JPS63125666A - Production of thin amorphous ta alloy film - Google Patents

Abstract

PURPOSE:To easily produce the titled thin amorphous alloy film having excellent mechanical properties, corrosion resistance, etc., by respectively heating Ti and Si to melt and evaporate in a vacuum and depositing the vapor thereof by evaporation on a cooled substrate, thereby forming the thin film expressed by the specific formula on the substrate. CONSTITUTION:Ta1 and Si2 are respectively held in crucibles 3, 4 and are cooled by cooling water. The substrate 6 is provided above the same and is satisfactorily cooled by liquid nitrogen 9. After the inside of a chamber 10 is evacuated to a vacuum by a vacuum pump 11, electron beams are generated by electron beam sources 12, 13 to simultaneously heat and melt materials 1, 2 to be evaporated, by which Ta and Si are evaporated in the atom state and are stuck in the form of a homogeneous alloy on the substrate 6. The thin amorphous Ta alloy film which is expressed by Ta1-xSix (x=0.1-0.4) and has a high crystallization temp. is thereby easily formed on the substrate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing an 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 crystalline 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 that it takes 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.

Ta--Si alloy has an extremely high melting point of about 23008C or higher. For this reason, Ta
-Si-based amorphous alloy has a crystallization temperature of 8008C
The temperature is extremely high at ~960°C, making it possible to significantly improve the problems of amorphous alloys (Patent application 1986-0123).
No. 85). Furthermore, this Ta-Si amorphous alloy is
Because it has excellent mechanical properties such as high strength and high hardness that are typical of general amorphous alloys, it can be applied to, for example, wear-resistant materials and electrode materials that are subject to temperature increases. Conceivable.

However, Ta-
Since the Si-based amorphous alloy has a ribbon-like shape with a width of several mm to several cm, there is a problem in that it is impossible to obtain an amorphous alloy with 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 and provides a method for producing a Ta-based amorphous alloy thin film that has a high crystallization temperature and has excellent mechanical properties, corrosion resistance, etc. With the goal.

(Means for Solving the Problems) The present invention is expressed by the formula Ta1 to xSix, where x=0.
1 to 0.4 is deposited on a substrate by heating and melting the metal in vacuum and evaporating the metal atoms to form an amorphous thin film.
This is a method for producing a thin film of an amorphous alloy.

(Function) In Ta-Si alloys, as shown in Examples later, T
The present inventor has discovered that an amorphous alloy can be formed in a composition range in which a is 60 at% to 90 at%. When the composition is outside this range, almost no amorphous structure is observed, and all the excellent properties characteristic of amorphous alloys are lost.

The crystallization temperatures of these amorphous alloys are as high as 800° C. or higher, corresponding to their high melting points. In addition, the mechanical properties of these amorphous alloys are high strength and high hardness, as is generally seen in amorphous alloys.

Also, in terms of corrosion resistance, it has corrosion resistance comparable to that of Ta.

The manufacturing method according to the present invention is a method in which a metal is heated and melted in a vacuum to evaporate metal atoms, thereby depositing them on a substrate to form an amorphous thin film. Since melting is carried out in a water-cooled crucible, there is almost no reaction between the raw material alloy and the crucible metal. This is because if the crucible metal is sufficiently cooled, even if high-temperature molten metal comes into contact with it, the temperature of the crucible metal is too low and alloying reactions are extremely unlikely to occur.

Further, the substrate needs to be cooled with a coolant such as water or liquid nitrogen. This is because if the substrate temperature during thin film production is too high, the formed alloy thin film will become crystalline and an amorphous phase will not be obtained.

Further, as the melting means, well-known methods such as electron beam melting and laser beam melting can be used.

In addition, the raw material to be dissolved is Ta of the desired composition.
-Si alloy or Ta and Si can be prepared separately. In the case of a Ta--Si alloy, the thin film can be formed by melting this alloy, or if Ta and Si are prepared separately, by melting each simultaneously and separately. In addition, the composition of the obtained alloy thin film can be easily changed by changing the composition of the Ta-Si alloy used as the raw material and by adjusting the vapor pressure of Ta and Si. It is possible to easily obtain an amorphous alloy thin film having the following composition.

As described above, by the production method of the present invention, a Ta-based amorphous alloy can be produced as a high-purity alloy thin film with controlled composition.
It can be uniformly formed over a large area on a substrate.

(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-based amorphous alloy thin film of the present invention. The apparatus shown in FIG. 1 is a high vacuum electron beam evaporation apparatus. Evaporated materials 1 and 2 are placed in crucibles 3 and 2, respectively.
It is held at 4. In this example, the evaporation material 1
Ta was used for the evaporation material 2, and Si was used for the evaporation material 2. 50 g of each evaporated material can be prepared in a crucible.

The crucibles 3 and 4 are made of copper, and are connected by a cooling water introduction pipe 5.
Even when water-cooled and the evaporation material is dissolved,
The temperature never rises.

The substrate 6 is fixed to a substrate holder 7. The substrate used was glass with a length of 50 mm, a width of 25 mm, and a thickness of 0.2 mm. The substrate holder 7 stores liquid nitrogen 9 introduced from a liquid nitrogen introduction pipe 8, and has a structure in which the substrate is sufficiently cooled.

When producing a thin film, first, the vacuum chamber 10 is evacuated to a vacuum level of 10 Torr using the vacuum pump 11. In this state, an electron beam is generated from the electron beam sources 12 and 13 to simultaneously heat and melt the evaporation materials 1 and 2. Ta and Si evaporate in atomic form from the melted material. During the first hour of vapor deposition, shutter 14
Preliminary deposition is performed with the chamber closed. Next, after the preliminary vapor deposition was completed, a thin film was produced on the substrate by opening the shutter. The evaporated atoms flying out from evaporation materials 1 and 2 are
They become mixed with each other near the substrate, and when attached to the substrate, they adhere as a homogeneous alloy. The degree of vacuum during the production of the thin film was on the order of 10-7 Torr. Moreover, when the substrate temperature during thin film production was measured by the thermometer 16 through the thermocouple 15, it was -180°C. Vapor deposition was carried out for 1 hour. The thickness of the obtained thin film was about 5 pm.

The structure of the obtained Ta--Si alloy thin film was evaluated by X-ray diffraction method. As a result, the composition of the thin film showed that Ta was 60at.
In the composition range of % to 90 at %, no sharp diffraction peaks due to crystals were observed in any of the ribbons, and a broad halo pattern was obtained, confirming that an amorphous alloy thin film was obtained. Table 1 shows the crystallization temperatures of these samples determined by differential thermal analysis. All exhibit high crystallization temperatures of 800°C or higher. Moreover, the mechanical properties of these samples showed excellent properties with Vickers hardness ranging from 800 to 1500. Furthermore, even when these samples were left in concentrated hydrochloric acid, concentrated nitric acid, concentrated sulfuric acid, and concentrated aqua regia for one day, no signs of corrosion were observed, and no change in weight was observed.

Table 1 Note that in this example, a method for producing a Ta-based amorphous alloy thin film using a high-vacuum electron beam evaporation apparatus was introduced. However, when producing an amorphous thin film, other vapor deposition methods such as laser It is also possible to use a beam evaporation method, a cluster ion beam evaporation method, etc.

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

[Brief explanation of the drawing]

Claims (1)

[Claims] It is expressed by the formula Ta_1_−_xSi_x, where x=0.1
An alloy having a composition of ~0.4 is made amorphous using a vacuum evaporation device that forms a thin film on a substrate by heating and melting the metal in vacuum and evaporating the metal atoms. A method for producing a Ta-based amorphous alloy thin film, characterized by: