JPH0638978B2 - Method for producing composite material using redox reaction - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a composite material in which fine particles of a reinforcing material and alloy oxide are finely dispersed in a matrix metal, and more particularly, to a redox reaction. The present invention relates to a method for producing such a composite material.

2. Description of the Related Art As one of the methods for producing a composite material such as a fiber-reinforced metal composite material or a particle-dispersed composite material, a so-called additive is used in which a porous material of a reinforcing material is formed and molten matrix metal is pressure-penetrated into the porous material. The pressure casting method is known. In order to produce a composite material having excellent properties such as strength, rigidity and wear resistance by such a pressure casting method, the molten matrix metal is satisfactorily infiltrated into the porous body, whereby the reinforcing material and the matrix metal are combined. Good adhesion is required. Therefore, the Japanese Patent Application No. Sho 55 filed by the same applicant as the applicant of the present application.
As proposed in No. -1074040, it has been conventionally practiced to preheat the porous body to a temperature above the melting point of the matrix metal before infiltrating the molten matrix metal into the porous body.

Problems to be Solved by the Invention In the pressure casting method for preheating the porous body to a temperature equal to or higher than the melting point of the matrix metal as described above, a relatively large amount of thermal energy is required for preheating the porous body, Therefore, it is difficult to manufacture a composite material at a low cost, and problems such as oxidation may occur depending on the reinforcing material.Therefore, it is necessary to set the atmosphere for preheating to an inert atmosphere or a reducing atmosphere. There is a problem in that the porous body, especially its surface temperature, is cooled by heat radiation or the like before it is formed into a composite with the matrix metal, so that the molten matrix metal cannot necessarily be satisfactorily permeated into the porous body.

Further, in the pressure casting method, the molten matrix metal must be infiltrated into the narrow voids of the porous body. Therefore, the matrix metal needs to have excellent melt flowability, so Therefore, there is a problem that a matrix metal having a preferable composition cannot be used. Further, in the pressure casting method, since the porous body made of the reinforcing material must be capable of holding a predetermined shape itself, the volume ratio of the porous body cannot be reduced, and accordingly, the strengthening is not possible. There is a problem that it is difficult to manufacture a composite material having a small volume ratio of the material.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional method for producing a composite material, particularly the pressure casting method, and an object thereof is to provide an improved method for producing a composite material so as not to cause these problems. I am trying.

Means for Solving the Problems According to the present invention, the above object is to form a porous body containing a reinforcing material and fine particles of an oxide of a first metal, and to form the porous body into the porous body. This is accomplished by a method of making a composite material that is impregnated with a molten matrix metal that includes a second metal that has a greater tendency to form oxides than the first metal.

EFFECTS AND EFFECTS OF THE INVENTION According to the method of the present invention, the oxide of the first metal in the porous body and the second metal in the molten matrix metal are included in the process of infiltrating the molten matrix metal into the porous body. A redox reaction occurs during the heating, and the heat generated at that time heats the reinforcing material to a high temperature in the molten matrix metal, so that the porous body is compared without any problems such as its oxidation. The porous matrix is heated to a relatively high temperature, so that the molten matrix metal can be satisfactorily penetrated into the porous body even if the preheating temperature of the porous body is not high.

According to the method of the present invention, the redox reaction between the oxide of the first metal and the second metal produces oxides of the first metal and the second metal as pure metals, The first metal acts as an alloying additive element to the matrix metal to alloy the matrix metal, and the oxide of the second metal is finely dispersed in the matrix metal to disperse and strengthen the matrix metal. It is possible to easily manufacture a composite material which is superior in strength of the matrix metal and the like as compared with the method.

Further, according to the method of the present invention, since a porous body containing a reinforcing material and fine particles of the first oxide is formed, a porous body composed of only the reinforcing material as in the case of the conventional pressure casting method. The volume ratio of the reinforcing material in the porous body can be set to be smaller than that in the case of forming the composite material, and thus a composite material having a small volume ratio of the reinforcing material can be easily manufactured.

