JPS6035325A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To attain magnetic characteristics and corrosion resistance which are comparable to or higher than those of a Co-Ni alloy at a low cost by using Fe as the principal component of a magnetic layer to be formed by a thin film deposition method, and adding fixed percentages of Co, Ni and other specified substance to Fe. CONSTITUTION:A magnetic layer is formed by a thin film deposition method such as vapor deposition by induction heating, vapor deposition by resistance heating, vapor deposition with electron beams, sputtering, ion plating or plating using an Fe-base material contg. Co, Ni and at least one among V, Nb, Ta, Mo and W. The desirable composition of the magnetic layer is represented by a formula (Fe1-xCox)1-(a+b)NiaXb, wherein X is at least one among V, Nb, Ta, Mo and W, 0<x<=0.5, 0.05<=a<=0.25, and 0.005<=b<=0.12 (weight ratio). The especially desirable composition consists of, by weight, 2-10% in total of one or more among V, Nb, Ta, Mo and W, 8-20% Ni, 15-40% Co and the balance Fe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium formed by a thin film deposition method, particularly to a magnetic recording medium with excellent corrosion resistance.

In recent years, research and development into manufacturing magnetic recording media using thin film deposition methods such as Mashiba deposition, sputtering, and plating have become active. Magnetic recording media made using these manufacturing methods very well satisfy the conditions for high-density recording, such as ■high residual magnetic flux density, ■ability to increase coercive force, and ■ability to make the magnetic layer thinner. . Conventionally, alloys containing CO and N1 as main components have been mainly used as magnetic materials for this recording medium, and among them, an Oo -20% N1 alloy has been widely studied. The reason for this is that this alloy has relatively good corrosion resistance, and the alloy beam containing 70 W't% or more of Co.
This is said to be because it has a c, , p structure, makes it easy to control magnetic anisotropy, and makes it easy to achieve excellent in-plane anisotropy. However, since this alloy contains 70% or more, usually around 80%, of CO, it is extremely expensive, and CO has the problem that its price fluctuates greatly due to changes in the international situation. In addition, corrosion resistance is insufficient for severe environmental conditions.

Therefore, the present invention aims to improve the above-mentioned drawbacks, reduce CO content, provide a magnetic recording medium that can be stably supplied at low cost, and has excellent performance in terms of magnetic properties and corrosion resistance. Its main purpose is to provide magnetic recording media.

In the present invention, a magnetic recording medium formed by a deposition method is characterized in that its magnetic layer mainly contains Fe, contains Co and N1, and further contains at least one of V, Nb, Ta, Mo, and W. It can be formed using a thin film deposition method such as a 1% induction heating evaporation method, a resistance heating evaporation method, an electron beam evaporation method, a sputtering method, an ion blasting method, or a plating method.

As the magnetic layer material, the sum of Co element and Fe element is 60vr.
Oo element is replaced with Fe so that Ire becomes the main component at t% or more.
By substituting elements, the magnetic properties can be changed from the conventional Oo
-It was recognized that an equivalent or better quality than the M1 alloy could be obtained. However, the corrosion resistance deteriorates by replacing the oo element with the Fe element, but V, Nt), Ta,
Mo.

By adding the W element alone or in a mixture at an appropriate ratio, it was possible to achieve an improvement equal to or higher than that of the conventional Oo-M1 alloy in terms of corrosion resistance without impairing the magnetic properties.

The magnetic recording medium of the present invention will be explained in more detail.

In the magnetic material used in the present invention, the Fe element increases the magnetic moment per atom, increases Br (residual magnetic flux density), and at the same time increases malleability and prevents the occurrence of cracks and cracks in the magnetic layer. On the other hand, as mentioned above, as the Fe element increases, the corrosion resistance deteriorates rapidly, and at the same time, the residual magnetic flux density B
The effect of increasing r is rather reduced. In addition, N1 has the effect of improving corrosion resistance and spreading property, and prevents cracking of the magnetic layer.
Prevents cracks from forming. Also, V, N'b, Ta,
By adding Mo and W alone or in a mixture,
In addition to improving corrosion resistance, it is also effective in improving the wear resistance of the magnetic layer. However, if the amount added is too large, the magnetic properties of the equimagnetic layer in which Br is reduced will be deteriorated.

As a result of the above, a good magnetic layer composition is (Fez −
x 00x ) l-(a+b) Nia XbXwV
, IJb, Ta, Mo, and W (7) are a kind of ash, and the Chongchang composition ratio is 0 < x < 0.5, 0.0
5<, a<o, 25° and o, oos<b<o,
12 ranges, especially V, Wb, 'f&, Mo
, W alone or in total is 2 to 1 Dwt%.

Ni is 8 to 20 wt%, Oo is 1 shi (Owt%,
It is preferable that the remainder be Fe. Furthermore, the optimal composition is
V, Wb.

