JP2002263823A - Metal/intermetal compound and metal/ceramic composite hollow tube and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite hollow tube which simultaneously establishes workability, toughness, heat resistance, oxidizing resistance, corrosion resistance and wear resistance. SOLUTION: Molten metal C is poured onto powder B of metal or non-metal or metal oxide, arranged in contact with the inner wall of the metal hollow tube A rotated at a high speed to generate molten or semi-molten intermetal compound or molten or semi-molten ceramic D with an exothermic reaction of B and C. Further, the inner wall of the metal hollow tube A rotated at a high speed is melted or semi-melted with the generated heat, and a change in concentration and fine structure is slantingly generated near a boundary face of the intermetal compound or the ceramic D and the metal hollow tube A to manufacture the composite hollow tube firmly joining both materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal composite material having both workability and toughness, heat resistance, oxidation resistance, corrosion resistance and wear resistance.

[0002]

2. Description of the Related Art Metals generally have workability and high toughness, but are inferior in heat resistance, oxidation resistance, corrosion resistance and wear resistance. In contrast, intermetallic compounds and ceramics are excellent in heat resistance, oxidation resistance, corrosion resistance, and wear resistance, but are poor in workability and toughness. This disadvantage can be solved by coating the metal surface with an intermetallic compound or ceramics.

[0003] Techniques for coating metal surfaces with intermetallic compounds have long been studied for the purpose of extending the life of nickel-based superalloys. For example, pack cementa
Tion method, chemical vapor deposition method, slury cement
Numerous methods such as the ation method and the hot dipping method have been proposed. Here, the superalloy is a general term for a heat-resistant alloy containing iron as a main component and having an alloy concentration of 50% or more, and a heat-resistant alloy based on nickel or cobalt. Among superalloys, nickel-based alloys are mainly used for high-strength alloys,
Many precipitation strengthened alloys to which titanium and aluminum are added have been developed.

[0004] However, these methods have the disadvantage that the processing temperature is high and the processing time is long because they are based on diffusion. On the other hand, a coating method using a thermite reaction or a combustion synthesis reaction has been proposed. (Odawara, Journal of the Japan Institute of Metals, 19
81, 316. ) (Matsuura, Metall.
Mater. Trans. A, 1999, 1605. )

[0005] Here, the thermite reaction is defined as Go in Germany.
This method was invented by ldschmidt, and is widely used for reduction of metal oxides, production of carbon-free iron, welding of steel materials, and the like. A typical reaction is a redox reaction between an aluminum powder and an iron oxide powder. The combustion synthesis reaction is also called a self-heating reaction. The compound has a high heat of formation and emits a large amount of heat of reaction when synthesized directly from the constituent elements. A material synthesis method utilizing this reaction heat positively and efficiently is a combustion synthesis method.

[0006] The above-mentioned method utilizing the reaction has the advantages that the external heating temperature for coating is low and the time is short since the reaction heat can be used. However, the base material and the reactant (mixed powder) must be heated together, and the reaction start temperature cannot be freely selected because the reaction starts spontaneously, so the ultimate temperature after the reaction cannot be controlled. The point is a problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and solves the above-mentioned drawbacks and simultaneously achieves workability, toughness, heat resistance, oxidation resistance, corrosion resistance, and wear resistance. It is an object of the present invention to provide a composite hollow tube in which a metal is coated with an intermetallic compound or ceramics. Further, another object is to easily form a composite hollow tube coated with a metal that simultaneously achieves workability and toughness, heat resistance, oxidation resistance, corrosion resistance, and wear resistance with an intermetallic compound or ceramics using an inexpensive device. It is an object of the present invention to provide a production method which can be produced in a country.

[0008]

Means for Solving the Problems To achieve the above object, the present inventors have conducted intensive studies, and as a result, a manufacturing method in which the combustion synthesis method or thermite synthesis method of the present invention and the centrifugal casting method are applied simultaneously, that is, Liquid metal C is injected into metal or nonmetal or metal oxide powder B disposed in contact with the inner wall of metal hollow tube A rotating at high speed, and molten or semi-molten intermetallic compound or molten or semi-molten ceramic D is poured. B
And the inner wall of the metal hollow tube A that rotates at a high speed due to the generated heat is melted or semi-melted, and the vicinity of the joint surface between the intermetallic compound or ceramics D and the metal hollow tube A It has been found that a composite hollow tube in which both are firmly joined can be produced by causing a gradient change in concentration and microstructure.

