JPH02102038A - Corrosion resistant metal plate - Google Patents

Abstract

PURPOSE:To form a composite film durable against an external damage and having excellent corrosion resistant effect on a metal plate by forming inorganic or organic film, or an inorganic-organic composite film on the surface of the plate, and forming a thin and dense plasma polymerizable film thereon. CONSTITUTION:An inorganic or organic film, or an inorganic-organic film is provided on a metal plate, and a plasma polymerizable film is provided thereon. In this case, it is desirable to form by varying the material of the polymerizable film in a sectional direction. The plate is desirably made of aluminum or aluminum alloy. Thus, the plate has excellent corrosion resistance, no corrosion even in acid or alkaline atmosphere, and the film can endure against an external damage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a metal plate having excellent corrosion resistance and having a composite coating on its surface.

(Prior Art) Conventionally, a film has been formed on the surface of a metal plate to improve its corrosion resistance. For example, an alumite film, a boehmite film, or Inorganic films such as phosphoric acid chromate films or organic films such as organic paint films,
Alternatively, a composite film consisting of an inorganic film and an organic film is formed.

(Problem to be Solved by the Invention) However, these films contain many pinholes caused by impurities present on the surface of the aluminum plate and evaporation of the solvent during drying of the paint. It is difficult to obtain the desired corrosion resistance effect, and these films tend to dissolve or blister due to alkali or acid, making it difficult to utilize conventional aluminum plate materials in these atmospheres.

In order to solve this problem, the present invention forms a dense film on the surface of a metal plate that contains almost no pinholes and is stable against alkalis and acids. The present invention provides a metal plate with excellent corrosion resistance.

(Means for Solving the Problem) As a result of various studies to achieve the above object, the present inventors have discovered that an organic monomer gas can be obtained by exposing an organic monomer gas to an electric field or plasma such as an inert gas. The plasma-polymerized film, which is formed by the polymerization reaction of active species of monomers on the solid surface, has a highly crosslinked, dense molecular structure, contains almost no pinholes, is chemically stable, and is The film speed is extremely slow ((<0.IILm/
m1n), it is not economical to make a plasma polymerized film alone to a thickness that can withstand external damage, but it is possible to form an inorganic or organic film or an inorganic/organic composite film of a certain thickness on the surface of a metal plate, and then apply dense plasma polymerization on top of it. The inventors have discovered that by forming a thin polymer film, it is possible to form a composite film on a metal plate that is resistant to external damage and has an excellent anticorrosion effect, and based on this knowledge, the present invention has been completed.

That is, the present invention provides (1) a corrosion-resistant metal plate characterized in that an inorganic or organic film or an inorganic/organic composite film is provided on the surface of the metal plate, and a plasma polymerized film is provided thereon;
(2) the corrosion-resistant metal plate described in (1) above, in which the film quality of the plasma polymerized film changes in the cross-sectional direction; and (3) the corrosion-resistant metal plate described in (1) or (2) above, wherein the metal plate is an aluminum or aluminum alloy plate. The present invention provides a corrosion-resistant metal plate.

The metal plate of the present invention includes a steel plate, a copper plate, an aluminum plate, a magnesium plate, a stainless steel plate, an alloy plate thereof, etc., and these include alloy plates thereof, and include all corrosive metals. . Further, the thickness and shape of the metal plate are not particularly limited.

In the present invention, the inorganic film formed on the surface of the metal plate is, for example, an alumite film.

These include a boehmite film, a phosphoric acid chromate film, and the like. Examples of organic films include coatings obtained using thermosetting organic paints such as acrylic, epoxy, polyester, and urethane paints. The thickness of these films is 0.5 to 10 ILm, excluding the boehmite film and phosphoric acid chromate film.
In particular, a range of 1 to 5 pm is preferable. If the film thickness is too thin, the film will have poor mechanical strength and will be easily scratched. If it is too thick, it will become uneconomical and at the same time it will be difficult to form a plasma polymerized film. In the case of a boehmite film and a phosphoric acid chromate film, the range is preferably from 0.01 to 0.5 JLm.

Further, in the case of forming an inorganic/organic composite film, the above-mentioned inorganic and organic films may be arbitrarily combined.

In addition, the plasma polymerized film can be prepared by
An organic monomer gas or a carrier gas and an organic monomer gas are introduced into the container, and a high frequency is applied to parallel plate electrodes provided in the container to generate plasma between the electrodes. At this time, the position of the metal plate having an inorganic, organic, or inorganic/organic composite film on its surface varies depending on the position of the gas inlet, but in most cases it is between opposing electrode plates or on the electrode plate.

The organic monomer used to form the plasma polymerized film may be in the form of gas, liquid, or solid at room temperature, and in the case of liquid or solid, it is of course possible to vaporize these. Examples of organic monomers include methane, ethane,
Propane, ethylene, acetylene, propylene, CF4
．． Gaseous monomers such as C2F4, C3F8, C2F4, C3F4, benzene, hexane, toluene, styrene,
Liquid monomers such as xylene and methyl methacrylate,
Any solid monomer such as naphthalene, anthracene, dibenzyl, etc. may be used, and as the carrier gas, for example, an inert gas such as argon, helium, etc. can be preferably used. The pressure inside the vacuum container is 0.001 to 0.5 Torr, preferably 0-001 to 0.0 Torr before the gas is introduced. ITorr, 0 when introducing organic monomer gas or carrier gas and organic monomer gas
．． 005 to 1 Torr, preferably 0.005 to 1 Torr, preferably 0. O1~0.5T
It is orr.