In the present invention, when the composite material to be manufactured is a fiber-reinforced metal composite material, the reinforcing material may be either long fibers or short fibers (including whiskers) and is manufactured. If the composite to be composed is a particle-dispersed composite,
The reinforcement may be powder, chips, flakes, and the like.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Example 1 32 g of silicon carbide whiskers (average fiber diameter 0.1 μ, average fiber length 30 μ) and 13 g of NiO powder (average particle size 3
μ) with a stirrer, and the mixture is filled in a stainless steel pipe.
By performing compression molding at a pressure of 0 kg / cm ² , a cylindrical porous body composed of silicon carbide whiskers and NiO powder and having a diameter of 34 mm and a length of 50 mm was formed. The bulk density of this porous body was 1.0 g / cm ³ (silicon carbide whiskers:
0.71 g / cm ³ , NiO: 0.29 g / cm ³ ).

Then, after preheating the porous body 1 to 600 ° C. in the atmosphere,
As shown in FIG. 1, it is placed in the mold 3 of the high-pressure casting apparatus 2 and has a purity of 99.7 wt% and a hot water temperature of 800 ° C. in the mold.
A pure aluminum melt 4 as a molten matrix metal is poured, and the melt is heated to 1000 kg /
Pressure was applied at a pressure of cm ^{2, and} the pressure was maintained until the molten metal 4 was completely solidified. After the molten metal 4 is completely solidified, the solidified body is taken out of the mold 3 by the knockout pin 6,
The solid material was subjected to machining to take out a composite material.

FIG. 2 shows a cross-sectional structure of the composite material manufactured as described above.
It is a microscope photograph shown at 00 times. Further, when the EPMA analysis and the X-ray diffraction test were performed on the composite material manufactured as described above, the NiO powder existing in the porous body was reduced by the Al of the molten metal, and a uniform Ni was formed together with the Al.
-Al alloy phase was formed, and it was confirmed that Al ₂ O ₃ generated by the oxidation of NiO by oxygen was uniformly and finely dispersed in the Ni-Al alloy phase. In FIG. 2, the whitish part is the NiA ₃ part, and the dark gray to black parts are the silicon carbide whiskers and A
This is a portion of a mixed structure with an aluminum alloy in which l ₂ O ₃ is finely dispersed. Thus, the composite material manufactured as described above is subjected to fiber reinforcement by silicon carbide whiskers and alloy strengthening and dispersion strengthening of the matrix metal, and the silicon carbide whiskers manufactured by the conventional pressure casting method are used as the reinforcing material for pure aluminum. It was confirmed that the composite material was superior in strength and heat resistance to the composite material using as a matrix metal. The volume ratio of silicon carbide whiskers was 22.4%.

Example 2 59 g Al ₂ O ₃ (average particle size 10 μ) and 10 g CoO
Powder (average particle size 5μ) and 10 g of Fe ₂ O ₃ powder (average particle size 2μ) were uniformly mixed with each other, the mixture was filled in a stainless steel pipe, and the mixture was mixed in the pipe. Was subjected to compression molding at a pressure of 820 kg / cm ² to form a cylindrical porous body having a diameter of 34 mm and a length of 50 mm. The bulk density of the porous body is 1.75 g / cm ³ (Al ₂ O ₃ :
1.31 g / cm ³ , CoO + Fe ₂ O ₃ : 0.44 g / c
m ³ ). Then, the porous body was preheated to 600 ° C. in the atmosphere, and then a composite material was manufactured under the same conditions and procedures as in the case of Example 1 described above.

When the EPMA analysis and the X-ray diffraction test were performed on the composite material thus produced, the CoO powder and the Fe ₂ O ₃ powder that were present in the porous body were reduced by the Al of the molten metal, and were uniformly distributed in the matrix metal. Co-Fe-Al
Forms an alloy phase, CoO and Fe ₂ O ₃ in oxygen by uniformly且微the Al ₂ O ₃ is in a matrix metal which was present in the Al ₂ O ₃ and the porous body was produced by being oxidized fine It was confirmed that they were dispersed in. It was confirmed that the composite material thus produced was superior in heat resistance to the composite material in which Al ₂ O ₃ powder was used as the dispersant and pure aluminum was used as the matrix metal. The volume ratio of Al ₂ O ₃ was 39.7%.

Example 3 100 g Fe powder was added to 40% HCl water to dissolve completely, thereby forming a 500 ml HCl solution in which Fe was present in the form of Fe ³⁺ ions. Next, 100 ml of lithium silicate binder containing 20% of SiO ₂ was added to this solution, and further 4 alumina short fibers (trade name "Safir") having an average fiber length of 3 mm and an average fiber diameter of 2 to 3 µ were added.
Add 8 g and stir them thoroughly to make
As shown in the figure, a slurry 8 having alumina short fibers 7 dispersed therein was formed. Next, as shown in FIG. 4, a net 9 made of stainless steel is placed in the slurry 8 and the net is pressed against the bottom wall 10a of the container 10 by a pressing means not shown in the drawing, By discharging the dispersion medium 11 on the container 9 from the container 10,
Fiber molding 12 impregnated with solution (20 × 50 × 15
0 mm) was formed.

