JPH0593284A - Production of metallic-core substrate - Google Patents

Abstract

PURPOSE:To obtain a metallic-core substrate capable of preventing deterioration, peeling or cracking, etc., even under severe high-temp. conditions and having an excellent electrical insulating property. CONSTITUTION:One soln. between the soln. contg. 3-10wt.% tantalum alkoxide as the metal oxide and the soln. contg. 3-10wt.% titanium alkoxide as the metal oxide is applied on a metallic substrate of stainless steel or nickel having <=0.1mum surface roughness and heated at 500-600 deg.C to form a ceramic insulating film having 0.1-0.2mum thickness on the metallic substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal core substrate in which a ceramic insulating film which is dense and has excellent heat resistance and electric insulation is formed on a metal substrate.

[0002]

2. Description of the Related Art As a method for forming a ceramic thin film on a metal substrate, a sputtering method, a vapor deposition method, a CVD method and the like are known. Recently, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-258646, a method of applying a metal alkoxide to a base material and thermally decomposing the metal alkoxide to make it into a thin film is inexpensive in the apparatus and large in area. It is attracting attention because it is easy.

The ceramic thin film formed in the conventional manner exhibits heat resistance up to its mineralization temperature (200 to 350 ° C.) and further exhibits excellent mechanical strength of 9H or more in transparency and pencil strength.

[0004]

A conventional metal core substrate coated with a ceramic thin film formed by thermal decomposition of a metal alkoxide solution is a silica containing a main metal alkoxide solution in the form of an oxide. (Si
O ₂ ) and alumina (Al ₂ O ₃ ) are used. These materials have a problem that a ceramic thin film is peeled off or cracked in a severe heating environment (for example, 400 ° C.), or the ceramic thin film itself is deteriorated to become white and its transparency is significantly lowered. Further, even though the appearance of uniform transparency is exhibited, there is a problem in that it has pores of 0.2 to 0.5 μm that can be recognized by an optical microscope and the electrical insulation is poor.

The present invention has been made in order to solve the above problems, and provides a method for producing a metal core substrate having excellent electric insulation, which prevents deterioration, peeling, cracking, etc. even under a more severe heating environment. The purpose is to obtain.

[0006]

According to the method for producing a metal core substrate of the present invention, a solution of at least one of tantalum alkoxide and titanium alkoxide containing 3 to 10% by weight in the form of a metal oxide has a surface roughness of 0. After applying to stainless steel or nickel metal substrate of 1 μm or less, 500 to 600 ° C.
Is used to form a ceramic insulating film having a thickness of 0.1 to 0.2 μm on the metal base material.

Another method of producing a metal core substrate according to the present invention is to use a solution of at least one of tantalum alkoxide and titanium alkoxide in the form of a metal oxide in an amount of 3 to 10% by weight to obtain a nickel having a thickness of 2 to 20 μm. Ceramic having a thickness of 0.1 μm or less by plating, applied to a copper, stainless steel or nickel metal base material and heated at 500 to 600 ° C. to have a thickness of 0.1 to 0.2 μm on the metal base material. This is a method of forming an insulating film.

[0008]

[Function] A ceramic insulating film and a metal substrate formed by using a metal alkoxide and its modified product were investigated and the film quality was evaluated. By selecting and combining the substrate metal and the metal alkoxide as in the present invention, a dense ceramic thin film having excellent electric insulation which cannot be found anywhere else is formed on the metal substrate.

[0009]

Examples As the metal alkoxide according to the present invention,
It is essential that the adhesiveness with the base material is excellent.
The concentration of the metal contained in the metal alkoxide is preferably 3 to 10% by weight, particularly 5 to 8% by weight in the form of the metal oxide. If the amount is less than 3% by weight, the metal alkoxide attached to the base material has a low viscosity and becomes thin, and the film thickness after heat treatment becomes as thin as 0.1 μm or less, and the surface roughness of the base material cannot be flattened and the base material is exposed. It is not preferable because it may occur. If it exceeds 10% by weight, the viscosity of the metal alkoxide becomes high and the adhered surface becomes dull. Also, since the film thickness exceeds 0.2 μm, the gas generated by thermal decomposition during the heat treatment is trapped inside the film, It is not preferable because it shrinks greatly and may peel off from the substrate. From the above, in order to obtain a dense film quality, the thickness of the ceramic insulating film according to the present invention is
Usually 0.12 to 0.20 μm, preferably 0.12 to
0.14 μm.

