JPH08169727A - Glass composition and magnetic head - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention has both low melting property and sufficient chemical durability.
Achieved quality improvement by using the glass composition
It is an object of the present invention to provide a magnetic head. [Constitution] Glass composition for joining magnetic core half pairs 3A, 3B
The fused glass 4, which is a product, was used. Of this fused glass 4
The composition range is 60 to 65% by weight of PbO, SiO ₂Is 2
0 to 26% by weight, B₂O₃2 to 10% by weight, TeO₂
Is 3 to 8% by weight, Na₂0 to 5 wt% O, ZrO₂But
It is 1 to 3% by weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass composition having low melting property and sufficient chemical durability, and a magnetic head using the same.

[0002]

2. Description of the Related Art Conventionally, in a magnetic head, a low melting point glass containing SiO ₂ , PbO, Na ₂ O, B ₂ O _3, etc. as a gap forming material, a gap filling material, a bonding material or an insulating material is used. Had been used.

However, in the conventional composition, the relationship between the melting point of glass and the chemical durability is very troublesome, and if one of them is prioritized, the other is inferior. That is, when lowering the melting point of this type of glass, a large amount of PbO or an alkali metal oxide is contained, but in this case, the chemical durability deteriorates. Further, in order to improve the chemical durability of glass, a large amount of SiO ₂ was contained, but in this case, the melting point becomes high.

[0004]

By the way, in general, magnetic properties of magnetic core materials for magnetic heads deteriorate at high temperatures.
Further, in the manufacturing process of the magnetic head, the glass is usually fused at a temperature at which the viscosity becomes about 10 ³ pa · s (hereinafter, referred to as working temperature), and then immersed in a grinding liquid or the like. Therefore, in the conventional composition, in order to prevent the deterioration of the magnetic characteristics of the magnetic head, if the lowering of the melting point is emphasized, the chemical damage of the glass part during the manufacturing process becomes a problem, and the chemical durability is improved. If it is emphasized, there is a problem that high magnetic characteristics cannot be obtained.

That is, the fused glass used as a bonding material or the like in the manufacturing process of the magnetic head is alkaline (pH 9 to 11) when the block after fusion is ground.
Since it is soaked in a grinding liquid and a cleaning liquid (about a degree), it must have particularly excellent alkali resistance in terms of chemical durability. For this reason, the working temperature is 700 ° C. in the conventional technique.
Without the above glasses, satisfactory results could not be obtained.

However, particularly in a metal-in-gap type head (an alloy film is formed in the gap portion for realizing high density recording, which will be referred to as an MIG head hereinafter), when the glass fusing operation is performed at a high temperature of 700 ° C. or higher, the magnetic force is generated. The characteristics are deteriorated, which hinders quality improvement and yield improvement. Therefore, there is a problem that glass that can be fused at 700 ° C. or lower must be used even if the chemical damage is neglected to some extent.

The present invention has been made in view of the above problems, and has realized a glass composition having both low melting property and sufficient chemical durability and quality improvement using the glass composition. An object is to provide a magnetic head.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a glass composition having both low melting property and sufficient chemical durability, and a magnetic head using the glass composition to improve quality. It is an object.

That is, in order to achieve the above object, the glass composition according to the present invention contains 60 to 65% by weight of PbO.
Composition range of 20 to 26% by weight of SiO _{2, 2} to 10% by weight of B ₂ O _{3, 3} to 8% by weight of TeO ₂ , 0 to 5% by weight of Na ₂ O, and 1 to 3% by weight of ZrO _2. It is characterized by having.

A magnetic head according to the present invention is characterized in that the above glass composition is used as a gap forming material, a void filling material, a bonding material or an insulating material.

[0011]

According to the glass composition of the present invention, the PbO content is 60%.
65 wt%, a SiO ₂ 20 to 26 wt%, B ₂ O ₃
2 to 10% by weight, TeO ₂ to 3 to 8% by weight, Na ₂ O
By setting the composition range of 0 to 5% by weight and ZrO ₂ to 1 to 3% by weight, excellent low melting property and sufficient chemical durability can be obtained.