Next, the fiber molded body 12 was heated to 800 ° C. in the atmosphere to completely dry the fiber molded body. In this case, when the fiber molded body was observed with a microscope, it was found that fine Fe ₂ O ₃ powder was uniformly attached in a dispersed state on the surface of the alumina short fiber. The bulk density of the fiber molding is 0.58 g / cm ³ (bulk density of alumina short fibers:
0.33 g / cm ³ , bulk density of Fe ₂ O ₃ powder: 0.25
g / cm ³ ).

Then, the fiber molded body as a porous body produced as described above is preheated to 600 ° C. in the atmosphere and then placed in the mold of the high pressure casting apparatus as shown in FIG. A molten pure aluminum having a purity of 99.7% and a temperature of 800 ° C. was poured, and the molten metal was pressurized at a pressure of 1000 kg / cm ³ , and the pressurized state was maintained until the molten metal was completely solidified. After the molten metal was completely solidified, the solidified body was taken out from the mold, and the solidified body was machined to take out the composite material. An EPMA analysis and an X-ray diffraction test were conducted on the composite material thus produced, and Fe ₂ O ₃ powder existing in the fiber compact was reduced by Al in the molten metal,
A uniform Fe-Al alloy phase is formed, and Al ₂ O ₃ produced by oxidizing Fe ₂ O ₃ with oxygen is finely and uniformly dispersed in the alloy phase. The composite material produced as described above is fiber-reinforced with alumina short fibers, alloy-reinforced with matrix metal, and dispersion strengthened with Al ₂ O ₃ , so that it becomes a composite material with short alumina fibers as reinforcing fibers and pure aluminum as matrix metal. It was confirmed that the strength and heat resistance were excellent.
The volume ratio of the alumina short fibers was 10%.

Example 4 To HCl was added 30 g of V ₂ O ₅ powder to dissolve completely, whereby 200 ml of H in which V was present in the form of V ⁵⁺ ions.
A Cl solution was formed. Then, add SiO ₂ to this solution.
50 ml of a lithium silicate binder containing 0% was added, and a bundle 14 of unidirectionally oriented carbon long fibers 13 (total weight 54 g) having a fiber length of 100 mm and a fiber diameter of 7 μ was dipped in the solution. The bundle was impregnated with an HCl solution, and the bundle was heated to 300 ° C. in the atmosphere to be completely dried. When the bundle thus treated was observed with a microscope, it was confirmed that fine V ₂ O ₅ was attached to the surface of the carbon long fiber in a state of being dispersed in the fiber. Then, the carbon long fibers having V ₂ O ₅ attached thereto are oriented in one direction and filled in a stainless steel case 15 having openings at both ends as shown in FIG. 6 to form a porous body. The fiber molded body 16 was formed. The bulk density of this fiber molding was 1.02 g / cm ³ (bulk density of carbon long fibers: 0.9 g / cm ³ , V ₂ O ₅ powder bulk density of 0.12 g / cm ³ ).

Then, the fiber molded body 16 together with the case 15 is vacuumed to 70
After preheating to 0 ° C., it is placed in a mold cavity 20 defined by a fixed die 18 and a movable die 19 of a die casting apparatus 17 as shown in FIG. 7, and 600 ° C. is placed in the mold cavity. Aluminum alloy (JI
A molten metal 21 of S standard ADC10) was injected by a plunger 22 and die casting was performed at a pressure of 500 kg / cm ² to penetrate the molten aluminum alloy between the carbon long fibers. After the molten metal was completely solidified, the solidified body was taken out from the mold cavity, and the solidified body was machined to take out the composite material.

An EPMA analysis and an X-ray diffraction test were conducted on the composite material thus produced. As a result, V ₂ O ₅ in the fiber compact was reduced by Al in the molten metal and a small amount of Mg, and a uniform V-Al-Mg alloy phase was obtained. And Al ₂ O ₃ and Mg formed by being oxidized by oxygen of V ₂ O ₅
It was found that O was uniformly and finely dispersed in the alloy phase. It was also found that the composite material thus produced was superior in heat resistance to a composite material in which unidirectionally oriented carbon long fibers were used as reinforcing fibers and an aluminum alloy (JIS standard ADC10) was used as a matrix metal. The volume ratio of the carbon long fibers was 50%.

