JP2532144B2 - Method for manufacturing metal / ceramic composite - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a metal / ceramic composite applied to a sensor, a functionally graded material, a superconducting conductor, a magnet, a cable and the like.

[Prior Art and Its Problems] Conventionally, as a metal / ceramic composite, one obtained by forming a raw material powder such as tungsten-tungsten carbide, copper-alumina, aluminum-alumina, or silver-cadmium oxide into a desired shape. There is. These metal / ceramic composites have characteristics such as wear resistance, heat resistance, high strength, good electrical conductivity, and good thermal conductivity. For this reason,
It is used for electrical contact materials, processing tools, machine structural members, etc.

However, these metal / ceramic composites are inexpensive but do not have sufficiently satisfactory properties.

In addition, as the metal-ceramics composite, for example, those obtained by coating ceramics on a metal such as those obtained by coating hastelloy with titanium boride,
For example, there are metallized ceramics such as metallized metals such as copper, nickel and tungsten on alumina. These metal / ceramics composites are used for machine tools such as cutting tools, electronic equipment members, and turbine blades.

However, these metal / ceramic composites are also inexpensive but do not have sufficiently satisfactory characteristics.

Furthermore, as a metal / ceramics composite, CFRM (ceramics fiber reinforced metal) in which filaments or whiskers of carbon, silicon carbide, alumina, etc. are compounded with metal, or MFRC (metal fiber reinforced ceramics) in which metal filaments and ceramics are compounded ). In these metal / ceramics composites, the strengthening metal or ceramics improves the strength and toughness of the composite. Therefore, practical application of this composite is underway.

However, these metal-ceramic composites are more expensive than the above two types of metal-ceramic composites. Therefore, the applications of these metal / ceramic composites are limited.

When compounding a metal-based superconductor such as NbTi, Nb ₃ Sn, Nb ₃ Al, or V ₃ Ga with a metal, Cu is present around the metal-based superconductor,
A conductive metal such as Al is placed and subjected to plastic working to make it ultra-fine multi-core or multi-layer. These composites are electrically stable due to the conductive metal surrounding the metallic superconductor.

However, since these metal-based superconductors are scarce as resources, they are expensive and their use is limited. Further, since the superconducting property of the metal-based superconductor is exhibited at the liquid helium temperature, liquid helium which is expensive is required when using the metal-based superconductor.

On the other hand, in recent years, attention has been paid to oxide-based ceramics superconductors having a high critical temperature. Oxide-based ceramics superconductors can exhibit superconducting properties by cooling with inexpensive liquid nitrogen, and thus can be applied to various applications. As such, for example, LnBaCu ₃ O _7-X (Ln: rare earth element), Bi ₂ Sr ₂ CaCu ₂ O ₈ , (Bi _1-X Pb _X ) ₂ Sr ₂ Ca ₂ Cu ₃ O ₁₀ , Tl _{2 Ba 2 CaCu 2 O 8, Tl} 2 Ba 2 Ca 2 Cu 3 O 10, TlBa 2 Ca 2 Cu 3 O 8.5 , and the like.

When the oxide-based ceramics superconductor is made into a wire, the following method is used because the oxide-based ceramics superconductor does not have plastic workability. The first method is to mix the oxide-based ceramics superconductor raw material powder with an organic binder and extrude the mixture into a desired shape. The second method is to fill a metal pipe with the oxide-based ceramics superconductor raw material powder and to extend the pipe. The third method is to melt and spin the oxide-based ceramics superconductor raw material powder.

However, the oxide-based ceramics superconducting wire obtained by these methods has poor thermal conductivity. Therefore, a large current cannot be stably applied. Therefore, this oxide-based ceramics superconducting wire cannot be used for a cable or the like. Further, the oxide-based ceramics superconductor causes a so-called quench phenomenon in which the superconducting state is destroyed by exceeding the critical state due to an electromagnetic phenomenon. Therefore, it is necessary to combine the stabilizer and the oxide-based ceramics superconductor so that all or part of the superconducting current in the portion where the quench phenomenon occurs can flow well. However, like the metal-based superconductor, it has not been made multi-core or multi-layered.

The present invention has been made in view of such points, excellent wear resistance, heat resistance, strength, electrical conductivity, and properties such as thermal conductivity, efficiently metal-ceramics composite, and It is an object of the present invention to provide a method for producing a metal / ceramic composite that can be easily produced.

[Means for Solving the Problems] In the present invention, a concentric laminated body is formed by concentrically arranging a plurality of ceramic cylindrical bodies produced by hydrostatically pressing a metallic cylindrical body and ceramic powder. A step of hydrostatically pressing the concentric laminated body, a step of reducing the diameter of the concentric laminated body subjected to the hydrostatic pressing, and a sintering temperature of the ceramics in the concentric laminated body after the diameter reducing processing. that's all,
And a step of performing a heat treatment at a temperature equal to or lower than the melting point of the metal, which is a method for producing a metal / ceramic composite body.

