JPH0357538B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic storage device (magnetic disk device,
magnetic storage bodies used in magnetic drum devices, etc.)
In particular, the present invention relates to a magnetic storage body using magnetic metal as a storage medium. Generally, magnetic storage bodies that use magnetic metal as a storage medium have the following two main practical problems. The first problem is associated with a recording/reproducing method for a magnetic storage device that includes a recording/reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body. After the head and the magnetic storage surface are set in contact at the start of operation, a space corresponding to an air layer is created between the head and the magnetic storage surface by giving the magnetic storage the required rotation, and this state is maintained. In the contact start-stop method (hereinafter referred to as the CSS method), which is a recording and reproducing method, the rotation of the vertical air storage body stops at the end of the operation, and at this time, the head and magnetic storage surface are in the same contact friction state as at the beginning of the operation. It is in. The frictional force generated between the head and the magnetic storage material under these contact friction conditions may wear out the head and the magnetic storage material, and may eventually cause scratches on the head and the metal magnetic thin film medium. Further, in the contact friction state, a slight change in the posture of the head makes the load applied to the head uneven, and may cause scratches on the surface of the head and the magnetic storage body. Furthermore, during recording and reproducing, the head suddenly comes into contact with the magnetic storage body, and a large frictional force is generated between the head and the magnetic storage body, often resulting in destruction of the head and the magnetic storage body. In order to protect the head and the magnetic memory from such contact friction, contact wear and contact breakage between the head and the magnetic memory, it is necessary to coat the surface of the magnetic memory with a protective coating. The second problem is that magnetic metals are easily corroded, and this corrosion causes the magnetic properties of the magnetic metals to deteriorate or disappear.
Alternatively, localized corrosion may lead to increased errors. Various protective films have been proposed to solve the above two problems, but no one has yet been found that is excellent in both wear resistance and corrosion resistance. For example, as seen in Special Publication No. 52-17402,
A protective film made by treating the surface of a magnetic memory element with an oxidizing agent containing chromic acid or its salts does not have sufficient wear resistance, and inorganic corrosion inhibitors such as chromic acid or its salts may actually attack magnetic metals. This leads to non-uniformity in the film thickness of the magnetic metal and increases errors. Corrosion inhibitors that act radically on magnetic metals in this way are difficult to apply to applications that require precision of magnetic metals, such as magnetic storage bodies. An object of the present invention is to provide a magnetic memory having a protective film that does not affect magnetic metals and has excellent corrosion resistance. That is, in the magnetic memory of the present invention, a metal magnetic medium is coated on a mirror-polished base body, and a nitrite of a primary, secondary, or tertiary amine is coated on this medium directly or via a nonmagnetic alloy. It is characterized by being coated with a protective film containing an organic corrosion inhibitor made of benzoate or carbonate. Next, the present invention will be explained in detail with reference to the drawings. 1 and 2 are partial cross-sectional views showing an embodiment of the magnetic storage body of the present invention. In FIG. 1, aluminum alloy is most often used as the base 1 of the magnetic memory body because it is light, easy to work with, and inexpensive, but titanium alloy may also be used in some cases. The surface of the base is machined into a surface with small undulations (less than 50 μm in the circumferential direction and less than 100 μm in the radial direction). Next, a nickel-phosphorus alloy is plated onto this base 1 as a base body 2, and the surface of this base body 2 is mechanically polished to a maximum surface roughness.
Mirror finish to 0.03μm or less. Next, a cobalt-nickel-phosphorus alloy is coated on the mirror-polished surface of the base body 2 as a metal magnetic medium 3 by plating, and a protective film 4 containing an organic corrosion inhibitor is coated on the metal magnetic medium 3. There is. In FIG. 2, the metal magnetic medium 3 is coated with a protective film 4 containing an organic corrosion inhibitor via a nickel-phosphorus alloy as a non-magnetic alloy 5. In FIG. The metal magnetic medium 3 may be any metal or alloy containing Co, Ni, or Fe. The protective film 4 is also made of glass, silicon oxide, silicon nitride,
Fixed silicon compounds such as silicic acid polymers (polysilicic acid), non-magnetic metals such as Rh and Cr, non-magnetic alloys such as NiP, metals such as Al, Co, Ni, Cr, Ti, Zr or Ce, or metals such as these Alloyed non-magnetic metal oxides can be used. As an organic corrosion inhibitor, it is 1st class, 2nd class or 3rd class.
Nitrite, benzoate or carbonate of grade amines are most effective, such as isopropylamine,
diisopropylamine, triethanolamine,
dicyclohexylamine, diisobutylamine,
These include the nitrite, benzoate or carbonate salts of cyclohexylamine, dibutylamine or triethylamine. Next, the magnetic memory of the present invention will be explained in detail with reference to Examples and Comparative Examples. Example 1 As the substrate 1, the base body 2 was placed on a disk-shaped aluminum alloy plate whose surface was finished with sufficiently small waviness (50 μm or less in the circumferential direction and 10 μm or less in the radial direction) by lathe processing and heat straightening. Nickel-phosphorus alloy is plated to a thickness of approximately 50μm,
This nickel-phosphorus plating film has the maximum surface roughness.
Mirror polished to a thickness of 0.02μm and 30μm. Next, a cobalt-nickel-phosphorus alloy is deposited on this nickel-phosphorus plating film as a metal magnetic medium 3.
It was plated to a thickness of 0.05 μm. The following solution was applied onto this cobalt-nickel-phosphorus plating film by spin coating, dried, and then baked at 200°C for 5 hours to form a 0.1 μm thick polysilicic acid film containing an organic corrosion inhibitor. A protective film 4 was coated to produce a magnetic disk having the structure shown in FIG. Tetrahydroxysilane 2% isopropyl alcohol solution 99.87g Dicyclohexylamine nitrite 0.13g Example 2 Same as Example 1, except that metal magnetic medium 3
A nickel-phosphorus alloy is placed on top of the non-magnetic alloy 5.
This nickel-phosphorus alloy was plated to a thickness of 0.02 μm, and a protective film 4 made of polysilicic acid containing an organic corrosion inhibitor was coated on the nickel-phosphorus alloy in the same manner as in Example 1 to obtain the structure shown in FIG. I made a magnetic disk. Example 3 Same as Example 1, except that metal magnetic medium 3
Sputter SiO ₂ as a protective film 4 on top of the
The SiO 2 film was coated to a thickness of 0.1 μm, and then immersed in a 2.2% isopropyl alcohol solution of dicyclohexylamine nitrite for 24 hours to fully incorporate the organic corrosion inhibitor into the SiO ₂ film to produce a magnetic disk. Example 4 Same as Example 2, except that metal magnetic medium 3
A magnetic disk was made using Co-Mn-P. Example 5 Same as Example 3, except that metal magnetic medium 3
A magnetic disk was made using Co-Cr. Example 6 Same as Example 1, except that metal magnetic medium 3
A nickel-phosphorus alloy with a thickness of 0.1 μm is applied as a protective film 4 on top.
The magnetic disk was then plated to a thickness of 100 ml, and then immersed in a 23% methyl alcohol solution of dicyclohexylamine nitrite for 10 hours to sufficiently incorporate the organic corrosion inhibitor into the nickel-phosphorus alloy protective film. Example 7 Same as Example 1, except that metal magnetic medium 3
The surface of the protective film 4 is oxidized to form a film made of oxides of Co and Ni, which is then immersed in a 9.2% ethyl alcohol solution of dicyclohexylamine nitrite for 16 hours to form a film made of oxides of Co and Ni. A magnetic disk was manufactured by sufficiently impregnating an organic corrosion inhibitor in a protective film consisting of the following. Example 8 Same as Example 7, except that metal magnetic medium 3
A nickel-phosphorus alloy was plated on top to a thickness of 0.1 μm, and the surface was oxidized to form a film made of Ni oxide to form the protective film 4. After that, 7.9% dioxane of dicyclohexylamine nitrite was plated. A magnetic disk was prepared by immersing it in a solution for 4 hours to fully impregnate the organic corrosion inhibitor in the protective film made of Ni oxide. Example 9 A magnetic disk was manufactured in the same manner as in Example 1, except that the following solution was used as the solution for forming the protective film 4. 2% tetrahydroxysilane-butyl alcohol solution 99.5g Dicyclohexylamine nitrite 0.5g Example 10 A magnetic disk was produced in the same manner as in Example 1, except that the following solution was used as the solution for forming the protective film 4. 2% tetrahydroxysilane-propyl alcohol solution 99.5g Diisopropylamine nitrite 0.5g Example 11 A magnetic disk was produced in the same manner as in Example 1, except that the following solution was used as the solution for forming the protective film 4. Tetrahydroxysilane 2% ethyl alcohol solution 99.5g Isopropylcyclohexylamine benzoate
0.5g Comparative Examples 1-11 Magnetic disks were made in the same manner as Examples 1-11, but without using an organic corrosion inhibitor, and were designated as Comparative Examples 1-11, respectively. Using each of the magnetic disks shown in Examples 1 to 11 and Comparative Examples 1 to 11, an underwater immersion test (120 hours) and an environmental test (90% relative humidity, 40°C humidity, 1 month) were conducted to determine the unit of corrosion point. The number of pieces per area and the rate of increase in the number of errors were investigated. As a result, the results shown in the table below were obtained.

