JPH0150965B2 - - 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, the dummy block is usually made of a material such as sendust, permalloy, or ferrite. 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. If a dummy block is made of conventional materials such as permalloy, high-hardness permalloy, sendust, or ferrite for a core made of such an amorphous magnetic alloy thin plate, the magnetic recording medium may be damaged or the dummy block may become uneven. There are various disadvantages such as wear, deterioration of frequency characteristics over time, and increase in output level fluctuations. To be more specific, when permalloy or high-hardness permalloy is used as a dummy block, the amorphous magnetic alloy has a higher hardness than these, causing 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. 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. In view of these actual circumstances, the present inventors first
When used in combination with an amorphous core, a dummy block with less uneven wear and less damage to the medium is made of Fe or Fe-Co and metalloid elements, which can be made into an amorphous thin plate using the so-called high-speed quenching method. We are making a proposal regarding a crystalline block body. However, the dummy blocks proposed above are still insufficient in terms of corrosion resistance. Further, there is a desire for further improvement in wear resistance, especially when the tape is run in contact at high speed with a shallow contact angle, such as when starting a recording tape. Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and provides a magnetic head, particularly a magnetic head having a core made of an amorphous magnetic alloy thin plate, with further improved wear resistance. Another main object of the present invention is to provide a magnetic head equipped with a novel dummy block having high corrosion resistance. 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 is made of a block body having a composition represented by the following formula [], and the core is a non-magnetic head having a composition represented by the following formula []. A magnetic head characterized in that it is formed from a crystalline magnetic alloy thin plate. [] Fe _p Y _q Cr _r Z _s {In the above formula [], Y represents Ni or a combination of Ni and one or more transition metal elements other than Co. Z represents B, P, B and P, or a combination of B, P or B and P with one or more of the A to A group elements. p+q+r+s=100at%, of which p
is 25-90at%, q is 0.1-30at%, r is 0.1-20at%
%, s is 5 to 50at%. } Formula [] T _x X _y {In the above formula [], T is Fe and Co,
or represents a combination of Fe and Co with one or more other transition metal elements, and X is B or Si
and B, or B or a combination of Si and one or more of B and other vitrifying elements. x+y
= 100 at%, and y is 20 to 27 at%. Furthermore, the amount of Fe is 1.5 to 5.6 at%, and the amount of Co is 45 to 78.5 at%.
It is. } 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 a block body having a composition represented by the above formula []. In the above formula [], Y is Ni or Ni and
Represents a combination with one or more transition metal elements other than Fe, Ni, and Cr. Other transition metal elements that may be contained in Y in combination with Ni may be any of (Sc~Zn; Y~cd; La~Hg; Ac or more), but in particular, Cu, Mo, W, V
One or more of the following are preferred. The content q of such Y is 0.1 to 30 at%. When q exceeds 30at%, wear resistance decreases,
Uneven wear increases. On the other hand, q is 0.1at%
In this case, the effects specified by the present invention become apparent, and the corrosion resistance and abrasion resistance become extremely good. In such Y, the essential components contained in Y
Ni content is 30at% or less, especially 0.1 to 30at%,
More preferably 2 to 25 at%, even more preferably 5
~20at%. With such a Ni content, both corrosion resistance and wear resistance become good. In addition, Fe, which is contained in Y as necessary,
The amount of other transition metal elements other than Ni and Cr is usually 10 at% or less under the condition that the total amount with Ni is 30 at% or less.
In particular, it is about 0.1 to 5 at%. On the other hand, the Cr content r is 0.1 to 20 at%. When r exceeds 20at%, uneven wear increases. In this case, if r is extremely small, the desired effects of the present invention will be less effective, so r is preferably 0.1 at% or more. And r is 0.1~20at
%, more preferably 5 to 15 at%, extremely favorable results are obtained in terms of wear resistance and corrosion resistance. On the other hand, the Fe content p is 25 to 90 at%. If p is any other value, the wear resistance will be insufficient. When p is 50 to 95 at%, extremely favorable results are obtained. Furthermore, Z is B, P, B and P, or B, P, or B and P and one or more of A to A group elements. Preferred examples of the A to A group elements other than B, P, and P that may be contained in combination with B, P, and B+P include one or more of Al, Si, Ge, and the like. In this case, when B and P are contained, their composition ratio can be set arbitrarily. Further, when A to A group elements other than B and P are contained in combination, it is preferable that the total amount of them is 15 at% or less. The content s of such Z is 5 to 30 at%.
Outside this range, wear resistance, corrosion resistance, etc. will still be insufficient. A block body having such a composition is substantially crystalline, and is manufactured by cutting into a predetermined shape after casting. 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 surface of the head that slides on the media remains stable. Good results are obtained in terms of less uneven wear and less fluctuation 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 density Bs and high retention. A composition represented by the following formula [] is preferable because it is suitable for a magnetomagnetic recording medium. 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 B or 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 the transition metal element whose essential components are Fe and Co is 73 to 80 at%, and the amount y of the vitrification element whose essential components are B or Si and B 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%, magnetostriction becomes large and 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 this way, when containing other transition metal elements other than Fe and Co, the total amount of these elements is 20at%.
The Co content is 47.4 to 78.5 at%, more preferably 47.5 to 78 at%, and the Fe content is 1.5 to 78 at%.
It is preferably 5.6 at%, 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. A thin plate having a composition as detailed above is an amorphous material 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, which will be described later, are similar, reducing uneven wear and deterioration of frequency characteristics and output fluctuations. 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 dummy block 3 is non-magnetic, as shown in FIGS. 2 and 3, the dummy block 3 is lined with a ferromagnetic lining part 6 provided in connection with a ferromagnetic shield case. The dummy block 3 may be fixedly housed in the case, and if it exhibits ferromagnetism, an adhesive may be applied to the non-magnetic support portion 5 provided in the case 4, as shown in FIG. It is also possible to securely store it using 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, using the dummy block of the magnetic head of the present invention, especially when combined with an amorphous core,
There is very little uneven wear, and very little increase in output fluctuations or deterioration of frequency characteristics. Also, there is less damage to the medium. It also has extremely high corrosion resistance. Furthermore, there is less wear during so-called cueing. In addition, crosstalk and induced noise are sufficiently small for practical use. Note that such an effect cannot be achieved with a dummy block whose composition does not contain Cr and Ni. 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 A master alloy was vacuum melted to have a composition of Fe ₅₅ Ni ₁₅ Cr ₁₀ (Si ₁₀ B ₉₀ ) ₂₀ at %, and after casting, 4×
It was cut into a size of 2 x 0.9 mm, spot welded into a shield case, and the corners were polished to obtain a dummy block 3 of the present invention 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℃.
It was run for 500 hours at 47.5cm/sec at 60% relative humidity, and the deterioration (dB) of the 14KHz/315Hz playback frequency characteristics (F special) and the output fluctuation (dB) of the 14KHz recording/playback output level were observed after running. It was measured. The results are shown in Table 1.