In the conventional combustion synthesis of B powder and C powder,
The reaction takes place at a temperature near the lower melting point of either the melting point of B or the melting point of C. Therefore, the reaction temperature could not be freely controlled. On the other hand, in the combustion synthesis between liquids and solids and liquids, separately heated reactants can be brought into contact at free temperatures, so that the reaction initiation temperature can be controlled freely, and therefore the ultimate temperature after reaction and the base temperature can be controlled. This has the advantage that the material melting depth can be controlled freely. Here, the fusion depth has a strong influence on the bonding strength. We developed a method for joining with a steel pipe by causing the combustion synthesis between solid and liquid in a steel pipe to which a centrifugal force is applied.

That is, the present invention is as follows. 1. The surface of the hollow metal material is coated with an intermetallic compound and / or ceramics, and the two materials are concentrated and / or finely divided between the hollow metal material and the coated intermetallic compound and / or ceramics. A metal-based hollow composite material having a layer that changes in a systematic manner. 2. 2. The metal-based hollow composite material according to the above item 1, wherein the metal hollow material is a metal hollow tube, and an inner wall surface of the hollow tube is coated with an intermetallic compound and / or ceramics. . 3. The metal hollow material is a metal hollow tube, and the inner wall surface of the hollow tube is coated with an intermetallic compound and / or ceramics, and the outer wall surface is coated with an intermetallic compound and / or ceramics. 2. The metal-based hollow composite material according to the above item 1, wherein the composite material is not provided. 4. The metal constituting the metal hollow material is an iron-based alloy and / or a nickel-based alloy, and the coated intermetallic compound is formed of nickel aluminide, iron aluminide, cobalt aluminide, titanium aluminide, niobium aluminide, and aluminum oxide 4. The metal-based hollow composite material according to any one of the above 1 to 3, which is at least one of the above. 5. A method for producing a metal-based hollow composite material, wherein the metal-based hollow composite material according to any one of 1 to 3 above is produced by simultaneously applying a combustion synthesis method or a thermite synthesis method and a centrifugal casting method. 6. After powder B of metal, non-metal or metal oxide is placed in the hollow of the metal hollow material A rotating at high speed so as to be in contact with the inner wall surface, liquid metal C is injected, and powder B and liquid metal C are mixed. To generate an intermetallic compound and / or ceramics D in a molten or semi-molten state,
A method for producing a metal-based hollow composite material, wherein an intermetallic compound and / or ceramics D is fused and coated on an inner wall surface in a molten or semi-molten state due to generated heat. 7. An inner wall surface of a metal hollow material A rotating at a high speed;
An intermediate layer in which both materials change in concentration and / or microstructure in a gradient manner is formed on the fusion bonding surface between the intermetallic compound and / or the ceramic D to be coated. A method for producing the metal-based hollow composite material according to the above. 8. The metallic hollow material A is a steel hollow tube which is rotated at a high speed to give a centrifugal force of a gravitational multiple of 80 or more and whose inner wall surface is heated to 700 ° C. or more.
A powder of one or more of nickel, iron, cobalt, titanium or niobium or an oxide thereof heated to 0 ° C. or higher, and the liquid metal C to be injected is liquid aluminum at a temperature of 1200 ° C. or higher An intermetallic compound, an aluminum-containing alloy or aluminum oxide is generated by an exothermic reaction between the powder and the liquid aluminum, and an intermetallic compound such as a nickel-aluminum alloy and / or a ceramic D are formed on the fusion bonding surface. A method for producing a metal-based hollow composite material, characterized in that a steel material constituting a hollow tube forms a layer that changes in concentration and / or microstructure in a gradient manner.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on embodiments shown in the drawings. In the embodiment of the present invention shown in the drawings (hereinafter, also simply referred to as the present invention), the metal to be coated in the composite hollow tube is iron, and the coated intermetallic compound or ceramic is nickel aluminide.
The metal to be coated is an iron-based alloy such as carbon steel or stainless steel or In.
The same applies to a nickel-based superalloy such as conel or the like, wherein the intermetallic compound or ceramic is iron aluminide, cobalt aluminide, titanium aluminide, niobium aluminide, or aluminum oxide. Further, as the iron hollow tube, a hollow tube formed by combining and arranging a plurality of iron plate members such as a curved plate having an arc-shaped cross section may be used.