Here, it is preferable that the diameter reducing step and the heat treatment step are alternately performed a plurality of times after the concentric laminate manufacturing step.

The metal to be composited with ceramics is such that the resulting composite can exhibit excellent properties such as electrical conductivity, thermal conductivity, ductility, toughness, weldability, plating property, and solderability. Good. Such as Cu,
Al, Ag, Au, Fe, Ni, Co, W, Mo, Nb, Ta, Ti, Zr, and alloys thereof, Ag-Pd, Cu-Zn, Cu-Sn, stainless steel, Fe-Ni, Fe-Ni -Co, Mo-Cr-Fe and other alloys can be mentioned.

Ceramics have excellent wear resistance,
Any material can be used as long as it can exhibit properties such as heat resistance, magnetism, and superconductivity. As such,
Al ₂ O ₃ , SiC, ZrO ₂ , YSZ (yttria-stabilized zirconia), MgO, BaTiO ₃ , Fe ₂ O ₃ , YBa ₂ Cu ₃ O _7-X , Bi ₂ SrCaCu ₂ O ₈ , Bi _1.6 Pb _0.4 Sr ₂ Examples thereof include Ca ₂ Cu ₃ O ₁₀ , Tl ₂ Ba ₂ CaCu ₂ O ₈ , Tl ₂ Ba ₂ Ca ₂ Cu ₃ O ₁₀ , TlBa ₂ Ca ₂ Cu ₃ O _8.5 and precursors thereof.

As a method for producing a concentric laminated body, a multifilament method in which ceramics are made ultra-fine and multicore, a sheet-shaped ceramic and a jelly-roll method in which metal is wound in multiple layers are used for stabilizing ordinary metal-based superconductors. Any method can be used. Further, particularly when the ceramic is a superconductor, the superconductor may be subdivided and distributed in the matrix of the stabilizing material. At this time, the metal plays a role of absorbing heat generated during the quench in addition to the electric passage.

The present inventors have found that the structure as shown in FIGS. 1 to 3 is effective for compounding ceramics and metals, which are difficult to process.

In FIG. 1, the concentric laminated body 1 has metal cylindrical bodies 11 and ceramic cylindrical bodies 12 alternately arranged, and the center thereof is ceramics. Further, in FIG. 2, the concentric laminated body 1 has metal cylindrical bodies 11 and ceramic cylindrical bodies 12 alternately arranged, as in FIG. 1, and the center thereof is metal. In FIG. 3, the center is an air core, and the metal cylindrical bodies 11 and the ceramic cylindrical bodies 12 are alternately arranged. Third
By making the structure with a hollow center as shown in the figure, a coolant such as liquid nitrogen can be flowed into this hollow part, and the cooling effect is improved in addition to the stabilization due to the combination with the metal, and quenching is prevented. It will be extremely excellent.

In order to take the structure shown in FIGS. 1 to 3, the following method is preferable.

First, a metal is processed into a cylindrical body having a desired outer diameter by a lathe or the like. Next, similarly, a ceramic powder is used to form a cylindrical body having a desired outer diameter. After that, the respective cylindrical bodies are alternately fitted to form a composite of metal and ceramics. At this time, a molded body formed by a cold isostatic pressing (CIP), a hot isostatic pressing (HIP) or the like may be used as the ceramic cylindrical body.

As another method, as shown in FIGS. 4 and 5, ceramic powder is tapped into the gap 14 of the metal cylinder 13 having one end closed, and the other end is sealed. Further, the ceramics in a molten state may be caused to flow into the gap 14 of the metal cylinder 13 to seal the other end. This method facilitates reducing the diameter of the concentric laminate. When the ceramic is an oxide-based superconductor, oxygen is required for exhibiting the characteristics, and therefore the heat treatment is preferably performed in an atmosphere containing oxygen.

[Operation] According to the method for producing a metal / ceramic composite of the present invention, a plurality of ceramic cylindrical bodies produced by isostatic pressing of the metal cylindrical body and the ceramic powder are alternately arranged concentrically. After making a concentric laminated body, then hydrostatic pressing is applied to this concentric laminated body, then the concentric laminated body is subjected to diameter reduction processing, and thereafter, the concentric laminated body is subjected to the sintering temperature of the ceramics or higher and the melting point of the metal or lower. Heat treatment is performed at the temperature. If necessary, the diameter reduction process and the heat treatment are repeated.

