JPH0762234B2 - Method for manufacturing high corrosion resistant composite material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material having excellent corrosion resistance and a method for producing the same.

[0002]

2. Description of the Related Art Crystalline metal tantalum has a relatively good corrosion resistance even in an environment with severe corrosiveness such as boiling concentrated hydrochloric acid or boiling concentrated nitric acid, which is corroded in general corrosion resistant metallic materials. However, if it is exposed to the atmosphere for a long period of time, even if it is crystalline metal tantalum, the corrosion progresses .

From the above, Japanese Patent Laid-Open No. 61-210143 discloses that a valve metal-iron group metal amorphous alloy based on Ni-Ta has superior corrosion resistance as compared with crystalline tantalum metal. It is disclosed. However, since such an amorphous alloy is usually produced by a liquid quenching method, the method is limited to a shape such as a ribbon, a thin wire, or a powder, and therefore it is not always satisfactory as a corrosion-resistant material that can be used in various shapes. It wasn't something.

Therefore, recently, techniques for forming an amorphous alloy film on the surface of a metal substrate by various film forming methods have been studied. The present applicant has already filed Japanese Patent Application No. 1-183605.
The formation of tantalum amorphous film, which was not obtained by the conventional method, is mainly applied to inert gas ions (especially Ar gas ions).
We have applied for it after successfully forming a film with high corrosion resistance. However, since the Ar ion beam usually has a high sputtering rate, the film forming rate is reduced, and there is a problem in terms of productivity and the like. In addition, since Ar that deteriorates the film quality may remain in the film, it is necessary to adopt a method of increasing the film formation temperature for the purpose of removing Ar. As a result, there is a problem that it becomes difficult to form a tantalum amorphous film on a substrate having low heat resistance.

On the other hand, when forming a film, it is usually used as a substrate.
A metal with excellent corrosion resistance is used, but if there are slight pinholes in the film itself or if minute cracks occur, corrosion progresses through the pinholes, etc., especially at the interface between the substrate and the film. An undermining phenomenon or the like in which the corrosion of the steel rapidly progresses occurs. In the magnetron sputtering method generally adopted for film formation, considering corrosion resistance,
The structure of the interface is improper, and it is difficult to manufacture a composite material having excellent corrosion resistance. From the above problems, there is a demand for more efficient film formation, ensuring high-quality film quality, and forming an interface between a base material and a film having excellent corrosion resistance.

The present applicant has already filed an application in Japanese Patent Application No. 2-58119 as a coating of a nitrogen-containing tantalum almorphus film satisfying the above-mentioned demand. However, as a result of repeated studies after that, it was clarified that the oxygen-containing tantalum almorphus film exhibits the same excellent effect as the nitrogen-containing tantalum almorphus film. Further, it has been clarified that a film having a composition in which a part of contained oxygen is replaced by nitrogen and / or carbon can be a similar tantalum amorphous film having high corrosion resistance.

The present invention provides a composite material coated with an oxygen-containing tantalum amorphous film having excellent corrosion resistance in a harsh environment, and a method for producing a composite material capable of efficiently forming the oxygen-containing tantalum amorphous film. Is what you are trying to do.

[0008]

The composite material according to the present invention comprises a metal base material and a surface thereof covered with an oxygen-containing tantalum amorphous film. The metal substrate may be any corrosion-resistant metal, such as a Ni-based alloy,
A Ti-based alloy, SUS or the like can be used. The composite material according to the present invention is manufactured by the following method. (1) Tantalum is vapor-deposited in an oxygen atmosphere on the surface of a metal base material to coat an oxygen-containing tantalum amorphous film to manufacture a composite material.

(2) A composite material is manufactured by vapor-depositing tantalum on the surface of a metal base material and at the same time coating an oxygen-containing tantalum amorphous film by an ion beam mixing method in which oxygen ion irradiation is performed. Another composite material according to the present invention is one in which the surface of a metal substrate having a tantalum phase formed on the surface thereof is coated with an oxygen-containing tantalum amorphous film. Another composite material according to the present invention is manufactured by the following method.

(3) After tantalum is ion-implanted into the surface layer of the metal base material to form a tantalum phase, tantalum is vapor-deposited on the surface of the base material in an oxygen atmosphere to coat an oxygen-containing tantalum amorphous film. To manufacture.

(4) Oxygen-containing tantalum amorphous by an ion beam mixing method in which tantalum is ion-implanted into the surface layer of a metal base material to form a tantalum phase, and then tantalum is vapor-deposited on the surface of the base material and at the same time oxygen ion irradiation is performed. The membrane is coated to produce a composite material.

