JPH02204344A - Bonding glass and magnetic head - 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] [Field of Industrial Application] The present invention relates to a bonding glass used for glass fusing of a magnetic head, and further relates to a bonding glass used for fixing or embedding a core. This relates to magnetic heads.

[Summary of the invention]

The present invention creates a bonding glass with a low fusing temperature and excellent water resistance by suppressing as much as possible glass components that have a high rate of deterioration when exposed to water, such as alkali and B20°, and replacing them with PbO. This is what we are trying to provide.

Furthermore, the present invention aims to provide a magnetic head having high multiplicity without the occurrence of steps due to weathering by using the above-mentioned bonding glass for fixing or embedding the magnetic core.

[Prior Art] In general, in the processing of magnetic heads mainly made of ferrite, the glass fusing process requires 80°C to prevent deterioration of the magnetic properties of the ferrite and the tightening of the fusing jig to prevent deterioration of the properties.
It is necessary to do this at 0'C or below.

In reality, it is desirable to set the temperature to 750°C or less with some margin, and furthermore, an operating gap is formed between the In of a soft magnetic metal such as sendust coated on ferrite or the like.

In a so-called metal-in-gap type magnetic head, it is necessary to lower the temperature during fusing to prevent the occurrence of a pseudo gap and film peeling.

Therefore, the bonding glass used for fusing must naturally have a fusing temperature (the so-called working temperature, which varies slightly depending on the flow method) below the above-mentioned temperature, and normally the fusing temperature is 750°C. Currently, glass with a temperature below °C is selected and used.

By the way, glasses with such a low melting temperature generally contain B t Oi and alkali components (N a !O, K!0L
For example, a magnetic head manufactured using glass with a low fusing temperature may be used for 6 months after processing. Even if the glass is left at room temperature, deterioration or unevenness on the surface of the glass part is often observed.

To reproduce this condition in an accelerated test, for example, you can place the magnetic head in boiling water, boil it for about 30 minutes, and then examine the steps on the glass surface by observing interference fringes. Bonded glass almost always has a level difference in this test. Of course, even if a step occurs in the accelerated test, for example, it may be immersed in a grinding fluid for several hours during machining, or left in a constant temperature atmosphere of 60°C 195% (relative temperature) for about 96 hours. Although they exhibit a certain degree of water resistance against the like, many of them cannot withstand long-term (long-term) weathering.

Magnetic head is a video tape recorder, TII! If the disk is equipped with a large disk drive device and is constantly sliding, new surfaces will always appear due to wear, so water resistance is not a big problem, but when stored for a long time in a warehouse etc. This is a major problem because it causes dents and steps in the glass and discoloration (adhesion of eluted compounds), which damages the magnetic recording medium.

[Problem to be solved by the invention]

As described above, conventional bonding glasses with low fusing temperatures still have problems in terms of water resistance, especially when used in areas such as the sliding surfaces of magnetic heads that require high multiplier resistance. The occurrence of step differences and the adhesion of eluted compounds have become major problems.

Therefore, the present invention has been proposed in view of the conventional situation, and an object of the present invention is to provide a bonding glass that has excellent water resistance despite having a low fusion temperature.

Another object of the present invention is to provide a bonding glass whose thermal expansion coefficient can be set to an appropriate value depending on the core material, etc., and which has less erosion-diffusion reaction with ferrite materials and ferromagnetic metal materials. .

Furthermore, it is an object of the present invention to provide a magnetic head that does not cause step formation or adhesion of eluted compounds even when stored for a long period of time, and in particular has a highly reliable recording medium sliding surface.

[Means to solve the problem]

The present inventors discovered that among the components that lower the melting temperature of glass, PbO
is alkali or B20. We discovered that the rate of deterioration with water is lower than that of 300%, and by suppressing alkali and BZOs as much as possible and replacing them with PbO, we lowered the fusion temperature to 750.
We succeeded in improving water resistance while keeping the temperature below °C.

That is, the bonding glass of the present invention has SIO,a
wt%, BaOb wt%, B2O3 and/or GeO,
C weight %, PbOd weight %.

Bi, 0. C weight%, Na! A bonding glass containing o and/or K2Of weight%, Fe2O3 and ZnOg weight%, the composition range of which is 40≦a+b≦50 (however, O≦b≦5) 0≦c≦5 34≦d+e≦ 40 (however, 0≦e≦5), 5≦f≦10, and 0≦g≦15.

Further, in the magnetic head of the present invention, the bonding glass contains SiOgal amount % and BaOb weight %.