Here, nickel aluminide refers to an intermetallic compound whose constituent elements are nickel and aluminum. FIG. 2 shows a phase diagram of the nickel-aluminum binary system. NiAl has a very high melting point of 1638 ° C., which has the advantage of having excellent heat resistance, but has the disadvantage that it is difficult to produce materials by melting and casting. A combustion synthesis method is known as a method for obtaining such a high melting point compound with a small amount of external heating. In the case of combustion synthesis of NiAl, the heat of reaction has a large value of 118 kJ per mol. The temperature of NiAl generated by this reaction increases from 2000 ° C. to 3000 ° C. depending on the initial temperature of Ni and Al. By utilizing this heat, NiAl can be synthesized and bonded to steel at the same time.

In the present invention, a vertical centrifugal casting apparatus shown in FIG. 3 was used. When the aluminum is melted in the crucible 6 installed in the melting furnace 7 and the plug 13 is removed, the aluminum is poured into the mold 17 through the runner 9. Inside the mold 17, the iron hollow tube 1
8 is placed on the inner wall of the iron hollow tube 18 with nickel powder 19.
Is placed. The mold 18 is preheated by the mold heating furnace 11 and is rotated by the motor 15.

The vertical centrifugal casting apparatus shown in FIG. 3 has a very short runner section as compared with the horizontal centrifugal casting apparatus, and as a result, the temperature of the molten aluminum and the casting amount can be controlled relatively easily. It has the feature that it can be. In the present invention, the preheating temperatures of the nickel powder and the iron hollow tube are set to 500 ° C. and 700 ° C., while the molten aluminum pouring temperature is set to 1 °.
000 ° C and 1200 ° C. Moreover, the gravity multiple G is set to 3
0, 50, and 80. Here, the gravity multiple G is obtained by normalizing the centrifugal force by gravity.

A composite hollow tube was manufactured by changing the injection temperature of molten aluminum and the preheating temperature of the nickel powder and the iron hollow tube, that is, the reaction temperature. Here, the multiple of gravity is 5
0 was set. FIG. 4 shows a schematic diagram of the cross-sectional structure of the composite hollow tube. Here, the left side of the figure corresponds to the inner peripheral portion of the hollow tube, and the right side corresponds to the outer peripheral portion of the hollow tube. The reaction is proceeding when both the molten aluminum injection temperature and the nickel powder and iron hollow tube preheating temperature are high. Either the molten aluminum injection temperature or the nickel powder and iron hollow tube preheating temperature It was found that no reaction took place when the temperature of was low. Therefore, the preheating temperature of the powder and the hollow metal tube is preferably 700 ° C. or higher, and the injection temperature of the liquid aluminum is 1200 ° C.
C. or higher is preferred.

Next, a composite hollow tube was manufactured by changing the multiple of gravity. Here, the injection temperature of the molten aluminum and the preheating temperature of the nickel powder and the iron hollow tube are each 120.
0 ° C. and 700 ° C. FIG. 5 shows a schematic diagram of the cross-sectional structure of the composite hollow tube. When the applied gravity multiple G is 30, the iron hollow tube, nickel powder, and aluminum are present in an unreacted state. The applied gravity multiple G is 50
In this case, the compound layer is formed of many layers, and is partially joined to the iron hollow tube. However, in many parts, voids remained between the compound layer and the iron hollow tube.

On the other hand, the applied gravity multiple G is 80
In the case of the above, it was found that the formed compound layer was more uniform than the sample having a gravitational multiple G of 50, and was bonded to the iron hollow tube in almost the entire range. Therefore, the applied gravity multiple G is preferably 80 or more.

