JP2010265492A - High-specific strength aluminum functional material having magnetism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new aluminum mixture structural material in which lightening is achieved by using a mixture including pure aluminum, and simultaneously, and to which strength is imparted and magnetism is imparted, and to provide a method for producing the same. <P>SOLUTION: The aluminum-ferrite sintered compact is obtained by subjecting a mixture in which the weight ratio of powdery pure aluminum to ferrite is 90-50 to 10-50 to mechanical alloying so as to obtain a pure aluminum-ferrite mixture having improved hardness, and thereafter performing discharge plasma sintering thereto. There is also provided the method of producing the aluminum-ferrite sintered compact. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high specific strength aluminum functional material having magnetism.

  Pure aluminum is characterized by high ductility and low strength. Pure aluminum has a very low strength compared to other aluminum alloys. For this reason, even if it is used for transportation equipment etc. with the intention of reducing the weight, pure aluminum is not intended to be applied to structural materials with the intention of increasing the strength or hardness. In order to increase the strength of pure aluminum, development of a method for producing a metal composite material composed of a metal porous preform and a matrix metal filled in the voids has been advanced. Specifically, using magnesium, aluminum, zinc or an alloy thereof as a matrix metal, the porous preform has continuous pores, the porosity is 80% or more, and the average diameter of the pore size is 0.1 mm or more. And a porous preform preheated to 473K or more is accommodated in a mold, and a molten metal of the matrix metal is put into a void of the porous preform by a die casting method, a low pressure casting method or a gravity die casting method. Filling (Japanese Patent Application Laid-Open No. 2008-266023) is known. In addition, an invention (Patent Document 2 Japanese Patent Application Laid-Open No. 2005-330585) for producing a metal alloy article having other additive components without melting the metal alloy is known. Such efforts can improve the strength of aluminum as a characteristic. Although physical properties such as strength can be improved to some extent, the characteristics are still limited to being non-magnetic.

At present, there is no material development aiming at a high specific strength aluminum functional material having a non-magnetic aluminum as a magnetic material and having magnetism, and there is no application example at present.
When it is desired to impart functionality to lightweight aluminum so as to have magnetism, it is generally considered to apply melting / casting methods that are generally performed in other technical fields.
In order to become a magnetic material, when trying to make a composite with aluminum using a component that becomes a magnetic material in aluminum, try to make a composite with a component that becomes a magnetic material that is an additive component with aluminum. In some cases, there is a difference in melting point and density between aluminum and additive components, and it has been generally considered difficult to overcome this difference and achieve the composite.
Even when the composite is possible, it is difficult to uniformly disperse the magnetic material in the aluminum as long as the melting / casting method is used.
For this reason, there is very little composite of aluminum and magnetic material. For example, it is known that 8 to 60% by weight of a fibrous ferromagnetic material is mixed with aluminum powder or aluminum alloy powder and heated and compressed (hot compressed) at 250 to 650 ° C. (Cited Document 3) 57-51231 gazette, patent document 4 Unexamined-Japanese-Patent No. 61-1040401). A magnetic aluminum composite material whose material has a network structure is disclosed (Japanese Patent Laid-Open No. 01-290734). Both have been shown to obtain magnetic materials. There is no particular mention of the high specific strength of the resulting aluminum composite material. Although it is possible to obtain an aluminum composite material having magnetism, a high specific strength aluminum functional material having magnetism cannot be found.
A magnetic aluminum composite comprising aluminum or an aluminum alloy and a magnetic material, the magnetic aluminum or aluminum alloy containing a strontium ferrite magnetic material, wherein the particles made of the magnetic material are dispersed in the aluminum or aluminum alloy. There is a magnetic aluminum composite (Patent Document 6, Japanese Patent Application Laid-Open No. 2006-257513) in which the average particle diameter of the particles is 5 μm or less.
In the magnetic aluminum composite material described in Patent Document 6, a magnetic material powder is pressed to form a magnetic material preform, and the preform is impregnated with a molten aluminum or aluminum alloy by pressure casting at 800 ° C. or higher. Therefore, it is difficult to uniformly disperse the magnetic material powder, and it is difficult to obtain sufficient magnetism. There is no provision for the particle size of the magnetic material powder. If the particle size of the magnetic material powder is large, the magnetic material powder may be deformed or cracked during preform production, resulting in magnetic properties. It may be difficult to uniformly disperse the material powder. Thus, the magnetic aluminum composite tends to fail to exhibit sufficient magnetism. On the other hand, in order to obtain sufficient magnetism, a method of increasing the content of the magnetic material in the magnetic aluminum composite is conceivable. There is a problem that can not. In the present invention, the characteristics are as follows: “The magnetic aluminum composite is not only light and lightweight, but also excellent in electrical conductivity, thermal conductivity and workability. Aluminum composites can be widely used as electronic and electrical equipment members such as motor magnets, solenoid valves, magnetic shield materials, etc. ", and are exclusively intended for magnetic materials and are used in structures. There is no intention about the material strength.
As a technique for realizing a high recording density of magnetic recording, a perpendicular magnetic recording system has attracted attention, and an invention of a structure in which a regular alloy material is filled in pores (Patent Document 7: JP-A-2007-107086) ) In this case as well, attention is paid to the characteristics of the magnetic material used for information recording, and the strength required for the structural material is not mentioned, and the structural material that can be generally used is not aimed at.
A method of manufacturing a light metal composite material in which a cavity of a mold is filled with an inorganic powder, and then a semi-molten light metal in a semi-molten state is pressurized and infiltrated into the inorganic powder in the cavity (Japanese Patent Application Laid-Open No. 2007-302952). In the publication, aluminum, aluminum alloy, magnesium, and magnesium alloy are used as light metals, and aluminum (Al), silicon (Si), titanium (Ti), strontium (Sr), magnesium (Mg), and copper (Cu) are used as inorganic powders. ), Barium (Ba), bismuth (Bi), yttrium (Y), and boron (B) selected from oxides, carbides, borides, or nitrides of one or more elements selected from It describes that functionalities such as photocatalytic activity, superconductivity, magnetism, luminescence, abrasion resistance, and heat resistance are imparted. In view of its outstanding magnetic material, it is not sufficient for use as a structural material.

