JPH0467433A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To optimize vapor deposition conditions and to obtain excellent magnetic characteristics by specifying the value of B.C/A.D within a 0.04 to 0.1 range when the pitch of the fine pores of notches is designated as A, the shortest distance between the pores, a vapor deposition drum as B and the oxygen blowing rate per unit hour per unit width as C, and a substrate feed speed as D. CONSTITUTION:Cobalt is used as an essential component and while oxygen is blown, a ferromagnetic metallic thin film is continuously formed with a rotating drum by a diagonal incident vapor deposition method. The value of B.C/A.D is specified within the 0.04 to 0.1 range when the pitch of the fine pores for blowing oxygen is designated as Acm, the distance between the fine pores and the vapor deposition drum as Bcm, the oxygen blowing rate per unit hour per unit width as C(cc/sec cm), and the substrate feed speed as D(cm/sec). The electromagnetic conversion characteristics of the Co magnetic film are improved in this way and the magnetic characteristics are uniformized.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a magnetic recording medium.

[Prior Art] Magnetic recording media that have been widely used in the past are coating-type media in which a magnetic layer is formed by coating a magnetic coating mainly consisting of acicular magnetic powder and a polymeric binder on a non-magnetic substrate. This is a magnetic recording medium.

Currently, there is a trend toward higher density magnetic recording TLT generation devices, and there is a demand for magnetic recording media with excellent short wavelength recording characteristics.

However, there are limits to the improvement of short wavelength recording characteristics in coated magnetic recording media. On the other hand, Co, CoNi,
Metal thin film type magnetic recording media, in which a ferromagnetic material mainly composed of Co, such as CoN1P or CoCr, is formed on a nonmagnetic substrate -L by vacuum evaporation, have a nonmagnetic binder mixed in the magnetic layer. Since there is no magnetic flux, a significantly high residual magnetic flux density can be obtained, and since the magnetic layer can be formed extremely thin, it has the advantage of high output and excellent short wavelength response. Due to this feature, thin film magnetic recording media have recently become the mainstream of magnetic media.

Thin-film magnetic recording media have a high magnetic recording density and excellent short-wavelength recording properties, but on the other hand, the cobalt is relatively easy to corrode, and because the magnetic layer is exposed, it is not monolithic and has poor magnetic properties. In addition to the disadvantage of being susceptible to deterioration, it also has the disadvantage of poor running performance, which is a problem unique to Amakawa.

In order to solve this problem, it has been proposed that, for example, when CO is vaporized, oxygen scum is sprayed onto the Co vapor to form a coating of Co oxide on the surface of the CO columnar particles. The presence of this Co oxide film improves the corrosion resistance and wear resistance of the Co@-based thin film.

[Problems to be solved by the invention] In order to obtain an excellent vapor-deposited raw fabric at a production pace, it is necessary to obtain an appropriate ratio of oxygen concentration and distribution, and to eliminate variations in properties (i.e., equalization of the oxygen concentration distribution). or is a necessary condition.

By the way, the introduction of oxygen gas is usually carried out by spraying 02 scum onto the evaporation surface from micro holes (nozzles) arranged in the [[] direction. B and C are small. On the other hand, from the point of view of increasing the oxygen degree and distribution in order to improve the characteristics, it is important to optimize other vapor deposition conditions.

Among these other deposition conditions, for example, 02 blowing 1) Is there a minimum distance (c-) between the holes and the deposition drum?When changing the holes, this shortest distance also does not change, and one characteristic It's not even a uniform film.

These steamers? I haven't been able to find any guidelines so far to make sure all the conditions are appropriate.

Therefore, an object of the present invention is to provide a method for manufacturing a magnetic recording medium that has excellent magnetic properties by optimizing the deposition conditions.

[Means for Solving the Problems] In order to achieve the above object, the present invention continuously deposits a ferromagnetic metal thin film on a rotating drum by an oblique incidence evaporation method while using cobalt as a main component and blowing oxygen into it. A method of manufacturing a magnetic recording medium comprising forming an oxygen-blown microporous hole.

1,000 is A cm, and the distance between the micropore and the deposition drum is B. □,
Oxygen blowing group in the middle of the middle time is C (cc/s
ec-cm), 1 and board feeding speed D (c-/5ec
), then B-C/A@I) (7) value is 0.04
Provided is a method for manufacturing a magnetic recording medium characterized in that the magnetic recording medium is within the range of -0.1.

In order to achieve uniformity in the direction and properties of the electromagnetic conversion characteristics, in addition to uniformity in the direction of force for oxygen introduction, it is necessary to ensure mechanical strength against sliding and to In order to obtain good magnetic properties, it is necessary to form a distribution in which the outermost surface of the magnetic grain R is CO0 and the inside is Co metal L.As shown in Figure 1, the distribution from the oxygen-enriched surface layer The intersection of the extension line and the horizontal axis is P
1 If the magnetic film thickness is OE and the surface oxygen 774 degrees is M (at%), 0P10E=0.08 to 0.13, and 50
A particularly preferable distribution state is when the condition of ≦M is satisfied.

