glass.

The sealing glass of this embodiment is preferably used for sealing in a reduced pressure atmosphere of 1.0 × 10 ⁻² Torr or less. If the reduced pressure atmosphere is 1.0 × 10 ⁻² Torr or less, the metal sealed object can be prevented from being oxidized. Further, in order to reliably prevent oxidation of the metal object to be sealed, it is more preferable to seal in a reduced pressure atmosphere of 1.0 × 10 ⁻³ Torr or less. On the other hand, if the pressure is larger than 1.0 × 10 ⁻² Torr, the glass is easily devitrified and deteriorated during sealing. In addition, if the pressure is reduced to 1.0 × 10 ⁻² Torr or less, it can be reached by a commonly used rotary pump.

In actual production of a metal double container or the like, the sealing atmosphere is often decompressed with an oil diffusion pump (diffusion pump) in order to increase the degree of vacuum in the container. In this case, the degree of vacuum in the sealing atmosphere is 1.0 × 10 ⁻³ Torr or less. The upper limit of the degree of vacuum of the sealing atmosphere is not particularly limited. In addition, when a rotary pump and a turbo molecular pump were used in combination to reduce the pressure to 1.0 × 10 ⁻⁶ Torr and a sealing test was conducted, devitrification and alteration were observed in the sealing glass of this embodiment. It has been confirmed that this was not possible. However, in actual production, it is difficult for the degree of vacuum in the sealing atmosphere to be 1.0 × 10 ⁻⁶ Torr or less due to the influence of the gas released from the sealing glass or metal sealing object.

The sealing glass of the present embodiment is preferably used for sealing in an atmosphere having an oxygen concentration of 5% by volume or less, for example, an inert atmosphere such as nitrogen or argon. This makes it difficult for the glass to be devitrified and altered during sealing, and also prevents the metal object from being oxidized. On the other hand, when the oxygen concentration in the sealing atmosphere is more than 5% by volume, the glass is easily devitrified and deteriorated, and the metal sealing object is easily oxidized. Even if a vacuum pump or the like is not used, if an inert gas such as nitrogen or argon is simply allowed to flow in the sealing atmosphere, and the atmospheric concentration of the inert gas is set to 95% by volume or more, the remaining in the sealing atmosphere The oxygen concentration can be 5% by volume or less.

Hereinafter, examples of the sealing glass of the present invention will be described in detail. The following examples are merely illustrative. The present invention is not limited to the following examples.

Tables 1 and 2 show examples (Nos. 1 to 11) of the present invention, and Table 3 shows comparative examples (Nos. 12 to 16).

 

 

 

Each sample was prepared as follows. First, glass raw materials were prepared so as to have the glass composition in the table. Further, as the phosphorus introduction raw material, orthophosphoric acid (orthophosphoric acid), which is a liquid raw material, was not used, but stannous pyrophosphate and zinc metaphosphate were used, and the phosphorus introduction raw materials were all solid raw materials. When all the raw materials for introducing phosphorus are made into solid raw materials, there is an advantage that the same production equipment as other glass systems can be used. In addition, if a liquid raw material is directly put into a melting furnace and melted as a raw material for introducing phosphorus, a problem of spilling easily occurs. And in order to avoid the problem of spilling, the glass raw material must be once dried.

Next, the prepared glass raw material was melted at 950 ° C. for 2 hours. In addition, in order to suppress the oxidation of SnO during melting, nitrogen was passed through the melting furnace. The residual oxygen concentration in the melting furnace at the time of nitrogen inflow was 1% or less.

Subsequently, the molten glass was formed into a cylindrical shape having a diameter of 5 mm and a length of 20 mm using a carbon jig. This molded sample was annealed, and the glass transition point, yield point, and thermal expansion coefficient in the temperature range of 30 to 300 ° C. were measured by a push rod type thermal dilatometer (TMA, manufactured by Rigaku). A similar cylindrical sample (annealed) was processed to a length of 3 mm and used for the evaluation of adhesion.

The presence or absence of adhesiveness was evaluated as follows. As a metal for evaluation, high-heat-resistant ferrite-based SUS430 was used instead of austenitic SUS304 generally used in a low temperature range. The shape of the metal for evaluation was a flat plate shape of 40 mm × 40 mm. Next, the above-described sample for evaluation was placed on the metal object to be sealed and fired in the atmosphere shown in the table.

The “reduced pressure firing” in the table is a result of firing while continuously reducing the pressure with a rotary pump. During firing under reduced pressure, the pressure fluctuated due to the foaming gas generated from the sealing glass, but it was confirmed by a pressure gauge that the pressure was 1.0 × 10 ⁻² Torr or less. The firing conditions were a firing temperature of 650 ° C. for 10 minutes, a heating rate of 20 ° C./min from room temperature to the firing temperature, and a cooling rate of 15 ° C./min to room temperature.

“Atmosphere firing” in the table is the one fired while continuously flowing the gas described in the table at 2.0 L / min. The oxygen concentration remaining at the time of firing was confirmed to be 5% by volume or less by an oxygen concentration meter. The firing conditions were a firing temperature of 550 ° C. for 10 minutes, a heating rate of 15 ° C./min from room temperature to the firing temperature, and a cooling rate of 10 ° C./min to room temperature.

