JPS62174339A - Production of alloy by plasma - Google Patents

Abstract

PURPOSE:To obtain an alloy which permits easy and exact control of compsn. and concn. by spraying a particulate metal which consists of >=2 kinds of molten raw material metals and is supplied into plasma flow to an object to be thermally sprayed to form an alloy layer then separating said alloy layer therefrom. CONSTITUTION:The plasma flow is formed by an ordinary plasma generator in a nonoxidizing atmosphere consisting of a rare gas such as He having preferably a low pressure lower than the atmospheric pressure. The particulate metal formed by supplying and melting at least two kinds of the raw material metals, for example, prescribed ratios of Ni powder and Ti powder into the plasma flow is sprayed to the object to be thermally sprayed to form the alloy layer. A metal such as, for example, Al, Zn or Mg is used for the above-mentioned object to be thermally sprayed. The above-mentioned alloy layer is separated from the object to be thermally sprayed, by which the intended alloy is obtd. Since the alloy is supplied to the plasma flow of a high temp. the metals are instantaneously heated and melted. The oxidation of the metals is thus prevented and the fluctuation of the compsn. during the production process is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an alloy, and more particularly to a method for producing an alloy that allows easy and precise control of the composition and concentration of the alloy.

[Prior art and its problems]

Conventionally, alloys are manufactured by heating, melting, and mixing alloy raw material metals with a predetermined ID in a melting furnace or the like.

Particularly when manufacturing alloys whose composition and concentration are strictly defined, accurately weighed three groups of raw materials are used in a vacuum melting furnace in a vacuum or in a non-oxidizing atmosphere. C is manufactured by heating, melting, alloying, and then cooling. For example, Cu-14,5A, which is an alloy with shape ↑j
JW Co., Ltd., which manufactures N-4,4Ni alloy, has the same composition as this alloy as ↑ body! Copper, pure aluminum, and nickel weighing v11 each, vacuum? 8 Heating and melting in a melting furnace
!・Mix and use cold IJ1 to make alloy into foil.

However, from 4^, in the conventional alloy gA manufacturing method, heating and melting
At the time of A, an oxide film was formed on the molten surface, and the alloy components melted into the slag, and the alloy components evaporated, resulting in a difference between the composition of the starting material and the composition of the prepared alloy. . Therefore, in the conventional alloy manufacturing method, it was necessary to determine the blending amount of Idemitsu raw materials in consideration of the loss of one member of the alloy component during the manufacturing process.

Furthermore, depending on the type of alloy components, extremely complicated steps are required, such as determining the melting order in consideration of the reactivity between the components.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to easily and accurately control the composition and concentration of an alloy without the need for complicated operations and procedures. ``Providing a method for producing gold.

[Means for solving problems]

As a result of conducting various tests and research for the above-mentioned purpose, the present inventor found that the object of the invention can be effectively formed by heating and melting metal in a plasma flow. This invention was completed.

That is, the method for producing the alloy of the present invention involves supplying at least two types of raw γ31 metals into a plasma stream, melting them, and spraying the molten fine metal particles onto a sprayed body to form an alloy layer.
Next, the obtained alloy layer is separated from the object to be thermally sprayed to remove the alloy.
This is a book that includes making lIJ.

In a preferred embodiment of this invention, the raw metal can be melted and sprayed in a low-pressure non-oxidizing atmosphere.

Alternatively, the composition of the source metal supplied to the plasma stream can be varied to create an 85 degree gradient in the 1q alloy layer.

The manufacturing method of this invention will be explained in more detail below.

There are no particular limitations on the type of alloy that can be applied to this invention. However, because the composition and concentration of the alloy can be easily and accurately controlled by the present invention, it can be used to produce alloys with extremely narrow composition tolerances, such as shape memory alloys, where the transformation temperature varies significantly depending on the alloy composition. Alloy manufacturing methods can be applied.

The plasma used in this invention may be a plasma stream obtained from a conventional plasma generator. For example, a direct current voltage is applied between an anode and a cathode to generate an electric arc. When Ar gas is injected here, it is heated by the arc and thermal ionization occurs, and free 11iff electrons are generated by the reaction of Ar→Ar+10−, resulting in high electrical conductivity. On the other hand, gas passing near the water-cooled anode wall is cooled and the Ar4-Ar++e- reaction progresses, resulting in a high electrical resistance. For this reason, the current is concentrated in the center with low electrical resistance, and the current density is reduced to 3000.
Extremely high temperatures, down to zero, are generated, and the gas expands into a violent jet that is ejected from the nozzle.

