JPH07330372A - Glass having low melting point - Google Patents

Abstract

PURPOSE:To obtain a glass of a low melting point having excellent properties for adhesion and sealing of a ceramic and a metal especially for adhesion and sealing of a magnetic head or a glass of a low melting point capable of being used as an optical glass, an acousto-optic glass, an infrared transmitting glass, etc. CONSTITUTION:This is a glass of low melting point obtained by replacing a part of oxygen in an oxide composition of TeO2 of 15-90wt.%, B2O3 of 3-50wt.%, ZnO of 3-55wt.% and Al2O3 of 0-10wt.% with fluorine and introducing 0.4-5wt.% of fluorine into 100wt.% of the glass.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a low melting point glass,
The present invention relates to a low melting point glass suitable as optical glass, acousto-optical glass, infrared transmissive glass, and the like, and also for adhesion and sealing of metals and ceramics, particularly for adhesion and sealing of magnetic heads.

[0002]

[Prior art and its problems] For example, PbO-based low-melting glass is widely used for adhesion and sealing of metals and ceramics. As an example, PbO-B ₂ O ₃ based PbO-B ₂
O ₃ -SiO ₂ system, PbO -B ₂ O _{3 -ZnO-based, PbO-B 2 O 3 -SiO} 2 -
Glasses such as Al ₂ O ₃ series are well known. However, since it contains PbO component, it deteriorates the working environment of heating and processing, and when it comes into contact with water, it elutes Pb and induces pollution problems, insufficient hardness, poor water resistance and chemical resistance, There are many problems such as easy reaction with adhesive materials.

Further, in a glass containing TeO ₂ , a method disclosed in Japanese Patent Laid-Open No. Sho 62-62
-288135 has TeO ₂ and BaO as essential components, and one or more of K ₂ O, Rb ₂ O, and Cs ₂ O as optional components, and
Various optical glasses for acousto-optical devices, containing a component selected from one or more of ZnO and PbO 2 and containing a halide as an optional component, are disclosed. Furthermore, Japanese Patent Publication Sho 52-28454
The publication discloses a glass for an acousto-optic device containing TeO ₂ and ZnO as essential components and Na ₂ O and Li ₂ O as selective essential components. In addition, JP-A-47-7336
No. 4, the essential components TeO ₂ , La ₂ O ₃ , Ta ₂ O ₅ , GeO
A high-refractive-index, highly-transparent optical glass containing ₂ as an optional component, B ₂ O ₃ , ZnF ₂ , Al ₂ O ₃ , and K ₂ O is disclosed.

The TeO ₂ based compositions of these disclosures are significantly different from the compositions of the present invention. In addition, the presence of the alkali components disclosed therein should not be contained in the present invention, such as impairing water resistance and chemical resistance. Similarly, the presence of the PbO 2 component disclosed should not be contained because it causes pollution problems as described above.

The low melting point glass in the present invention can be produced at a low heat treatment temperature, and is particularly effectively used for bonding and sealing ceramics and metals. In that case, the coefficient of thermal expansion is well matched to that of the material to be adhered, the working temperature is compatible, it is excellent in water resistance and chemical resistance, there is no interaction with the material to be adhered, mechanical High strength is required, and in the field of magnetic head sealing, compatibility of magnetic expansion coefficient with magnetic material, non-reactivity with magnetic material, magnetic insulation, transparency, hardness, etc. are also important factors. However, the present invention provides a new low melting point glass satisfying those factors, and can be applied as an optical glass, an infrared transmissive glass and the like.

[0006]

The present invention relates to a low-melting glass, which has an oxide composition of TeO ₂ 15 to 90 wt% B ₂ O _{3 3 to} 50 wt% Zn 0 _{3 to} 55 wt% Al ₂ O ₃ 0 to 10 wt% %, And part of the oxygen content is replaced with fluorine, and the fluorine is introduced into 100 wt% of the glass in an amount of 0.4 to 5 wt%.

In the present invention, it is suitable as an optical glass, an infrared transmissive glass, etc., but has excellent properties as an adhesive / sealing glass. That is, by appropriately selecting the component composition, a thermal expansion coefficient of 60 × 10 ^-7 / ° C order to 150 × 10 ^-7 / ° C order can be obtained, so that the thermal expansion coefficient of metals, ceramics, especially magnetic head materials The yield point can be appropriately adjusted according to the
Can adhere and seal materials to be adhered such as metals and ceramics that do not deteriorate at temperatures of up to 600 ℃, and has excellent water resistance.
It has a high hardness, and it does not interact with the magnetic material when adhering and sealing the magnetic head, and it has excellent magnetic insulation properties. It is suitable not only for adhering various metals and ceramics but also for magnetic head sealing. It has various characteristics.

In this component system, TeO ₂ is 15 wt% to 90 wt%
Glass formation is good and stable in the range of
If it exceeds 15%, the glass formation becomes unstable, the hardness of the glass is lowered, and even if it is less than 15 wt%, problems such as difficulty in forming the glass occur. It is preferably in the range of 19 to 86 wt%.

Similarly, B ₂ O ₃ also has good and stable glass formation in the range of 3 wt% to 50 wt%, and when it exceeds 50 wt%, the glass formation becomes unstable and the durability and weather resistance of the glass deteriorate, On the other hand, if it is less than 3% by weight, glass formation becomes unstable. It is preferably in the range of 4 to 42 wt%.

ZnO is contained in the TeO ₂ —B ₂ O ₃ system in an amount of 3 wt% to 55 wt%.
Introduced in the range of, to expand the vitrification region of TeO ₂ -B ₂ O ₃ system, improve the water resistance of the glass, have the effect of increasing the hardness, etc., but less than 3 wt% However, these actions are not effective, and if it exceeds 55 wt%, glass formation becomes difficult and devitrification is likely to occur. Preferably 4
The range is up to 49 wt%.