Example 5 30 g of WO ₃ powder was added to 30% aqueous NaOH and completely dissolved, thereby forming a 100 ml NaOH solution in which W was present in the form of WO ₄ ²⁻ . Then, excess NaOH is neutralized with HCl, and then stainless steel having a fiber length of 3 mm and a fiber diameter of 50 μ is added to the solution (JIS standard SUS.
304) A 20 × 20 × 60 mm fiber molded body having a bulk density of 1.56 g / cm ^{3 made} of short fibers is dipped, whereby the solution is impregnated into the fiber molded body, and the fiber molded body is further exposed to the atmosphere. Completely dried by heating to 400 ° C. In this case, the surface of the stainless steel fiber has fine N
The a ₂ WO ₄ was uniformly attached, and the bulk density of the entire fiber molded body was 1.84 g / cm ³ .

Next, after preheating the fiber molded body to 600 ° C. in the atmosphere,
Place the seventh mold cavity of such die casting apparatus shown in FIG, pouring a melt of YuAtsushi 650 ° C. for magnesium alloy (JIS standard AZ91A) into the template, a pressure of 500 kg / cm ² The molten magnesium alloy was infiltrated between the stainless steel short fibers by die casting. After the molten metal was completely solidified, the solidified body was taken out from the mold cavity, and the solidified body was machined to take out the composite material.

When the EPMA analysis and the X-ray diffraction test were performed on the composite material manufactured as described above, Na ₂ WO ₄ existing in the fiber compact was reduced by the Mg of the molten metal, and a uniform Na-W-Mg alloy was obtained. It was found that MgO, which forms a phase and is formed by oxidation of Na ₂ WO ₄ by oxygen, is uniformly and finely dispersed in the alloy phase. In addition, a uniform Fe-
It was confirmed that the W-Mg alloy phase was formed. Further, the composite material manufactured as described above is superior in heat resistance to a composite material using stainless steel fibers (JIS standard SUS304) short fibers as reinforcing fibers and magnesium alloy (JIS standard AZ91A) as matrix metal. Admitted. The volume ratio of the stainless steel short fibers was 20%.

Example 6 11 g of NiWO ₄ powder was added to NH ₃ water and completely dissolved, whereby Ni and W were present in the form of complex ions 1.
To form a NH ₃ solution of 100 ml. Then average fiber length 3m
m, a alumina compact fiber having a fiber diameter of 2 to 3 μ, and a bulk density of 0.16 g / cm ³ of 20 × 40 × 80 mm to form a fiber compact, and the fiber compact is immersed in an NH ₃ solution. , Thereby impregnating the NH ₃ solution into the fiber molded body,
Furthermore, the fiber molded body was completely dried by heating to 800 ° C. in the atmosphere. In this case, the bulk density of the whole fiber compact was 0.27 g / cm ^3, and it was confirmed that fine NiWO ₄ was uniformly dispersed and adhered to the surface of the alumina short fiber.

Next, the fiber molded body 23 is preheated to 600 ° C. in the atmosphere, and then placed in the mold 25 of the centrifugal casting apparatus 24 as shown in FIG. 8, and the purity of 99.3% and the hot water temperature are placed in the mold. 55
Centrifugal casting was carried out by pouring pure zinc molten metal 26 at 0 ° C. and rotating the mold around the axis 27 at 250 rpm. After the molten metal 26 was completely solidified, the solidified body was taken out from the mold 25, and the solidified body was machined to take out the composite material.

When the EPMA analysis and the X-ray diffraction test were performed on the composite material manufactured as described above, the NiW
O ₄ is reduced by Zn in the molten metal, and uniform Ni-W-
It was confirmed that ZnO phase was formed and ZnO produced by oxidation of NiWO ₄ by oxygen was uniformly and finely dispersed in the alloy phase. It was also found that the composite material thus produced was superior in strength and heat resistance to a composite material containing alumina short fibers as reinforcing fibers and pure zinc as a matrix metal. The volume ratio of the alumina short fibers was 5%.