In addition, when forming a plasma polymerized film by applying high frequency to the facing flat electrode, the high frequency power output and the energy density of the electrode surface are preferably 10 to 500 W, 0 to 500 W, respectively.
1~2W/crn”, more preferably 50~
200W, adjusted to the range of 0.2~IW/cm''.

When an inorganic, organic, or inorganic/organic composite film is formed on a metal plate and a plasma polymerized film is formed thereon, the thickness of the plasma polymerized film is 0.05 to 2 ILm, preferably 0.02 ILm.
The thickness of the plasma polymerized film is preferably 1 to 11 Lm. If the thickness of the plasma polymerized film is too thin, it will be difficult to obtain a uniform film, and if it is too thick, the film formation time will be long, which will be uneconomical, and the adhesion of the film will also deteriorate.

By the way, in the formation of a plasma polymerized film, a certain range of m
A plasma polymerized film formed under the conditions of drift force and organic monomer gas or carrier gas and organic monomer gas pressure (at the time of gas introduction) has good adhesion to the surface of the treated material.

That is, the range of the power supply output and the mixed gas pressure of the organic monomer gas or the carrier gas and the organic monomer gas in which good adhesion is obtained are both 0.005 to ITorr.

If the film is formed at a higher power or a lower gas pressure than this range, the adhesion will deteriorate, but the film will become denser and the corrosion resistance will be better. Therefore, in order to simultaneously satisfy adhesion to the surface of the treated material and corrosion resistance, a plasma polymerized film with good adhesion in the lower layer and dense and good corrosion resistance in the upper layer is formed by changing the film forming conditions continuously or intermittently. An effective method is to form it by Conditions to be changed include power output and gas pressure.

(Example) Next, the present invention will be explained in more detail based on Examples.

Example 1 Lightly etched and degreased, thickness 0.5 mm, diameter 130 mm
A polyester paint (trade name: KP9401 manufactured by Kansai Paint Co., Ltd.) was applied and baked on the surface of the 105011 alloy disc using a roll-type test coater to form a coating film with a thickness of 2 ILm. This was fixed on opposing flat electrodes in a vacuum container with a diameter of 250 mm, and a vacuum pump was used to
It was set to ITorr. Argon gas and styrene monomer gas were introduced into this container to adjust the pressure to 0.2 Torr. Thereafter, a high frequency wave with a frequency of 13.56 MHz and a power output of 100 W was applied to the electrode to generate plasma and form a styrene plasma polymerized film with a thickness of 0.51 Lm on the coating film. CA about the A-view alloy disc with the composite film of polyester coating film and styrene plasma polymerized film obtained in this way.
The results of the SS (J I 5H8681) test were
As a comparative example shown in Table S1, a 1050 alloy disc (Comparative Example 1) on which a polyester coating film was formed with a thickness of 2ILm after degreasing the surface, and a 1050A1 alloy disc with the same coating film on a thickness of 41Lm A plate (Comparative Example 2) was used.

As is clear from the results in Table 1, in Example 1, CASS
Although the sample surface did not change even after the test (100 hours), many large corroded bits were generated on the entire surface of the sample in Comparative Examples 1 and 2.

Example 2 Lightly etched and degreased thickness 0.5mm, diameter 130m
Electrolyte: 15% H2 on the surface of the 1050A1 alloy disk of
A sulfuric acid alumite film with a thickness of Igm was formed using SO4 and an electrolytic current density of IA/d.

On top of that, apply polyester coating II in the same manner as in Example 1!
(thickness 2gm), styrene plasma polymerized film (thickness 0.5gm), styrene plasma polymerized film (thickness 0.5gm)
1 Lm) was formed. CAS on the A5L alloy disk with a composite coating of sulfuric acid alumite coating, polyester coating and styrene plasma polymerized coating obtained in this way.
The results of the S test are shown in Table 2. As a comparative example, a sulfuric acid alumite film was applied to the surface after degreasing. pm formation,
Furthermore, 1050A with 21Lm of polyester coating film formed on it! The same plate of L alloy (Comparative Example 3) was used.

As is clear from the results in Table 2, in Example 2, CASS
Although the sample surface did not change even after the test (100 hours), corrosion bits were generated on the sample surface of Comparative Example 3.

(Effects of the Invention) The metal plate of the present invention has extremely excellent corrosion resistance, does not corrode even in an atmosphere containing acid or alkali, and
The film has an excellent effect of being resistant to external damage.

Claims (3)

[Claims] (1) A corrosion-resistant metal plate characterized in that an inorganic or organic film or an inorganic/organic composite film is provided on the surface of the metal plate, and a plasma polymerized film is provided thereon. (2) The corrosion-resistant metal plate according to claim 1, wherein the quality of the plasma polymerized film changes in the cross-sectional direction. (3) The corrosion-resistant metal plate according to claim 1 or 2, wherein the metal plate is an aluminum or aluminum alloy plate.