In the above methods (1) to (4), as the tantalum vapor deposition means, for example, an electron beam vapor deposition method, an ion beam sputter vapor deposition method using a tantalum target, or the like can be adopted. In the case of the sputter deposition method, an Ar ion beam is usually used. However, although the sputtering rate is low due to the formation of the oxygen-containing tantalum amorphous film, it is also a good idea to use an oxygen ion beam depending on the conditions.

[0013]

According to the present invention, by coating the surface of a metal substrate with an oxygen-containing tantalum amorphous layer, the oxygen-containing tantalum amorphous film has a high density and a high corrosion resistance, so that a composite having excellent corrosion resistance in a harsh environment can be obtained. The material can be obtained.

Further, by depositing tantalum on the surface of the metal base material in an oxygen atmosphere, an oxygen-containing tantalum amorphous layer excellent in compactness and high corrosion resistance can be efficiently formed on the base material, and in a harsh environment. It is possible to manufacture a composite material having excellent corrosion resistance.

Further, a film formed by depositing tantalum on the surface of a metal substrate and forming a film by an ion beam mixing method in which oxygen ion irradiation is performed at the same time, that is, a film is formed by using an oxygen ion beam as an ion beam. Since the ratio of is sputtered by the ion beam is considerably lower than that of the Ar ion beam, the amount of the formed film desorbed from the substrate surface by the ion sputtering can be reduced,
The film formation rate can be increased accordingly. In addition, since the amorphization progresses due to the oxygen content, it is not necessary to consider the presence of Ar in the film, unlike the irradiation of Ar ion beam,
An oxygen-containing tantalum amorphous film can be easily formed.
Furthermore, by adopting the mixing film formation method by ion beam irradiation, it is possible to control the sputter rate of the film formed by changing the acceleration voltage, current, irradiation angle, etc. of the ion beam, and control the degree of mixing as well. Since it is easy to perform, it is possible to achieve densification of the film for enhancing the corrosion resistance, formation of an optimal interfacial structure, improvement of adhesion to the substrate, and the like.

On the other hand, as the base material of the composite material, Ni-based alloy, Ti-based alloy, SUS material, etc. which are corrosion resistant metals are used. Adhesion with the oxygen-containing tantalum amorphous film coated by forming a tantalum phase in the surface layer of the base material when the base material composed of these materials does not contain a tantalum component compositionally or when the content is small. And the corrosion resistance at their interface can be improved. As a result, it is possible to improve the interfacial structure by the tantalum phase formed in the surface layer even under conditions where a very small amount of pinholes, minute cracks, etc. occur in the amorphous film and the progress of the pitting reaction is concerned. A composite material having excellent corrosion resistance can be obtained.

The tantalum phase is formed on the surface layer of the base material by a tantalum ion implantation method. In such an ion implantation method, the concentration, distribution, etc. of the tantalum phase can be arbitrarily controlled, and a graded structure of the tantalum phase in the depth direction can be formed. The tantalum phase formed on the surface layer of the base material is preferably an amorphous phase, but the effect is great even if it is crystalline, and oxygen may be contained. Therefore, by forming an oxygen-containing tantalum amorphous film by vapor deposition or an ion mixing method in the oxygen atmosphere of tantalum described above after the ion implantation of tantalum, a very small amount of pinholes or minute cracks are generated in the amorphous film. By modifying the interfacial structure with the tantalum phase formed in the surface layer, it is possible to manufacture a composite material having excellent corrosion resistance even under conditions where the progress of the pitting corrosion reaction is a concern. In particular, the combination of the ion implantation of tantalum and the formation of the oxygen-containing tantalum amorphous film by the ion mixing method makes it possible to obtain a composite material having excellent adhesion and more excellent corrosion resistance.

When forming an oxygen-containing tantalum amorphous film, depending on the forming conditions, it may be observed by electron diffraction observation with a TEM or the like that an extremely fine crystalline phase is mixed during film formation. However, it is a well-known fact that the rapidly solidified microcrystalline stainless steel does not cause compositional fluctuations such as segregation in the grain boundary portion even if the grain boundary density, which is a crystal defect due to the fine grains, is high, and is amorphous. Shows high corrosion resistance equivalent to that of phase. Also in the present invention, it has been confirmed that the presence of the extremely fine crystalline phase does not hinder the high corrosion resistance of the film.

[0019]

EXAMPLES Examples of the present invention will be described in detail below. Example 1

First, a 304L plate having a size of 22 × 70 × 2 mm is prepared as a base material, one surface of which is mirror-polished and ultrasonically cleaned, and then, inside a vacuum chamber equipped with ion irradiation and vapor deposition functions. Installed in the holder. Then, after vacuuming the inside of the chamber to 5 × 10 ⁻⁶ torr, Ar ions were irradiated from the ion source to the mirror surface of the plate for 5 minutes under the condition of an acceleration voltage of 5 kV to perform a pretreatment for surface cleaning. gave.

Then, O ₂ gas was introduced into the chamber,
The inside of the vacuum chamber is an oxygen atmosphere of 1 × 10 ^-4 torr, and tantalum (Ta) is 3 angstroms on the surface of the 304 L plate on the holder heated to 300 ° C. by the single-hase electron beam evaporation method. 1 μm thickness at vapor deposition rate of 1 / sec
A composite material was manufactured by forming a film. When the film on the surface of the composite material was measured by X-ray diffraction, EPMA, Auger, etc.,
It was confirmed that the film was an amorphous Ta film containing oxygen. Example 2

The 304L plate was mirror-polished in the same manner as in Example 1,
Ultrasonic cleaning and pretreatment in the vacuum chamber
Then, Ta from the ion source of the mass separation method⁺ Extraction of ions
Acceleration voltage of 180 keV, beam current of 0.2 mA, and
Dose 1.0 × 10¹⁷Pieces / cm² Surface layer of the plate under the conditions of
Then, a Ta ion implantation phase was formed. Next, inside the chamber
To O₂Gas is introduced and the inside of the vacuum chamber is 1 × 10^-Fourtorr
Oxygen atmosphere and Ta is a single hearth type electronic
-30 on the holder heated to 300 ° C by the vapor deposition method
The thickness of the surface of 4L plate at the deposition rate of 3 Å / sec.
A film having a thickness of 1 μm was formed to manufacture a composite material. Composite surface
The film was measured by X-ray diffraction, EPMA, Auger, etc.
However, it must be an amorphous Ta film containing oxygen.
Was confirmed. Example 3

The 304L plate was mirror-polished in the same manner as in Example 1,
After ultrasonic cleaning, pretreatment in a vacuum chamber and formation of a Ta ion-implanted phase on the surface layer as in Example 2 were performed. Subsequently, Ta is heated on the holder by a single hearth electron beam evaporation method to 300 ° C.
While depositing at a rate of 3 Å / sec on the surface of a 4 L plate, oxygen ions are extracted from the ion source, and a 1 μm thick film is formed by an ion mixing method in which ion irradiation is performed under conditions of an acceleration voltage of 33 kV and a beam current of 16 mA. The material was manufactured. X-ray diffraction, EPM of the film on the composite material surface
When measured by A, Auger, etc., it was confirmed to be an amorphous Ta film containing oxygen. Example 4

The 304 L plate on the holder was heated at 300 ° C. at room temperature to form a composite material by forming a film having a thickness of 1 μm by the same ion mixing method as in Example 3. When the film on the surface of the composite material was measured by the same method as in Example 3, it was confirmed to be an amorphous Ta film containing oxygen. Example 5

The 304L plate on the holder is kept at room temperature without heating to 300 ° C., and the acceleration voltage of oxygen ions is 1 kV and the beam current is 16 mA in the ion mixing method.
A composite material was produced by forming a film with a thickness of 1 μm in the same manner as in Example 3 except that the ion irradiation was performed under the conditions of. When the film on the surface of the composite material was measured by the same method as in Example 3, it was confirmed to be an amorphous Ta film containing oxygen. Example 6

In the ion mixing method, the ion irradiation was performed under the conditions that the acceleration voltage of oxygen ions was 0.1 kV and the beam current was 350 mA.
m to form a composite material. When the film on the surface of the composite material was measured by the same method as in Example 3, it was confirmed to be an amorphous Ta film containing oxygen. Comparative Example 1

The 304L plate was mirror-polished in the same manner as in Example 1,
After ultrasonic cleaning, pretreatment in a vacuum chamber and formation of a Ta ion-implanted phase on the surface layer as in Example 2 were performed. Subsequently, Ta is heated on the holder by a single hearth electron beam evaporation method to 300 ° C.
A composite material was manufactured by forming a film having a thickness of 1 μm on the surface of a 4 L plate at a vapor deposition rate of 3 Å / sec. When the film on the surface of the composite material was measured by X-ray diffraction, it was confirmed to be a crystalline Ta film. Comparative example 2

The 304L plate was mirror-polished in the same manner as in Example 1,
After ultrasonic cleaning, the same pretreatment was performed in the vacuum chamber. Subsequently, a composite material was manufactured by depositing Ta in a thickness of 1 μm at a deposition rate of 3 Å / sec on the surface of the 304L plate on the holder at room temperature by an electron beam deposition method of a single hearth system. When the film on the surface of the composite material was measured by X-ray diffraction, it was confirmed to be a crystalline Ta film.

