JPH0579751B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention has excellent properties such as ultra-high corrosion resistance and high wear resistance, as well as toughness, and can be used in various industrial and consumer fields including chemical plants. The present invention relates to a new amorphous aluminum alloy.

[Prior Art] Conventionally, various aluminum alloys have been put into practical use as corrosion-resistant materials. On the other hand, Ta, Nb, Zr,
Both Ti are high melting point metals, especially Ta and Nb.
does not melt even at the boiling point of Al, so it is difficult to obtain alloys of Ta and Nb with Al and alloys in which a portion of Ta and Nb in these alloys is replaced with Zr or Ti using normal methods that involve melting.

[Problems to be Solved by the Invention] Passive films that can protect metal materials in a mild environment are easily destroyed in hydrochloric acid. Hydrochloric acid is particularly corrosive and there are no metal materials that can be used safely, and the previously known aluminum alloys mentioned above are naturally difficult to use for this purpose. Therefore, there is a strong desire for a new metal material that can withstand use in such a corrosive environment where it is extremely difficult to use normal metal materials.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention uses Al alloys, which are difficult to create by ordinary melting methods, as highly corrosion-resistant and highly resistant alloys, rather than as non-uniform crystalline alloys. It is obtained as an amorphous alloy that has both wear resistance and toughness.

That is, the first invention is a highly corrosion-resistant amorphous aluminium alloy containing a total of 7 to 75 atomic % of either one or both of Ta and Nb, with the remainder being substantially Al; The second invention is
5 in total of one or two of Ta and Nb
atomic % or more and one or two of Zr and Ti
Contains 7 to 75 atomic percent in total including seeds, and the remainder is substantially
A highly corrosion-resistant amorphous aluminum alloy consisting of Al.

Normally, the total crystallizes in a solid state, but if you apply a method that prevents the formation of long-period regularity in the atomic arrangement during the solid formation process, such as limiting the total composition and ultra-rapidly solidifying it from the molten state, it is possible to crystallize. An amorphous structure similar to that of a liquid is obtained, and alloys with such a structure are called amorphous alloys. Amorphous alloys are mostly homogeneous single-phase alloys of supersaturated solid solutions, have significantly higher strength than conventional practical metals, and exhibit various properties, including unusually high corrosion resistance, depending on their composition.

As a result of extensive research on the properties of unknown amorphous alloys, the present inventors have discovered that by utilizing the sputtering method, which does not require mixing by melting, to form an alloy, a low melting point metal and a high They discovered that it is possible to create amorphous alloys with melting point metals, and completed the above-mentioned alloys of the present invention.They also have low oxidizing power such as hydrochloric acid, form a stable protective film even in harsh corrosive acids, and are self-destructive. It was discovered that it has high corrosion resistance that makes it work.

A sputtering method is used to produce the alloy of the present invention. In the sputtering method, a target consisting of multiple crystalline phases having the same average composition as the amorphous alloy to be produced but not a single phase is prepared by sintering or melting, or a target is made from the main component of the amorphous alloy to be produced. This is done by embedding the element to be alloyed into a metal plate.

Although it is difficult to use the Al-Ta or Al-Nb alloy as a target in the present invention by a melting method, it is possible to use it as a target by embedding Ta and/or Nb in an Al plate. The amorphous aluminum alloy of the present invention can be obtained by a sputtering method using such a buried target. In this case, in order to avoid nonuniformity depending on the location of the amorphous alloy produced, for example, as shown in FIG. It is desirable to rotate the substrate 2 itself around the central axis 1 attached to the chamber 6, as well as to rotate the substrate 2 itself. Then, a target 3 is placed corresponding to the locus of the substrate 2. Furthermore, in order to vary the composition of the amorphous alloy produced over a wide range, for example, as shown in FIG. 2, one target 4 is an Al plate with Ta and/or Nb embedded in it, and the other The two targets 5 are either Ta or Nb, the two targets 4 and 5 are tilted to each other, and a substrate 2 that revolves around the central axis 1 and rotates on its own axis is arranged near the intersection of the perpendicular lines of the two targets, These two targets are operated simultaneously with two power supplies controlling their outputs. The concentration of alloying elements in the amorphous alloy produced by this method can be freely changed, and as a variation of this method,
Al-Ta, Al-Nb,
Al−Ta−Nb, Al−Ta−Ti, Al−Ta−Zr, Al
-Nb-Ti, Al-Nb-Zr, Al-Nb-Ti-Zr,
Al−Ta−Ti−Zr, Al−Ta−Nb−Ti, Al−Ta
Highly corrosion-resistant amorphous alloys such as -Nb-Zr and Al-Ta-Nb-Ti-Zr can be obtained. In the method using two targets, the revolution and rotation of the substrate are especially necessary in order to create a uniform amorphous alloy.