It has been found that the reaction progresses well as the applied gravity multiple increases. Increasing the gravitational acceleration not only works to favor the penetration of aluminum into the nickel powder, but also promotes bonding by strongly pressing the reaction product against the iron hollow tube.

When the injection temperature of molten aluminum is 1200
Table 1 shows the analysis results of the elemental concentrations by EPMA of the samples manufactured under the conditions of 700C, the preheating temperature of the nickel powder and the iron hollow tube was 700C, and the gravity multiple G was 50. Here, the area in Table 1 is the area displayed in FIG. In the sample manufactured under the condition that the gravity multiple G is 50, formation of nickel aluminide containing a large amount of iron is recognized, but the progress of the reaction is still insufficient, and many unreacted portions remain.

[Table 1]

Next, the injection temperature of molten aluminum is set to 12
00 ° C, preheating temperature of nickel powder and iron hollow tube is 700
FIG. 1 shows a concentration distribution diagram of a sample manufactured under the conditions of ° C. and a gravity multiple G of 80. Here, the horizontal axis of the graph is the distance from the initial interface. The composition of the formation layer was such that nickel, aluminum, and iron had substantially the same concentration near the interface, and aluminum Al increased and Ni and Fe decreased toward the inner periphery of the hollow tube. In addition, the interface after coating moved from the initial interface to the iron hollow tube side. This interfacial movement is due to the melting of the inner wall of the iron hollow tube due to the heat generated by the reaction between the nickel powder and the aluminum melt. At this time, such a gradient of the iron concentration appeared in the compound layer due to the diffusion of the molten iron.

A nickel powder heated to 700 ° C. or more is placed on the inner wall of an iron hollow tube which is rotated at a high speed and heated to 700 ° C. or more so that a centrifugal force of 80 or more is applied to a gravity multiple G. Injecting liquid aluminum at a temperature of, the exothermic reaction between the nickel powder and the liquid aluminum to produce a nickel aluminide intermetallic compound,
In addition, the generated heat melts the inner wall of the iron hollow tube which rotates at a high speed, causing a gradient change in concentration and microstructure near the coating interface between the nickel-aluminum alloy containing an intermetallic compound and the metal hollow tube. Thereby, it has become possible to manufacture a composite hollow tube in which both are firmly joined.

As described above, according to the present invention, the surface of the metal hollow material is coated with the intermetallic compound and / or ceramics, and the metal hollow material is coated with the coated intermetallic compound and / or ceramic. It is possible to provide a metal-based hollow composite material having a layer in which both materials change in a concentration and / or microstructure gradient with respect to ceramics (Claim 1).
A metal hollow composite material wherein the metal hollow material is a metal hollow tube, and the surface of the inner wall of which is coated with an intermetallic compound and / or ceramics (claim 2); The hollow material is a metal hollow tube, and the surface of the inner wall of the hollow tube is coated with an intermetallic compound and / or ceramics;
Further, a metal-based hollow composite material whose outer wall surface is not coated with an intermetallic compound and / or ceramics can be provided.

Further, the metal constituting the metallic hollow material is an iron-based alloy and / or a nickel-based alloy, and the coated intermetallic compound is formed of nickel aluminide, iron aluminide, cobalt aluminide, titanium aluminide,
One of niobium aluminide and aluminum oxide
A metal-based hollow composite material of at least one kind can be provided (claim 4).

In addition, the combustion synthesis method or thermite synthesis method and the centrifugal casting method are simultaneously applied (claim 5).
After the powder B of a nonmetal or metal oxide is placed in contact with the inner wall surface, the liquid metal C is injected, and the powder B and the liquid metal C are caused to undergo an exothermic reaction to form a molten or semi-molten intermetallic compound. And / or to form an intermetallic compound and / or ceramics D by fusing and coating the inner wall surface in a molten or semi-molten state by the generated heat (claim 6). A layer in which both materials change in a concentration and / or microstructural manner on the inner wall surface of the hollow metal material A to be formed and the fusion bonding surface between the intermetallic compound and / or the ceramics D to be coated. By forming (claim 7), a composite hollow tube in which both are firmly joined can be manufactured.