  A small piece or granular matrix metal material and a reinforcing material are mixed by a ball mill machine to attach the reinforcing material to the matrix metal material, and then the mixture is sieved to separate a material having a predetermined size or more. There is known a method for producing a metal matrix composite material (Patent Document 9, Japanese Patent Application Laid-Open No. 09-295122) characterized in that it is used for injection molding in a semi-molten or molten state. This manufacturing method does not mean that it can be suddenly applied to the treatment of aluminum.

As is clear from the above, there is a great demand for magnetically imparted aluminum structural material that achieves weight reduction by using pure aluminum and at the same time has high specific strength. It has been demanded.
JP 2008-266023 A JP-A-2005-330585 JP-A-57-51231 JP 61-1040401 A JP-A-01-290734 JP 2006-257513 A JP 2007-107086 A JP 2007-302952 A JP 09-295122 A

  An object of the present invention is to provide a novel aluminum mixture structural material which is lightweight and achieves strength by using a mixture containing pure aluminum and at the same time is magnetized, and a method for producing the same.

The present inventors have studied the above-mentioned problems, and have found the following and completed the present invention.
(1) When a pure aluminum and ferrite mixture is to be obtained from pure aluminum and ferrite, aluminum is sufficiently adsorbed on the ferrite, and in this state, the aluminum mixture is produced on the ferrite having improved hardness. It was important to consider that it is necessary not to decompose the ferrite powder when sintering the ferrite and aluminum mixture.
(2) When trying to obtain a pure aluminum and ferrite mixture, it is difficult in the prior art to produce a mixture of aluminum on ferrite with improved hardness in the state where aluminum is sufficiently adsorbed on the ferrite. The melting point is a high temperature, high density magnetic material, and the melting point is lower than that of magnetic material, and the low density aluminum can be kept in a uniform state. A target aluminum and ferrite mixture sintered body can be obtained by producing an aluminum and ferrite mixture and using this as a precursor and performing discharge plasma sintering under specific conditions.
(3) Specifically, the present invention is as follows.
(A) A mixture of pure aluminum and ferrite with improved hardness, obtained by mechanical alloying of powdery pure aluminum and ferrite.
(A) The weight ratio of the powdery pure aluminum and ferrite is 90 to 50:10 to 50. The pure aluminum and ferrite mixture having improved hardness as described in (a) above.
(C) A method for producing a pure aluminum and ferrite mixture with improved hardness, characterized by mechanical alloying of powdery pure aluminum and ferrite.
(D) The method for producing a pure aluminum / ferrite mixture with improved hardness according to (c), wherein the weight ratio of the powdery pure aluminum and ferrite is 90-50 to 10-50.
(E) An aluminum and ferrite mixture sintered body obtained by spark plasma sintering the pure aluminum and ferrite mixture having improved hardness as described in (a) or (b) above.
(F) A method for producing an aluminum and ferrite mixture sintered body, characterized in that after the pure aluminum and ferrite mixture having improved hardness described in (c) or (d) is produced, discharge plasma sintering is performed.

  According to the present invention, a novel material to be adsorbed by the aluminum-containing magnetism can be obtained. Sintering with this material makes it possible to create a new aluminum alloy that can be attached to a magnet, etc., and is currently in the field of materials. New materials can be provided. It is possible to provide breakthrough characteristics to industrial appliances, home appliances, and products used in the office equipment industry.