When a part of the ceramic or its precursor is melted and cooled by the heat treatment, the crystal of the ceramic is oriented in the longitudinal direction of the composite during recrystallization. Therefore, the excellent characteristics of ceramics are exhibited. Further, since it is compounded with a metal, the electrical conductivity and thermal conductivity are improved as compared with ceramics alone, and the composite is stabilized. Quenching, which is a phenomenon peculiar to ceramics, is prevented.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

Example 1 First, powders of Bi ₂ O ₃ , SrCO ₃ , CaCO ₃ , and CuO were mixed with Bi: Sr: Ca: C.
Weighed and mixed so that u = 2: 2: 1: 2. The mixed powder was calcined in air at 850 ° C. for 5 hours. The powder after calcination was sufficiently crushed. Crushed powder, rod-shaped with a length of 100 mm and an outer diameter of 4 mmφ, 100 mm in length, an outer diameter of 11 mmφ, and an inner diameter
7 mmφ pipe-shaped, 100 mm long, outer diameter 18 mmφ, inner diameter
14 mmφ pipe-shaped, 100 mm long and 25 mm outer diameter
It was molded into a pipe shape with φ and an inner diameter of 21 mmφ. The powder was molded by the cold isostatic pressing (CIP) method.

Next, an Ag rod having a length of 120 mm and an outer diameter of 30 mmφ was processed into a metal cylinder having one end closed as shown in FIG. 3
The size of each gap is 100 mm in length x 11 mm in outer diameter.
φ x inner diameter 7 mmφ, length 100 mm x outer diameter 18 mmφ x inner diameter 14 mmφ,
The length was 100 mm × outer diameter 25 mm φ × inner diameter 21 mm φ.

A molded body formed of powder was fitted to the Ag metal cylinder processed as described above. Then, the other end of the Ag metal cylinder was sealed. 700 in Ag metal cylinder with both ends closed
Hot isostatic pressing (HIP) under conditions of ℃ and 1000atm
Treated.

The metal cylinder after the HIP treatment was swaged to have an outer diameter of 10 mmφ. The swaged metal cylinder was rolled to produce a wire rod having a thickness of 6.0 mm.

Next, the obtained wire was heated in air at 920 ° C. for 1 hour. Further, this wire was heated in air at 850 ° C. for 50 hours to obtain a metal / ceramics composite.

The critical current density (Jc) and orientation rate (F) of the obtained metal / ceramics composite were measured. The results are shown in Table 1 below. The critical current density was measured in a magnetic field of 77 K and 0.1 T (tesla). The orientation ratio (F) was measured by an X-ray diffractometer, and the result was used to calculate by the following formula.

F = (P ₀ −P ₀₀ ) / (1−P ₀₀ ) P ₀₀ = ΣI (00l) / ΣI (hkl) where I (hkl) is the X-ray in the plane of the crystal whose Miller index is [hkl]. The peak intensity of diffraction is shown. P ₀₀ indicates the peak intensity ratio of the X-ray diffraction of the ceramic non-oriented material.
P ₀ represents the X-ray diffraction peak intensity ratio of the measurement sample.

Examples 2 to 6 Metal-ceramic composites were obtained in the same manner as in Example 1 except that the metal cylinder was rolled to the thickness shown in Table 1 below. If the metal cylinder has a thickness of 2.0 mm or less, H
Swaging the metal cylinder after IP treatment to reduce the outer diameter.
It was set to 5 mmφ.

The critical current density (Jc) and orientation rate (F) of the obtained metal / ceramics composite were measured in the same manner as in Example 1. The results are also shown in Table 1 below.

Comparative Examples 1 to 6 Examples except that the wire rod after rolling was not subjected to heat treatment at 920 ° C. for 1 hour in air and the metal cylinder was rolled to a thickness shown in Table 1 below. A metal / ceramics composite was obtained in the same manner as in 1. When the metal cylinder had a thickness of 2.0 mm or less, the metal cylinder after HIP treatment was swaged to have an outer diameter of 5 mmφ.

The critical current density (Jc) and orientation rate (F) of the obtained metal / ceramics composite were measured in the same manner as in Example 1. The results are also shown in Table 1 below.

As is clear from Table 1, the metal-ceramic composites (Examples 1 to 6) obtained by the method of the present invention are
The crystal orientation ratio was high and it showed excellent superconducting properties. On the other hand, in the metal / ceramic composites (Comparative Examples 1 to 6) obtained by the conventional method, the crystals were not oriented at all, and the superconducting properties were low.

Example 7 First, a powder of TiB ₂ having a length of 100 mm, an outer diameter of 7 mmφ and an inner diameter of 4 m was used.
Pipe with mφ, length 100mm, outer diameter 14mmφ, inner diameter 11
mmφ pipe type, length 100mm, outer diameter 21mmφ, inner diameter 1
8 mmφ pipe-shaped, 100 mm long and 28 mm outer diameter
It was molded into a pipe shape with φ and an inner diameter of 25 mmφ. The powder was molded by the cold isostatic pressing (CIP) method.