The hollow material A made of metal has a gravitational multiple of 80.
Using a steel hollow tube that is rotated at high speed to give the above centrifugal force and whose inner wall surface is heated to 700 ° C. or more, the powder B placed in the hollow is heated to 700 ° C. or more. , By using one or more powders of cobalt, titanium or niobium or oxides thereof, and injecting the liquid metal C using liquid aluminum having a temperature of 1200 ° C. or more, the powder and liquid aluminum can be separated. Compound produced by the exothermic reaction of the above, an intermetallic compound, an aluminum-containing alloy or aluminum oxide, and a steel material forming a hollow tube with an intermetallic compound such as a nickel-aluminum alloy and / or ceramics D on the fusion bonding surface It has become possible to provide a method for producing a metal-based hollow composite material in which a layer is formed which changes in concentration and / or microstructure in a gradient manner. 8).

If the heat resistance, oxidation resistance, corrosion resistance and abrasion resistance of a metal can be further improved, the range of use will be greatly expanded. Further, if the workability and toughness of the intermetallic compound and ceramics can be further improved, the range of use will be greatly expanded. The above disadvantages can be overcome by coating the metal surface with an intermetallic compound or ceramics.

As a method for coating a metal surface with an intermetallic compound or ceramics, a coating method utilizing a thermite reaction or a combustion synthesis reaction has been proposed. The method utilizing the above reaction has the advantages that the external heating temperature for coating is low and the time is short since the reaction heat can be used.
However, in the conventional method using the reaction between solid and solid, the reaction starts spontaneously, and the reaction start temperature cannot be freely selected.
Therefore, the ultimate temperature after the reaction could not be controlled.

On the other hand, in the present invention, by utilizing the combustion synthesis between solid and liquid, it is possible to bring the separately heated reactants into contact at a free temperature, and the reaction starting temperature can be freely controlled. For this reason, the ultimate temperature after the reaction and the melting depth of the base material can be freely controlled. in addition,
At the same time, the application of centrifugal force is advantageous in that the molten metal penetrates into the powder, and the bonding is promoted by strongly pressing the reaction product against the metal hollow tube.
It has become possible to produce a composite material having a higher coating strength than the conventional method.

【The invention's effect】

According to the present invention, an intermetallic compound or ceramic having excellent heat resistance, oxidation resistance, corrosion resistance and abrasion resistance can be firmly adhered to the surface of a metal member, and the inherent properties of metal (workability) And toughness) and the properties of intermetallic compounds and ceramics (heat resistance, oxidation resistance, corrosion resistance and abrasion resistance), and in particular, a metal composite hollow tube can be obtained. Also, since this method can realize mass production at low cost, various industrial applications are expected. In particular, the use for piping in a chemical plant that is susceptible to corrosion is effective.

[Brief description of the drawings]

FIG. 1 is a diagram showing a concentration distribution near a coating interface in a sample manufactured under the conditions of a molten aluminum injection temperature of 1200 ° C., a preheating temperature of nickel powder and an iron hollow tube of 700 ° C., and a gravity multiple G of 80. is there.

FIG. 2 is an equilibrium diagram of a Ni—Al system.

FIG. 3 is a schematic view of a vertical centrifugal casting apparatus used in the present invention.

FIG. 4 is a schematic diagram of a cross-sectional structure of a hollow tube manufactured by changing a reaction temperature.

FIG. 5 is a schematic diagram of a cross-sectional structure of a hollow tube manufactured by changing a multiple of gravity.

