JPS63171883A - Insulating stainless steel sheet having excellent heat resistance and its production - Google Patents

Abstract

PURPOSE:To produce an insulating stainless steel sheet having excellent heat resistance, by forming an oxide polymer film consisting of Al, etc., contg. powder of alumina, etc., on the surface of a stainless steel sheet and forming an oxide polymer film thereon. CONSTITUTION:Alumina or silica powder having 0.01-5mum average grain size is added to or mixed with an alcohol soln. contg. >=0.1wt.% >=1 kinds of alkoxide or acetyl acetonate metal salt of Al, Zr, Ti, and Si. Such soln. mixture is coated on the surface of the stainless steel 1 and is heated at 300-500 deg.C to form a lower layer 2 consisting of the oxide polymer of powder 3-contg. Al, Zr, Ti, and Si having about >=5mum film thickness. An >=0.005% alcohol soln. similar to the above-mentioned soln. is then coated on said layer 2 and is heated to form an upper layer 4 consisting of the oxide polymer to about 0.01-0.3mum film thickness thereon to eliminate the pinholes and ruggedness of the layer 2. The insulating stainless steel sheet having good flexibility and workability and excellent heat resistance is thereby obtd.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a stainless steel plate which has heat resistance and electrical insulation properties by forming a multilayer polymer film of metal oxide on the surface of the stainless steel plate, and a method for manufacturing the same. Regarding.

(Prior Art) Processed heat-resistant glass or ceramic plates have conventionally been used for applications that require heat resistance and insulation, such as protective members for electrical heating elements. However, plates made of these materials have poor visibility, so when processing the plate into the desired shape,
There was a problem that the plate thickness had to be made thinner, and if it was made thinner, the strength would decrease.

In order to solve this problem, some attempts have been made to use a material in which a heat-resistant organic resin coating or enamel coating is formed on a metal plate.

(Problems to be Solved by the Invention) Among the former materials, those with relatively high heat resistance have a polyimide coating, but even this material has a low heat resistance limit of about 400°C.

On the other hand, the latter material has excellent heat resistance, but the enamel film generally produces pinholes during firing, so the film thickness is usually 50 μm to achieve insulation properties of IOMΩ or higher.
It was necessary to make it thicker than m. However, when the enamel film is made thicker in this way, its workability deteriorates and cracks are more likely to occur during processing (and its adhesion to the metal plate is also poor).

For this reason, there has been a demand for a material that has a film formed on the surface of the steel plate that has a high heat resistance, excellent insulation properties, and flexibility.

(Means for Solving the Problems) The present invention uses a stainless steel plate as the metal plate, and as a film with excellent heat resistance, insulation, and flexibility on the surface of the steel plate.
Al containing ceramic powder in the lower layer, Zr%Ti%S
A multilayer film of one or more oxide polymers of i was formed. Then, this oxide polymer film was formed by applying a solution of the alkoxide or acetylacetonate metal salt of the metal and performing dehydration condensation.

That is, the present invention forms an oxide polymer film of one or more of Al, Zr, and Ti%Si containing powders of alumina, silica, or both as a lower layer on the surface of a stainless steel plate, and then An oxide polymer film of one or more of ^l, Zr, Ti* or Si is formed on the lower layer, and each of these oxide polymer films is made of Al, Zr, Ti%Si alkoxide or acetyl. Adding alumina powder or silica powder or a mixture of both powders with an average particle size of 0.01 to 5 μm to an alcohol solution containing 0.1% by weight or more of one or more acetonate metal salts, Apply the additive solution to the surface of the stainless steel plate and heat it to 300 to 500℃.
A lower layer is formed by heating with
One or more types of cetyl 7cetonate metal salts are added at 0.
Applying an alcohol solution containing 0.005% by weight or more,
It was heated to 300-500°C to form an upper layer.

The attached drawings schematically show the cross section of the steel plate of the present invention.
1 is a stainless steel plate, 2 is a lower layer, which is made of Al, Zr containing powder 3 of alumina or silica or both of these.
, Ti, Si, oxide polymer film of one or more types, 4 is the upper layer, Al, Zr%Ti.

It is a polymer film made of one or more oxides of Si.

In the present invention, in the case of the lower layer oxide polymer film, for example, in the case of ^1 oxide, ^1 comrades are bonded to each other through oxygen to become a polymer, and the same applies to each oxide of Zrs Ti% Si. It is made into a polymer by bonding. The powder alumina and silica contained in this oxide polymer film are crystalline and do not form a polymer.

