JP2968022B2 - Adhesive glass - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive glass, and more particularly, to an adhesive glass used for a gap portion of a magnetic head.

[Prior Art] There are various types of magnetic heads used for magnetic recording, one of which is a ferrite magnetic head. In this magnetic head, as shown in the drawing, after the rod-shaped bonding glass 3 is disposed between the two ferrite cores 1 and 2, heat treatment is performed to soften and flow the bonding glass 3 to fill the gap portion 4, The ferrite cores 1 and 2 are assembled by bonding and integrating them.

[Problems to be Solved by the Invention] The bonding glass described above has a thermal expansion coefficient matching ferrite, and destroys the structure of ferrite,
The heat treatment temperature is required to be 800 ° C. or less so as not to lower the magnetic properties.

However, conventional adhesive glass, even if it satisfies the above requirements, is susceptible to erosion of ferrite at the time of heat treatment, so that the track width becomes narrow or the gap depth becomes inaccurate, so that the desired There is a problem that it is difficult to obtain magnetic characteristics.

The present invention has been made in view of the above circumstances, and provides an adhesive glass having a thermal expansion coefficient matching ferrite, a heat treatment temperature of 800 ° C. or less, and not corroding ferrite during heat treatment. The purpose is to do.

[Means for Solving the Problems] The present inventors have conducted various studies to achieve the above object, and as a result, the PbO-SiO ₂ glass containing B ₂ O ₃ or Li ₂ O contains ferrite. erosion and it is easy, also containing Fe ₂ O ₃ and ZnO is a component of the other hand ferrite PbO-S
The present inventors have found that iO ₂ -based glass hardly causes corrosion of ferrite, and propose the present invention.

That is, the bonding glass of the present invention has a weight percentage of PbO 3
_{5.0~44.5%, SiO 2 30.0~45.0%,} Al 2 O 3 0.5~5.0%,
_{Na 2 O 0~6.0%, K 2} O 0~6.0%, Fe 2 O 3 0.5~5.0%, ZnO
Made 0.5 to 5.0%, characterized in that it essentially free of B ₂ O ₃ and Li ₂ O.

[Function] The adhesive glass of the present invention has a coefficient of thermal expansion at 30 to 300 ° C. that of ferrite (100 to 120 × 10 ⁻⁷ / ° C.).
A 0~105 × 10 ^-7 / ℃, also softening point can bond the ferrite cores at the heat treatment temperature of 800 ° C. or less for a five hundred ninety to six hundred forty ° C., yet is one which does not cause erosion of the ferrite.

Next, the reasons for limiting the composition of the bonding glass of the present invention as described above will be described below.

PbO is a component for adjusting the softening point of glass, and its content is 35.0 to 44.5%. If the content of PbO is less than 35.0%, the softening point of the glass becomes high, so that the heat treatment cannot be performed at 800 ° C or lower, and if it is more than 44.5%, the water resistance deteriorates.

SiO ₂ is a component that extends the vitrification range, and its content is 30.0 to 45.0%. If the content of SiO ₂ is less than 30.0%, the glass will not be stable during vitrification, and if it is more than 45.0%, the softening point will be high.

Al ₂ O ₃ is a component that enhances so-called durability such as water resistance and abrasion resistance of glass, and its content is 0.5 to 5.0%.
If the content of Al ₂ O ₃ is less than 0.5%, the above effects cannot be obtained, and 5.
If it is more than 0%, at a heat treatment temperature of 800 ° C. or less, the viscosity of the glass is not sufficiently reduced, so that the fluidity is deteriorated and the adhesion of the ferrite core becomes difficult.

Na ₂ O and K ₂ O are both components added to adjust the coefficient of thermal expansion, and their contents are each 0 to 6.0%. Na ₂
If the contents of O and K ₂ O are more than 6.0%, the water resistance will be poor.

Further, the present invention improves the wettability of ferrite and prevents erosion by containing Fe ₂ O ₃ and ZnO in addition to the above components. The contents of Fe ₂ O ₃ and ZnO are each 0.5 to 5.0%, and if each is less than 0.5%, there is no effect. Also F
If e ₂ O ₃ is more than 5.0%, the glass is colored and it is difficult to measure the gap depth. On the other hand, if ZnO is more than 5.0%, the glass tends to be devitrified.

In the present invention, the reason that B ₂ O ₃ and Li ₂ OS are not contained is that if these components are contained, the glass is likely to corrode ferrite.

[Examples] Hereinafter, the bonding glass of the present invention will be described based on examples.

The following table shows Examples (Samples Nos. 1 to 4) and Comparative Examples (Samples Nos. 5 and 6) of the present invention.

Each sample of Nos. 1 to 6 in the table was prepared as follows.

First, a raw material batch prepared so as to have the composition shown in the table in terms of percentage by weight is put in a platinum crucible, melted at 1500 ° C. for 2 hours, molded into a predetermined shape to prepare a sample, and then subjected to thermal expansion coefficient, softening point, and heat treatment. The temperature and the presence or absence of corrosion on the ferrite were measured.

As is clear from the table, each sample of Examples Nos. 1 to 4 has a coefficient of thermal expansion of 90 to 105 × 10 ⁻⁷ / ° C. and a softening point of 590 to 640.
° C and the heat treatment temperature were in the range of 700 to 780 ° C, and no corrosion was observed on the ferrite. On the other hand, the samples of Comparative Examples Nos. 5 and 6 have a thermal expansion coefficient of 100 × 10 ⁻⁷ / ° C.
And 95 × 10 ⁻⁷ / ° C., the softening points were 600 ° C. and 640 ° C., and the heat treatment temperatures were 720 and 800 ° C., but corrosion to the ferrite was observed.

These facts indicate that the bonding glass of the present invention has B ₂ O ₃ and Li
_This indicates that ferrite does not corrode because it does not contain ₂ O and contains Fe ₂ O ₃ and ZnO.

The coefficient of thermal expansion was measured by a mean linear coefficient of thermal expansion measuring device using a sample obtained by molding each glass into a rod shape of 5φ × 20 mm. The softening point was measured by a differential thermal analyzer. The heat treatment temperature was measured temperature fluidity necessary for adhesion of the ferrite cores are obtained, i.e. the temperature at which the viscosity of the glass exhibits a 10 ⁴ poise by high temperature viscosity meter. In addition, the presence or absence of erosion on the ferrite is determined on a 10 × 20 × 3 mm size ferrite with a mirror-polished surface.
A sample was prepared by placing a glass formed into a rod shape of 0.5 φ × 20 mm and treating it at the heat treatment temperature shown in the table, then cutting the center of the sample and observing the cut surface with an electron microscope It is.

[Effects] As described above, the bonding glass of the present invention has a thermal expansion coefficient suitable for ferrite, can be heat-treated at 800 ° C. or less, and does not corrode ferrite. It is suitable for bonding.

[Brief description of the drawings]

The drawing is an explanatory view showing a state in which a stick-like bonding glass is arranged between ferrite cores. 1,2 ... ferrite core 3 ... adhesive glass 4 ... gap

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C03C 8/00-8/24 C03C 3/04-3/118

Claims (1)

(57) [Claims] (1) 35.0 to 44.5% by weight of PbO and 30% of SiO ₂ .
_{0~45.0%, Al 2 O 3 0.5~5.0} %, Na 2 O 0~6.0%, K 2 O 0
_{~6.0%, Fe 2 O 3 0.5~5.0} %, consists 0.5 to 5.0% ZnO, essentially bonding glass characterized in that it does not contain B ₂ O ₃ and Li ₂ O.