The alloy of the present invention produced by the sputtering method is a single-phase amorphous alloy in which each of the above-mentioned elements is uniformly dissolved in solid solution. The amorphous amorphous alloy of the present invention, which is a homogeneous solid solution, forms a protective film that is extremely uniform and guarantees high corrosion resistance.

Metal materials easily dissolve in a hydrochloric acid solution with poor oxidizing power, so in order to use metal materials in such an environment, it is necessary to provide the metal materials with the ability to form a stable protective film. This is achieved by creating an alloy containing the required amount of the effective elements. However, in the case of crystalline metals, adding a large amount of various alloying elements often results in a multiphase structure with different chemical properties, and it may not be possible to achieve a desired corrosion resistance. Moreover, the occurrence of chemical non-uniformity is rather detrimental to corrosion resistance.

On the other hand, the amorphous amorphous alloy of the present invention is a homogeneous solid solution and uniformly contains the required amount of effective elements that can form a stable protective film. Demonstrates sufficiently high corrosion resistance.

That is, a condition that a metal material that can withstand hydrochloric acid, which has weak oxidizing power, must have is that it has a high ability to form a protective film that is stable and uniform on the material in a non-oxidizing environment. This is achieved with the alloy composition of the present invention, and the amorphous structure of the alloy allows alloys with complex compositions to be produced as single-phase solid solutions, ensuring uniform protective film formation.

Next, the reason for limiting the composition of each component in the present invention will be described.

Both Ta and Nb are elements that form an amorphous structure when they coexist with Al. In order to form an amorphous structure by sputtering, it is necessary to contain 7 to 75 at.% of one or both of Ta and Nb. There is. In addition, a part of Ta and Nb in these alloys can be replaced with one or both of Ti and Zr, but in order to form an amorphous structure, one of Ta and Nb must be replaced.
Since it is necessary to contain at least 5 atom % of the species or two species, in the second invention, 5 atom % or more of any one or two of Ta and Nb and any one or two of Zr and Ti are used. 7 to 75 atomic% of the total
It is necessary to do so.

Further, Ta, Nb, Ti, and Zr are all elements responsible for corrosion resistance by forming a protective film in non-oxidizing acids, and the alloys of the present invention all exhibit sufficient corrosion resistance in hydrochloric acid.

Note that the amorphous amorphous alloy of the present invention contains 5 at.%
Even if the following Mo and W are included, there is no problem in achieving the purpose of the present invention.

[Example] Examples of the present invention will be described below.

Example 1 Using a target in which 4 pieces of Ta with diameters of 20 mm and 10 mm were embedded alternately at equal intervals on the circumference of an Al disk with a diameter of 100 mm and a thickness of 6 mm with a radius of 29 mm from the center, Ar was applied at 5 ml/min. 1× while flowing at the speed of
Sputter deposition was performed on rotating and revolving aluminum and glass substrates at a vacuum of 10 ^-4 Torr with a power output of 640W. As a result of X-ray diffraction, it was confirmed that the resulting alloy was amorphous, and analysis using an X-ray microanalyzer revealed that its composition was Al-19.7.
It was revealed that it is an atomic% Ta alloy. When the anode polarization curve of this alloy was measured in 1N HC1 at 30°C, it was found to be a highly corrosion-resistant amorphous alloy with self-passivation and an extremely high film breakdown potential of 0.48V (SCE).

Example 2 Using an Al target with a diameter of 100 mm and a thickness of 6 mm and a Ta target of the same shape, a vacuum of 1 × 10 ^-4 Torr was maintained while flowing Ar at a rate of 5 ml/min.
Using rotating and revolving aluminum and glass substrates, the Al target is
A Ta target was used for sputter deposition at a power output of 172W and a power output of 460W. The alloy produced as a result of X-ray diffraction was confirmed to be amorphous, and analysis using an X-ray microanalyzer revealed that its composition was an Al-74.0 atomic % Ta alloy. When the anode polarization curve of this alloy was measured in 1N HC1 at 30°C, it was self-passivated and the film breakdown potential was 1.54V (SCE)
It turned out to be an amorphous amorphous alloy with extremely high corrosion resistance.