B $ Os and/or GeO, C wt%, PbOd wt%, Bi2O3C wt%, Na, O and/or KgO
f weight%, Fe2O3 and ZnOg weight% (however, 40
≦a+b≦50, 0≦b≦5, 0≦c≦5.34≦d+
e≦40.0≦e≦5.5≦f≦10, 0≦g≦15)
It is characterized by using glass containing.

Among the components of the bonding glass having the above composition, Sin
g forms a network structure, improving the reliability and water resistance of the glass, and also plays the role of expanding the range of vitrification.Additionally, BaO maintains the water resistance of the glass if added at 5% by weight or less. The fusion temperature can be lowered while maintaining the same temperature. However, since Sing increases the yield point and increases the glass viscosity (and therefore the melting temperature),
The upper limit is determined automatically.

In the present invention, the 5ift contains fa (!:Ba.

The total content of 51a is 40 to 50% by weight. If the total amount of these is less than 40% by weight, it becomes difficult to ensure water resistance, and, for example, a step occurs in a 30-minute boiling test. Also, conversely, the total amount of these is 50
If it exceeds 800° C. by weight, the fusion temperature will become higher than 800°C.

B2O3 and G e Ot lower the viscosity of glass and lower the fusing temperature, but since they have a high rate of deterioration with respect to water, if too large amounts are added, water resistance will deteriorate.

Therefore, B, 0. When the total amount of C and GeO is reduced to 5% by weight, the composition range is 5% by weight or less. By adding B2Os, Ge01, or both within this range, the fusion temperature can be lowered while maintaining the water resistance of the glass. If the total amount C exceeds 5% by weight, a difference in level will occur in the 30 minute boiling test.

PbO and Bi2O3 are components that significantly lower the fusion temperature of glass, and PbO in particular is an alkali component and B8
Bi□ has a lower deterioration rate with water than O1 etc
0. If added in an amount of 5% by weight or less, the fusion temperature can be lowered while maintaining the water resistance of the glass.

Therefore, in the present invention, these components are used to prepare the above-mentioned B! Replaces the reduced alkaline component of 03 and those described below, achieving low melting temperature and water resistance at the same time. However, the sum of the content ld of pbo and the content i1e of BigOs @ d + e
If it is less than 34% by weight, it will not be able to withstand a boiling test for 30 minutes with the fusion temperature below 800'C, and if the total lid+e exceeds 40% by weight, the fusion temperature should be lowered. However, since a difference in level occurs in a 30-minute boiling test, the content is set in the range of 34 to 40% by weight.

Na, O, and KtO are components that significantly increase the thermal expansion coefficient of the obtained glass and set it to a value suitable for ferrite and ferromagnetic metal materials, and Na□0. By adding □O or both of these, the coefficient of thermal expansion can be increased to 90X.
IO-'~110X1. It can be raised to about O-'['C-'].

However, if a large amount of these alkaline components are contained, the reliability (especially water resistance) of the glass will be reduced, so the content i1f is set to 5 to 10% by weight here. If the content of these substances exceeds 10% by weight, the water resistance will deteriorate;
For example, a step occurs during a 30 minute boiling test. Conversely, if the Ir content is less than 5% by weight, it is difficult to make the thermal expansion coefficient of the glass 90 x 10-'('C'') or more.

Fezes and ZnO are components to prevent reactions at the interface between ferrite and metal thin films and glass.
From this point of view, it is added in an amount of 15% or less. Even if the content (g) of FetO3 and ZnO exceeds 15% by weight, no further effect of preventing the erosion-diffusion reaction can be expected, and moreover, ferrite components tend to precipitate in the glass. Of course, it contains 1g of Fe, 03 and ZnO.
If there are too few components, the effect of preventing erosion-diffusion reactions cannot be expected, but if these components are not added, the glass transition point will be higher, the glass itself will become transparent, and the conditions for drawing the glass will be eased. (Since the above-mentioned components tend to cause phenomena such as precipitation on the ceiling, temperature control during glass production becomes strict.) Therefore, it is preferable to use them selectively depending on the required properties.

In addition, the ratio of Fetrs and ZnO is 4 by weight.
(Preferably 160-70:30, Fe2O
If the ratio of 3 is less than 40, hardly any reaction prevention effect can be expected; conversely, Fete.

When the ratio of Mn exceeds 70, the Mn used in the magnetic head
Since the proportions of -Zn ferrite and Fetus components are equal or higher, if these components are precipitated in the glass, they may become magnetic components and there is a risk of forming a pseudo-I gap.