[Table] For comparison, Table 1 also shows the results when the dummy block 3 was formed from permalloy. In addition, the composition of the amorphous magnetic alloy thin plate forming the cores 2, 2' is as follows: one that does not contain Ru and Cr, or one that excludes Ru or Cr;
Furthermore, when similar experiments were conducted using Ti and Ta in addition to Ru and Cr, almost the same results were obtained. Example 2 Various dummy blocks having the compositions shown in Table 2 below were prepared in the same manner as in Example 1. A magnetic head was made from each of these dummy blocks in exactly the same manner as in Example 1, and the deterioration of the reproduction frequency characteristics (F characteristics) at 14KHz/315Hz was measured, and 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 47.5 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 500 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 corrosion resistance. Furthermore, at 40℃ and 70% relative humidity, γ-Fe ₂ O ₃
The tape was run for 1000 hours, and the amount of wear under high temperature and high humidity was measured using a surface roughness meter. In addition, crosstalk between 125 Hz, 160 nwb/m recording and playback tracks of each magnetic head 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 a dummy block made of the alloy of the present invention has less F-characteristic deterioration and less wear than when using a dummy block that does not contain Ni and Cr. , it can be seen that the corrosion resistance is high. Example 3 Wear resistance during cueing was evaluated using a commercially available audio cassette deck that has an auto-reverse mechanism and reads out a so-called Q signal for cueing. In this case, the tape running speed when reading the Q signal was approximately 1 m/sec. 14K after repeatedly running γ-Fe ₂ O ₃ tape (C-60) 100 times at 25℃ and 60% relative humidity.
The Hz output variation (dB) was measured. Table 3 below shows the results of magnetic heads using two types of dummy blocks: Fe ₆₀ Ni ₁₀ Cr ₁₀ B ₂₀ in Example 2 and Fe ₈₀ B ₂₀ for comparison.

[Table] From the results shown in Table 3, it can be seen that the dummy blocks of the examples containing Ni and Cr had little uneven wear and small output fluctuations during high-speed running during cueing.

[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 is composed of a block body having a composition represented by the following formula [], and the core has a composition represented by the following formula []. A magnetic head characterized in that it is formed from an amorphous magnetic alloy thin plate. Formula [] Fe _p Y _q Cr _r Z _s {In the above formula [], Y represents Ni or a combination of Ni and one or more transition metal elements other than Co. Z represents B, P, B and P, or a combination of B, P or B and P with one or more of the A to A group elements. p+q+r+s=100at%, of which p
is 25-90at%, q is 0.1-30at%, r is 0.1-20at%
%, s is 5 to 50at%. } Formula [] T _x X _y {In the above formula [], T is Fe and Co,
or represents a combination of Fe and Co with one or more other transition metal elements, and X is B or Si
and B, or B or a combination of Si and one or more of B and other vitrifying elements. x+
y=100 at%, and y is 20 to 27 at%. Furthermore, 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 Y is Ni or a combination of Ni and one or more of Cu, Mo, V and W. 3. The magnetic head according to claim 1 or 2, wherein the block body is substantially crystalline. 4. The magnetism according to any one of claims 1 to 3, wherein T is Fe, Co and Ru, or a combination of Fe, Co and Ru with one or more other transition metal elements. Head.