JPS60182015A - Vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a vertical magnetic recording medium which is provided with required mechanical strength and workability and has a uniform magnetic film by forming a substrate of a material having excellent mechanical strength and workability, for example, an Al alloy or the like and forming a high-purity Al layer by a method using vapor growth such as vapor deposition on such substrate. CONSTITUTION:An Al alloy AA5086 is subjected to finishing to a specular surface and a pure Al layer is formed on the surface thereof by electron beam vapor deposition using high-purity Al as a raw material. The alloy is thereafter subjected to an anodic oxidation treatment in an oxalic acid bath to obtain an anodized film. The alloy is then immersed in a mixed bath consisting of sulfamic acid and phosphoric acid to expand the pores and in succession the alloy is subjected to AC electrolysis in the soln. of ammonium iron (II) sulfate and boric acid to deposit iron in the pores. The number of defects of the vertical magnetic recording medium is decreased by forming the pure Al layer on the Al alloy plate in the above-mentioned way. The good magnetic characteristic is obtd. if the high-purity Al film having the characteristic of 2.7-3.2muOMEGAcm electric resistivity rho is used as the high-purity Al film to be formed on the Al alloy substrate.

Description

[Detailed description of the invention]

3.1 Technical Field of the Invention The present invention relates to a perpendicular magnetic recording material obtained by filling a ferromagnetic material into micropores (hereinafter referred to as bores) formed in an anodized film of At or its alloy. It is. 3.2 Behind the Technology 1 There are two methods for recording digital signals on magnetic recording media: an in-plane recording method in which the magnetic layer is magnetized horizontally to the surface, and an in-plane recording method in which the magnetic layer is magnetized in a direction perpendicular to the surface. , a perpendicular recording method that magnetizes in the thickness direction. Conventionally, a longitudinal recording method has been used, but in recent years, with the increase in recording density and the increasing burden on people, perpendicular magnetic recording media with excellent high recording density have become popular, and are being put into practical use in various places. Optimization research and development is in progress. 3.3 Problems with conventional technology When the alloy Δ or A is anodized in an acid or alkaline bath, an At oxide film is formed on the surface. A bore is formed with the axis perpendicular to the surface to the right. By electrolyzing this in a solution containing a ferromagnetic metal salt A, the bore can be filled with a ferromagnetic material. The magnetic film obtained in this manner has an easy magnetization direction perpendicular to the film surface, and the magnetic properties can be varied over a wide range depending on the film formation conditions. , strong I in the bore produced by anodizing treatment.
It is possible that a material filled with silica can be used as a single perpendicular magnetic recording medium. When creating a magnetic recording medium for the LA disk 19 using the principle described above, it has conventionally been common to use an alloy for Δ as the substrate, but when using an At alloy as the base, Impurities such as intermetallic compounds and nonmetallic inclusions contained in the alloy, and surface defects such as bottle balls! In other words, it is not possible to obtain a uniform anodic oxide film in the long axis direction (bore diameter - X') or in the distribution ratio. Furthermore, when such a film is filled with a ferromagnetic material to form a perpendicular 18-magnetic recording medium, the surface defects cause dropouts of recording signals, crashes of the magnetic head, and the like. There were drawbacks such as. Intermetallic compounds and nonmetallic inclusions will still be introduced to some extent during various processes such as melting, VI forming, and rolling, even if the purity of the raw materials used to make Δ is increased. is unavoidable. Therefore, from the viewpoint of obtaining a uniform magnetic film, it is desirable to use 111A/- as the substrate. However, on the other hand, pure At has weak mechanical strength and poor workability, so when it is formed into a thin plate such as a rotating magnetic disk, it is difficult to process the surface into a mirror finish. Therefore, pure At is also inappropriate to be used as a substrate for a rotating magnetic disk. 3.4 Purpose of the present invention In view of the above points, the present invention provides a method for manufacturing a rotating magnetic disk.
It has the required single-layer structural strength and workability when
The present invention also aims to provide a perpendicular magnetic recording medium having a uniform magnetic film. 3.5 Structure and Effects of the Present Invention In order to achieve the above object, the present invention has the following features:
High-purity Alt is formed by vapor phase formation such as evaporation, olefining, sputtering, etc., and the estimate is (^1). When manufacturing, the At alloy plate has high mechanical strength and good workability, so the predetermined processing viscosity is
be qed. In addition, when anodizing is performed, the collar is treated with high-purity rubber, so it is not affected by impurities or surface defects.

