JPS5846767B2 - Method for smoothing the surface of a magnetic disk substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for smoothing the surface of a magnetic disk substrate to ensure final flying.

Magnetic disks are generally formed by applying magnetic paint onto an aluminum substrate and baking it at a high temperature, but the surface is finished by puff polishing, tape polishing, or the like.

Further, it is manufactured by forming a film of iron oxide (aFe203) on an alumite substrate by sputtering and then changing it to aFe202, or by forming a film of magnetic metal on the substrate.

In this case, many microprotrusions with a height of 0.1 μm or more remain on the surface of the magnetic disk after polishing on which a magnetic coating is formed.

This is due to hard non-magnetic particles such as L-alumina that are mixed into the magnetic paint to increase the strength of the coating.
The presence of such particles has adverse effects such as abrasion and deterioration of the magnetic head and deterioration of head flying performance.

In particular, when a magnetic material is formed on a substrate by sputtering or vapor deposition, it is desirable to smooth the substrate surface even before forming the magnetic coating.

To solve this problem, we used a burnish head (the head shape is the same as the actual head, made of hard material such as alumina) with a mirror-polished slider surface to lower the flying height and fly back and forth over the rotating magnetic disk. Conventionally, a method has been adopted in which the microprotrusions that collide with the head are removed by causing the head to collide with the head.

However, with such a method, the burnishing efficiency was poor, and microprotrusions on the disk surface could not be completely removed.

This is because the slider has a mirror surface that only serves to crush minute protrusions that are flying obstacles.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a method for smoothing the surface of a magnetic disk substrate, which can efficiently remove minute protrusions on the surface of a disk substrate.

The invention will now be described in detail in conjunction with the drawings.

In the figure, 1 is a magnetic disk substrate, and 2 is a slider.

The magnetic disk substrate 1 has a surface finish, and minute protrusions 3 are present on the surface.

The slider 2 is made of a hard material such as alumina, SiC, print, garnet, etc., and a rough surface portion 4 is formed on the slider surface by abrasive grains as described later.

This rough surface portion 4 has a surface roughness of 1 to 30 μm RmaX (3 to 30 μm
20 μmRmaX is desirable).

When the burnish head equipped with such a slider 2 is moved back and forth in the direction of the arrow while in contact with the rotating magnetic disk substrate 1, the minute protrusions 3 on the magnetic disk substrate 1 are removed from the rough surface portion 4, and the surface In this case, an excellent burnishing effect can be achieved by simply moving the burnish head back and forth several times, and the flying performance of the head is improved.

According to experiments, the surface roughness before burnishing is 0.15~
0.3' pm, and the minimum flying height was 0.25 pm or more, but after burnishing, the surface roughness was 0.05 pm.
The minimum flying height was 0.1 μm or less.

In the above explanation, an example was described in which the slider is made of a hard material. However, it is also possible to make the slider of a normal material and to apply an abrasive layer made of fine particles of a hard material such as alumina dispersed in a binder on the slider surface. A coating may be formed, or a commercially available lapping film having abrasive grains of hard material such as alumina with a grain size of 0.3 to 20 μm (preferably 1 to 9 μm) on the surface may be attached to the slider surface. .

In these cases as well, there is a burnish effect similar to that described above.

Also, since the rough surface is formed by abrasive grains, compared to forming a rough surface by etching or machining,
The sharpness of the protrusions is high and the varnishing efficiency is extremely high because the protrusions can be formed densely, and the process does not require much effort, which is an advantage that cannot be overlooked.

Note that these sliders do not float above the rotating magnetic disk substrate like normal sliders, but are always in contact with the rotating magnetic disk substrate, and the height of the protrusion that can be removed is reduced to 0.
Although it may be 1 to 0.05 μm or less, if the friction between the rough surface of the slider and the magnetic disk is large, problems such as burning of the contact surface between the two may occur.

To prevent this, the surface of the magnetic disk substrate may be lubricated with a liquid lubricant or a solid lubricant.

As described above, according to the present invention, a burnish head having a hard rough surface formed on the slider surface is slid in contact with a rotating magnetic disk substrate, that is, a substrate before or after a magnetic coating is formed. An excellent burnishing effect can be achieved simply by making the burnish back and forth several times, and it is possible to significantly improve head flying performance.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of a slider of a burnish head for carrying out the method for smoothing the surface of a magnetic disk according to the present invention. In the figure, 1 is a magnetic disk substrate, 2 is a slider, and 3 is a microprotrusion. , 4 is a rough surface portion.

Claims (1)

[Claims] 1. A magnetic disk substrate, which is characterized in that a magnetic disk substrate is rotated, and a burnish head having a rough surface formed of an abrasive grain layer containing hard fine particles reciprocates over the substrate in contact with the slider surface. Surface smoothing method.