JPH0150962B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION A. Technical Field The present invention relates to magnetic heads. More specifically, the present invention relates to a contact type magnetic head comprising a core and a dummy block, particularly to improvements in the dummy block. B. Prior Art In a contact type magnetic head, a dummy block is placed along with a core for recording or reproducing on the sliding surface of a magnetic recording medium such as a tape, and when the medium is in contact with another track or the other track of the medium. Considerations have been taken to ensure sliding contact with unused areas, improve media running performance, prevent uneven wear of the magnetic head core and case, and prevent crosstalk between tracks and induced noise. ing. In this case, in a conventional magnetic head having a core made of sendust, permalloy, ferrite, etc., a dummy block made of the same material as the core is used. By the way, amorphous magnetic alloy thin sheets have recently attracted attention as core forming materials for magnetic heads due to their excellent soft magnetic properties, and magnetic heads with cores made of amorphous magnetic alloy thin sheets have been put into practical use. has been moved to. In a magnetic head having a core made of such an amorphous magnetic alloy thin plate, since the amorphous magnetic alloy cannot be obtained as a block body, the dummy block is made of the same material as the core, as in the past. cannot be formed from On the other hand, if a dummy block is formed from conventional magnetic head core materials such as permalloy, high-hardness permalloy, sendust, and ferrite for a core made of an amorphous magnetic alloy thin plate, the magnetic recording medium may be damaged or the frequency characteristics may deteriorate. There are various disadvantages such as deterioration over time and increased output level fluctuations. To be more specific, when permalloy or high-hardness permalloy is used as a dummy block, the hardness of the amorphous magnetic alloy is higher than that of permalloy, which causes uneven wear of the dummy block and poor contact between the medium and the head. With use, frequency characteristics may deteriorate or output level fluctuations may increase. In addition, when using sendust, since the amorphous magnetic alloy for the magnetic head is a Co-based alloy, a local battery is formed between the sendust dummy block and the amorphous magnetic alloy head, especially at high temperatures. Corrosion occurs in the dummy block under humidity, resulting in deterioration of frequency characteristics, causing poor running, increased output fluctuations, and even poor appearance. In addition, sendust is difficult to forge or roll, so it is ground after casting to make a dummy block, but the presence of the cast structure causes damage to the medium, and it is also inefficient in manufacturing. , the cost will be high. Furthermore, when ferrite is used, since it has a higher hardness than an amorphous magnetic alloy, uneven wear occurs, resulting in undesirable phenomena such as deterioration of frequency characteristics, poor media running, and increased output level fluctuations. On the other hand, the present inventors previously reported that 1 to 40 wt.
% of Ni, and if necessary, Mn, Si, etc., as a dummy block. Especially when the Fe--Ni alloy dummy block proposed above is combined with an amorphous core, uneven wear is significantly reduced, and deterioration of frequency characteristics and increase in output fluctuation are significantly reduced. In addition, the dummy block has a high corrosion resistance, and has various characteristics such as less occurrence of poor running of the tape, corrosion, poor appearance, etc. as the medium is run and stored. However, the previously proposed Fe--Ni alloy dummy block is still insufficient in terms of corrosion resistance, and further improvements are desired, especially in terms of storage stability under high temperature and high humidity conditions. Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and is directed to a magnetic head, particularly a magnetic head having a core made of an amorphous magnetic alloy thin plate, which is particularly suitable for use under high temperature and high humidity conditions. The main object of the present invention is to provide a magnetic head equipped with a novel Fe--Ni alloy dummy block with further improved storage stability. The present inventors have conducted various studies in order to find a new dummy block material that meets these objectives, especially when used in combination with an amorphous magnetic alloy core, and have now accomplished the present invention. It is. That is, the present invention provides a magnetic head comprising a dummy block and a core, in which the dummy block has a Ni content of 1 to 40 wt% and a Cr content of 1 to 15 wt%.
