JPH0526736B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a glass composition suitable for bonding ceramics and ferrite constituting a floppy head core by the flow-in method. [Prior art] As shown in Figure 1, the recording/reproducing core and erasing core of a tunnel type floppy head are bonded together using a sandwich structure consisting of a thin I core (ferrite), a C core (ferrite), and a T core (ceramics) arranged in the center. There are two parts. A floppy head core having such a structure is generally manufactured as follows. As shown in Figure 2, the I core 2 is made of ferrite such as Ni-Zn ferrite.
The glass rod 8 is placed against a T core made of ceramics such as TiO ₂ -BaO system so that a predetermined gap is maintained. This is heated to a predetermined temperature and the glass is melted and poured into it to produce the T1 block 7 . Next, as shown in Figure 3, T1 block 7 and Ni
- C cores 3 made of ferrite such as Zn ferrite are butted together to form a predetermined gap, glass is installed, and then heated to melt and flow the glass.
Create a T1C block. Thereafter, the floppy head core shown in FIG. 1 is manufactured through processing such as flat grinding, wrapping, and cutting. As mentioned above, bonding with glass is done twice.
The glass used to join the T1 block and the C core has a softening point of 600°C or higher because the recording/reproducing core and erasing core are assembled at 500°C or higher. In order to allow this glass to flow sufficiently into the gap between the T1 block and the C core, it is necessary to bond them at a temperature approximately 100° C. or higher (700° C. or higher) higher than the softening point of the glass. Therefore, the glass that joins the T core and I core is required to be a glass with a high softening point that softens at a processing temperature of 700°C so that the T1 joint does not move and affect dimensional accuracy. Conventionally, PbO-SiO ₂ -K ₂ O-based glasses have been used as glasses that meet this requirement. For example, PbO47% in weight % - SiO ₂ 47
%, K ₂ O 6% has a relatively low softening point of 600°C, but has poor fluidity and is difficult to maintain the bonding temperature.
Even at 980°C, the glass did not completely flow into the abutting portion of the T core and I core, resulting in a problem of weak adhesive strength. Furthermore, if the treatment is carried out at a temperature of 1000°C or higher, the inflow will be complete, but the reaction between the ferrite and the glass will be severe and there will be problems with magnetic properties, so the processing temperature will be limited to 1000°C or lower. [Problems to be solved by the invention] As mentioned above, the PbO-SiO ₂ -K ₂ O glass has the following problems:
This was a problem due to poor fluidity and weak adhesive strength at bonding temperatures below 1000°C. The object of the present invention is to have a softening point of 650°C or higher (preferably 700°C or higher) and a bonding temperature of 900 to 1000°C.
The object of the present invention is to provide a glass composition which can sufficiently flow into the abutting portion of a T core and an I core at a temperature of 0.degree. C. to obtain a T1 block with high adhesive strength. [Means for solving the problems] The present invention provides BaO25 to 40% and PbO15 to 40% by weight.
25%, _SiO2 15~ ₂₅ %, _B2O3 15~25%, _{Al2O3 1} ~
5%, and 1 to 5% CaO. Hereinafter, % represents weight %. In the present invention, PbO-
To improve the fluidity of the SiO ₂ −K ₂ O system, approximately 50% of SiO ₂ should be replaced with B ₂ O ₃ , which lowers the viscosity without adversely affecting the thermal expansion coefficient and chemical durability of SiO ₂ . I made it. In addition, if the ceramic is TiO ₂ -BaO-based, BaO may become a solute in the glass that flows in at high temperature and deteriorate fluidity, so PbO
A part of was replaced with BaO. In this case BaO is PbO
Since it works in the same way as , it is thought that there will be no adverse effect on the physical properties of other glasses. Furthermore, since K ₂ O significantly lowers the softening point and worsens water resistance, CaO is used instead of K ₂ O to improve water resistance.
Al ₂ O ₃ was blended. The reason why BaO is limited to 25 to 40% in the present invention is because when it is 25% or less, the fluidity increases, and when it is 40% or more, the softening point becomes high. The reason why we limited PbO to 15-15% is that when PbO is below 15%, the softening point becomes high, and when it is above 25%,
This is because the effect of BaO decreases and fluidity deteriorates. The reason why SiO ₂ is limited to 15 to 25% is that water resistance deteriorates when SiO ₂ is less than 15%.
% or more, the softening temperature becomes high. _B2O3 is limited to 15-25% because _{B2O3 is 15} %
This is because if it is below, there is no effect of lowering the viscosity, and if B ₂ O ₃ is 25% or more, the softening point is lowered. The reason why CaO and Al ₂ O ₃ are limited to 1 to 5% is because if CaO and Al ₂ O ₃ are less than 1%, there is no effect of improving water resistance.
This is because if Al ₂ O ₃ exceeds 5%, the water resistance effect will not be significantly improved and the viscosity will increase, which is undesirable. [Example] Glasses having various compositions shown in Table 1 were manufactured,
The I core and T core of Ni-Zn ferrite and TiO ₂ -BaO ceramics were butted together as shown in Figure 2, and glass was installed and bonded for 10 minutes at 980°C to measure the degree of glass inflow into the butted area. compared.
In addition, softening point and water resistance tests of various glasses (40℃,
90%R・H, 1000h) was also performed. The result is the first
Shown in the table. In Table 1, the degree of inflow is indicated by ○ when the glass completely flows into the abutting portion and there is no gap, and by × when the glass flows incompletely and there is poor adhesion. In addition, for water resistance, those with no change are indicated by ○, and those with severe changes are indicated by ×. According to the present invention, it is possible to provide a floppy magnetic head core that has no practical problems because the degree of inflow of glass, which has conventionally been insufficient, is greatly improved and has excellent water resistance.

【table】

【table】 [Brief explanation of the drawing]

Fig. 1 is a plan view of the recording/reproducing core of a floppy magnetic head, Fig. 2 is a plan view of the I core and T core arranged with glass rods, and a perspective view of the T1 block after bonding. Fig. 3 is the T1 block. and C core were glued together.
FIG. 3 is a perspective view of the T1C block. 1 : Recording/playback core, 2: I core, 3: C core,
4: T core, 5, 6: Glass adhesive part, 7 : T1 block, 8: Glass rod, 9: T1C block.

Claims (1)

[Claims] 1 Weight%: BaO25-40%, PbO15-25%,
_{SiO2 15-25} %, _B2O3 15-25%, _{Al2O3 1-5} %,
A glass composition consisting of 1 to 5% CaO.