The purpose of containing alumina or silica powder in the lower layer is to prevent cracks from occurring when the oxide polymer film is made thick. In other words, when forming an oxide polymer film such as ^I or Zr, if the film thickness is increased to approximately 1 μm or more, the film shrinks greatly when it becomes a polymer due to dehydration condensation reaction, resulting in countless cracks. 1μ
If the temperature is less than m, the insulation properties will decrease, but if alumina or silica powder is filled into the film, these powders will not shrink in volume, so the shrinkage of the film will be alleviated, and the film thickness will be reduced. (Even if you do this, cracks will no longer occur.)

These powders may be a single substance or a mixture of alumina or silica, but those having an average particle size of 0.01 to 5 μm are used.

Fine particles smaller than 0.0 μm are expensive, and particles larger than 5 μm are difficult to disperse evenly during film formation, and the film becomes uneven. The powder content is between 20 and 80 parts by weight, preferably 50 parts by weight, based on parts by weight of the oxide polymer skin@ioo.

If the amount is less than 20 parts by weight, cracks will occur in the film and the film will peel off when the thickness of the lower layer is 10 μm or more.
If the amount exceeds parts by weight, the adhesion to the steel plate will decrease.

The thickness of the lower layer is 5 μm or more, preferably 5 to 25 μm, and generally 10 μm. If it is less than 5 μm, there will be many pinholes, and if it is thicker than 25 μm, visibility will decrease, cracks will occur, and peeling will occur.

The upper oxide polymer coating is similar to the lower oxide polymer coating. This is because if only the lower layer is provided with this upper layer, pinholes will exist, the insulation will be insufficient due to moisture absorption, and there will be unevenness due to alumina or silica powder. To avoid pinholes only in the lower layer,
The film thickness must be 50 μm or more, but as mentioned above, if it exceeds 25 μm, visibility will decrease.

However, even with a thickness of 25 μm, there are still pinholes and unevenness, and the insulation is poor, with a resistance value of only about 10-Ω.Therefore, an upper layer is provided to eliminate the pinholes and unevenness.

The insulation of the entire film should be 10 MΩ or more, and in order to reduce unevenness, the thickness of the upper layer should be 0.01 to 0.3 μm, generally about 0.1 μm. If it is less than 0.01 μm, pinholes and unevenness cannot be covered sufficiently, and even if it is thicker than 0.3 μm, the effect will not change.

The formation of the lower layer film is performed by preparing an alcohol solution containing 0.1% by weight or more of one or more of the alkoxide or acetylacetonate metal salt of 31% Zr5TisSi, and adding an average particle size of 0.01% to the solution. It is formed by adding ~5μ ring alumina powder, silica powder, or a mixture of both powders, applying the added solution to the surface of a stainless steel plate, and heating it at 300 to 500°C. When an alcohol solution of the metal alkoxide or acetylacetonate metal salt is applied to a steel plate,
It is easily hydrolyzed by moisture in the air, and when heated, a dehydration condensation reaction occurs, and the metals bond together through oxygen, forming a polymer film. In order to promote hydrolysis, the solution contains a trace amount of water, acid (e.g. hydrochloric acid, sulfuric acid, phosphoric acid, etc.) or alkali (e.g. ammonia, etc.), for example, 0.01% by weight or more in the case of water, 0.0% in the case of acid or alkali. ．．
0.001% by weight or more may be added.

To make the solution concentration 0.1% by weight or more, the lower layer thickness should be 5 μm.
The heating temperature for dehydration condensation was set at 300 to 5 m.
The reason for setting the temperature to 00℃ is that if the temperature is lower than 300℃, the dehydration condensation will not proceed completely, so a complete oxide film will not be formed, and the temperature will be lower than 50℃.
When the temperature exceeds 0°C, the solvent alcohol evaporates rapidly, causing pinholes.

Preferred examples of alkoxides of SZr, Ti, and Si to be applied to the lower layer include aluminum ethoxide, aluminum isopropoxide, aluminum ethoxide, zirconium tetrapropoxide, zirconium tetrabutoxide, titanium tetraethoxide, titanium tetrabutoxide, Methyl silicate, ethyl silicate, etc., and 7cetylacetonate metal salt,
Examples include zirconium acetylacetonate, aluminum acetyl 7cetonate, and titanium 7cetyl 7cetonate.

Application of these compounds is carried out by dissolving one or more of the above compounds in an amount of 0.1% by weight or more in alcohol.
The alcohol used is not particularly limited as long as it can uniformly disperse the above compound, and methanol, ethanol, isopropyl alcohol, butanol, etc. are sufficient, for example. In addition to alcohol, a low boiling point solvent such as toluene or xylene can also be used.

The solution may be applied to the steel plate by any method capable of uniformly applying the solution, such as a roll-coating method, a spray method, a bar-coding method, or a dipping/pulling method.