The specific evaporation conditions to achieve this are as follows: the nozzle fine hole pitch is set to A1, and the shortest distance between the holes and the evaporation drum is set to B1.
When the amount of oxygen blown per unit width of burial time is 01 and the board feeding speed is D, the value of B・C/A@D is 0.04
It was discovered that it is sufficient if the value is within the range of ~0.1.

If the value of [B-C/A・■] is outside the above range, the characteristics may be poor because it does not conform to the oxygen distribution described above, or there may be problems such as unevenness in the characteristics due to non-uniformity of the oxygen degree. come.

In the production method of the present invention, Co alone or Co is -1:.

alloys such as CoNi, CoCr and C
This method can be applied to magnetic materials such as oFe.

“Let Co be 1:, the body” 7, Q is CO is 50
It means more than at%.

The manufacturing method of the present invention can be carried out when the magnetic material is obliquely deposited on a non-magnetic substrate. Vapor deposition is preferably performed by a vacuum evaporation method. The vacuum evaporation method is a method in which a ferromagnetic metal is heated in a vacuum to evaporate or multiply, and the vapor is deposited and condensed on a non-magnetic substrate to form a thin film.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

Devitrification 1 Using the electron beam heating evaporation apparatus 1 shown in FIG. 2, a CoNi film was formed using a PET film (10 μm thick) as the ferromagnetic metal material 3 and the Co-20wt%N I N substrate 5. At this time, the oxygen gas is
Microscopic oxygen blowing holes 9 were introduced at a predetermined pitch A using a certain type of screwdriver, but the deposition conditions at this time were A=0.
．． 5cm, B=l c+w, C:4 Qcc/n+in
, cm, D= 20 m/min B-C/A-D=
It was 0.04. In FIG. 2, reference numeral 11 represents an adhesion prevention plate, 13 represents a can, 15 represents an unwinding roll, 17 represents a take-up roll, and 19 represents an exhaust duct.

K hill 92 deposition conditions are A"0.5cm1B=0.7cm1C"
40 cc/m:n, cm, I) = 16m/min
, B*C/A-D=0.035, but under the same conditions as Example 1.

Disaster box 1 Vapor deposition conditions are A=0.7cm, B=1.0c-1C=
40cc/min, cm, l) = 18 m/min
It was produced under the same conditions as in Example 1 except that X B IIC/A-D = 0.031.

Stop tree LLL Vapor deposition conditions are A”0.5cm, B=2.5cm, C=
40 cc/min, cm, [) = 18m/min
, B was prepared under the same conditions as Example 1 except that C/A-D=0.111.

Stop tree d outside 2- Vapor deposition conditions are A=l 00m1B=1cm, C=30c
c/mln, cml D= 18 m/min 1
It was produced under the same conditions as in Example 1 except that B e C/ A *D = 0.017.

The 20-inch wide vapor-deposited original fabrics obtained in the Examples and Comparative Examples were used to prepare magnetic tapes with a width of 81 mm. The coercive force distribution in the width direction and electromagnetic conversion characteristics of these magnetic tape samples were measured using conventional methods. The results are summarized in Table 1 below. In Table 1 below, ΔHc max indicates the value of Hcmax-He ratio 1n for each sample. Further, the C/N ratio is expressed as the ratio of signal η voltage/noise voltage to MP (metal tape) during medium wavelength recording.

As is clear from the results shown in Table 1 above, the magnetic tape samples prepared according to the embodiments of the present invention have excellent coercive force distribution uniformity and excellent electromagnetic conversion characteristics.

[Effect of the invention] As explained above, according to the production method of the present invention, Co
It is possible to improve the electromagnetic conversion characteristics of the system magnetic film and to make the magnetic characteristics uniform.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the oxygen concentration distribution in the depth direction of the Co-based magnetic film, and FIG. 2 is a characteristic diagram showing the oxygen concentration distribution in the depth direction of the Co-based magnetic film.
FIG. 3 is a schematic diagram of the vacuum evaporation apparatus used to produce the oNi magnetic film, and FIG. 3 is an enlarged schematic perspective view of the nozzle portion thereof. ■...Vacuum deposition equipment, 3...Ferromagnetic metal. 5... Board, 7... Oxygen blowing nozzle. 9... Oxygen blowing hole, 11... Anti-adhesion plate. 13... Can, 15... Unwinding roll. 17... Winding roll, 19... Exhaust duct Diagram Magnetic film〉Military

Claims (1)

[Claims] (1) While blowing oxygen into the main component of cobalt,
In a method for producing a magnetic recording medium, which comprises continuously forming a ferromagnetic metal thin film on a rotating drum by an oblique incidence evaporation method, the pitch of the oxygen-blown micropores is Acm, the distance between the micropores and the evaporation drum is Bcm, When the amount of oxygen blown per unit time unit width is C (cc/sec cm) and the substrate feeding speed is D (cm/sec), B C
A method for manufacturing a magnetic recording medium, characterized in that the value of /A·D is within a range of 0.04 to 0.1.