The metal base material according to the present invention is a metal base material that withstands the firing temperature for mineralizing the metal alkoxide solution which is the starting material of the ceramic insulating film formed thereon and does not oxidize. The surface of the base material has a ceramic insulating film thickness of 0.12 to 0.14 μm formed in one step.
Since it is m, it is necessary to use a metal base material having a surface roughness of 0.1 μm or less. When a film is formed on a base material having a surface roughness of more than 0.1 μm, scratches on the base material surface,
It is not preferable because there is a risk that the roughness cannot be filled and that it is reflected as it is in the ceramic insulating film, resulting in deterioration of insulating properties. Since an ordinary metal base material has scratches and dents and surface roughness due to oxidation during firing, it is necessary to perform some surface treatment such as mirror surface treatment and plating to satisfy the above condition. In another invention of the present invention,
As a surface treatment, nickel plating was applied for the purpose of smoothing the surface of the metal substrate and preventing oxidation. Plating thickness is 2-20μ
m, particularly 3 to 10 μm is preferable. If it is less than 2 μm, it is not effective in preventing the oxidation of the metal base material, and the surface is roughened. 20μ
If it exceeds m, not only is it time-consuming for plating, but also the total amount of plating is peeled off from the metal substrate after heating, which makes film formation impossible, which is not preferable. The metal used for plating is not limited to nickel as long as it does not easily undergo oxidative deterioration during firing and has good wettability with a metal alkoxide solution.

As a result of various studies on the selective combination of the above-mentioned base material and metal alkoxide, when a combination of a stainless steel or nickel metal base material and at least one of tantalum alkoxide and titanium alkoxide, and a copper, stainless steel or nickel metal base material, When a nickel-plated metal substrate was used in combination with at least one of tantalum alkoxide and titanium alkoxide, excellent properties not seen elsewhere were exhibited.

As a method of applying the metal alkoxide to the metal substrate, the same method as the conventional method can be adopted. That is, a spray method, a dipping method, a spin coating method and the like can be mentioned. In the present invention, the film formation on both surfaces of the substrate is considered, so the dipping method is preferable. Further, the thickness of the ceramic insulating film can be adjusted by repeating the application and heating of the metal alkoxide. Next, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Embodiment 1. 50mm x mirror-finished size
A stainless steel plate having a thickness of 50 mm and a thickness of 0.3 mm is ultrasonically cleaned with toluene and degreased. This is dipped in a modified ethyl tantalate containing 5% of Ta ₂ O ₅ for 5 minutes and then pulled up at a rate of 10 cm / min to coat the solution. Next, after drying at 100 ° C. for 15 minutes, it is transferred to an electric furnace, heated to 550 ° C. at a rate of 10 ° C./minute and held for 30 minutes, then the electric furnace is turned off and allowed to cool in the furnace. This operation was repeated 5 times to form a ceramic thin film on the stainless steel substrate to obtain a metal core substrate according to one example of the present invention. The ceramic thin film is an optical microscope for appearance color, transparency, pinholes and presence of cracks, and a film thickness is measured by a stylus type surface roughness meter (DEKTAK3030 manufactured by Sloan) for insulation resistance and breakdown voltage by a picoampere meter (YHP4140).
Measurement was carried out in B), and the results are shown in Table 1.

[0014]

[Table 1]

Example 2. A metal core substrate according to another example of the present invention was obtained in the same manner as in Example 1 except that a mirror-finished nickel thin plate was used in place of the stainless thin plate in Example 1, and the characteristics are shown in Table 1.

Embodiment 3. A metal core according to another embodiment of the present invention is the same as that of the first embodiment except that a mirror-finished nickel thin plate is used instead of the stainless thin plate and a modified butyl titanate is used instead of the modified ethyl tantalate. A substrate was obtained and its characteristics are shown in Table 1.

Example 4. In Example 1, except that instead of the modified ethyl tantalate, a mixture of modified ethyl tantalate and modified ethyl titanate in equal amounts was used.
A metal core substrate according to still another example of the present invention was obtained in the same manner as in Example 1, and the characteristics thereof are shown in Table 1.

Comparative Example 1. In Example 1, instead of the modified ethyl tantalate, 5% by weight calculated as SiO _2.
Example 1 except using the modified ethyl silicate containing
A ceramic thin film was formed on the stainless steel substrate in the same manner as in, but many pinholes were found in the film. The characteristics are shown in Table 1.