Contains Co, Mo, Cu, B and P
Made of Fe--Ni alloy, the core has the following formula [V]
A magnetic head characterized in that it is formed from an amorphous magnetic alloy thin plate having a composition represented by: Formula [] T _x X _y {In the above formula [], T represents Fe and Co or a combination of Fe and Co with one or more other transition metal elements, and X represents B or Si and B
Alternatively, it represents B or a combination of Si and B with one or more other vitrifying elements. x+y=
100 at%, and y is 20 to 27 at%. moreover,
The amount of Fe is 1.5 to 5.6 at%, and the amount of Co is 45 to 78.5 at%. } Specific Configuration of the Invention The specific configuration of the present invention will be described in detail below. The dummy block in the magnetic head of the present invention is made of a Fe--Ni alloy having a predetermined composition. In this case, the content of Ni contained as an essential component in the Fe--Ni alloy is 1 to 40 wt%, more preferably 10 to 30 wt%. When the Ni content exceeds 40 wt%, the amount of wear is greater than that of an amorphous magnetic alloy, and uneven wear becomes large. Furthermore, if the Ni content is less than 1 wt%, the standard potential of the dummy block will be lower than that of permalloy, etc., resulting in a decrease in corrosion resistance. And Ni
When the content is 10 to 30 wt%, uneven wear is significantly reduced and corrosion resistance is significantly improved. In addition, the Cr content, which is also an essential component, is 1 to 1.
It is 15 wt%, more preferably 2 to 10 wt%. In this case, if the Cr content becomes 0, the desired effects of the present invention will not be achieved, and corrosion resistance, that is, storage stability under high temperature and high humidity conditions will not be satisfied. In this case, when the Cr content is 1wt% or more, particularly 2wt% or more, corrosion resistance is sufficiently improved. On the other hand, if the Cr content exceeds 15 wt%, an oxide film is formed on the surface, the strength of spot welding with the shield case etc. is low, and workability during head assembly is deteriorated. When the content is 15wt% or less, especially 10wt% or less, the welding strength becomes sufficient. Furthermore, the Fe content as an essential component is 33~
It is preferably 98wt%, more preferably 60-89wt%. If it is less than 33wt%, uneven wear will increase and 98wt%
%, corrosion resistance decreases. And Fe
When the content is 60 to 89 wt%, uneven wear is significantly reduced and corrosion resistance is significantly improved. The Fe--Ni alloy according to the present invention may be composed of Fe, Ni, Cr, and one or more other elements as long as the Ni, Fe, and Cr contents are within the ranges described above. In such a case, when the Fe--Ni alloy consists only of Fe, Ni and Cr, it is preferable to have a composition represented by the following formula []. Formula [] Fe _a Ni _b Cr _cIn the above formula [], a+b+c=100wt%
, a is 45-98wt%, b is 1-40wt%, c
is 1 to 15 wt%. In this case, a is 60~88wt
%, b is 10 to 30 wt%, and c is 2 to 10 wt%,
This is preferable because uneven wear is reduced, corrosion resistance is improved, and deterioration of frequency characteristics and output level fluctuations is further reduced. On the other hand, when the Fe-Ni alloy consists of Fe, Ni, and one or more other elements, the other elements that may be included include Ti, Zr, Hf, V, Nb, Ta,
Examples include one or more transition elements such as W, Mn, and Zn, and nonmetallic elements such as Si and Al. and,
The content of one or more of these other elements is 20wt%
It is as follows. If the total amount of other additive elements exceeds 20 wt%, the effects of the present invention will be reduced. Such Fe-Ni alloys containing one or more elements other than Fe, Ni, and Cr contain 33 wt% or more and less than 98 wt%, more preferably 60 to 88.9 wt%.
Fe and 1 to 40 wt%, more preferably 10 to 30 wt%
% Ni and 15wt% or less, more preferably 1~
It contains 15 wt% of Cr and 20 wt% or less, especially 0.1 to 20 wt% of one or more other elements. Among these, particularly preferred are those having the compositions shown in the following formulas [] to []. Formula [] Fe _a Ni _b Cr _c Mn _dIn the above formula [], a+b+c+d=
100wt%, a is 43wt% or more and less than 98wt%,
b is 1 wt% or more and 40 wt% or less, c is 1 to 15 wt%,
d is 2wt% or less. In this way, the Fe-Ni alloy containing Mn in addition to Fe and Ni has a Mn content c of 0.1 wt%.