F (fluorine) is essential for lowering the viscosity, yield point and transition point of glass and facilitating glass melting. For that purpose, 0.4 wt% or more should be contained in 100 wt% of glass. is necessary. If it exceeds 5% by weight, the stability of the glass is lowered and the volatilization of F 2 at high temperature becomes remarkable, which causes disadvantages. It is preferable to set it in the range of 0.4 to 3 wt%. The means of introducing F is not specified, but especially
It may be contained in the raw material in the form of a fluoride such as ZnF ₂ .

Al ₂ O ₃ is appropriately introduced, and TeO ₂ --B ₂ O ₃
In the system, there is a region of low transparency, which is presumably due to mutual phase separation, but it can be eliminated by introducing a small amount of Al ₂ O ₃ . However, introduction of a large amount of Al ₂ O ₃ results in viscosity,
Since there is a risk of impeding the present invention such as increasing the yield point and the transition point, the amount should be kept to about 10 wt% or less.

Further, for example, SiO ₂ , TiO ₂ , SrO, BaO, Bi ₂ O _{3 and the} like are used to improve the hardness and water resistance of the glass, and V ₂ O _{5 and the} like are used to improve the stability of the glass. , MgO, CaO 2 or the like for improving the meltability, or a small amount of the above-mentioned components for adjusting the thermal expansion coefficient. However, it does not substantially contain harmful components such as PbO.

The melting of the raw material is carried out by using an oxide raw material containing the above components,
Fluoride raw materials, hydroxide raw materials, compound raw materials such as carbonates are blended according to a predetermined composition, for example, a heating furnace using alumina-based furnace material or platinum-gold (5%)-based furnace material, or in a crucible Then, it may be melted at a temperature of about 1000 ° C to 1200 ° C. Although no special adjustment of the atmosphere in the furnace is required, appropriate design and ingenuity such as circulating the atmosphere can be made.

[0015]

The present invention will be described in detail below with reference to examples. [Sample Preparation] Tellurium dioxide as a TeO ₂ source, boric acid as a B ₂ O ₃ source, zinc oxide as a ZnO source, zinc fluoride as an F source and a ZnO source used in combination with the zinc oxide (tetrahydrate), Al ₂ O ₃ Using aluminum hydroxide (Al ₂ O ₃ may be mixed from the alumina crucible) as the source, mix each raw material in the desired ratio,
After filling the alumina crucible, cover the crucible and set it in an electric furnace that has been heated and maintained at an appropriate temperature of 1050 ° C to 1200 ° C in advance.
Melted for 20-30 minutes. The obtained melt was once poured onto a carbon plate and then gradually cooled in an electric furnace to obtain a sample. The cation component of each sample was analyzed by a known wet method and fluorescent X-ray method, and the oxide composition (total 100
wt%). In addition, the F content in the glass was subjected to a wet analysis and displayed as the wt% content rate in the glass. The results are shown in Table 1.

[Measurement of Physical Properties] Each sample was heated with a differential thermal expansion meter using silica glass as a standard substance at a temperature rising rate of 5 ° C./min.
Measure the thermal expansion under the conditions of, the average coefficient of thermal expansion of 30 ~ 300 ℃,
The glass transition point and the yield point were determined. The hardness was measured with a Vickers micro hardness meter, and the weight loss rate (water resistance) was determined by immersing in distilled water at 95 ° C for 20 hours.

The results are also shown in Table 1.

[0018]

[Table 1]

[Results] In Table 1, Examples 1 to 18 are in the composition range of the present invention, and Comparative Examples 1 to 5 are out of the composition range.

As is clear from the display, the material of the present invention has a coefficient of thermal expansion of about 60 to 150 × 10 ⁻⁷ / ° C., which is compatible with a wide range of metals to be adhered and ceramics, and has a yield point of 300 to 500 ° C. The table, and therefore the working temperature can be set as low as about 500 to 600 ℃, can be used for bonding and sealing many metals and ceramics, and the water resistance (weight reduction rate) is 0.4% or less, especially
It is very excellent such as 0.1% or less, there is no elution of Pb in water, there is no fear of pollution, and the Vickers hardness is
It is suitable as a glass for adhesion / sealing having a relatively high hardness of 300 to 400, particularly a glass for magnetic head sealing.

Incidentally, none of the comparative examples could be vitrified,
It is clear that devitrification is remarkable and clear glass cannot be obtained.

[0022]

According to the present invention, the coefficient of thermal expansion is 60 to 15.
It is compatible with adherend metals and ceramics in a wide range of 0 × 10 ^-7 / ℃, and the yield point is in the range of 300 ℃ to 500 ℃, so the working temperature can be set as low as 500 to 600 ℃, so many metals, It can be used for adhesion and sealing of ceramics, has excellent water resistance, there is no fear of pollution problems, and Vickers hardness is 300.
To 400, which has a relatively high hardness such as 400, and is suitable as a glass for bonding and sealing, in particular, a glass for sealing a magnetic head,
Alternatively, there is an effect that it can be used as an optical glass, an acousto-optical glass, an infrared transmissive glass, or the like.

Claims (1)

[Claims] 1. Oxide component composition: TeO ₂ 15 to 90 wt% B ₂ O _{3 3 to} 50 wt% Zn 0 _{3 to} 55 wt% Al ₂ O _{3 0 to} 10 wt%, and part of the oxygen content is fluorine. A low melting point glass, characterized in that the fluorine is replaced and 0.4 to 5 wt% is introduced into 100 wt% of the glass.