Bonded glass that satisfies all of the above conditions exhibits excellent water resistance while maintaining a low fusing temperature (fusing temperature of 750'C or less), and has better performance during long-term storage than conventional low melting glass. Greatly improved in terms of sex.

On the other hand, the magnetic head of the present invention has the magnetic cores bonded to each other by the bonding glass described above, or the bonding glass described above is embedded in the track width regulating groove, etc., and is particularly required to have high magnification performance. The above-mentioned bonding glass is used for parts such as the sliding surface of the magnetic recording medium.

Therefore, examples of magnetic heads to which the present invention is applied include magnetic heads for audio tape recorders, magnetic heads for video tape recorders, in which a pair of magnetic cores forming a closed magnetic path are butted against each other, and magnetic heads for recording/reproducing heads and erasing heads. Examples include a magnetic head for a floppy disk drive in which a central core made of magnetic or non-magnetic material is interposed as necessary, and a magnetic head for a hard disk drive in which a magnetic core is embedded in a slider member. It will be done.

Note that in each magnetic head, the magnetic core may be made of a single oxide magnetic material such as ferrite, or
It may be made of a composite of a ferromagnetic metal material such as a Fe-AN-Si alloy (so-called sendust) and an oxide magnetic material or a non-magnetic oxide material. When glass is used, this bonding glass may be used as it is as a gap spacer, or a SiO□ film or the like may be deposited on the bonding surface of the magnetic core as a gap spacer in advance, and the bonding glass may be used as a mere machine. It may also be used only for physical connections.

[Effect]

PbO is a component that significantly lowers the fusing temperature of glass, but its deterioration rate with water is lower than that of alkaline components (Na□O and □O), B, 01, and the like.

Therefore, alkaline components (Na, O, 0) and B!
By reducing 03 as much as possible and supplementing the amount with PbO, the fusion temperature can be maintained at 750° C. or lower, and water resistance can be ensured.

However, alkaline components (Na, O, etc., 0) are necessary components to control the coefficient of thermal expansion, and by adding a specified amount within a range that does not impair the water resistance, the coefficient of thermal expansion of the glass can be changed to that of ferrite. Set to a value suitable for metal thin films.

Furthermore, by adding Fe□O8 and ZnO as necessary, erosion and diffusion reactions at the interface between ferrite, gold (1) XIIIQ, and glass are prevented.

On the other hand, in the magnetic head of the present invention, bonding glass with excellent water resistance is used especially in the parts exposed to the sliding surface of the magnetic recording medium, such as bonding the magnetic cores together and embedding the track width regulating grooves. This eliminates the occurrence of step differences and adhesion of eluted compounds during storage.

In addition, since the bonding glass has a low fusing temperature, the magnetic properties of the magnetic core made of ferrite, ferromagnetic metal materials, etc. do not deteriorate, and the so-called metal-in-glass
In the gap type magnetic head, the occurrence of pseudo gaps and unprinting are also prevented.

Table 1 〔Example〕 The present invention will be described below based on specific examples.

First, S i OH, P b O, Na go,
BaO3°Ferns, ZnO and BaO were mixed in the proportions shown in Table 1, and a bonding glass (test f41~
Sample 3) was prepared.

(Left below) For each bonding glass obtained (Samples 1 to 3), the glass transition point (the temperature at which the coefficient of thermal expansion changes), the yielding point (the temperature at which the shape does not return even if cooled if the temperature is increased further) ), fusion temperature (varies depending on working temperature and flow method), coefficient of thermal expansion (here, value at 100 to 400°C)
was measured.

Although the fusion temperature varies depending on the fusion method, the shape of the adherend, the fusion atmosphere, etc., the temperature used here is that of a typical magnetic head casting method. i.e. width 15011rn
, a ferrite block with a width of 40 m was prepared, in which track width regulating grooves with a depth of 120 pm were provided at 20 μ intervals, and further provided with glass grooves and S-line grooves, and this was combined with a ferrite block in which only track width regulating grooves were provided. The gears were butted together with a length of about 0.5 μm, a glass rod was inserted only into the glass groove, and the temperature at which each groove was completely filled with glass when heated at an angle of about 20' was determined as the fusion temperature. The atmosphere during the fusion bonding was 100% nitrogen, and the distance M from the glass groove to the tip of the ferrite block (distance over which the glass was flowed) was approximately 3. The results are shown in Table 2.

Table 2 As can be seen from Table 2, the fusing temperatures of each bonding glass (Samples 1 to 3) to which the present invention is applied are as follows:
The temperature is kept below 750'C.