With the above, oxidation resistance during hot forging etc. is improved, the surface finish during hot processing such as forging is good, the surface accuracy of the dummy block is extremely good, and defects during casting are extremely reduced. The wear resistance is further improved, and damage to the media is extremely reduced. In this case, in the above formula [], a is 60~
88.9wt%, especially 60-87.9wt%, b 10-30wt%,
c is 1-15wt%, especially 2-10wt%, d is 0.1-15wt%
At 1wt%, uneven wear is further reduced, corrosion resistance is further improved, and deterioration in frequency characteristics and output level fluctuations is further reduced. Formula [] Fe _a Ni _b Cr _c Si _eIn the above formula [], a+b+c+e=
100wt%, a is 35wt% or more and less than 99wt%,
b is 1-40wt%, c is 1-15wt%, e is 10wt%
It is as follows. In this way, Fe-Ni alloys containing Si in addition to Fe and Ni have good castability, a reduced cast structure, and improved wear resistance, especially when the Si content is 0.1wt% or more. Improve even further. However, when the Si content d exceeds 10wt%, the workability deteriorates,
Since processing such as rolling and wire drawing becomes difficult, d is
It is less than 10wt%. In this case, in the above formula [], a is 60~
88.9wt%, especially 60-87.9wt%, b 10-30wt%,
c is 1-15wt%, especially 2-10wt%, e is 0.1-10wt%
At 5wt%, uneven wear is further reduced, corrosion resistance is further improved, and deterioration in frequency characteristics and output level fluctuations is further reduced. Formula [] Fe _a Ni _b Cr _c Mn _d Si _eIn the above formula [], a+b+c+d+e=
100wt%, a is 33wt% or more and less than 98wt%,
b is 1-40wt%, c is 1-15wt%, d is 2wt%
Hereinafter, e is 10wt%. In this way, Fe-Ni alloys containing Mn and Si have particularly low Mn and Si contents, respectively.
When it is 0.1wt% or more, both oxidation resistance and castability improve, the surface accuracy and surface defects of the block body are extremely reduced, and the frequency characteristics, output level fluctuations, amount of wear, damage to the medium, etc. are further reduced. Become. In this case, in the above formula [], a is 60~
88.8wt%, especially 60-87.8wt%, b 10-30wt%,
c is 1-15wt%, especially 2-10wt%, d is 0.1-15wt%
1wt% and e is 0.1 to 2wt%, uneven wear is further reduced, corrosion resistance is further improved, and frequency characteristics, deterioration of output level fluctuations, damage to the medium, etc. are extremely reduced. In order to obtain a dummy block from such an alloy, the master alloy is first melted, for example in a vacuum, and then cast. After this, a forging process is usually performed.
As a result, casting structures or defects are significantly reduced. After that, if necessary, it is subjected to rolling wire drawing, etc. to adjust the shape, and in some cases, it is pickled, etc., and then cut, and if necessary, it is welded or bonded to obtain the desired shape. A dummy block is obtained by polishing the corners etc. On the other hand, the core in the magnetic head of the present invention is usually formed from a thin plate of an amorphous magnetic alloy. When an amorphous magnetic alloy is used as a core material, it has good properties as a core, and even after extremely long-term use, there is no difference in the amount of wear between the dummy block and the core, and the media sliding contact surface of the head is Good results are obtained in terms of less uneven wear and less variation in frequency characteristics and output level. When an amorphous magnetic alloy thin plate is used as the core material, its composition may be of various compositions known for use in cores of magnetic heads, but it may have a particularly high saturation magnetic flux density Bs and high retention. The following formula [] is suitable for magnetic magnetic recording media.
