JPS63125665A - Production of thin amorphous ta-w alloy film - Google Patents

Abstract

PURPOSE:To easily produce a thin amorphous Ta-W alloy film having excellent mechanical properties, corrosion resistance, etc., by sputtering the Ta-W-B alloy expressed by the specific formula and depositing said alloy by evaporation in the amorphous state on a cooled substrate. CONSTITUTION:The Ta-W-B alloy having the compsn. expressed by the formula (Ta1-xWx)1-yBy (x=0.01-1, y=0.1-0.4) is installed as a target 1 in a chamber 3 and is cooled with cooling water. The substrate 2 is installed thereabove and is cooled with liquid nitrogen 12 down to a room temp. or below. The inside of the chamber 3 is then evacuated to a vacuum by a vacuum pump 4 and gaseous Ar is introduced through an introducing pipe 7 into the chamber until a prescribed pressure is attained. A high-frequency power supply 8 is turned on and sputtering is executed by a conventional method. The thin amorphous Ta-W alloy film having a high crystallization temp. is thereby easily formed on the substrate 2 over a wide area with uniform quality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a Ta--W amorphous alloy having a high crystallization temperature.

(Prior Art) In recent years, various amorphous materials have been developed and are attracting a lot of attention in the field of metal materials. Unlike conventional crystalline alloys, these alloys do not have a crystal structure, and many of their properties are not found in conventional metal materials, such as mechanical properties, wear resistance, corrosion resistance, and soft magnetism. Due to its excellent electrical properties, various uses are being developed as a material that can replace crystalline metals, and materials suitable for these uses are also being developed. These alloys have conventionally been generally produced by a liquid quenching method such as a single roll method.

(Problems to be Solved by the Invention) The biggest problem with amorphous alloys is that they are thermally unstable. This is due to the fact that the amorphous state is a thermodynamically non-equilibrium metastable state, and can be said to be the fate of amorphous alloys. In other words, each amorphous alloy generally has its own specific crystallization temperature, and when that temperature is exceeded, it changes to a more thermally stable crystalline alloy, and the superiority seen in the amorphous state is lost. All the characteristics that were previously acquired are lost. Although this crystallization temperature varies depending on the material, it is generally known to take a value of about 0.4 to 0.6 times the melting point measured in absolute temperature. Therefore, in order to obtain an alloy with a high crystallization temperature, an alloy with a high melting point must be made amorphous.

The Ta-8i-B alloy has an extremely high melting point of about 2300°C or higher. For this reason, T
The a-8i-B amorphous alloy has a crystallization temperature of 800
°C to 1000 °C, making it possible to significantly improve the problems of amorphous alloys (Japanese Patent Application No. 2385, 1981-01).Furthermore, this Ta-8i-B Amorphous alloys have excellent mechanical properties such as high strength and hardness that are characteristic of general amorphous alloys, so they can be used, for example, as wear-resistant materials and electrodes that are subject to temperature increases. Possible applications include industrial materials.

However, when the Ta-8i-B-based amorphous alloy is actually used in a high-temperature environment, aging becomes a problem, so the operating temperature range is limited to a maximum of about 6008C.

Furthermore, Ta-8i-B produced by liquid quenching method
Since the amorphous alloy has a ribbon shape with a width of several mm to several cm, there is a problem in that it is impossible to obtain an amorphous alloy having a wide area.

Furthermore, it has not been possible to form the amorphous alloy in the form of a thin film on a certain substance using conventional liquid quenching methods.

The present invention solves the problems of the prior art, has a high crystallization temperature, can withstand higher temperature environments than the Ta-based amorphous alloy, and has improved mechanical properties, corrosion resistance, etc. It is an object of the present invention to provide a method for producing an excellent Ta-W based amorphous alloy thin film.

(Means for Solving the Problems) The present invention provides an alloy represented by the formula (Tal -xWx)1-yBy, where x=0.01 to 1 and y=0.1 to 0.4, A Ta-W amorphous alloy thin film characterized in that it is made amorphous by forming a thin film on a substrate by bombarding a target material with ions and ejecting the target material in a gaseous state. This is the manufacturing method.

(Function) In the Ta-W-B alloy thin film, as shown in the examples later, the present inventors have discovered for the first time that an amorphous alloy can be formed in the composition range of Ta and Wl or W in the range of 60 at% to 90 at%. I found it. When the composition is outside this range, the amorphous structure becomes almost invisible, and all the excellent properties characteristic of amorphous alloys are lost. Also, set the range of X to 0.0
The reason why it is limited to 1 or more and 2 is because in this range, the crystallization temperature becomes higher than when only Ta is used or when a small amount of W is added.

The crystallization temperatures of these amorphous alloys are as high as 1000° C. or higher, corresponding to their high melting points. In addition, the mechanical properties of these amorphous alloys are high hardness, as is generally seen in amorphous alloys. Also, in terms of corrosion resistance, it has corrosion resistance comparable to that of Ta and W.

