JPH0395726A - Fiber reinforced glass substrate - Google Patents

Abstract

PURPOSE:To improve strength, rigidity and surface smoothness by sintering a glass prepreg for one part of matrix glass for which heat resistant inorganic long fiber is two-dimensionally arranged. CONSTITUTION:The heat resistant inorganic long fiber forms a compound by arranging two-dimensionally in the matrix glass and further, one part of the matrix glass, at least, is obtained by sintering the glass prepreg solution. In such a way, the compound obtains satisfactory adhesivity between the inorganic long fiber and the matrix glass and accordingly, a reinforcing effect is made high and the strength or the rigidity is improved. Since the substrate is covered with a glass material on an external surface, the surface smoothness is made satisfactory. Simultaneously, since a surface layer is made of the glass, high hardness can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fiber-reinforced glass substrate, which has characteristics such as high strength, high rigidity, and surface smoothness that can be used particularly for magnetic disk substrates and parts for hard disk drives. This invention relates to a fiber-reinforced glass substrate with excellent properties.

[Conventional technology]

In recent years, magnetic disk drives have been increasing in capacity and recording density. Along with this, magnetic disk substrates are now required to have various properties such as high surface smoothness, small waviness and no microprotrusions, high hardness, strength, and elastic modulus. .

Conventional magnetic disk substrates that meet these demands include argonium alloy substrates, aluminum alloy substrates with an alumite coating on the surface, and aluminum alloy substrates with a Ni-P plating film on the surface. Ni--P plated substrates, glass substrates, ceramic substrates, etc. have been proposed.

(Problems to be Solved by the Invention) However, conventional magnetic disk substrates, that is, argonium alloy substrates, tend to generate intermetallic compounds, which fall off during grinding and polishing of the substrate, causing dents and scratches on the surface. In addition, this conventional board had the disadvantage that it had low rigidity, so when it rotated at high speed, recording and reading errors were likely to occur due to elongation and waviness of the board. Ta.

Next, since a film is formed on the alumite substrate using the underlying aluminum to be anodized, the IT impurities in the aluminum alloy are precipitated as intermetallic compounds, and the aluminum alloy substrate is bonded to the aluminum alloy substrate. Similarly, surface smoothness deteriorates. In addition, there was a problem in that cracks were likely to occur in the film due to the difference in thermal expansion coefficient between the aluminum alloy and the alumite.

Next, the Ni-P plated substrate requires pre-treatment before plating, which not only complicates the treatment process and makes it expensive, but also causes the problem that the plating easily peels off during the combustion process. was there.

Next, although the glass substrate has excellent surface smoothness, it has a problem in that it has poor reliability in strength, and in order to improve this, a strengthening treatment is required, making it expensive.

Furthermore, the ceramic substrate has a complicated molding process and is difficult to process, resulting in high cost.

The purpose of the present invention is to provide a fiber-reinforced glass substrate and a fiber-reinforced glass substrate that can solve the problems faced by each of the above-mentioned conventional substrates, such as poor surface smoothness, low strength, and complicated manufacturing process and high cost. The purpose is to propose a manufacturing method for it.

[Means to solve the problem]

In view of the above-mentioned circumstances, in the present invention, the substrate surface is covered with a glassy material in order to improve the surface smoothness, and the matrix glass is covered with a glass precursor solution using a glass precursor solution in order to ensure the mechanical strength of the substrate. As a result, we have overcome the above problems. That is, the present invention comprises a composite layer of a matrix glass and a sheet-like molded body in which heat-resistant inorganic long fibers are two-dimensionally arranged, and a glassy surface layer covering the surface of the composite layer, and A fiber-reinforced glass substrate, characterized in that at least a portion of the substrate is made of glass produced by firing a glass precursor, and the fiber-reinforced glass substrate has at least the following (1) to It is characterized in that it is produced through step (3).

(1) First, a sheet-like molded body made of two-dimensionally oriented heat-resistant inorganic long fibers is impregnated with a solution mainly consisting of a glass precursor, and then dried to generate matrix glass and prepare it. A step of obtaining a molded body; (2) A step of producing a fired composite by pressurizing and firing the preformed body after drying at a temperature of 500"C or higher; (3) A surface of the fired composite. [Function] The fiber-reinforced glass substrate of the present invention is made of a heat-resistant inorganic material, as described in the above-mentioned solution section. It is a composite in which long fibers are two-dimensionally arranged in a matrix glass, and it can be said that at least a part of the matrix glass is obtained by firing a glass precursor solution. Therefore, such a complex is
Since a product with excellent adhesion between the inorganic long fibers and the matrix glass can be obtained, a product with a high reinforcing effect and high strength and rigidity can be obtained. In addition, since a substrate with high strength can be obtained, the thickness can be made thinner than that of conventional substrates, and as a result, it is effective in reducing the size and weight of magnetic disk devices and the like.

In addition, since the outer surface of the substrate of the present invention is covered with a glassy material, a substrate with excellent surface smoothness can be obtained.
At the same time, since the surface layer is glassy, a product with high hardness can be obtained.

Here, the heat-resistant inorganic long fibers used in the substrate according to the present invention include alumina fibers, silica fibers, silicon carbide fibers,
At least one type of continuous fiber such as tyranno fiber, carbon fiber, zirconia fiber, silica/alumina fiber, etc. is selected and used.

Next, the glass materials used for the shape of the matrix glass and the glassy surface layer include soda lime glass, alkali ξ nosilicate glass, lead borate glass, soda alkali ξ nosilicate glass, lead alkali glass, and borosilicate glass. At least one selected from among , barium glass, alumina phosphate glass, etc. is used.

The fiber-reinforced glass substrate according to the present invention configured as described above is manufactured through the following steps.

The specific processing method of each step will be explained below.

First, the first step is to prepare a sheet-like molded product made of two-dimensionally oriented heat-resistant inorganic long fibers, impregnate it with a glass precursor solution, and then dry it. This is the step of obtaining a preformed body supported by matrix glass.

In the above process, the heat-resistant inorganic long fibers forming the sheet-like oval body include alumina fibers, silicate fibers, silicon carbide fibers, tyranno fibers, carbon fibers, zirconia fibers, silica-alumina fibers, etc. At least one selected continuous fiber is used.

The sheet-like molded article is a two-dimensional fabric made by weaving these fibers.

Further, the present invention uses a glass precursor as a glass component to be impregnated into the sheet-like hollow body to form a matrix. Such a glass precursor is one that produces glass by heat treatment. For example, at least one selected from aqueous solutions and organic solvent solutions of various metal alkoxides and their hydrolysates, nitrates, acetates, chlorides, carbonates, and hydroxides, various sols such as silica sol, alumina sol, etc.
Use seeds. Glasses produced by heat-treating such glass precursors include soda-lime glass, aluminosilicate glass, lead-borate glass, and soda-aluminum glass.
At least one selected from the group consisting of nosilicate glass, lead alkali glass, borosilicate glass, barium glass, and alumina phosphate glass is suitable.

In addition, fine powder of at least one type of glass selected from the above-mentioned various glasses may be mixed with the glass precursor solution.

Next, in the second step of the present invention, the preform obtained in the step (1) is pressure-fired at a temperature of 500° C. or higher, thereby producing a fired composite about the preform. This step is a step of obtaining a sheet in which the glass precursor impregnated in the preform becomes glass through pressure firing in this step, and the heat-resistant inorganic long fibers are two-dimensionally oriented. The voids in the molded body are sealed by the infiltration of the glass produced from the glass precursor, and a fired composite with high density, high strength, and high rigidity is easily formed.

Next, the third step of the present invention is a step of coating the surface of the shakikai composite obtained in step (2) with a glassy material to form a smooth surface layer. The purpose of forming this glassy smooth surface layer is to improve the surface smoothness of the substrate. Methods of coating glassy materials on both sides of the fired composite include glazing method, sputtering method, vacuum evaporation method,
Use methods such as ion plating. Other methods may also be used, such as applying the glass precursor solution and then burning it. Note that as the glassy material, it is preferable to use at least one type selected from the various types of glasses mentioned above.

In addition, the thickness of the smooth surface layer coated in this step (3) is preferably 0.3 μm to 600 μm, particularly ? 0～
20 μm is suitable.

In addition, when the above-mentioned substrate according to the present invention is used as a magnetic disk substrate, in order to improve the surface smoothness, it is more preferable that the smooth surface layer is further polished by a known method. be. In this case, the surface roughness (Rmax) after polishing is 0.002 to 0.1 μm.
It is desirable that it be within the range of 0. 005~0.
More preferably, the surface roughness is in the range of 0.02 μm.