FIG. 6 is a schematic view of the structure of a sample manufactured under the conditions of a molten aluminum injection temperature of 1200 ° C., a preheating temperature of nickel powder and an iron hollow tube of 700 ° C., and a gravity multiple G of 50.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Aluminum concentration 2 ... Iron concentration 3 ... Nickel concentration 4 ... Initial interface 5 ... Interface after coating 6 ... Crucible 7 ... Melting furnace 8 ... Molten aluminum 9 ... Runner 10 ... Heat resistant material 11 ... Mold heating furnace 12 ... frame 13 ... plug 14 ... shaft 15 ... motor 16 ... belt pulley 17 ... mold 18 ... iron hollow tube 19 ... nickel powder 20 ... unreacted aluminum 21 ... unreacted nickel powder 22 ... iron hollow tube 23 ... Ni- Al—Fe intermetallic compound 24—joint 25—Ni 3.5 at% -Al 90.1 at% -Fe
6.4 at% phase 26 ... Ni 6.0 at% -Al 64.8 at% -Fe2
9.2 at% phase 27 ... Ni 9.3 at% -Al 80.3 at% -Fe1
0.4 at% phase 28 ... Ni 75.2 at% -Al 15.0 at% -Fe
9.9 at% phase 29 ... 90.5 at% Ni-2.4 at% Al-Fe
7.1 at% phase 30 ... Ni 52.8 at% -Al 2.9 at% -Fe4
4.2 at% phase 31 ... Ni 28.2 at% -Al 29.2 at% -Fe
42.5 at% phase 32 ... Ni 0.3 at% -Al 0.4 at% -Fe9
9.5at% phase

Of the front page Continued (51) Int.Cl. ⁷ identification mark FI theme Court Bu (Reference) C23C 24/10 C23C 24/10 (72) inventor Kiyotaka Matsuura Hokkaido Eniwa Meguminohigashi 2-chome No. 2 4 F-term (reference) 4K044 AA02 AB03 BA02 BA06 BA10 BA13 BB06 BC01 BC02 BC05 BC11 CA02 CA11 CA23 CA25

Claims (8)

[Claims] 1. The surface of a metal hollow material is coated with an intermetallic compound and / or ceramics, and both materials have a concentration between the metal hollow material and the coated intermetallic compound and / or ceramics. A metal-based hollow composite material characterized by having a layer which changes in terms of target and / or microstructure. 2. The metal hollow material is a metal hollow tube, and the surface of the inner wall of the hollow tube is coated with an intermetallic compound and / or ceramics.
The metal-based hollow composite according to the above. 3. The metal hollow material is a metal hollow tube, the surface of the inner wall of the hollow tube is coated with an intermetallic compound and / or ceramics, and the surface of the outer wall is an intermetallic compound and / or The metal-based hollow composite according to claim 1, which is not coated with a ceramic. 4. The metal constituting the metal hollow material is an iron-based alloy and / or a nickel-based alloy, and the coated intermetallic compound is nickel aluminide, iron aluminide, cobalt aluminide, titanium aluminide, niobium aluminide. The metal-based hollow composite material according to any one of claims 1 to 3, which is at least one of aluminum oxide and aluminum oxide. 5. A combustion synthesis method or a thermite synthesis method,
Claims 1-3 by applying centrifugal casting simultaneously.
A method for producing a metal-based hollow composite material, comprising: producing the metal-based hollow composite material according to any one of the above. 6. A metal, non-metal or metal oxide powder B is placed in the hollow of a hollow metal material A rotating at a high speed so as to be in contact with the inner wall surface, and then a liquid metal C is injected. And the liquid metal C to generate an intermetallic compound and / or ceramics D in a molten or semi-molten state, and an intermetallic compound and / Or ceramics D
A method for producing a metal-based hollow composite material, comprising fusing and coating. 7. An inner wall surface of a metal hollow material A rotating at a high speed, and an intermetallic compound and / or ceramics D to be coated.
7. A method for producing a metal-based hollow composite material according to claim 6, wherein a layer in which both materials change in concentration and / or microstructure in a gradient manner is formed on the fusion-bonded surface between the two. . 8. The metal hollow member A is rotated at a high speed so as to give a centrifugal force of a gravitational multiple of 80 or more, and the inner wall surface is at 700 ° C.
It is a steel hollow tube heated as described above, wherein the powder B disposed in the hollow is heated to 700 ° C. or more, nickel,
A powder of one or more of iron, cobalt, titanium or niobium or oxides thereof, wherein the injected liquid metal C is liquid aluminum at a temperature of 1200 ° C. or more, An intermetallic compound, an aluminum-containing alloy or aluminum oxide is generated by the exothermic reaction, and an intermetallic compound such as a nickel-aluminum alloy and / or ceramics D and a steel material constituting a hollow tube are formed on the fusion bonding surface. A method for producing a metal-based hollow composite material, which comprises forming a layer which changes in a concentration and / or microstructure gradient.