Further, according to the magnetic head of the present invention, by using the above glass composition as the gap forming material, the gap filling material, the bonding material or the insulating material,
It is possible to improve quality.

[0013]

EXAMPLES An example of the glass composition of the present invention will be described below with reference to FIG. 2 and Table 1.

First, the composition ratio of the glass composition according to this example is shown in Samples B, C and D of Table 1. Samples A and E in the table have the conventional composition.

[0015]

[Table 1]

The fused glass for a magnetic head is manufactured as follows. That is, each of the components shown in Table 1 was sampled in a predetermined amount, and the temperature was set to 1100 to 1300 ° C. in a platinum crucible.
Then, the mixture is dissolved and mixed for about 1 hour, and this is usually drawn into a lot.

The properties of the fused glass thus obtained, that is, the coefficient of thermal expansion and the working temperature are shown in the lower column of Table 1.

As shown in Table 1, the obtained samples B, C,
The fused glass D has a feature of being excellent in low melting property. That is, the working temperatures of the fused glasses of Samples B, C, and D are 580 ° C, 600 ° C, and 610 ° C, respectively.
Which is 580 for samples A and E, respectively.
And 780 ° C.

As described above, the working temperatures of the samples B, C, and D are about the same as those of the sample A, and are significantly lower than those of the sample E. In addition, Sample A shown in Table 1 ~
All of E have a thermal expansion coefficient suitable for a magnetic head.

Next, for the samples A to E listed in Table 1,
The alkali resistance was inspected. Here, the method of the alkali resistance accelerated test will be described.

First, a container containing each of the obtained lot-shaped glass samples A to E is prepared. At this time, the size of the sample was 0.6 mm in diameter and 50 mm in length. Next, a 4N-NaOH solution as a strong alkali is placed in each container in a fixed amount and the sample is dipped. Then, the weight of the sample was measured over time.

According to this test, the smaller the weight loss, the higher the alkali resistance.

FIG. 2 shows the results of the alkali resistance acceleration test conducted by the method described above. In FIG. 2, it can be seen that the weights of the samples A and E are reduced earlier than those of the samples B, C and D. That is, the samples B, C, and D have higher alkali resistance than the fused glass of the sample A, which is a high-melting glass, as well as the sample A.

Therefore, if the fused glass of the above samples B, C and D is used as a gap forming material, a gap filling material, a bonding material or an insulating material of a magnetic head using ferrite as a magnetic core, a low temperature of about 600 ° C. In addition to fusing, it is possible to reduce chemical damage during the manufacturing process of the magnetic head and to manufacture a good quality magnetic head having excellent magnetic characteristics with a good yield. Particularly, in order to prevent the deterioration of magnetic characteristics, the present invention can be applied to a MIG head that requires fusion at a low temperature of 700 ° C. or less, and a high effect can be obtained.

The fused glass composition according to the present invention is
60-65 wt% PbO, SiO ₂20 to 26 weight
%, B₂0₃2 to 10% by weight, TeO₂Is 3 to 8 weight
%, Na₂0 to 5 wt% O, ZrO₂1-3% by weight
It has a composition range of
The same effect is shown, and B, C, and
It goes without saying that the composition ratio is not limited to that shown in D.
Yes.

Further, the above composition range was found as a result of various studies for solving the above problems, and it is not always clear how each component interacts, but The reason for limiting the composition range is as follows.

PbO is the main component of low melting point glass.
If the PbO content is less than 60% by weight, the melting point of the glass will be high, and if the PbO content exceeds 65% by weight, the alkali resistance will be poor.

SiO ₂ is an essential component for forming the stitches of glass and is effective in improving alkali resistance. Si
If O ₂ is less than 20% by weight, alkali resistance becomes poor,
If it exceeds 26% by weight, the melting point of glass becomes high,
It interferes with fusion.

