JPH07211052A - Magnetic disk analysis mechanism - Google Patents

Abstract

PURPOSE:To take in and analyse a gas component generated by sliding from the surface of a magnetic disk in the atmosphere with high efficiency. CONSTITUTION:A gas collector 1 with a gas introduction port 2 and gas extraction port 3 are put on a magnetic disk 4. A carrier gas is supplied from a bomb 6 and a gas component generated by sliding and the like between a disk surface and a magnetic head to analyse it. An experiment can be made with a disk being rotated by leaving spaces between the collector and the disk, and when the space is made sufficiently narrow, the loss of the generated gas can be reduced.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device.

2. Description of the Related Art In order to increase the capacity of a magnetic disk device, it is essential to narrow the spacing between the magnetic head and the magnetic disk. However, the frequency of contact and friction between the head and the disk increases accordingly, which is a serious problem in maintaining reliability. In order to maintain reliability under such circumstances, it is necessary to accurately grasp the phenomenon occurring at the head / disk interface. As one of the effective means for understanding the phenomenon, the analysis of the gas generated at the head / disk interface has been attracting attention. For example, IEEE
Transactions on Magnetics, vol 29, p. 253
(1993) reported that the lubricant decomposition gas generated from the disk surface by sliding in a vacuum was captured by a mass spectrometer.

In the above prior art, sliding is performed in vacuum. However, the actual magnetic disk operates in the atmosphere, and the usefulness of the obtained information is limited if it cannot be analyzed in the atmosphere. However, in the atmosphere, the gas volatilized from the disk surface or the gas generated by sliding is diffused into the air and diluted, which makes it difficult to perform a highly sensitive analysis. Moreover, if the circumference of the disk is covered with a container with a small volume, the degree of dilution can be suppressed to a low level, but for that purpose, dedicated experimental equipment is required, which lacks versatility and convenience. Under such circumstances, there has been an urgent need to develop a mechanism that can be easily applied to an ordinary magnetic disk device and that can efficiently collect generated gas.

As a result of studying various gas sampling methods for achieving the above object, as shown in FIG. 1, a box-shaped gas collector is covered so as to cover the surface of the disk,
It has been found that a mechanism in which nitrogen or air is introduced as a carrier gas and the generated gas is sent out is effective. Particularly effective is a method in which a carrier gas is sent near the center of the disk and taken out from the peripheral area of the disk. If the disc and the collector are installed in another container that can be sealed, the efficiency of collecting the gas becomes higher. The collector must be installed in a position where it does not come into direct contact with the disk so as not to hinder the rotation of the disk, but in order to reduce gas leakage from the gap, the interval should be 1 mm or less, and even 0.5 mm or less. Is desirable. Also, a window for inserting a magnetic head or the like can be provided on the side surface of the collector.
The atmospheric pressure ionization mass spectrometer is most suitable as a method for analyzing the collected gas because it can be used under atmospheric pressure and has high sensitivity.

The method of covering one side of the disk with a box-shaped gas collector can be easily applied without making a great improvement to the ordinary disk drive device, and is high by reducing the internal volume of the collector. Collection efficiency can be easily realized. Further, if the disk and the gas collector are sealed in another container to have a double structure, the collection efficiency can be further improved. The gas generated from the surface of the disk can only come out by diffusion as it is. Therefore, the gas collector is provided with a gas introduction port and a gas sampling port to introduce a carrier gas for flowing out the generated gas. If the gas inlet is provided in the central part of the collector and the sampling port is provided in the peripheral part of the collector, the carrier gas flows spirally from the center to the periphery as the disc rotates, The generated gas can be efficiently picked up and transported to the sampling port. It is necessary to have a certain distance between the collector and the disk so as not to disturb the rotation of the disk. For example, when the gas collector having the shape shown in FIG. 2 is used, the change in the collection efficiency when the distance between the lower end of the gas collector and the disk is changed is as shown in FIG. To obtain a collection efficiency of 30% or more when the disk rotation speed is 100 rpm, the interval is 1 mm or less,
It can be seen that in order to obtain a collection efficiency of 50% or more, it must be 0.5 mm or less. The gas collector can be provided with a window for inserting a magnetic head or other instrument. If the window is made too large, the collection efficiency is lowered, but as a result of an experimental study, it was found that there is not much influence up to about 10% of the window area with respect to the side area of the collector, as shown in FIG. found. The gas taken out from the gas sampling port can be analyzed by various well-known methods, and the atmospheric pressure ionization mass spectrometer is particularly effective for the analysis of trace components on the order of ppb under atmospheric pressure.