Comparative Example 2. In Example 1, 5% by weight calculated as Al ₂ O ₃ instead of modified ethyl tantalate
A ceramic thin film was formed on a stainless steel substrate in the same manner as in Example 1 except that the modified butyl aluminate contained was used, but shell-like cracks were formed in the film, and the characteristics could not be evaluated.

Example 5. Surface roughness 0.1 μm or more 1 μm
Hereinafter, a stainless steel thin plate having a size of 50 mm × 50 mm and a thickness of 0.3 mm is ultrasonically cleaned with toluene and degreased. Electroless plating of nickel was applied to this surface to form a total nickel film having a thickness of 3 μm. The surface roughness at this time is 0.
It was 08 μm. This was dipped in modified ethyl tantalate containing 5% in terms of Ta ₂ O ₅ for 5 minutes and then 10 mm /
Coat withdrawal solution at a rate of minutes. Then 1
After drying at 00 ℃ for 15 minutes, transfer to an electric furnace and
The temperature is raised to 550 ° C. at a rate of 30 minutes and kept for 30 minutes, then the electric furnace is turned off and allowed to cool in the furnace. This operation was repeated 5 times to form a ceramic thin film on a nickel-plated stainless steel substrate to obtain a metal core substrate according to another embodiment of the present invention. The above-mentioned ceramic thin film is an optical microscope for appearance color, transparency, presence or absence of pinholes and cracks, and a film thickness for a stylus surface roughness meter (DEKTAK3030 manufactured by Sloan).
The insulation resistance and breakdown voltage with pico ampere meter (Y
HP4140B) and the results are shown in Table 2.

[0021]

[Table 2]

Embodiment 6. In Example 5, a metal core substrate according to another embodiment of another invention of the present invention was obtained in the same manner as in Example 5 except that a copper thin plate having a surface roughness of 0.43 μm was used instead of the stainless thin plate. The characteristics are shown in Table 2.

Example 7. Another embodiment of the present invention is performed in the same manner as in Example 5 except that a copper thin plate having a surface roughness of 0.43 μm is used instead of the stainless thin plate and a modified butyl titanate is used instead of the modified ethyl tantalate. A metal core substrate according to another example of Example 1 was obtained, and its characteristics are shown in Table 2.

Example 8. In Example 5, except that modified ethyl tantalate and modified ethyl titanate were mixed in equal amounts instead of modified ethyl tantalate,
A metal core substrate according to still another embodiment of the present invention was obtained in the same manner as in Example 5, and the characteristics thereof are shown in Table 2.

Comparative Example 3. In Example 5, 5% by weight calculated as SiO ₂ instead of modified ethyl tantalate
Example 5 except using the modified ethyl silicate containing
A ceramic thin film was formed on a nickel-plated stainless steel substrate in the same manner as in, but many pinholes were found in the film. The characteristics are shown in Table 2.

Comparative Example 4. In Example 5, 5% by weight calculated as Al ₂ O ₃ instead of modified ethyl tantalate
A ceramic thin film was formed on a nickel-plated stainless steel substrate in the same manner as in Example 5 except that the modified butyl aluminate contained was used, but shell-like cracks were formed in the film, and the characteristics could not be evaluated.

Comparative Example 5. A ceramic thin film was formed in the same manner as in Example 6 except that a mirror-polished copper thin plate having a surface roughness of 0.06 μm was used instead of the nickel-plated copper thin plate in Example 6, but the surface of the copper after firing was changed. Oxidation and peeling of the film were remarkable, and the characteristics could not be evaluated.

As is clear from Tables 1 and 2, the metal core substrate having the ceramic insulating film formed according to the embodiment of the present invention is excellent in heat resistance and electric insulation, so that it is used as a component in a cathode ray tube. When used, the ceramic insulating film does not deteriorate and peel off even when exposed to the glass sealing temperature, that is, around 400 to 500 ° C., and the initial characteristics can be maintained. Moreover, since the thickness of the ceramic insulating film formed by one operation is as thin as 0.1 to 0.2 μm, a uniform and dense ceramic insulating film can be formed even if the base material has a complicated shape. When the thickness of the ceramic insulating film is required due to the required characteristics, the film thickness can be adjusted by repeating the dipping and firing steps, as shown in the above embodiment.
Further, according to another invention of the present invention, copper can be used as the metal of the metal core substrate, and the usefulness is improved.