The atmosphere in which plasma spraying is carried out is preferably a low pressure, non-oxidizing atmosphere at a pressure lower than atmospheric pressure. Specific examples of such atmospheres include rare gases such as helium and argon,
Hydrogen, nitrogen, etc.

The metal heated and melted in the plasma stream becomes fine particles that collide with the surface of the object to be thermally sprayed, where they adhere and accumulate, and are cooled and solidified. The material to be thermally sprayed used in this invention can be made of any material that can be separated from the obtained alloy without any trouble.
The shape doesn't matter.

Its shape includes a simple flat plate, a mandrel, and a template with various irregularities on its surface. The materials to be thermally sprayed include metals such as aluminum, zinc, and magnesium that easily dissolve in acids or alkalis, and metals that easily dissolve in water, etc.
Examples include inorganic substances such as sodium chloride, potassium chloride, and sodium 5A acid, heat-resistant Plus Deck, and ceramics, and may be composite materials of the above substances and other substances.

Next, the alloy manufacturing method of the present invention will be explained with reference to the accompanying drawings. FIG. 1 shows a low-pressure plasma melting apparatus that can be used in the alloy manufacturing method of the present invention. This plasma spraying apparatus 1 mainly includes a thermal spraying gun 2 that generates a plasma stream, a thermal spraying chamber 3 into which the plasma stream is blown, and a sample stage 4 located inside the thermal spraying chamber 3 and on which the plasma stream collides. The thermal spray gun 2 is connected or communicated with a melting electrolyte 5 and a plasma arc gas supply source 6 . In order to supply raw metal powder to the plasma flow generated from the thermal spray gun 2, a raw metal powder supply port is provided near the melting Q1 gun 2, and a powder supply device 7 communicates with the supply port. Also, thermal spraying? An IJF' pneumatic gas chamber 8 is installed to maintain a low pressure inside the δ3, and communicates with the thermal spraying chamber 3 via a pressure sensing device 9.In order to make the atmosphere inside the thermal spraying chamber 3 non-oxidizing. , atmospheric gas source 1
0 communicates with the thermal spraying port 3 via a valve 11.

The alloy manufacturing method of the present invention is carried out using the plasma spraying apparatus described above. First, the object to be thermally sprayed 12 is placed on a sample stage 4 that can be moved and rotated in the XYZ axis directions, and the interior of the thermal spraying chamber 3 is brought to a low pressure of Q, 1 TOrr or less using the exhaust device 8, and then the atmospheric gas source is For example, argon gas is introduced into the firing chamber 3 from 10 to 5 Q Q
Set the pressure to Torr culm. Energy and gas are supplied from a thermal spray power supply 5 and a plasma arc gas source 6 to cause the thermal spray gun 2 to discharge a plasma stream. The plasma stream 13 is blown into the sprayed character 3. The raw metal powder 11 is supplied from a supply device 7 into a plasma stream near the thermal spray gun. The metal is heated and melted by the high-temperature plasma, becoming fine particles of molten metal, which collide with the plasma flow and adhere to the surface of the object to be sprayed 12 on the sample stage 4, and are cooled and solidified to form an alloy layer. do.

FIG. 2 is a perspective view showing a state in which an alloy layer 22 is formed on a flat plate-shaped object 21 to be thermally sprayed. FIG. 3 is a top view of the workpiece 21 of the mandrel on which the alloy layer 22 has been formed.

For example, if the material is a metal such as aluminum, the material to be thermally sprayed with an alloy layer formed thereon is dissolved in acid or alkali, and if the material is a water-soluble MQ material, it is immersed in water and dissolved. The layer is separated from the sprayed object.

FIG. 4 shows an alloy in which the metal layer 22 shown in FIG. 2 has been separated from the FIm body 21. In FIG. Furthermore, the XS5 diagram shows an alloy in which the alloy layer 22 shown in FIG. 3 is separated from the f8 projectile 21.

The alloy separated from the object to be thermally sprayed may be used as is or may be subjected to mechanical processing such as rolling or heat treatment.

〔Example〕

This invention will be specifically explained with reference to the following examples.

Nickel powder and titanium powder with an average grain size of 10 to 44μ are mixed in an atomic% ratio of 50:50 (Iffi% is 55.1
0:44.90) and mechanically stirred to prepare raw metals. In addition, 1-lium chloride with a diameter of 2
A material to be thermally sprayed was prepared by molding the material into a cylindrical shape with a length of 100 m under 1tif pressure.