Example 7 40 g of CrCl ₂ powder was added to water and dissolved completely, forming a 100 ml solution in which Cr was present in the form of Cr ²⁺ ions. Next, a fiber molded body made of the same alumina short fibers as the fiber molded body formed in Example 6 is formed, and the fiber molded body is dipped in the above-mentioned aqueous solution to prepare an aqueous solution in the fiber molded body. Was further impregnated, and the fiber molded body was completely dried by heating to 800 ° C. in the atmosphere. In this case, the bulk density of the whole fiber molding was 0.27 g / cm ^3, and it was confirmed that fine Cr ₂ O ₃ was uniformly dispersed and adhered to the surface of the alumina short fiber. It was

Next, after preheating the fiber molded body to 600 ° C. in the atmosphere,
It is placed in the mold 25 of the centrifugal casting apparatus 24 shown in FIG. 8, and pure zinc molten metal 26 having a purity of 99.3% and a hot water temperature of 550 ° C. is poured into the mold 25, and the mold 25 is rotated around the axis 27. To 250
Centrifugal casting was carried out by rotating at rpm. After the molten metal 26 was completely solidified, the solidified body was taken out from the mold 25, and the solidified body was machined to take out the composite material.

When the composite material prepared as described above was subjected to EPMA analysis and X-ray diffraction test, Cr ₂ in the fiber molded body
O ₃ is reduced by Zn in the molten metal, and uniform Cr-Zn
It was confirmed that ZnO, which forms an alloy phase and is formed by oxidation of Cr ₂ O ₃ by oxygen, is uniformly and finely dispersed in the alloy phase. It was also found that the composite material produced as described above is superior in wear resistance to a composite material in which alumina short fibers are used as reinforcing fibers and pure zinc is used as a matrix metal. The volume ratio of the alumina short fibers was 5%.

Although the present invention has been described above in detail with reference to some embodiments, the present invention is not limited to these embodiments, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing one high-pressure casting apparatus suitable for carrying out the method for producing a composite material of the present invention, and FIG. 2 is a silicon carbide whisker produced according to the present invention as a reinforcing fiber for aluminum. An optical micrograph showing a cross-sectional structure of a composite material using an alloy as a matrix metal at 100 times magnification,
FIG. 3 is a solution showing a slurry in which alumina short fibers are dispersed, FIG. 4 is a solution showing a procedure for forming a fiber molding from the slurry shown in FIG. 3, and FIG. FIG. 6 is a perspective view showing a binding body, FIG. 6 is a perspective view showing a fiber molded body made of long carbon fibers filled in a stainless steel case, and FIG. 7 is used for carrying out the method for producing a composite material of the present invention. FIG. 8 is a vertical cross-sectional view showing one die casting apparatus suitable for being manufactured, and FIG. 8 is a vertical cross-sectional view showing one centrifugal casting apparatus suitable for carrying out the method for producing a composite material of the present invention. DESCRIPTION OF SYMBOLS 1 ... Porous body, 2 ... High pressure casting apparatus, 3 ... Mold, 4 ... Molten metal, 5 ... Plunger, 6 ... Knockout pin, 7 ... Alumina short fiber, 8 ... Slurry, 9 ... Net, 10 ... Container,
10a ... Bottom wall, 11 ... Dispersion medium, 12 ... Fiber molding, 1
3 ... Carbon long fiber, 14 ... Carbon long fiber bundle, 15 ... Case, 16 ... Fiber molding, 17 ... Die casting apparatus,
18 ... Fixed die, 19 ... Movable die, 20 ... Mold cavity, 21 ... Molten metal, 22 ... Plunger, 23 ... Fiber molding, 24 ... Centrifugal casting device, 25 ... Mold, 26 ... Molten metal, 27 ... Axis line

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Claims (4)

[Claims] 1. A second metal which forms a porous body containing a reinforcing material and fine particles of an oxide of the first metal, and has a higher tendency to form an oxide in the porous body than the first metal. A method for producing a composite material, which comprises infiltrating a molten matrix metal containing: 2. The method for producing a composite material according to claim 1, wherein in the step of forming the porous body, fine particles of the reinforcing material and an oxide of the first metal are included. A method for producing a composite material, which comprises forming a mixture with the fine particles. 3. The method for producing a composite material according to claim 2, wherein the mixture is compression molded. 4. The method for producing a composite material according to claim 1, wherein the porous body forms a solution in which the first metal is present in an ionic state in a solvent, Is impregnated into the porous molded body of the reinforcing material, and the molded body is heated to oxidize the first metal, thereby forming a composite material.