It is preferable that the composition is as shown below. Formula [] T _x X _y In the above formula [], T represents Fe and Co or a combination of Fe and Co with one or more other transition metal elements. In this case, if necessary, other additive elements added in combination with Fe and Co are Fe and Co.
other transition metal elements (Sc~Zn; Y~Cd; La
~ Hg; Ac or higher), such as Ni, Ti, Zr,
Hf, V, Nb, Ta, Cr, Mo, W, Mn, Ru,
Specific examples include one or more of Rh, Pd, Os, Ir, and Pt. On the other hand, X represents B, Si and B, or a combination of Si and B with one or more other vitrifying elements. In this case, examples of other vitrifying elements added in combination with B or Si and B, if necessary, include one or more of P, C, Ge, Sn, Al, and the like. On the other hand, in the above formula [], x+y=100at
%, and y is 20 to 27at%. That is, the amount x of transition metal elements whose essential components are Fe and Co is 73 to 80 at%, and B or
The amount y of the vitrifying element components, which include Si and B as essential components, is 20 to 27 at%. If y is less than 20 at%, it will be difficult to make it amorphous, and if it exceeds 27 at%, the residual magnetic flux density Bs will decrease. Further, the contents of the essential components Fe and Co in the transition metal element components are Fe: 1.5 to 5.6 at% and Co: 45 to 78.5 at%, respectively. Fe content is less than 1.5at% (Co content is 78.5at%)
(larger) or exceeding 5.6 at%, the magnetostriction becomes large and the magnetic permeability decreases. When Co becomes less than 45at%, Bs decreases. In this case, in the above formula [], T may consist of only Fe and Co, or may consist of Fe, Co, and one or more of the other additive elements mentioned above, within the above content range. When T consists only of Fe and Co, the Fe content is
1.5 to 5.6 at%, more preferably 2 to 5.5 at%, Co content is 67.4 to 78.5 at%, more preferably 67.5 to
It is 78at%. When T contains one or more other elements in addition to Fe and Co, one or more of the other transition metal elements can usually be contained up to a total of 25 at%.
If the content exceeds this range, problems such as decreased Bs and poor surface properties will occur. One example of such an element is Ni. Ni
Addition has the effect of replacing Co and reducing material costs, but as the amount of Ni increases, Bs decreases, so the Ni content is preferably 8 at% or less. On the other hand, one or more other elements may be transition metal elements other than the iron group (Fe, Co, Ni), but the total amount of one or more transition metal elements other than the iron group is 12 at% or less. It is preferable that there be. At this time,
The decrease in Bs is small, and excellent effects unique to each additive element are realized. Such elements include Ru and/or
Or Cr is preferred. In particular, when Ru is added in an amount of 0.5 to 8 at%, wear resistance is improved, and surface properties, punching workability, etc. are improved. Moreover, when 1 to 8 at% Cr is added, corrosion resistance is improved. When Ru of 0.5 to 8 at% and Cr of 1 to 8 at%, especially 2 to 6 at% are added in combination, these effects are further improved and more favorable results are obtained. Furthermore, in addition to these Ru, Cr, Ni, etc., Ta,
It is also possible to contain one or more of Ti, W, Mo, and the like. In addition, when containing transition metal elements other than Fe and Co in this way, the total of these is 20 at% or less, and the Co content is 47.4 to 78.5 at%, more preferably 47.5 to 78 at%, and the Fe content is The amount is 1.5~5.6at
%, more preferably 2 to 5.5 at%. On the other hand, the vitrification element component X is B or
Contains Si and B as essential components. In this case, when the B content is 3.3 to 27 at% and the Si content is 0 to 16.2 at%, Bs increases, the surface properties of the thin plate improve, and favorable results are obtained. Then, when the B content is 14.1 to 26.9 at% and the Si content is 0.1 to 5.4 at%, Bs becomes even higher,
The surface properties are further improved, and the effect of adding additional elements such as Ru and Cr is also significant, resulting in more favorable results. Note that the vitrification element component X may contain one or more elements other than Si and B, if necessary. However, if the total amount exceeds 0.5 at%, it becomes difficult to become amorphous, so the content is
It is preferably 0.5at% or less. The thin plate having the composition as detailed above is an amorphous body having substantially no long-range regularity. Further, the plate thickness is approximately 10 to 200 μm. Such an amorphous magnetic alloy thin plate is manufactured according to a known high-speed quenching method. Such amorphous magnetic alloy thin plates are usually laminated with an insulating adhesive interposed therebetween to form core halves of a desired shape, and these are butted together to form a core half as shown in FIG. 1, for example. , cores 2 and 2'. Alternatively, the thin plates are not laminated, but core halves of a desired shape are formed from the thin plates themselves, and the core halves are butted together to form a core. In addition to forming the cores 2 and 2' from such an amorphous thin plate, it is also effective to form them from sendust. This is because at this time, the hardness or wear resistance of the core and the dummy block described later are similar, uneven wear is reduced, and deterioration of frequency characteristics and output fluctuations is reduced. The magnetic head 1 of the present invention includes the cores 2, 2' and the dummy block 3 as described above, as shown in FIG. 1, FIG. 2, or FIG. 3, for example. That is, for example, cores 2 and 2', which are wound with wire, are placed in a shield case 4 made of permalloy or the like.
