JP2569833B2 - Manufacturing method of high permeability magnetic alloy with excellent wear resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a high-permeability magnetic alloy having excellent wear resistance and a method for producing the same. The wear resistance impairs the magnetic properties of a substrate by forming BN. We want to improve without.

The present invention relates to a high-permeability magnetic alloy having excellent wear resistance used for a magnetic head core material, a shield case material, and other magnetic shield members.

(Prior Art) When a high-permeability magnetic alloy is used for a magnetic tape recording / reproducing device for audio and VTR, abrasion of a magnetic head by a magnetic tape is a serious problem.
That is, when the magnetic head is worn, problems such as a decrease in adhesion between the tape as the magnetic recording medium and the magnetic head, a remarkable decrease in the reliability of recording and reproduction due to a change in the magnetic head gap depth, and a change in head characteristics are caused. However, the core material of the magnetic head and the shield material such as the shield case, which were conventionally used, were mainly Mo Permalloy materials equivalent to JIS PC, but their hardness was as low as about 120 Torr even after magnetic annealing. For this reason, the wear by the magnetic tape was remarkably severe.

On the other hand, in order to improve the wear resistance, a technique of adding a strengthening element such as Nb or Ti to increase the hardness has been proposed. That is, in JP-B-47-29690 and JP-B-47-25697, high magnetic permeability and high hardness are simultaneously achieved by adding an appropriate amount of Nb.

Japanese Patent Application Laid-Open No. 50-51413 discloses that Mo 0.3-2%, Nb 0.3-1.2
% And 0.5 to 6% of Ti are added to simultaneously achieve high magnetic permeability and high hardness.

(Problems to be Solved by the Invention) In the above-described conventional technology, the saturation magnetic density is reduced by adding Ti, Nb, or the like. That is, the magnetic flux density when a magnetic field is applied in 100e in any of the prior art (hereinafter referred to as B ₁₀₎ is at most 6500 g, is B ₁₀ with the original PC permalloy becomes low when the value of 7500~8000G . Thus if the magnetic flux density has a magnetic head using a slightly lower permalloy, high dynamic range is somewhat s narrowed compared to permalloy 7500~8000G in the B _10, also with extremely high holding force In today's increasing number of cases where magnetic tapes for recording density are used as recording magnetic heads, it has become difficult to say that satisfactory performance is exhibited.

Furthermore, in order to respond to recent demands for current sound reproduction and clearer reproduced images, it is essential to prevent the head characteristics from deteriorating with time. For this reason, any head material requires a higher wear property. It has arrived. For such a demand, it is conceivable to further add a strengthening element to the current component, but in this case, as described above, the problem of further lowering B ₁₀ or the balance of the component is lost. A problem arises that permalloy cannot exhibit its original magnetic properties, so that it is far from practical. That is, although there is a great demand for a material for a magnetic head having higher wear properties while maintaining the current magnetic properties, such a material has not yet been obtained.

"Constitution of the Invention" (Means for Solving the Problems) The present invention has been made by repeatedly studying to solve the problems in the conventional one described above, and relates to a conventional permalloy for a magnetic head. The magnetic properties thereof are to further improve abrasion while maintaining the conventional level, and are as follows.

1. High Ni-Fe alloys as base material: Ni: 35 wt% or more and less than 82 wt%, C: 0.010 wt% or less, Mn: 1.5 wt% or less, O: 0.0030 wt% or less, S: 0.0020 wt% or less , P: 0.0050% by weight or less, B: 0.0010-0.0050% by weight, N: 0.0010-0.0050% by weight, and 0.5 ≦ [B] / [N] ≦ 1.5. Cu, Cr, Nb, Ti, Si
Of a high Ni-Fe alloy containing 1 to 10 wt% in total and containing Fe and inevitable impurities to form BN 25 to 200 mm on the surface A method for producing high permeability magnetic alloys with excellent wear resistance.

(Action) The present invention provides a BN having a specific thickness on the surface of an Fe-Ni-based alloy containing 35 to 82% of Ni as a base material without deteriorating its magnetic properties. The technical point is to improve the wear property, the technical point is to form B and N added in appropriate amounts in the high Ni-Fe alloy of the base material as a dense BN during the final magnetic annealing on the surface of the base material, and Appropriate amounts of B and N and the limited thickness of BN do not impair the original magnetic properties of the Fe-Ni alloy of the base material.

Reasons for limiting the constituent elements of the present invention are as follows.