The upper layer oxide film is formed by Al, Zr, Ti, Si
1 of the alkoxide or acetylacetonate metal salt of
An alcohol solution containing 0.005% by weight or more of the species or two or more species may be applied. Here, the solution concentration is 0.0
The reason for setting the amount to be 0.05% by weight or more is to make the upper layer film thickness 0.01 μm or more. The acetylacetonate metal salt and solvent used as the alkoxide of the metal may be those mentioned in the case of the lower layer, and the heating for causing the dehydration condensation reaction may be at the same temperature (300 to 500°C).

(Example) Example 1 0.1 mol/e of acetyl 7cetonate norconium
0.3 sol/9 of alumina powder having an average particle size of 0.1 μm was added to an isopropyl alcohol solution and uniformly dispersed. This solution was applied to a 0.4-thick stainless steel plate and placed in an electric furnace at 400°C for 10 minutes to form the lower layer coating (I
A thickness of approximately 10 μm was formed.

Next, this steel plate was immersed in a 0.1 mol/g isopropyl alcohol solution of the following alkoxide, pulled up at a constant speed of 51/sec, and coated uniformly.

(a) Zirconium acetylacetonate (b) Titanium tetrabutoxide (c) Aluminum isopropoxide (d) Ethyl silicate After coating, place in an electric furnace at 500°C for 5 minutes to remove the upper layer!
! (film thickness: 0.1 μm) was formed.

The heat resistance, insulation properties, and processing adhesion of these stainless steel plate coatings were as shown in Table 1. The film adhesion should be evaluated by the bending R value at which the film peels off when a stainless steel plate is bent 90 degrees at a curvature of 5°C to 100mmH, then cellophane tape is crushed on the bent part and the film is peeled off. Similar evaluations were made in Example 2.3 below).

Example 2 0.2 mol/gn of titanium acetyl 7cetonate
- Uniformly disperse silica powder with an average particle size of 0.3 μm in a butanol solution, apply this solution uniformly to a stainless steel plate with a thickness of 0.3 μm, and place it in an electric furnace at 450°C for 7
The mixture was soaked for a minute to form a lower layer film (12 μm in film thickness).

Next, the steel plate was immersed in a 0.1 wol/6 n-butanol solution of acetyl heptatonate metal salt shown below and pulled up at a constant speed of 10 am 1 sec to uniformly coat the lower coating on the steel plate.

(a) Zirconium 7cetylacetonate (b) Titanium acetylacetonate (c) After coating acetyl 7cetonate aluminum, place it in an electric furnace at 400°C for 10 minutes to form upper layer II (film thickness 0.07 μm) did.

The heat resistance, insulation properties, and processing adhesion of these stainless steel plate coatings were as shown in Table 2.

Example 3 Ethyl silicate 509, butanol 1909, water 45
9 and hydrochloric acid with an average particle size of 2.0μ.
0.1-ol/g of alumina powder and silica powder each
Add this solution uniformly to a plate with a thickness of 0.1-
This was applied uniformly onto a stainless steel plate and placed in an electric furnace at 450° C. for 7 minutes to form a lower layer film (II thickness approximately 8 μm).

Next, this steel plate was mixed with 0.05 mol/8 of the following alkoxide.
It was immersed in an ethanol solution and pulled up at a constant speed of 21111/sec to uniformly coat it.

(a) Zirconium tetraisopropoxide (b) Titanium tetraisopropoxide (c) Aluminum butoxide (d) Methyl silicate After coating, place in an electric furnace at 450°C for 7 minutes to coat the upper layer (
A film thickness of 0.07 μm was formed.

The heat resistance, insulation properties, and processing adhesion of these stainless steel plate coatings were as shown in Table 3.

(Effects) As described above, the stainless steel sheet of the present invention has a heat-resistant coating and
Although it is a metal compound with excellent insulation properties, it also has excellent workability, so it can be processed into various shapes.

[Brief explanation of the drawing]

The accompanying drawing is a schematic sectional view of the stainless steel plate of the present invention.

Claims (2)

[Claims] (1) Al containing alumina, silica, or both powders as a lower layer on the surface of the stainless steel plate.
, Zr, Ti, and Si, and furthermore, on this lower layer, the Al, Zr
An insulating stainless steel sheet with excellent heat resistance, characterized by forming an oxide polymer film of one or more of Ti and Si. (2) One or more types of alkoxides or acetylacetonate metal salts of Al, Zr, Ti, and Si at 0.
In an alcohol solution containing 1% by weight or more, an average particle size of 0.
Alumina powder, silica powder, or a mixture of both powders of 01 to 5 μm are added, and the added solution is applied to the surface of a stainless steel plate and heated at 300 to 500°C to form a lower layer. Al, Z on top
300 to 500
A method for manufacturing an insulating stainless steel sheet with excellent heat resistance, which comprises heating to ℃ to form an upper layer.