Next, a Ni rod having a length of 120 mm and an outer diameter of 33 mmφ was processed into a metal cylinder body having one end closed as shown in FIG. The sizes of the four gaps are 100 mm in length x 11 mmφ outside diameter x 7 mmφ inside diameter, 100 mm length x 18 mmφ outside diameter x 14 inside diameter
mmφ, length 100 mm × outside diameter 25 mmφ × inside diameter 21 mmφ. In addition, a Ni rod having a length of 100 mm and an outer diameter of 4 mmφ was prepared.

A molded body formed of powder was fitted into the Ni metal cylinder processed as described above. A Ni rod was fitted in the center. After that, the other end of the Ni metal cylinder was sealed. A Ni metal cylinder whose both ends were closed was subjected to hot isostatic pressing (HIP) treatment for 4 hours at 800 ° C. and 2000 atm.

The metal cylinder after the HIP treatment was hot extruded at a temperature of 800 ° C.
Subsequently, the extruded metal cylinder was subjected to a drawing process using a draw bench to produce a bar material having an outer diameter of 7.5 mmφ.

Next, the obtained rod was subjected to HIP treatment for 18 hours at 1300 ° C. and 2000 atm to obtain a Ni—TiB ₂ -based metal / ceramic composite.

The obtained Ni-TiB ₂ composite was cut into pellets.
Using this pellet, the wear test and contact voltage drop of the Ni-TiB ₂ composite were examined. The results are shown in Table 2 below. The abrasion test was performed at a load of 10 g and a sliding speed of 10 cm / sec. The contact voltage drop was measured when a current of 0.1 A was applied.

Example 8 Ni-NiB ₂ -PdB system metal was used in the same manner as in Example 7 except that a mixture of NiB ₂ powder and PdB powder in a ratio of 1: 1 was used instead of TiB ₂ powder.・ A ceramic composite was obtained.

The wear test and contact voltage drop of the obtained Ni-NiB ₂ -PdB composite were examined in the same manner as in Example 7. The results are also shown in Table 2 below.

Comparative Example 7 Ni-TiB was prepared in the same manner as in Example 7 except that HIP treatment was not performed for 18 hours under the conditions of 1300 ° C. and 2000 atm.
_{A 2} type metal-ceramics composite was obtained.

The wear test and contact voltage drop of the obtained Ni-TiB ₂ composite were examined in the same manner as in Example 7. The results are also shown in Table 2 below.

Comparative Example 8 Ni-NiB was prepared in the same manner as in Example 8 except that HIP treatment was not performed for 18 hours under the conditions of 1300 ° C. and 2000 atm.
_{A 2-} PdB system metal-ceramics composite was obtained.

The wear test and contact voltage drop of the obtained Ni-NiB ₂ -PdB composite were examined in the same manner as in Example 7. The results are also shown in Table 2 below.

Comparative Example 9 A Ni-3vol% ThO ₂ based dispersion type alloy was manufactured by an ordinary powder metallurgy method.

The abrasion test and contact voltage drop of the obtained Ni-3vol% ThO ₂ dispersion alloy were examined in the same manner as in Example 7. The results are also shown in Table 2 below.

As is clear from Table 2, the metal / ceramic composite bodies (Examples 7 and 8) obtained by the method of the present invention had a small amount of wear and a small voltage drop. On the other hand, the metal-ceramic composites (Comparative Examples 7 to 9) obtained by the conventional method had a large amount of wear.

[Effects of the Invention] As described above, the method for producing a metal / ceramic composite according to the present invention provides a metal / ceramic composite having excellent characteristics such as wear resistance, heat resistance, strength, electrical conductivity, and thermal conductivity. This is a method for producing a metal / ceramics composite, which enables efficient and easy production of a ceramics composite.

[Brief description of drawings]

1 to 3 are explanatory views showing the structure of a concentric laminated body used in the method of the present invention, FIG. 4 is an explanatory view showing an example of a metal cylinder used in the present invention, and FIG. 5 is FIG. 4 is a sectional view taken along the line IV-IV ′ of FIG. 4. 1 …… Concentric laminated body, 11 …… Metal cylinder, 12 …… Ceramic cylinder, 13 …… Metal cylinder, 14 …… Gap.

Claims (1)

(57) [Claims] 1. A process of concentrically arranging a plurality of ceramic cylinders produced by hydrostatic pressing a metal cylinder and a ceramic powder to form a concentric laminate, and the concentric laminate. A step of applying a hydrostatic press, a step of subjecting the concentric laminate subjected to the hydrostatic press to a diameter reduction process, and a concentric layer body after the diameter reduction process having a sintering temperature of the ceramics or more,
And a step of performing heat treatment at a temperature equal to or lower than the melting point of the metal, the method for producing a metal-ceramic composite body.