BN improves the abrasion resistance to the tape by being formed on the surface of the magnetic head material of the Fe—Ni alloy targeted in the present invention. If the thickness is less than 25 mm, the above effect cannot be obtained properly. Therefore, the lower limit of the BN film thickness is 25 mm. Note that the upper limit is 200 °, and if it exceeds 200 °, economical efficiency at the time of manufacturing is inferior, and magnetic properties and other properties as a high-permeability magnetic alloy deteriorate.

In the formation of BN, B may be subjected to magnetic annealing with or before or after magnetic annealing of the base material, chemical vapor deposition including B, physical vapor deposition, sputtering, ion beam, ion plating, dropping, etc. Alternatively, a method may be used in which B and N added in appropriate amounts to the Fe-Ni alloy are formed as dense BN on the surface of the base material during the final magnetic annealing.
The formation of BN by magnetic annealing can be performed in any atmosphere. However, in order to further enhance the denseness of the BN film to be formed, it is preferable that the atmosphere at the time of cooling be a vacuum. If so, its denseness is further improved.

In the case where BN is formed at the time of final annealing as described above, it is preferable to limit the chemical composition of the Fe-Ni-based alloy of the base material, and the reason for limiting the chemical composition of the Fe-Ni-based alloy of such a base material. Is expressed as wt% (hereinafter simply referred to as%) as follows.

Ni is a basic component of the present alloy. If the Ni content is less than 35% or 82% or more, the magnetic properties of the alloy of the base material deteriorate, and the properties as a soft magnetic material cannot be exhibited. Ni was set to 35% or more and less than 82%.

C exists as an interstitial element in the target alloy of the present invention, and when its amount is large, the magnetic permeability is reduced. Therefore, C is a harmful element to the magnetic properties. Since the deterioration was remarkable, this was set as the upper limit.
C is also an element harmful to the formation of BN on the surface of the base material during magnetic annealing, and if it exceeds 0.010%, the suppression of BN formation becomes remarkable. Therefore, the upper limit is set to 0.010% in this sense. In order to further increase the denseness of the formed BN and further improve the wear resistance, it is preferable that C be lower.

If Mn exceeds 1.5%, hot workability deteriorates, so the upper limit was made 1.5%.

O is present as an oxide-based inclusion in the alloys targeted by the present invention, and if its amount is large, it inhibits grain growth during final hydrogen annealing, and the grain size during annealing is small, so that the magnetic permeability is improved. It is an element that is extremely harmful to magnetic properties because it does not. That is, if the O content exceeds 0.0030%, the soft magnetic properties deteriorate as described above, so 0.0030% was made the upper limit.

P is detrimental to the hot workability of the high-Ni-Fe alloy targeted in the present invention, and significantly reduces the formation of BN on the high-Ni-Fe alloy surface during final annealing, which is characterized by the present invention. Harmful. That is, this P segregates on the substrate surface before the formation of BN,
This is because the formation of BN is suppressed. When P exceeds 0.0050%, the formation of BN is significantly suppressed, so this is set as the upper limit.

S is extremely harmful to the hot workability of the high Ni-Fe alloy targeted in the present invention, and inhibits grain growth during final hydrogen annealing through formation of sulfide, and the grain size after annealing is small. Therefore, since the magnetic permeability does not improve, it is an extremely harmful element to the magnetic properties. Further, like P, it is a harmful element that segregates on the substrate surface before the formation of BN and suppresses the formation of BN. If this S exceeds 0.0020%, hot workability,
Since the magnetic permeability deteriorates and the formation of BN is significantly suppressed,
The upper limit was 0020%.

Mo, Cu, Cr, Nb, Ti, and Si are high Nis targeted in the present invention.
-It is an element effective for improving the magnetic properties and wear resistance of the Fe alloy base material. Each of these elements is effective when the total amount of 1% or more alone or in combination of two or more types is 1% or more. However, if the total amount of these elements alone or in combination of two or more types exceeds 10%, the magnetic properties, especially the saturation magnetic density, decrease. Therefore, when higher wear resistance is required while improving magnetic properties, 1 to 10% of these elements alone or in total is added.

As described above, B is an essential element together with N for BN precipitation on the surface of the alloy base material targeted in the present invention. If this B is less than 0.0010%, BN can be formed only less than 50 ° after magnetic annealing, so the lower limit was made 0.0010%. B is 0.00
If it exceeds 50%, the magnetic properties of the high Ni-Fe alloy of the base material deteriorate, so the upper limit was set.

N is an essential element in the present invention like B, and if less than 0.0010%, BN can form less than 25 ° after magnetic annealing, so the lower limit is 0.0010%. Note that this N
If it exceeds 0.0050%, the magnetic properties of the high Ni-Fe alloy of the base material are significantly deteriorated, so the upper limit is made 0.0050%. Further, in order to further suppress the deterioration of magnetic properties due to N, it is necessary to set the amount of N in a range satisfying 0.5 ≦ [B] / [N] ≦ 1.5 in accordance with the amount of B.