Ta, Mo, and W are non-German or 2 to 9 wt% in total, N
i is 10-16 wt%, co is 20-60 wt%, and the rest is in the Pg(7) range.

The present invention will be explained below with reference to Examples. FIG. 1 shows an apparatus for manufacturing vapor-deposited tape, which is one of the magnetic recording media. A film unwinding shaft 2, a winding shaft 6, an intermediate reel roller 4, a cooling can 5, a vapor deposition material storage container 7, and an electron beam generation source 8 are arranged in a vacuum chamber 1, Ml 100 mm,
A polyethylene terephthalate film 9 having a thickness of 15 μm is sent from the film unwinding shaft 2 to the film winding shaft B via an intermediate free roller 4 and a cooling can 5. The vapor deposition material 6 is placed in a vapor deposition material storage container 7, placed opposite the cooling can 5, and heated by an electron beam from an electron beam generation source 8. The heated vapor deposition material becomes a vapor flow 6' and adheres to the film 9 on the cooling can 5 to form a magnetic layer, but is prevented by the deposition prevention plate 11 from forming the magnetic layer. Inside the vacuum chamber 1, the degree of vacuum during film formation is maintained at 1 by an exhaust device 1o.
．． The pressure was maintained at X10 to 5 X10 Torr. The film feeding speed was 10 m/min, and the thickness of the formed magnetic layer was approximately 1000A.

FIG. 2 shows the composition of the magnetic layer of the vapor-deposited tape produced by the above method and the results of the corrosion resistance test. Corrosion resistance test was performed by placing the above tape in a constant temperature and humidity chamber at 6ffC and 90% humidity for 100D.
After allowing the tape to stand for a period of time, the change in residual magnetic flux density 11r of the tape was measured. In Figure 2, ◎ means the decrease in Br is less than 5%, No. 0 means 5-10%, and × means 10%.
represents the above.

Figure 6 shows the playback output when recording and playing back using a home VTR deck. Curve 20 shows the playback output of tape AB of the present invention, and curve 21 shows the playback output of Oo-Ni tape A5 produced under the same conditions for comparison. The playback output of the tape of the present invention is equivalent to or approximately 2 dB compared to the conventional tape A5.
expensive. (from A6 table), &7, A11 in Figure 2
, Ni-14, A17, and A19 composition tapes also had good corrosion resistance and at the same time, a reproduction output higher than that of the Go-Ni tape was obtained.

As mentioned above, since the magnetic recording medium number of the present invention has Fθ as its main component, the conventional magnetic recording medium number Qo −N has CO as its main component.
In addition to being much cheaper than i-alloy recording media, the addition of a small amount of V, IJb, Ta, Mo, and W reduces corrosion, which is a drawback of magnetic recording media whose main component is Fθ. It has a reproduction output and corrosion resistance that are equal to or higher than Oo-Ni alloys.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the vapor deposition tape manufacturing apparatus used in this example. FIG. 2 is a table showing a comparison between the composition of the magnetic layer and the results of the corrosion resistance test. FIG. 6 is a graph showing a comparison of reproduction outputs of the A6 tape in FIG. 2 and the Co-Ni tape at each frequency. 1... Vacuum chamber, 2... Film unwinding shaft, 6...
Film end-of-life axis, 4es threat middle 7 Lee 4-ra, 5...
・Cooling can, 6... Vapor deposition material, 7... Vapor deposition material storage container, 80・Electron beam generation &, 9 oss polyethylene terephthalate film, 10-・Exhaust device, 1
1..φ adhesion prevention plate, 20.. Reproduction output curve of an example of the present invention, 21. Reproduction output curve of fist.Co-Ni. 119 Procedural amendment (method) ■ Indication of the case 1982 Patent application No. 144112 2 Name of the invention Magnetic recording medium 3 Person making the amendment 1 ■ Person with Ding I 4I Patent applicant (l Jlli Tokyo resident III II) f” Do Maruko 3-
30-21.1) Location b: ++46 East All Tue t, l (
Ward Yζmaru f-3-30-2 Kijutsuno Co., Ltd. (Telephone 7
5B-2111) 5. Date of amendment order: November 290, 1982 (shipment date) 6. Specification subject to amendment, engraving of detailed statement of contents of amendment (no change in content).

Claims (1)

[Claims] (1) In a magnetic recording medium having a magnetic layer formed by a thin film deposition method on a nonmagnetic substrate, the magnetic layer mainly contains Fθ, contains co and N1, and further contains V and Nb.
, Ta, Mo, or W. ■The composition of the magnetic layer is (Fθx −x aox) 1−(a+b) Nia
xbX-V, at least one of Nb, Ta, Mo, and W, the weight composition ratio is O<
05<a<0.25. and 0.005 <b<0
．． 12. A magnetic recording medium according to claim 1.