【table】

[Table] Incidentally, the magnetic disks of Examples 1 to 5 and 9 to 11 were subjected to CSS repetition tests 20,000 times, but no abnormality such as scratches or wear marks on the surface was observed. From the above, it was found that the magnetic memory of the present invention has excellent environmental resistance and wear resistance.

[Brief explanation of drawings]

1 and 2 are partial cross-sectional views of the magnetic storage body of the present invention, respectively. In the figure, 1 is a base, 2 is a base body, 3 is a metal magnetic medium, 4 is a protective film, and 5 is a nonmagnetic alloy.

Claims (1)

[Scope of Claims] 1. A metal magnetic medium is coated on a mirror-polished base body, and a nitrite, benzoic acid of a primary, secondary or tertiary amine is coated on this medium directly or through a non-magnetic alloy. A magnetic memory comprising an organic corrosion inhibitor consisting of an acid salt or a carbonate and coated with a protective film made of a hard solid material. 2. The magnetic memory according to claim 1, wherein the protective film is a silicon compound. 3. The magnetic memory according to claim 2, wherein the silicon compound is polysilicic acid. 4. The magnetic memory according to claim 1, wherein the protective film is a nonmagnetic metal or alloy. 5. The magnetic storage body according to claim 4, wherein the non-magnetic metal or alloy is Rh, Ni-P or Cr. 6. The magnetic memory according to claim 1, wherein the protective film is a metal oxide. 7. The magnetic memory according to claim 6, wherein the metal oxide is an oxide of Al, Co, Ni, Cr, or an alloy thereof. 8. The magnetic memory according to claim 1, wherein the organic corrosion inhibitor is dicyclohexylamine nitrite.