〔Example〕

Example 1 (1) The final glass composition is SiO:7
5 sail%, 8203: 19IIit%, Na, 0:
A glass precursor solution was prepared by adding and mixing silicon, boron, and sodium alkoxides, water for hydrolysis, and predetermined amounts of ethyl alcohol as a solvent to a concentration of 5 wt %, and concentrating the mixture.

(2) Overlapping two sheets of alumina fiber cloth, impregnating this polymerized cloth with the precursor solution of step (1) above,
It was then dried. Is this process performed 6 times? Then, a preform was prepared.

(3) The preform obtained in step (2) above was pressure-fired at a temperature of 750°C in the atmosphere to produce a fired composite.

(4) Both sides of the fired composite obtained in step (3) above are coated with the glass precursor solution obtained in step (1) above, and then dried at a temperature of 750°C in the atmosphere. A glassy smooth surface layer with a thickness of 140 μm was formed.

(5) Transfer the substrate obtained in step (4) above to A1■03
Polished using abrasive grains and a lapping machine, surface roughness: Rma
xO. A fiber-reinforced glass substrate of the present invention having a thickness of 0.01 μm was produced.

A mechanical test was performed on the substrate thus obtained, and the tensile strength was 63 kg/++n''.
The Young's modulus was 8,600 kg/w'', and it was confirmed that the fiber-reinforced glass had the high strength, Young's modulus, and surface smoothness necessary for a magnetic disk substrate.

Example 2 (1) The composition of the most commonly produced glass is SiO■
:70-L%, BzO3: 18Wt%, PbO: 1
A predetermined amount of each alkoxide of silicon, boron, and lead, water for hydrolysis, ethyl alcohol as a solvent, and an organic acid are added and mixed so that the concentration is 2 wt%, and the same glass fine powder as described above is added. (-300 mesh)
The glass precursor solution was prepared by adding 10 wt % of and concentrating it.

(2) Two sheets of silicon carbide fiber cloth were overlapped, and this polymerized cloth was impregnated with the precursor solution of step (1) above, and then dried. This process was repeated twice in total to create a preform.

(3) The preform obtained in step (2) above was pressure-fired at a temperature of 700° C. in the atmosphere to produce a fired composite.

(4) On both sides of the fired composite obtained in the above step (3), the glass precursor solution in the state before adding the glass fine powder in the above step (1) is spin coated, and then dried. , burned in the air at a temperature of 700℃, with a thickness of 18
A glassy surface layer of 0 μm was formed.

(5) The surface was polished in the same manner as in Example 1 to obtain a surface roughness of Rmax O. A fiber-reinforced glass substrate of the present invention having a thickness of 0.03 μm was prepared.

Mechanical tests were conducted on the substrate thus obtained, and the tensile strength was 58 kg/+u2, and the Yank modulus was 8100 kg/2. It was confirmed that the substrate was a fiber-reinforced glass substrate with a smooth surface.

(Effects of the Invention) As explained above, according to the present invention, which is a substrate made of a matrix glass composite reinforced with heat-resistant inorganic long fibers and a glassy surface layer, it has excellent strength, rigidity, and surface smoothness. A fiber-reinforced glass substrate that can be advantageously used as a magnetic recording substrate capable of high-density recording can be provided.

Claims (1)

[Scope of Claims] 1. Comprising a composite layer of matrix glass and a sheet-like molded product in which heat-resistant inorganic long fibers are two-dimensionally arranged, and a glassy surface layer covering the surface of the composite layer, and A fiber-reinforced glass substrate characterized in that at least a part of the matrix glass is made of glass produced by firing a glass precursor. 2. A method for manufacturing a fiber-reinforced glass substrate, comprising at least the following steps (1) to (3). (1) First, a sheet-like molded body made of two-dimensionally oriented heat-resistant inorganic long fibers is impregnated with a solution mainly consisting of a glass precursor, and then dried to generate matrix glass and prepare it. Step of obtaining a molded body; (2) Step of producing a fired composite by pressurizing and firing the preformed body after drying at a temperature of 500° C. or higher; (3) Adding glass to the surface of the fired composite. 3. In the treatment of step (1), each treatment of impregnating with a glass precursor solution and drying is repeated multiple times. 2. The manufacturing method described in 2. 4. The manufacturing method according to claim 2 or 3, characterized in that in the treatment of the step (1), glass fine powder is added to the glass precursor solution.