[ ) A uniform anodic oxide film can be obtained. Therefore, if the magnetic material filling treatment is applied to the substrate on which the #3 polar oxide film is placed on the right side, the recording signal dropout error 1-
It is possible to obtain a highly reliable and safe perpendicular 18-degree recording medium that does not cause magnetic head crashes or the like. 3.6 Examples of the present invention Next, some examples of the present invention will be described. Example 1 The At alloy ΔΔ50BG, which is generally used as a substrate for magnetic disks, was CvL-cut on a Thai X7 Monde lathe.
There are 11 layers on the surface, and the surface has a pure lff99.99.
Electron beam evaporation was performed using 9% high-purity At as a raw material to form a pure At layer with a thickness of 19 and 5 μm. After that, 3wt
(Quickly) 1st column at 20℃ and DC40V in a % sikolic acid bath.
The anodized film with a thickness of 4 μm was then immersed in a mixed bath of 5 wt% sulfamic acid and IIN% phosphoric acid at 30°C for 20 minutes to enlarge the bore. 5
AC electrolysis was carried out in a wt% am[nium ferrous sulfate and 3W% boric acid solution to precipitate iron in the bore. After that, the surface was polished by about 2 μm, and the surface mj was observed under a microscope to check the size and number of defective parts. Table w1 area 1m+8
Table 1 shows the results of the investigation regarding 2. For comparison, the results of examining the defects when the same month 1.1 (AA508G), which was not subjected to vapor deposition, was treated in the same manner are shown in Table 1 (71). Example 2 Instead of the vapor deposition of Example 1, the same Purity 99°999%
A film with a thickness of 5 μm was formed using high-purity At as Tergutsu 1 using the C magnetron sputtering method. Other processing is the same as in the first embodiment. The results of counting the defective parts are shown in Table 1. Example 3 Instead of the vapor deposition in Example 1, an ion-blating method was used to form a 5 μm thick film of high purity Δ. Other processing is the same as in the first embodiment. The number of defects is shown in Table 1. Table 1 3.7 Description of Embodiments As mentioned above, by forming a pure At layer on an At alloy plate, the number of defects in a perpendicular magnetic recording medium can be significantly reduced. As a result of detailed experiments on At mtA grown in a vapor phase in order to obtain good magnetic properties as a perpendicular magnetic recording medium, the present inventor found that high-purity A temporarily formed on a Δ-alloy.
The characteristics of the T film are C1 electrical 11 (resistance ρ is 2.7 to 3.2
It was found that μQcrn had better magnetic properties by 1:7. In the experiment, pure Δ was made L+ by avoiding various conditions such as vacuum degree during film formation, solidification JXim degree, substrate temperature, etc., but the higher the vacuum degree, the lower the electrical resistivity. ,I19
The higher the growth rate, the lower the electrical resistivity. However, when I changed the temperature of the base 4 (t), the electricity 11 (changed to the rate of li") did not occur. I made the above-mentioned articles by changing the anode or made a temporary one under the same conditions. After performing oxidation treatment, bore enlargement treatment, and magnetic substance precipitation treatment, we measured the characteristics of the magnetic film. As a result, the coercive force 11c (±
゛, (Jpo constant l)
111 is 1°I, or the saturation magnetic flux density 13s is pure Δl
It was found that it depends largely on the electrical resistivity of . The results are shown in FIG. In the same figure, the solid line, chain line, and dashed-dotted line show the measurement results of the film by W COD (J), the film by IAN ZORADING method, and the film by J, sputtering method, respectively. When used as a medium, the larger Bs is, the better the signal-to-noise ratio of the TI'i raw signal and the higher the recording density. It can be seen from this measurement result that a material having an electrical resistivity ρ in the range of 2°7 to 3.2 μΩam is suitable.

[Brief explanation of the drawing]

FIG. 1 is a graph C showing the relationship between the electrical resistivity and the saturation magnetic flux density of the high-purity At layer of the substrate according to the present invention. 14th edition Applicant Shun Takahashi Part 2.5 3.5 Electric transmission rψΩcml 1'T +i'l Agency Director Kazuo Wakasugi 1, =I;
fl display Showa ()0zu12LI2ε31] I'l I! f of 2
l Please RT 1) 2. Name of invention Q'-, sin,
'-Metaru Self-Magnetic Recording Medium 3, Correction 4 Riruseki "Old '1 Which Relationship 1:1 Mu' 4. Agent〒105 (111i middle 5rr capital port 1me leopard i bridge 3) eye'155th bow (3, n + li iE pair (() 明1i'1llf!f's 'l'l i1'l Contents of Scope of Claims Column and Revised Explanation of Invention Column 7, Sleeve 11- 8.1” ”・ Attachment J3 Re '59.3.74. Contents of amendment (1) The scope of claims is attached as an attachment. Noto d3 has been corrected. 2) From "L'A4 Alloy" on page 4, line 15 of the detailed description, up to line 18 has been corrected as follows. 1. Excellent mechanical strength and workability. For example, △ is an alloy, glass, hard 7' (plastic, relamic, etc. (hereinafter typically referred to as At alloy)) C substrate is made, and a chemical process such as vapor deposition, ion brain ink, or sputtering is applied on the substrate. Noj2), -c high purity △tFi by phase growth
was formed. (3) Specification -) Correct 1 JJ plate-1 on page 14, line 19 to 1 magnetic recording medium. (4) Specification C, page 9, da 18? In the darkness of the jth line and the 9th line, enter the following sentence. In the first embodiment, an At alloy is used as a substrate and the LC is developed. J! Is there a similar outcome when using trade plastics or reramic?
It seems that it will be J. ''lll i'f range of quality (1) j' Positive 4 of aluminum (hereinafter referred to as At)
This is a perpendicular magnetic recording medium manufactured by filling a strong 141 material into a small amount of oxide skin 114) produced by eJ:4i oxidation treatment. A perpendicular magnetic recording medium is formed using C as a substrate and is highly purified on this substrate by a vapor phase growth method such as evaporation, ion plating, or sputtering. (2) The high Tk degree At layer has an electrical resistivity of 2.7. To 3
．． The perpendicular magnetic recording medium according to claim 11ji of the 14th edition, characterized in that the perpendicular magnetic recording medium is in the range of 2 μΩcm.

Claims (2)

[Claims] (1) The substrate of a perpendicular magnetic recording medium, which is manufactured by filling a ferromagnetic material into the fine pores produced by anodizing, is made of aluminum (hereinafter referred to as F) alloy by vapor deposition,
A perpendicular magnetic recording medium characterized in that a high-purity A1 layer is formed using the h method 'C' by vapor phase growth such as ion brazing or sputtering. (2) The electrical resistance of the high-purity At layer is 2.7 to 3.2
The perpendicular magnetic recording body according to claim 1, characterized in that the perpendicular magnetic recording body can be set within the range of μOff+.