(Examples) Specific examples of the present invention will be described as follows.

Example 1. A high-Ni-Fe alloy of the present invention and a comparative alloy having the chemical components shown in the following Table 1 were melted in a vacuum and melted, hot-worked, and descaled. Prepared as a cold rolled material.

Each material shown in Table 1 was cold-rolled and annealed to form a 0.1 mm thin plate sample. A JIS ring having an outer diameter of 10 mm and an inner diameter of 6 mm was punched out of these samples to obtain samples. The magnetic properties of these samples were measured by holding them at 1100 ° C for 3 hours in a dry hydrogen atmosphere.
BN was formed on the surface (however, test materials Nos. ^6, 10 and 26 did not contain B and thus did not form BN), and were then measured with a sample obtained by cooling under a vacuum of 1 × 10 ⁻⁶ Torr. The effective magnetic permeability at 1 KHz at 5 mOe and the magnetic flux density when an external magnetic field of 1000 A / m at DC were applied were determined. The BN film thickness was determined by Auger analysis of the ring sample surface after the magnetic annealing.

The abrasion depth was measured using a cassette deck with a measured magnetic tape at normal temperature and normal humidity, and the magnetic tape was replaced every 100 hours, and was measured after a total of 500 hours. The results are shown in Table 2 below.

That is, No. 1, 3, 5, 7, 9, 13, 15, 17, 19, 21,
Each of the materials 23 and 25 has Ni, Mn, C, O, S, P, B and N amounts and [B] / [N] within the range specified in the present invention, and the BN film thickness is 25 ° or more. The wear depth is smaller and the wear resistance is excellent as compared with the comparative example of the same component system. On the other hand, in each of Nos. 2, 16, and 24, the P amount exceeds the upper limit of the present invention, and in each of Nos. 6, 10, 20, and 26, the B amount exceeds the upper limit of the present invention. Although, the BN film thickness is less than 25 mm, the wear depth is greater than the invention example of the same component system,
Poor wear resistance. In other words, in order to form BN of 25 mm or more for the purpose of securing abrasion resistance intended in the present invention, B,
It was confirmed that this can be achieved only by adding an appropriate amount of N and reducing the amounts of C, P and S. No.4, 6, 8, 10, 14, 1
The magnetic properties of the materials 8, 20, and 22 are lower than those of the alloy of the present invention having the same component system. In these comparative materials, C,
The content of any of O, B, S, and N exceeds the upper limit of the specified range of the present invention. Therefore, the predetermined magnetic properties are not obtained unless these components are within the specified range of the present invention. It is understood that it is exerted.

In addition, in the No. 12 material, the B content exceeds the upper limit of the specified range of the present invention, and other components are within the specified range of the present invention.
Although the film thickness is larger than the BN film thickness of the No. 11 alloy material of the same component system as 180 ° and has excellent wear resistance, the magnetic characteristics are clearly lower than the No. 11 material of the present invention example . That is, it is understood that the addition of B beyond the range specified in the present invention deteriorates the magnetic properties.

`` Effect of the Invention '' According to the present invention as described above, the wear resistance can be further improved at low cost without impairing the magnetic properties of the high Ni-Fe based high permeability magnetic alloy,
When this alloy of the present invention is used as a core for a magnetic head, a shield plate for a magnetic head, a case material for a magnetic head, etc., the alloy exhibits excellent magnetic properties and is further improved in abrasion resistance. This is an invention which is industrially effective because it can further increase the life and reliability of the magnetic head and can appropriately respond to recent demands of the electronics industry.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyoshi Ohkita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (56) References JP-A-62-275308 (JP, A) JP-A Sho 63-92385 (JP, A) JP-A-63-297578 (JP, A)

Claims (1)

(57) [Claims] 1. A high Ni-Fe alloy as a base material comprises: Ni: 35 wt% or more and less than 82 wt%, C: 0.010 wt% or less, Mn: 1.5 wt% or less, O: 0.0030 wt% or less, S: 0.0020 wt% or less, P: 0.0050 wt% or less, B: 0.0010 to 0.0050 wt%, N: 0.0010 to 0.0050 wt%, and in a range satisfying 0.5 ≦ [B] / [N] ≦ 1.5. , Mo, Cu, Cr, Nb, Ti, Si
Of a high Ni-Fe alloy containing 1 to 10 wt% in total and containing Fe and inevitable impurities to form BN 25 to 200 mm on the surface A method for producing high permeability magnetic alloys with excellent wear resistance.