Dummy block 3 is stored, and core 2,
2' and dummy blocks 3 are arranged in a predetermined arrangement on the sliding surface of the medium. In this case, the structure and manufacturing method can be based on various known structures and methods. In addition, when the Fe--Ni alloy constituting the dummy block 3 is non-magnetic, as shown in FIGS. The dummy block 3 may be fixedly housed in the case by lining the dummy block 3 with ferromagnetism.
It can also be fixedly stored on the non-magnetic support portion 5 provided in the case 4 using an adhesive or the like. Specific Effects of the Invention The magnetic head of the present invention can be used in various applications such as audio, video, measurement, and digital applications. In this case, the dummy block of the magnetic head of the present invention is made of a predetermined Fe--Ni alloy, and the wear resistance of the dummy block is good, and the frequency characteristics change based on the uneven wear of the dummy block. Deterioration and output level fluctuations are much less. Further, the corrosion resistance of the dummy block is extremely high, and there is no possibility of poor running or poor appearance due to moisture in the air as the tape runs over time. Even when stored under high temperature and high humidity conditions, corrosion is extremely rare. In this case, the storage stability under high temperature and high humidity conditions is significantly improved compared to Fe--Ni alloys that do not contain Cr. Furthermore, damage to the medium caused by dummy blocks is extremely small. In addition, the occurrence of crosstalk, induced noise, etc. can be effectively prevented. Further, if the core is made of an amorphous magnetic alloy thin plate, the characteristics of the core will be good, and uneven wear between the core and the dummy block will be further reduced. Specific Embodiments of the Invention Next, more specific embodiments of the present invention are listed.
The present invention will be explained in further detail. Example 1 Fe75.6wt%, Ni17.9wt%, Cr5wt%,
A master alloy with a composition of 0.5wt% Mn and 1wt% Si was vacuum melted and cast into a 40mmφ round bar, which was then forged at 800°C with a forging ratio of 68% to obtain a 13mmφ round bar. Thereafter, this was cold rolled into a 3 x 3 mm square bar, heat treated in air at 1200°C, pickled, and 3 x
It was cut to 4 mm, spot welded into a shield case, and the corners were polished to obtain a dummy block 3 as shown in FIGS. 2 and 3. The atomic composition of the amorphous magnetic alloy thin plate forming the cores 2 and 2' is (Fe _5.5 Co _94.5 ) ₇₂ Ru ₁ Cr ₄
(Si ₁₀ B ₉₀ ) ₂₃ was used to fabricate the magnetic head of the present invention as shown in FIGS. 2 and 3. Using a coating type γ-Fe ₂ O ₃ tape, it was heated at 25℃.
Deterioration of 14KHz/315Hz playback frequency characteristics (dB) and 14KHz green re-output level fluctuation (dB) after running at 47.5cm/sec for 500 hours at 60% relative humidity.
was measured. The results are shown in Table 1.

[Table] Table 1 shows the results when dummy block 3 was formed from permalloy as comparison 1, and the results when dummy block 3 was formed from permalloy as comparison 2.