EXAMPLES Examples of the present invention will be shown below. (Example 1) FIG.
Install a gas collector with a shape like the one below, and a thin film magnetic disk with a diameter of 5.25 inches whose surface is coated with a fluorine-based lubricant. Insert a normal thin film magnetic head through the window on the side of the collector. Then, a sliding experiment was conducted at a rotation speed of 300 rpm. Air of 1 liter / min was introduced from the gas inlet of the collector, and the gas taken out from the gas inlet was analyzed by an atmospheric pressure ionization mass spectrometer. The analysis result is shown in FIG. Carbon dioxide is generated according to the change in the frictional force between the head and the disk, and continuous fluorine-based organic substances are also generated.
The amount of gas generated was on the order of tens of ppb for carbon dioxide and hundreds of ppt for organic fluorine compounds. (Example 2) Diameter with a fluorine-based lubricant applied to the surface 5.
A gas collector having a shape as shown in FIG. 2 was attached to a 25-inch thin film magnetic disk, the disk was rotated at a rotation speed of 300 rpm, and gas volatilized from the surface was analyzed in the same manner as in Example 1. did. Since there was no sliding by the magnetic head, generation of carbon dioxide was not seen, but about 100 ppt of fluorine-based organic matter was detected. The shape of the collector is
In addition to the shape shown in FIG. 2, the shape shown in FIGS. 2 and 6 show a method of forming a gas sampling port by forming a hole in the side wall, and FIGS. 7 and 8 show a shape in which a gas sampling tube is simply inserted. In addition, the sectional shape of the lower end of the side wall is also shown in FIG.
The flat type as described above, the type having a stepped portion as shown in FIG. 2 to improve the collecting efficiency, and the type having the outer periphery of the disk held as shown in FIGS. 6 and 8 can be used. Example 3 A disk was covered with a gas collector having a shape as shown in FIG. 2, and the container was sealed in a container having a volume of 3 liters. Carbon dioxide having a concentration of 1 ppm was sent together with a carrier gas from a gas inlet and analyzed by an atmospheric pressure ionization mass spectrometer. The result is shown in FIG. The signal sharply rises immediately after the introduction of carbon dioxide, and reaches the saturation point at which quantitative analysis can be performed in 1 to 2 minutes. (Comparative Example) A gas inlet tube and a gas sampling tube were fixed to 1 to 2 cm above the disc without a gas collector, and the container was sealed in a container having a volume of 3 liters. Carbon dioxide having a concentration of 1 ppm was sent together with a carrier gas from a gas introduction tube and analyzed by an atmospheric pressure ionization mass spectrometer. The result is shown in FIG. The amount of carbon dioxide detected gradually increases and has not yet reached saturation after 25 minutes. In the above examples, an atmospheric pressure ionization mass spectrometer is used as an analysis method, but a gas chromatograph-mass spectrometer, various chromatographies, atomic absorption analysis and the like can be applied.

As described above, according to the present invention, a gas component generated by sliding or the like on the surface of a magnetic disk rotating under atmospheric pressure can be removed without making a great improvement to an ordinary magnetic disk device. It enables efficient collection and analysis.

[Brief description of drawings]

FIG. 1 is an explanatory view of a gas collection mechanism.

FIG. 2 shows an example of a gas collector.

FIG. 3 shows changes in collection efficiency depending on the distance between the gas collector and the disk.

FIG. 4 shows changes in collection efficiency depending on the area ratio of the window of the gas collector.

FIG. 5 is an example of analysis using the present invention.

FIG. 6 is a first example of the shape of the gas collector.

FIG. 7 is a second example of the shape of the gas collector.

FIG. 8 is a third example of the shape of the gas collector.

FIG. 9 is a diagram showing the response of the gas collector.

FIG. 10: Detection of gas without collector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas collector, 2 ... Gas inlet, 3 ... Gas sampling port, 4 ... Magnetic disk, 5 ... Magnetic disk spindle, 6 ... Carrier gas cylinder, 7 ... Analyzer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Mr. Tomoaki Mizoue 3-3, Fujibashi, Ome-shi, Tokyo 2 Hitachi Hitachi Electronics Co., Ltd.

Claims (7)

[Claims] 1. A box-shaped gas collector having a gas inlet and a gas outlet on one side of a magnetic disk that is rotating or stopped under an arbitrary pressure and has a side surface and one bottom surface. In a mechanism for collecting gas components generated from the surface of the magnetic disk, the gas collector is installed at a predetermined distance from the magnetic disk, and a carrier gas is poured from the gas inlet, An analyzing mechanism for a magnetic disk, wherein a gas component generated from the surface of the magnetic disk is taken out from the gas sampling port together with a carrier gas for analysis. 2. The magnetic disk analyzing mechanism according to claim 1, wherein the magnetic disk and the gas collector are installed in another container that can be sealed. 3. The magnetic disk analyzing mechanism according to claim 1, wherein the gas inlet of the gas collector is provided in the central portion of the collector, and the gas sampling opening is provided in the peripheral portion of the collector. 4. The magnetic disk analysis mechanism according to claim 1, wherein the distance between the gas collector and the magnetic disk is 1 mm or less. 5. The magnetic disk analyzing mechanism according to claim 1, wherein the distance between the gas collector and the magnetic disk is 0.5 mm or less. 6. A magnetic disk analyzing mechanism according to claim 1, wherein said gas collector is provided with a window into which a magnetic head or the like can be inserted. 7. The magnetic disk analysis mechanism according to claim 1, wherein the gas collected by the gas collector is analyzed by an atmospheric pressure ionization mass spectrometer.