The above-mentioned raw metal rice and the object to be thermally sprayed were loaded into a plasma spraying apparatus, and an alloy was manufactured by plasma flow. The specifications of the plasma molten steel % F surface used in this example are as follows.

Electric K! 60-70 [
kv] Plasma arc gas Argon plasma temperature 15000 (℃) Molten CD confined atmosphere Argon pressure 1
The alloy layer with a thickness of 50 (torr) 1 mm was separated by immersing it in water iδ to avoid melting the 1 to 1-lium material to be subjected to CIH. The chemical composition of the circular in-shaped nickel-ditane alloy was measured and the results are shown in Table 1.

L-electrolytic nickel and sponge titanium at atomic% of 50
The alloy ingot was charged into a vacuum melting furnace at a ratio of 55.10:44.90 (at a strain of 1%) to form an alloy ingot of 1!'7. This nickel-titanium alloy ingot was hot rolled and A 1.7 mta alloy plate was prepared.The chemical composition of this alloy plate was measured.The results are shown in Table 1.

As can be seen from this table, the alloy produced by the method of the present invention (Example 1) shows almost no change from the starting composition (target composition), whereas the conventional melting process causes significant compositional fluctuations. It's happening.

Table 1 Example 3 An alloy layer with a thickness of 1 mm was formed on the surface of the liquid q4 body in the same manner as in Example 1 except that aluminum was used for the body to be melted. This melted body 04 was melted by immersion iδ in a 0.3N caustic soda solution to form a cylindrical nickel-titanium alloy 19. The chemical composition of this alloy showed the same measured values as in Example 1.

Example 4 At one end of the object to be thermally sprayed, nickel and titanium powders with an average particle size of 10 to 4471H were supplied to the plasma stream at a ratio of 50:50 at %, and the composition ratio was changed while moving the position of the object to be thermally sprayed. An alloy layer was formed in the same manner as in Example 10, except that the ratio of nickel and titanium was changed to 51:49 at the other end of the object to be thermally sprayed. This alloy layer was separated from the object to be thermally sprayed to obtain a desired alloy. When the chemical composition of this alloy was measured, it was found that the composition ratio of nickel and titanium changes continuously depending on the position of the alloy.

[Function and effect of the invention] In the alloy manufacturing method of this invention, the original RI is 15,000'
The metal is heated and melted instantaneously because the metal is heated and melted instantaneously.Moreover, the metal is heated and melted instantaneously. Therefore, oxidation of the metal can be prevented, and compositional fluctuations during the manufacturing process can be reduced.

By changing the composition ratio of the raw metals supplied to the plasma stream, it is possible to extremely easily manufacture an alloy with a concentration gradient, which was completely impossible with the conventional alloy manufacturing method using a melting furnace.

In the present invention, since the metal is heated and melted in a plasma stream, it is possible to easily prepare alloys between metals with a large difference in specific gravity, which was impossible with conventional alloy manufacturing methods.

Because the alloy is produced with a composition substantially the same as the starting composition, the transformation temperature varies considerably with composition, making it suitable for producing alloys with compositions within very narrow tolerances.

By forming desired irregularities on the surface of the liquid solution Q=j and forming a mold, the formation and molding process of the alloy layer can be performed in the same manner as in (5).

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a Blaz 7 melt OA neck that can be used in the method of the present invention, Figs. 2 and 3 are views showing an object to be thermally sprayed on which an alloy layer is formed, and Fig. 4 a3 and FIG. 5 is a diagram showing the alloy layer separated from the object to be melted. 1... Plasma melting device, 2... Thermal spray gun, 3...
・Solution Q('l, 4...sample stage, 5...power supply, 6...
・Plasma arc gas, 7... Raw material supply device d, 8.
... Exhaust device, 9... Pressure detector, 10... Atmospheric gas source, 11... Valve, 12... Body to be melted, 13...
- Plasma flow, 21... object to be thermally sprayed, 22... alloy layer. Applicant's agent: Akira Sa -〃t'$1 Figure

Claims (1)

[Claims] 1. At least two kinds of raw material metals are supplied into a plasma stream and melted, the molten fine metal particles are sprayed onto the object to be thermally sprayed to form an alloy layer, and then the obtained alloy layer is covered. An alloy manufacturing method characterized by manufacturing the alloy separately from the thermal sprayed body. 2. The alloy manufacturing method according to claim 1, wherein the raw metal is melted and sprayed in a low-pressure non-oxidizing atmosphere. 3.Claim 1 in which a concentration gradient is created in the alloy layer by changing the composition of the raw metal supplied to the plasma stream.
The method for producing the alloy according to item 1 or 2.