Therefore, Examples 1 to 6 and Comparative Example 1,
The composite material of No. 2 was kept at 1300 mV (SCE) for 2 hours in 8 N nitric acid at 100 ° C. to measure the corrosion rate. Since the corrosion rate depends on the current density, the corrosion was judged by comparing the current densities. The results are shown in Table 1 below. As is clear from Table 1, the composite materials of Examples 1 to 6 have high corrosion resistance of 1/6 to 1/80 as compared with Comparative Examples 1 and 2. Example 7

As a base material, a Hastelloy B (corrosion-resistant Ni-based alloy) plate having a size of 10 × 30 × 2 mm was prepared, and this Hastelloy B plate was mirror-polished and ultrasonically cleaned in the same manner as in Example 1, and further vacuumed. Pretreatment was performed in the chamber. Next, Ta is 3 by the electron beam evaporation method of the single hearth method.
While depositing at a rate of 3 Å / sec on the surface of the Hastelloy B plate on the holder heated to 00 ° C., oxygen ions were extracted from a non-separable basket ion source under the conditions of an acceleration voltage of 33 kV and a beam current of 16 mA. A composite material was manufactured by forming a film with a thickness of 1 μm by an ion mixing method of irradiating with ions. When the film on the surface of the composite material was measured by X-ray diffraction, EPMA, Auger, etc., it was confirmed to be an amorphous Ta film containing oxygen. Example 8

As a base material, a Hastelloy B plate similar to that of Example 7 was prepared, and this Hastelloy B plate was subjected to mirror polishing and ultrasonic cleaning as in Example 1, and further pretreated in a vacuum chamber. . Next, from the ion source of mass separation method, T
a ⁺ Extraction of ions, acceleration voltage 180 keV, beam current 0.2 mA, dose 1.0 × 10 ¹⁷ ions / cm ² Under the above conditions, a Ta ion-implanted phase was formed on the surface layer of the Hastelloy B plate. Then, in the same manner as in Example 7, a composite material was manufactured by forming a film with a thickness of 1 μm by an ion mixing method in which Ta was vapor-deposited and oxygen ions were simultaneously irradiated. When the film on the surface of the composite material was measured by X-ray diffraction, EPMA, Auger, etc., it was confirmed to be an amorphous Ta film containing oxygen. Comparative Example 3

As a base material, a Hastelloy B plate similar to that of Example 7 was prepared, and this Hastelloy B plate was subjected to mirror polishing and ultrasonic cleaning as in Example 1, and further pretreated in a vacuum chamber. Later, Ta ⁺ from the ion source of the mass separation method Ion extraction, acceleration voltage 180 keV, beam current 0.2
mA, dose 1.0 × 10 ¹⁷ pieces / cm ² Under the above conditions, a Ta ion-implanted phase was formed on the surface layer of the plate. Next, T
a is a single hearth electron beam evaporation method at 300 ° C.
3 on the surface of Hastelloy B plate on the holder heated to
A composite material was manufactured by depositing a crystalline Ta film having a thickness of 1 μm at a deposition rate of angstrom / sec.

Then, the composite materials of Examples 7 and 8 and Comparative Example 3 were immersed in 6N hydrochloric acid at 50 ° C. for 24 hours, cut at a surface perpendicular to the film after immersion, and the cut surfaces were observed by SEM. I observed. As a result, in the composite material of Comparative Example 3, the corrosion progressed at the interface between the Hastelloy B plate and the Ta film, which are the base materials, and the progress of corrosion on the base material surface was considerably observed. In contrast,
In the composite materials of Examples 7 and 8, no progress of corrosion was observed at the interface.

[0034]

As described in detail above, according to the present invention, a dense oxygen-containing tantalum amorphous film is coated on a substrate with good adhesion, and has excellent corrosion resistance even in a severe corrosive environment, and It is possible to provide a highly versatile composite material that is not constrained in shape and a method for easily manufacturing such a composite material.

Claims (2)

[Claims] 1. A tantalum phase is formed by ion-implanting tantalum into a surface layer of a metal base material, and then tantalum is vapor-deposited in an oxygen atmosphere on the surface of the base material to coat an oxygen-containing tantalum amorphous film. A method for producing a high corrosion resistant composite material. 2. An oxygen-containing tantalum amorphous film by an ion beam mixing method in which tantalum is ion-implanted into a surface layer of a metal base material to form a tantalum phase, and then tantalum is vapor-deposited on the surface of the base material and at the same time, oxygen ion irradiation is performed. A method for producing a highly corrosion-resistant composite material, comprising coating