JPS6016006B2 - Manufacturing method of magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a coating film constituting a magnetic layer in a magnetic disk as a recording medium of a magnetic disk device.

In recent years, magnetic disk drives have become more densely packed with contacts.
The start-stop method is adopted to reduce the flying gap between the magnetic head and the magnetic disk, so the magnetic disk coating on the media is wear-resistant without damaging the monolithic type magnetic head. There is a demand for high strength materials with excellent head crush resistance and head flying properties.

Therefore, it has been considered to form a coating film by adding hard alumina, silica, etc. to the coating material, but while this improves the strength of the coating film, it destroys the magnetic head, resulting in a decrease in output and worsening recording characteristics. In view of these points, it is an object of the present invention to provide an improved method for manufacturing a magnetic disk so as to form a strong coating film without destroying the magnetic head, and to cure the resin without oxidizing it. Focusing on the fact that it is possible to obtain suitable strength, we put a thermosetting resin in the paint together with a magnetic oxide to form a coating film, and then we coated the coating film in a vacuum with heat absorbing properties against the resin. It uses an infrared heater with a very long wavelength to cure the material by oxidation without oxidizing it.

The present invention will be specifically explained below with reference to the drawings. For example, gamma iron oxide (yFe20) with a content of 65% in the paint
Acrylic or epoxy-based thermoset crab fat is added together with magnetic oxides such as 3), and this is applied thinly and uniformly onto an aluminum disk substrate by spin coating or the like to form a magnetic layer coating.

After that, this coating film is subjected to an orientation treatment, etc., and then placed in a vacuum high temperature furnace in a vacuum atmosphere, and heated to about 200℃ for about 1 to 5 minutes using an infrared heater with a long wavelength of 50 degrees Fahrenheit or more. death,
Competitive heat treatment is performed by heating for a short period of time. Then, the thermosetting resin in the coating film is surrounded by a vacuum atmosphere, and long-wavelength infrared rays are absorbed very well into the resin, so it hardens in a short time without oxidizing, forming a magnetic disk. is manufactured. Next, the coating strength of the magnetic disk according to the present invention manufactured in this way will be explained.A high-density head of 600 ship PI is used, and the strength of the magnetic disk according to the present invention is 1/1 of the normal head load.
The attached drawings show the head crush resistance and abrasion resistance test results of the coating film when contact start/stop was performed for 100 days at 0 times.

In this), the solid line A is manufactured according to the present invention, and the broken line B is the product manufactured according to the present invention.
is baked and heat-treated in the atmosphere using a normal high-temperature furnace, which makes it possible to contact, start, and
It can be seen that while the number of stops is 100 or less, the method of the present invention can be stopped more than 300 times, which is about three times that number, and the coating strength is significantly increased. In addition, in a bending test of the paint film when the outer diameter was about 6 yen and bent 180 degrees using a palm tree, there was no peeling of the paint film even when the bent pole was wiped with gauze. Very strong. In addition, if the coating film is similarly heat-treated using a long-wavelength infrared heater in an inert gas, the thermosetting resin can be cured without oxidizing, and in this case, the drawing , contact start as shown by the dashed line c.
It becomes possible to make more than 20 stops.

As described above, according to the manufacturing method of the present invention, the strength of the magnetic disk is significantly increased without causing damage to the magnetic head due to hard additives such as alumina and silica.

In addition, the heat treatment time is extremely short, which improves workability.

[Brief explanation of the drawing]

The attached drawing is a diagram showing the test results of the head crush resistance and abrasion resistance of the coating film.

Claims (1)

[Claims] 1. A magnetic disk characterized in that a coating material containing at least a magnetic oxide and a thermosetting resin is applied onto a substrate to form a coating film, and the coating film is cured by baking with a long wavelength infrared heater in a vacuum. Production method.