B₂O₃Is SiO₂Glass edition as well
It is an essential component that forms the eyes. B ₂O₃Is 2% by weight
If the amount is less than 10% by weight, the glass will not stabilize.
It is difficult to obtain the desired coefficient of thermal expansion.

TeO ₂ is a component that improves alkali resistance by substituting a part of PbO. TeO ₂
However, if it is less than 3% by weight, this effect cannot be obtained, and 8% by weight
If it exceeds, it will be difficult to obtain the desired coefficient of thermal expansion.

Na ₂ O increases the coefficient of thermal expansion and lowers the melting point of the glass, but if its content exceeds 5% by weight, the coefficient of thermal expansion becomes too large, so that the glass will crack after fusion. Will end up. Therefore, the range of Na ₂ O is limited in this way in order to obtain the desired thermal expansion coefficient.

ZrO ₂ is a component that improves alkali resistance. When ZrO ₂ is less than 1% by weight, it is not effective in improving the alkali resistance, and when it exceeds 3% by weight, the melting point of glass becomes high, which causes a problem during fusion.

From the above, according to this example, the glass can be fused at a low temperature and the chemical durability higher than that of the high melting point glass was realized. Therefore, if this is used as a bonding material for magnetic heads, etc., it can prevent the magnetic deterioration of the magnetic core material due to heating during fusion bonding, and suppress the chemical damage to the glass part due to the grinding liquid during block processing. This can contribute to improving the quality and yield of the magnetic head.

Next, an example of a magnetic head using the above glass composition will be described with reference to FIG.

FIG. 1 shows a MIG head. This head includes substrates 1A and 1B made of Mn-Zn ferrite or the like in which gap width regulating grooves 5A and 5B are formed.
The magnetic core half pairs 3A and 3B formed by forming metal magnetic thin films 2A and 2B such as sendust are opposed to each other, and the metal magnetic thin film surfaces are butted against each other through the protective films 6A and 6B. It is integrated by 4.

As described above, in the magnetic head, since the fused glass according to this example is used for joining the magnetic core halves to each other, the magnetic head is not heated to a high temperature of 700 ° C. or more during fusion. It can be manufactured. Moreover, the glass portion is not damaged even when immersed in a grinding liquid or the like in the grinding process or the like. Therefore, high quality products can be produced with high yield.

The glass composition of the present invention is not limited to the magnetic head as in the above-mentioned embodiment, and it is necessary to perform glass fusion bonding at a place where high temperature heating is not allowed and chemical durability is required. Needless to say, it can be used in any field if it exists.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0039]

As described above, according to the present invention, glass fusion can be performed even at a relatively low temperature. Further, the chemical durability of the glass can be made superior to that of the high melting point glass. By using this fused glass when manufacturing a magnetic head,
The magnetic core halves can be joined together without heating to a high temperature of 0 ° C. or higher. Therefore, it is possible to prevent magnetic deterioration of the magnetic core material and the like due to heating during fusion. Moreover, it is possible to suppress damage to the glass portion due to erosion of the grinding liquid during grinding. Therefore, a high-quality magnetic head can be produced with a high yield.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic head of the present invention.

FIG. 2 is a diagram showing the results of an alkali resistance accelerated test of the glass composition of the present invention and a conventional glass composition.

[Explanation of symbols]

 1A, 1B Substrate 2A, 2B Metallic magnetic thin film 3A, 3B Magnetic core half pair 4 Fused glass 5A, 5B Gap width regulation groove 6A, 6B Protective film

Claims (2)

[Claims] 1. PbO of 60 to 65% by weight and 20 to 2
6 wt% SiO₂And 2-10 wt% B₂O₃When,
3-8 wt% TeO₂And 0-5% by weight Na ₂O
And 1-3 wt% ZrO₂Characterized by containing and
Glass composition. 2. A magnetic head using the glass composition according to claim 1 as a gap forming material, a void filling material, a bonding material or an insulating material.