Therefore, we further conducted a boiling test on these glasses,
The erosion-diffusion reaction was investigated. The results are shown in Table 3. The boiling test was conducted by boiling a ferrite head using each of these samples as bonding glass in pure water, and observing the steps on the sliding surface of the head using interference fringes. O in the judged 0 table means that there is no step difference,
Δ indicates that a slight level difference was observed, and × indicates that a clear level difference was observed. In addition, the erosion-diffusion reaction was performed by fusing glass at 700°C on top of mirror-finished ferrite. 0 in the table, determined by observing with a microscope from the side, indicates that the interface is kept in a mirror state and there is almost no erosion-diffusion reaction, and × indicates that the interface is disturbed due to erosion-diffusion reaction.

(Margin below) Table 3 From Table 3, it can be seen that there were no problems with each sample in the 30 minute boiling test. However, in sample 2 in which BaO was added up to the upper limit, generation of steps was observed in the 150 minute boiling test. In addition, ferrite components (FexOz, Zn0
), an erosion-diffusion reaction was observed in sample 3 without the addition of .

Next, a magnetic head was manufactured using the bonding glass described above.

Figure 1 shows an example of a manufactured magnetic head, in which Mn
- Half-hole magnetic core made of Zn ferrite, etc. (1), (2
) are integrally bonded together using bonding glass (4). In addition, for one magnetic core half-break (2),
1 for the magnetic head! A winding groove (3) is cut into which a coil for supplying or extracting a signal by magnetic transduction is wound.

Here, the bonding glass (4) was coated with sample 1 prepared previously. Therefore, in this magnetic head, the bonding glass (4) is also embedded in the track width regulating grooves (la) and (2a) of each magnetic core half-hole (1) and (2), and the magnetic recording medium This bonded glass with excellent water resistance on sliding surfaces (4)
will be exposed.

Therefore, this magnetic head has high durability against weathering and the like, and no level difference occurs in the glass portion even after long-term storage.

In fact, when this magnetic head was boiled in hot water for 30 minutes, no steps were generated on the glass portion, and even when it was immersed in a strong alkali having a pH of 12 to 13 for several minutes, no steps were formed.

Moreover, this bonding glass (4) had a very clean interface because there was little erosion-diffusion reaction with ferrite.

In the magnetic head having the above configuration, a gap film such as SLO may be used as the gap material, or this bonding glass (4) may also be used, but in the latter case, glass Care must be taken as the effective gap may be much larger than the apparent gap unless the fusion is performed at the lowest possible temperature.

Figure 2 shows an example applied to a magnetic head that requires heat resistance.It has almost the same configuration as the magnetic head shown in Figure 1, but the bonding glass (5) on the front gap side is Sample 1 was used as the bonding glass (6) on the back gap side, and sample 3 was used as the bonding glass (6) on the back gap side.

Generally, in order to remove processing distortion of ferrite materials, etc.
A magnetic head is sometimes subjected to heat treatment after processing, but the heat treatment temperature is near the glass transition point, so that the fused glass may begin to melt and cause track misalignment. To prevent this, it is necessary to use different types of glass for the front side and the bank side, use glass with a higher glass transition point on the back side than the front side, and securely fix the glass on the back side.

Here, sample 3 used for the back side has a high glass transition point and excellent heat-resistant mechanical strength, but since no ferrite component is added, it is expected that an erosion-diffusion reaction will occur. It should be used only on the back gap side where the influence of this reaction is not a problem. Although sample 1 has a slightly low glass transition point, it will be used on the front gap side because no steps occur in the boiling test and there is no erosion-diffusion reaction to ferrite.

In the magnetic head having such a configuration, the water resistance of the sliding surface of the magnetic recording medium is ensured as in the previous example, and the heat-resistant mechanical strength is also significantly improved.

Figure 3 shows the ferrite parts (Ila) and (1
The magnetic core halves (11) and (12) constituted by the magnetic core halves (11) and (12) made up of the magnetic core (2a) and metal Il films (llb) and (12b) are integrally bonded together using bonding glass (14). In this example, the winding groove (
13) is provided, and each magnetic core half-off (1,1),
The fact that the inside of the trunk convergence regulating groove (12) is filled with the bonding glass (14) is similar to that shown in FIG. 1 above.