[0029]

As described above, the present invention provides a solution of at least one of tantalum alkoxide and titanium alkoxide containing 5 to 8% by weight in the form of a metal oxide.
By coating a stainless or nickel metal substrate having a surface roughness of 0.1 μm or less and then heating at 500 to 600 ° C. to form a ceramic insulating film having a thickness of 0.1 to 0.2 μm on the metal substrate, Another invention of the present invention is to provide a surface roughness by subjecting a solution of at least one of tantalum alkoxide and titanium alkoxide containing 3 to 10% by weight in the form of a metal oxide to nickel plating having a thickness of 2 to 20 μm. More severe than applying to a copper, stainless steel or nickel metal substrate having a thickness of 0.1 μm or less and heating at 500 to 600 ° C. to form a ceramic insulating film having a thickness of 0.1 to 0.2 μm on the metal substrate. Degradation, peeling and cracking are prevented even in a heating environment, and a method for producing a metal core substrate having excellent electrical insulation can be obtained.

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[Procedure amendment]

[Submission date] April 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

As the metal base material according to the present invention, a metal base material that withstands the firing temperature for mineralizing the metal alkoxide solution which is the starting material of the ceramic insulating film formed thereon and does not oxidize is used. The surface of the base material has a ceramic insulating film thickness of 0.12 to 0.14 μm formed in one step.
Since it is m, it is necessary to use a metal base material having a surface roughness of 0.1 μm or less. When a film is formed on a base material having a surface roughness exceeding 0.1 μm, scratches on the base material surface,
It is not preferable because there is a risk that the roughness cannot be filled and that it is reflected in the ceramic insulating film as it is, resulting in deterioration of insulating properties. Since an ordinary metal base material has scratches and dents and surface roughness due to oxidation during firing, it is necessary to perform some surface treatment such as mirror surface treatment and plating to satisfy the above conditions. In another invention of the present invention,
As a surface treatment, nickel plating was applied for the purpose of smoothing the surface of the metal substrate and preventing oxidation. Plating thickness is 2-20μ
m, particularly 3 to 10 μm is preferable. If it is less than 2 μm, it is not effective in preventing the oxidation of the metal base material, resulting in surface roughness. 20μ
If it exceeds m, not only the plating will take time, but also the plating layer will peel off from the metal base material after heating, which makes film formation impossible, which is not preferable. The metal used for plating is not limited to nickel as long as it does not easily undergo oxidative deterioration during firing and has good wettability with a metal alkoxide solution.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Example 5. Surface roughness 0.1 μm or more 1 μm
Hereinafter, a stainless steel thin plate having a size of 50 mm × 50 mm and a thickness of 0.3 mm is ultrasonically cleaned with toluene and degreased. Electroless plating of nickel was performed on this surface to form a nickel layer having a thickness of 3 μm. The surface roughness at this time is 0.
It was 08 μm. This was dipped in modified ethyl tantalate containing 5% in terms of Ta ₂ O ₅ for 5 minutes and then 10 mm /
Coat withdrawal solution at a rate of minutes. Then 1
After drying at 00 ℃ for 15 minutes, transfer to an electric furnace and
The temperature is raised to 550 ° C. at a rate of 30 minutes and kept for 30 minutes, then the electric furnace is turned off and allowed to cool in the furnace. This operation was repeated 5 times to form a ceramic thin film on a nickel-plated stainless steel substrate to obtain a metal core substrate according to another embodiment of the present invention. The above-mentioned ceramic thin film is an optical microscope for appearance color, transparency, presence or absence of pinholes and cracks, and a film thickness for a stylus surface roughness meter (DEKTAK3030 manufactured by Sloan).
The insulation resistance and breakdown voltage with pico ampere meter (Y
HP4140B) and the results are shown in Table 2.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

[0021]

[Table 2]

Claims (2)

[Claims] 1. A solution of at least one of tantalum alkoxide and titanium alkoxide containing 3 to 10% by weight in the form of a metal oxide is applied to a stainless steel or nickel metal substrate having a surface roughness of 0.1 μm or less, 500 ~
0.1 to 0.2 μm on the metal base material by heating at 600 ° C.
A method of manufacturing a metal core substrate for forming a thick ceramic insulating film. 2. A solution of at least one of tantalum alkoxide and titanium alkoxide containing 3 to 10% by weight in the form of a metal oxide is plated with nickel having a thickness of 2 to 20 μm to reduce the surface roughness to 0.1 μm or less. Applied to a copper, stainless steel or nickel metal base material,
A method of manufacturing a metal core substrate, comprising heating at 00 ° C. to form a ceramic insulating film having a thickness of 0.1 to 0.2 μm on the metal base material.