Example 3 A Nb target with a diameter of 100 mm and a thickness of 6 mm was placed on the circumference of an Al disk of the same shape with a radius of 29 mm from the center.
Ar
A vacuum of 1 × 10 ^-4 Torr was maintained while flowing at a rate of 5 ml/min, and the Nb target was applied at a power of 140 W to the rotating and revolving aluminum and glass substrates, and the embedded target was applied at a power of 140 W.
Sputter deposition was performed with an output of 246W.
As a result of X-ray diffraction, it was confirmed that the resulting alloy was amorphous, and analysis using an X-ray microanalyzer revealed that its composition was an Al-52.0 atomic % Nb alloy. When the anode polarization curve of this alloy was measured in 1N HC1 at 30°C, it was found to be self-passivated and the film breakdown potential was
It turned out to be an amorphous amorphous alloy with extremely high corrosion resistance of 1.84V (SCE).

Example 4 An Al target with a diameter of 100 mm and a thickness of 6 mm was placed on the circumference of an Al disk of the same shape with a radius of 29 mm from the center.
Ar
A vacuum of 1 × 10 ^-4 Torr was maintained while flowing at a rate of 5 ml/min, and the Al target was applied with a power of 172 W, and the embedded target was applied to the rotating and revolving aluminum and glass substrates.
Sputter deposition was performed with an output of 344W.
As a result of X-ray diffraction, it was confirmed that the resulting alloy was amorphous, and analysis using an X-ray microanalyzer revealed that its composition was an Al-14.0 atomic % Nb alloy. When the anodic polarization curve of this alloy was measured in 1N HC1 at 30°C, it was found to be a highly corrosion-resistant amorphous amorphous metal with self-passivation and an extremely high film breakdown potential of -0.07V (SCE).

Example 5 Combinations of various targets, such as Ta-embedded target and Nb-embedded target, Ta and
Ti-embedded target and Ta-embedded target, Ta-embedded target and Zr-embedded target, Ta and Nb-embedded target and
Various amorphous alloys shown in the table were prepared using a target embedded with Ti and the same method as shown in Examples 3 and 4.
It was confirmed by X-ray diffraction that all of these were amorphous. When the anodic polarization curves of these alloys were measured in 1N HC1 at 30°C, it was found that they were all self-passivated and were highly corrosion-resistant amorphous alloys with extremely high film breakdown potentials as shown in the table.

Table Film breakdown potential of amorphous amorphous alloy and 1NHC1 at 30°C Alloy Film breakdown potential [V (SCE)] Al−7Ta 0.08 Al−15Ta 0.10 Al−22Ta 0.55 Al−37Ta 0.67 Al−48Ta 0.73 Al−52Ta 0.79 Al− 7Nb 0.07 Al−22Nb 0.59 Al−33Nb 0.81 Al−42Nb 0.99 Al−22Ta−30Nb 2.02 Alloy Film breakdown potential [V(SCE)] Al−6Ta−30Ti −0.15 Al−37Ta−13Ti 0.72 Al−40Nb−15Ti 1.12 Al−41Ta−10Zr 0.72 Al−7Nb−40Zr −0.25 Al−39Nb−20Zr 0.93 Al25Ta−23Nb−15Ti 0.53 Al−15Ta−35Nb−17Zr 1.77 Al−15Ta−15Nb−10Ti−10Zr 0.58 [Effect of the invention] Details above As mentioned above, the amorphous amorphous material of the present invention is made of Ta and
An Al-valve metal alloy containing Nb as an essential element, it forms a stable protective film and becomes self-passivating even in severely corrosive environments such as hydrochloric acid with poor oxidizing power, and has high corrosion resistance with an extremely high film breakdown potential. It is an alloy.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of manufacturing examples of the product of the present invention. 1... Central axis, 2... Substrate, 3, 4, 5
...Target, 6...Chamber.

Claims (1)

[Scope of Claims] 1. A highly corrosion-resistant amorphous aluminium alloy containing a total of 7 to 75 atomic % of one or both of Ta and Nb, with the remainder being substantially Al. 2 Contains 5 atomic % or more of Ta and Nb in total and 7 to 75 atomic % of Zr and Ti in total, and the remainder consists essentially of Al. Highly corrosion resistant amorphous aluminum alloy.