The manufacturing method according to the present invention involves ionizing gas atoms or molecules such as argon gas in a high electric field or high-frequency electric field, and further accelerating them by the electric field to cause them to collide with the target surface and knock out the target material from the target surface. Because a thin film is formed on the substrate, it can be applied over a large area.
Moreover, a homogeneous alloy thin film can be formed.

In addition, as a target material, Ta-W-
A ternary B alloy or a composite material in which Ta, W and B are combined in an appropriate area ratio is used. Therefore, the composition of the obtained alloy thin film can be easily changed by changing the composition of the target alloy or by appropriately changing the area ratio of the composite material, so that the desired composition can be changed. Amorphous alloy thin films can be easily obtained.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of an apparatus for producing the Ta--W amorphous alloy thin film of the present invention. The apparatus shown in FIG. 1 is a high-frequency dipole magnetron sputtering apparatus, and in the figure, 1 is a target and 2 is a substrate. As target 1, a composite target was used in this example. That is, the diameter is 100 mm,
An appropriate number of W and B plates each having a square shape with a negative side of 10 mm and a thickness of 1 mm were placed on a Ta target with a thickness of 5 mm. At this time, on the second side of the Ta target, W and B
The plates were set so that they were distributed as evenly as possible. By changing the numbers of W and B, the composition of the resulting alloy thin film was changed. For the substrate 2, glass was used with a length of 50 mm, a width of 25 mm, and a thickness of 0.2 mm.

When creating a thin film, first open the valve 5 and use the vacuum pump 4 to heat the vacuum chamber 3 to 1O-7 Torr.
Evacuate the table to vacuum. Thereafter, the barrier pull leak valve 6 is opened, and argon gas is introduced from the argon gas introduction pipe 7 until the pressure reaches the 10-3 Torr level. In this state, the high frequency power source 8 is turned on to start sputtering. The input power was 500W. At this time, the target 1 is water-cooled by the cooling water introduction pipe 10. Further, the substrate 2 is cooled to below room temperature by the liquid nitrogen 12 introduced by the liquid nitrogen introduction pipe 11. This is because in order to make the Ta--W alloy thin film amorphous, it is necessary to cool the substrate with a coolant such as water or liquid nitrogen. The substrate temperature is measured through the thermocouple 14 and the thermometer 15
It was found that the temperature had been cooled down to -180°C. For the first hour of sputtering, the shutter 9 was closed and press sputtering was performed. In this sputtering apparatus, a permanent magnet 13 is attached to the back side of the target, and high-speed sputtering can be performed by the magnetic field created by this on the target surface. After the press sputtering was completed, the shutter 9 was opened to form a thin film on the substrate. Thin film preparation was performed for 1 hour. The thickness of the obtained thin film is
It was about 511m.

The structure of the obtained Ta-W-B alloy thin film was evaluated by X-ray diffraction method. As a result, in the thin film compositions of Ta and W, and in the composition range of 60 at% to 90 at% W, no sharp diffraction peaks due to crystals were observed in any of the thin films, and a broad halo pattern was obtained. It was confirmed that an amorphous alloy thin film was obtained. Table 1 shows the crystallization temperatures of these samples determined by differential thermal analysis. All samples show a high crystallization temperature of over 1000°C, which is even higher than that of the Ta-8i-B amorphous alloy.
It can be seen that the crystallization temperature is 00°C to 200°C higher. In addition, these samples were heated at 800 °C for 100
It was found that the amorphous alloy maintained its amorphous structure even after annealing for 0 hours, and had extremely high heat resistance. Furthermore, the mechanical properties of these samples have a Vickers hardness of 90
It showed excellent properties in the range of 0 to 1600.

Furthermore, these samples showed no signs of corrosion even after being left in concentrated hydrochloric acid, concentrated nitric acid, concentrated sulfuric acid, and concentrated aqua regia for a day. Although we have introduced a method for producing a Ta-W amorphous alloy thin film using a magnetron sputtering device, other sputtering methods, such as normal DC dipole sputtering and high-frequency dipole sputtering, are recommended when producing an amorphous thin film. It is also possible to use a sputtering method, a dipole or quadrupole sputtering method, a bias sputtering method, an ion beam sputtering method, a reactive sputtering method, etc.

(Effects of the Invention) As explained in detail above, the method for producing a Ta-W amorphous alloy thin film according to the present invention has a high crystallization temperature and an amorphous film with excellent mechanical properties, corrosion resistance, etc. A thin alloy film of high quality can be easily obtained, and its effects are great.

[Brief explanation of the drawing]

Claims (1)

[Claims] An alloy represented by the formula (Ta_1_-_xW_x)_1_-_yB_y, with a composition of x = 0.01 to 1 and y = 0.1 to 0.4, is bombarded with ions against a target material,
A method for producing a Ta--W based amorphous alloy thin film, characterized in that the target material is made amorphous by using a sputtering device that forms a thin film on a substrate by ejecting the target material in a gaseous state.