JPH0446029A - Glass composition for welding - 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 (Industrial Field of Application) The present invention relates to a welding glass composition that can be filled into a gap in a magnetic head or the like and can be welded at a relatively low temperature.

[Conventional technology]

In recent years, magnetic recording and reproducing devices such as video tape recorders are required to have a high-density recording and reproducing function, and accordingly, magnetic heads that can perform high-density recording and reproducing are also required.

Therefore, a thin film made of an alloy magnetic material having high magnetic permeability and high saturation magnetic flux density, such as sendust alloy or amorphous alloy, is formed on the gap-opposing surface of a substrate made of a non-magnetic material such as crystallized glass, and a pair of each of the above-mentioned materials is formed. Increasingly, magnets are being used for magnetism using cores made of blocks welded together with welding glass.

The gap formed in the core is also filled with the glass used for welding, and the welding glass is a low melting point glass containing lead as a bead component.

[Problems to be Solved by the Invention] However, when the above-mentioned substrate, amorphous alloy thin film, alloy thin film by vapor deposition, etc. are welded using the above-mentioned conventional glass, thermal deformation of the above-mentioned substrate and peeling of the alloy thin film due to thermal stress may occur. In order to prevent this, it is desirable to perform welding at a temperature as low as possible (600°C or less). However, in general, many glasses that can be used at such temperatures have problems such as hardness. In addition, in order to prevent uneven wear of the filled glass, it is necessary to ensure a Vickers hardness of 500 or more, but glass with such hardness is
At temperatures below 600'C, there are few materials with low viscosity and excellent wettability, resulting in poor weldability.

Furthermore, lead glass, which is most commonly used as glass for welding, undergoes a reaction called nucleation with the alloy thin film during welding, and the nucleated part of the alloy thin film loses its magnetism. Since the glass portion becomes brittle, it is prone to cracking and chipping, resulting in deterioration of magnetic properties.

Therefore, in the manufacture of magnetic heads made using the above-mentioned conventional glass, the yield is reduced due to each of the above-mentioned problems.

[Means to solve the problem]

Therefore, in view of the above-mentioned conventional problems, the inventors of the present application have conducted extensive research on welding glass used for manufacturing magnetic heads made of the above-mentioned substrate and alloy magnetic material, and have developed a new glass composition. Based on these findings, we have come up with the present invention.

In order to solve the above problems, the welding glass composition according to the present invention contains Si0224-27% by weight, PbO38-27% by weight.
43% by weight, 5-13% by weight of Na2O, 2-6% by weight of K2O, B2O. 3-7% by weight 1.12031-3% by weight
, Tl20S~16% by weight, and SrO1~2% by weight.

[Function] According to the above configuration, since nucleation is suppressed by the action of SrO, the occurrence of parts where magnetism is lost in the alloy magnetic material is reduced, and on the other hand, cracking and chipping of the above glass composition is reduced. let In addition, since it contains a relatively large amount of Tl2O, it becomes a glass with low viscosity and high wettability at temperatures below 600°C, and has excellent weldability at temperatures below 600"C. Furthermore, due to the action of SrO, Vickers The hardness is 500 or more, which means it has excellent wear resistance and less uneven wear.Furthermore, since welding can be performed at temperatures below 600°C, thermal deformation of the substrate and peeling of the alloy thin film due to thermal stress can be prevented. can.

(Example〕 An embodiment of the present invention will be described below.

Si C1z, Pb 01Naz○, KzOlB2O
゜, Al2O3, Tl2O and Sr2O were each taken in fixed amounts according to the composition ratios shown in Table 1, and sample 1 was prepared by melting and mixing them in a platinum crucible at a temperature of 1200°C for about 1 hour.

The physical properties of the obtained glass composition of Sample 1 were measured, and the results are also shown in Table 1.

[Margin below] Table 1 α100-30+): Coefficient of thermal expansion at 100 to 30°C In the above glass composition thus obtained, the first
As shown in the table, the yield point of this glass composition is 400
'C or less, and in the welding process of magnetic head manufacturing,
Even when the welding operation temperature was set at 580°C, the glass composition had low viscosity, good wettability, and excellent weldability.

Furthermore, since welding can be performed at a relatively low temperature of 600° C. or lower, internal stress due to heat is small, and occurrences such as deformation of the substrate and peeling of the alloy thin film can be suppressed.

Furthermore, magnetic materials created using this glass composition
In this case, nucleation at the interface between the glass composition and the alloy thin film was suppressed. From this, the occurrence of areas where magnetism was lost in the alloy thin film was reduced, and the occurrence of cracks and chips in the glass composition used was reduced.
Deterioration of magnetic properties was suppressed.

On the other hand, the Vickers hardness was 500 or more, which showed excellent wear resistance and little uneven wear.

As described above, since the glass composition for welding has various excellent properties, the yield of magnetic heads manufactured using this glass composition has been improved.

[Effect of the invention] The welding glass composition according to the present invention has Si 0□24 to
27% by weight, pb○ 38-43% by weight, Na2O5-1
3% by weight, K2O2~6% by weight, B! 0.3-7% by weight
, AN2Ch 1-3% by weight, T1.08-16% by weight
, 5rol to 2% by weight.

Therefore, nuclearization suppression and improvement of magnetic properties from this,
In addition, it has excellent weldability with low viscosity and good wettability at a relatively low temperature of 600°C or less, and the ability to weld at a relatively low temperature reduces thermal stress and thermal deformation.
It has excellent properties such as wear resistance.

As a result, the above-mentioned welding glass composition can be suitably used for manufacturing magnetic heads, and the yield of magnetic heads can be improved.

Patent applicant: Sharp Corporation, Mi-W

Claims (1)

[Claims] 1. SiO_224-27% by weight, PbO38-43% by weight, Na_2O5-13% by weight, K_2O2-6% by weight, B_2O_33-7% by weight, Al_2O_31-3
A welding glass composition comprising 8-16% by weight of Tl_2O and 1-2% by weight of SrO.