In this example, the bonding glass (14) is
However, the glass (sample 1) can be fused even at about 650'C by adjusting the fusion method such as the atmosphere and shape of the furnace, and it is possible to fuse the glass (sample 1) even at a temperature of about 650'C.
1, 2b) No film peeling or property deterioration occurs.
In addition, since the bonding glass (14) has excellent water resistance, it ensures the excellent performance of the sliding surface of the magnetic recording medium and has excellent long-term storage stability. be.

Next, an example in which the present invention is applied to a magnetic head installed in a floppy disk drive will be described.

The magnetic head for floppy disks is shown in Figures 4 and 5.
As shown in the figure, a magnetic core (21) made of ferrite
, (22) and magnetic cores (23), (24) are respectively joined and integrated to constitute a recording/reproducing head section and an erasing head section, and at the same time, these recording/reproducing head section and erasing head section are integrally fixed. Furthermore, guard materials made of ceramics or the like are bonded to both sides in the running direction of the magnetic recording medium.

That is, the magnetic cores (21), (22) and the magnetic cores (23), (24) are respectively bonded and integrated by a single flame-glazed glass (26), and the recording/reproducing head section and the erasing head section which are integrated with these are integrated. It is further fixed with a two-socket glass (27).

Here, the previous sample 1 was added to the 1 fire-spotted glass (26), and the 2
The above sample 2 was used as the fire adhesion glass (27).

Finally, sample 2 used for the 2-fire adsorption glass (27) is
Both the glass transition point and the fusion temperature are lower than those of Sample 1, so that the first-flame glass (26) will not melt out during the second-flame adhesion and cause no track deviation or the like.

In addition, 1-fire bonding glass (26), 2-fire bonding glass (26)
27) Since both have excellent water resistance, no steps or the like will occur on the sliding surface of the magnetic recording medium.

〔Effect of the invention〕

As is clear from the above explanation, the bonding glass of the present invention exhibits excellent water resistance despite its low fusing temperature, and simultaneously satisfies the conflicting properties of reliability and workability. Its practical value is great.

In addition, the bonding glass of the present invention has a thermal expansion coefficient that can be easily controlled, and addition of Fe2O3 and ZnO suppresses erosion-diffusion reactions with ferrite and metal magnetic thin films, making it suitable for actually manufacturing magnetic heads. Very advantageous.

On the other hand, since the magnetic head of the present invention uses glass that has a low melting temperature and excellent water resistance as the bonding glass, there will be no steps or elution on the sliding surface of the magnetic recording medium, especially when stored for a long time. A magnetic head with excellent reliability can be provided without the occurrence of compound adhesion or the like.

In addition, since the bonding glass has a low fusing temperature,
It is possible to provide a magnetic head with excellent electromagnetic conversion characteristics without degrading the magnetic characteristics of the ferrite or gold RF4RA thin film or causing film peeling.

4. Explanation of the FJ car on the v1 side. Fig. 1 is a schematic perspective view showing an example of a magnetic head to which the present invention is applied, and Fig. 2 is a schematic perspective view showing another example of the magnetic head to which the present invention is applied. , FIG. 3 is a schematic perspective view showing still another example of a magnetic head to which the present invention is applied.

FIG. 4 is a schematic perspective view showing an embodiment in which the present invention is applied to a magnetic head installed in a floppy disk drive, and FIG. 5 is a plan view of the sliding surface of the magnetic recording medium.

1.2, 11.12...Magnetic core half-off 4.5, 6.1
4...Bonding glass 21.22, 23.24
...Magnetic core 26...1 Fire-adhesive glass 27...2 Fire-adhesive glass Patent applicant Sony Corporation representative Patent attorney Akira Kowa (2 others)

Claims (2)

[Claims] (1) SiO_2 a weight%, BaO b weight%, B_
2O_3 and/or GeO_2 c wt%, PbO d
Weight %, Bi_3O_3 e Weight %, Na_2O and/
or K_2O fwt%, Fe_2O_3 and ZnO
A bonding glass comprising g weight %,
Its composition range is 40≦a+b≦50 (however, 0≦b≦5), 0≦c≦5, 34≦d+e≦40 (however, 0≦e≦5), 5≦f≦10, 0≦g≦15. bonded glass. (2) SiO_2 a weight% as bonding glass
, BaO bwt%, B_2O_3 and/or GeO_
2 c wt%, PbO d wt%, Bi_2O_3 e
wt%, Na_2O and/or K_2O fwt%, F
e_2O_3 and ZnO g weight% (however, 40≦a+
b≦50, 0≦b≦5, 0≦c≦5, 34≦d+e≦4
0, 0≦e≦5, 5≦f≦10, 0≦g≦15).