The results for Mn0.5wt%-Si1wt% are also shown. From the results in Table 1, the dummy block of the present invention is
It can be seen that uneven wear is extremely low. In addition,
The composition of the amorphous magnetic alloy thin plate forming 2,2' is
In the above, similar experiments were carried out using products that did not contain Ru and Cr, those that excluded Ru or Cr, and even those that added Ti and Ta in addition to Ru and Cr. Got the results. Example 2 A dummy block with the composition shown in Table 2 below was
It was produced in the same manner as in Example 1. From these 16 types of dummy blocks, a magnetic head was created in exactly the same way as in the example, and a 14KHz/315Hz
When the deterioration of the reproduction frequency characteristic (F characteristic) was measured, the results shown in Table 2 below were obtained. Furthermore, for each of the 16 types of magnetic heads formed from each of these dummy blocks, γ-
Fe ₂ O ₃ tape, running speed 4.75 cm/sec, 25°C,
The amount of wear after running for 500 hours at 60% relative humidity was measured using a surface roughness meter. In addition, after storing for 1000 hours at 40℃ and 70% relative humidity, the corrosion layer on the surface of each dummy block was removed.
The amount of corrosion was measured using a surface roughness meter to evaluate the storage stability. Furthermore, crosstalk between recording and playback tracks of each magnetic head at 125 Hz, 160 nwb/m, and induced noise in a 50 Hz, 30 e parallel magnetic field were measured. These results are also listed in Table 2 below.

[Table] From the above results, the magnetic head equipped with the dummy block made of the Fe-Ni alloy of the present invention shows extremely little deterioration in frequency characteristics, little wear, and extremely high corrosion resistance, and also reduces crosstalk and induction. It can be seen that practically satisfactory values for noise can also be obtained. In particular, it can be seen that the storage stability is significantly improved compared to Fe--Ni alloys that do not contain Cr.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention. FIG. 2 is a partially omitted perspective view showing another embodiment of the present invention, and FIG. 3 is a partial end view of FIG. 2. 1... Magnetic head, 2, 2'... Core, 3...
dummy block.

Claims (1)

[Claims] 1. A magnetic head comprising a dummy block and a core, wherein the dummy block has a Ni content of 1
~40wt%, containing 1~15wt% Cr, Co, Mo,
1. A magnetic head comprising a Fe--Ni alloy containing no Cu, B, or P, wherein the core is formed from an amorphous magnetic alloy thin plate having a composition represented by the following formula [V]. Formula [] T _x X _y {In the above formula [], T represents Fe and Co or a combination of Fe and Co with one or more other transition metal elements, and X represents B or Si and B
Alternatively, it represents B or a combination of Si and B with one or more other vitrifying elements. x+y=
100 at%, and y is 20 to 27 at%. moreover,
The amount of Fe is 1.5 to 5.6 at%, and the amount of Co is 45 to 78.5 at%. } 2. The magnetic head according to claim 1, wherein the Fe--Ni alloy has a composition represented by the following formula []. Formula [] Fe _a Ni _b Cr _c {In the above formula [], a+b+c=100wt%
, a is 45 to 98 wt%, and b is 1 to 40 wt%
%, and c is 1 to 15 wt%. } 3 Fe-Ni alloy containing 33wt% or more and less than 98wt%
Fe, 1-40wt% Ni, 1-15wt% Cr,
The magnetic head according to claim 1, comprising at least 20 wt% of one or more other elements. 4. The magnetic head according to claim 3, wherein the Fe--Ni alloy has a composition represented by the following formula []. Formula [] Fe _a Ni _b Cr _c Mn _d {In the above formula [], a+b+c+d=
100wt%, a is 43wt% or more and less than 98wt%,
b is 1-40wt%, c is 1-15wt%, d is 2wt%
It is as follows. } 5. The magnetic head according to claim 3, wherein the Fe--Ni alloy has a composition represented by the following formula []. Formula [] Fe _a Ni _b Cr _c Si _e {In the above formula [], a+b+c+e=
100wt%, a is 35wt% or more and less than 98wt%,
b is 1-40wt%, c is 1-15wt%, e is 10wt%
It is as follows. } 6. The magnetic head according to claim 3, wherein the Fe--Ni alloy has a composition represented by the following formula []. Formula [] Fe _a Ni _b Cr _c Mn _d Si _e {In the above formula [], a+b+c+d+e=
100wt%, a is 33wt% or more and less than 98wt%,
b is 1-40wt%, c is 1-15wt%, d is 2wt%
Hereinafter, e is 10 wt% or less. }