As apparent from Tables 1 and 2, Sample No. 1 to 11 have a coefficient of thermal expansion of 69.6 × 10 ⁻⁷ to 83.7 × 10 ⁻⁷ / ° C. in a temperature range of 30 to 300 ° C., a glass transition point of 389 to 463 ° C., and a yield point of 416 to 472. In addition, both low-pressure firing and atmosphere firing were free from devitrification and deterioration after firing, and showed good adhesion to the metal object. Therefore, sample no. Nos. 1 to 11 were suitable as glass for sealing in the middle temperature range.

On the other hand, sample No. 12, 13, and 16 were neither devitrified nor altered after firing in both reduced-pressure firing and atmosphere firing, but they did not have adhesiveness to metal and were peeled off from the metal object after sealing. Sample No. 14 was neither devitrified nor altered after firing in both reduced pressure firing and atmosphere firing, but because the molar ratio SnO / ZnO was larger than 5, it flowed excessively on the metal sealed object, and the metal sealed The glass protruded from the stationary article, and the adhesiveness could not be evaluated. Sample No. No. 14 has a melting point that is too low to be used in the middle temperature range. Sample No. No. 15 was neither devitrified nor altered after firing in both reduced-pressure firing and atmosphere firing, but was hardly flowable on the metal object to be sealed, so the adhesion could not be evaluated.

Hereinafter, examples of the composite material for sealing of the present invention will be described in detail. The following examples are merely illustrative. The present invention is not limited to the following examples.

Table 4 shows examples (Nos. 17 to 20) of the present invention.

Each sample was produced by mixing the glass powder described in Table 4 and the refractory filler at a predetermined ratio. Incidentally, the average particle diameter D ₅₀ of the glass powder and the refractory filler and 10 [mu] m.

 

The thermal expansion coefficient in a temperature range of 30 to 300 ° C. was measured with a push rod type thermal dilatometer (TMA, manufactured by Rigaku). In addition, what measured each sample densely was used as the measurement sample.

The presence or absence of adhesiveness was evaluated as follows. First, each sample was sintered to produce a sintered body having a diameter of 20 mm and a thickness of 1 mm. Next, this sintered body was placed on a 40 mm × 40 mm SUS430 metal plate, and a 40 mm × 40 mm alumina plate was further placed on the sintered body to prepare a sample for evaluation. Subsequently, this evaluation sample was fired in the atmosphere shown in the table. Finally, the presence or absence of adhesion between the metal plate of SUS430 and the alumina plate was evaluated.

As is apparent from Table 4, sample No. Nos. 17 to 20 have a thermal expansion coefficient of 59.2 × 10 ⁻⁷ to 64.5 × 10 ⁻⁷ / ° C. in the temperature range of 30 to 300 ° C., and devitrification and alteration are caused by firing in the atmosphere in the table. There was no good adhesiveness.

Since the glass for sealing of the present invention can satisfactorily seal a metal object in an intermediate temperature range, for example, sealing of a diode, sealing of glass and jumet wire, sealing of the mouth of a sheathed heater Suitable for sealing of magnetic heads, and by adding a refractory filler or the like to match the thermal expansion coefficient of the metal object to be sealed, sealing of metal and ceramic, for example, sealing of IC package, etc. Also, it can be suitably used.

Claims (11)

1. A sealing glass for sealing a metal object to be sealed,
   As a glass composition, SnO 15-30% (however, 30% not included), P ₂ O ₅ 20-40%, WO ₃ 5-20% (however, not including 5%), ZnO A sealing glass comprising 3.4 to 30% (but not 30%) and having a molar ratio SnO / ZnO of 1 or more and 4.5 or less.
2. The glass for sealing according to claim 1, which is substantially free of PbO.
3. The glass for sealing according to claim 1 or 2, wherein the glass transition point is 350 to 500 ° C.
4. The sealing glass according to any one of claims 1 to 3, wherein the sealing glass is used for sealing in a reduced pressure atmosphere of 1.0 × 10 ^-2 Torr or less.
5. The glass for sealing according to any one of claims 1 to 4, which is used for sealing in an atmosphere having an oxygen concentration of 5% by volume or less.
6. The glass for sealing according to any one of claims 1 to 5, wherein the metal object to be sealed is a metal double container.
7. The sealing glass according to any one of claims 1 to 6, wherein the sealing temperature is 450 to 800 ° C.
8. The sealing glass according to any one of claims 1 to 7, wherein the sealing glass is formed by a drop forming method.
9. The sealing glass according to any one of claims 1 to 8, which is cut after the molding.
10. In the sealing composite material containing glass powder and refractory filler,
    A sealing composite material, wherein the glass powder comprises the sealing glass according to any one of claims 1 to 9.
11. The composite material for sealing according to claim 10, wherein the content of the glass powder is 45 to 100% by volume and the content of the refractory filler is 0 to 55% by volume.

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