In the present invention, fine powder of pure aluminum is used. Pure aluminum means aluminum composed of aluminum produced by a normal manufacturing method and unavoidable impurities.
As the fine powder of pure aluminum, aluminum fine powder obtained by an ordinary production method is used. For example, an Australian ECKA granules company can be mentioned. The aluminum fine powder can be obtained by re-particulating aluminum fine powder particles produced by a spraying method.
The purity is 99.7% by weight or more of aluminum, 0.10% by weight or less of silicon, 0.20% by weight or less of iron, and 0.02% by weight or less of other components.

  According to Coulter LS130 laser diffraction, the particle size distribution of the aluminum fine powder was a maximum particle size of 100 μm, and 90% or more was 60 μm or less. The diffraction results are shown in FIG.

In the present invention, ferrite fine powder containing inevitable impurities is used.
The average particle diameter of ferrite is 1.8 μm.

  Mechanical alloying of pure aluminum and ferrite. The weight ratio of the powdery pure aluminum and ferrite of pure aluminum and ferrite when performing mechanical alloying is 90 to 50:10 to 50. By maintaining this weight ratio, it is possible to obtain a state in which aluminum is sufficiently adsorbed on the ferrite.

Mechanical alloying refers to a process in which the mixture of pure aluminum and ferrite of the above-mentioned weight ratio is pulverized by mechanical means using a planetary ball mill, a vibration ball mill, a high-speed rotating ball mill or the like and simultaneously subjected to a mechanochemical reaction.
In the present invention, an 8000 type vibration type ball mill was adopted by SPEX, USA. In operation, 1425 rpm which is the rotation speed described in the catalog was adopted. This condition is a normal operating condition. Even when other models are used, it can be performed according to the normal operating conditions of each model.

The results of measuring the hardness of the ferrite, pure aluminum and ferrite mixture mechanically alloyed for 2 to 8 hours are shown in FIG. The time can take more than 8 hours. This is a matter to proceed by examining the content that can be obtained.
In mechanical alloying of a pure aluminum and ferrite mixture, the Vickers hardness of the resulting mixture is highest when the weight ratio is 50:50 (indicated by ▲ for 52, 54, 58 AlFR). Next, when the weight ratio is 70:30 (indicated by ● in the case of 32, 34, 38 AlFR), the Vickers hardness is the next highest. When the weight ratio is 90:10 (indicated by ▪ for 12, 14, 18 AlFR), the resulting mixture has the lowest Vickers hardness.
Pure aluminum (indicated by ◆) has the lowest Vickers hardness.
Ferrite (indicated by ▼) indicates that the Vickers hardness is lower than ferrite and pure aluminum and ferrite mixtures.
In view of the results for pure aluminum and ferrite, it was unexpected that mechanical alloying of a mixture of pure aluminum and ferrite could give high Vickers hardness results.
10 mass% ferrite 90 mass% aluminum Vickers hardness 8 hours treatment
150HV
30 mass% Ferrite 70 mass% Aluminum Vickers hardness 8 hours treatment
190HV
50 mass% ferrite 50 mass% aluminum Vickers hardness 8 hours treatment
275HV
Pure ferrite Vickers hardness 8 hours treatment
80HV
With pure alloy alone, mechanical alloying results in a decrease in hardness over time. The effect of adding ferrite to pure aluminum can be confirmed.

  From the above results, it was found that pure aluminum and ferrite mixture with improved Vickers hardness compared to the original Vickers hardness of pure aluminum and ferrite can be obtained by mechanical alloying of powdered pure aluminum and ferrite. It was. As specific numerical values, numerical values between 150 HV and 275 HV are confirmed (FIG. 2).

  Changes in saturation magnetic flux density and coercive force due to mechanical alloying of ferrite and pure aluminum and ferrite mixture are as shown in FIG.

Changes in saturation magnetic flux density due to mechanical alloying of ferrite and pure aluminum and ferrite mixture are as follows.
When mechanically alloying a pure aluminum and ferrite mixture, the case where the weight ratio is 50:50 (indicated by ▲ in the case of 52, 54, 58 AlFR) is high. Next, when the weight ratio is 70:30 (indicated by ● in the case of 32, 34, and 38 AlFR), the transition is the next highest. When the weight ratio is 90:10 (indicated by ▪ in the case of 12, 14, 18 AlFR), the transition is lowest.
In the case of pure ferrite (indicated by ▼), it is higher than the highest case.
It shows that the mechanical alloying is not very affected by time.
It shows that the saturation magnetic flux density of pure ferrite (indicated by ▼) is higher than that of pure aluminum and ferrite mixture.
Pure ferrite 8 hours later Saturation magnetic flux density 0.3T

50 mass% ferrite 50 mass% aluminum
8 hours later Saturation magnetic flux density 0.1T
30 mass% ferrite 70 mass% aluminum
8 hours later Saturation magnetic flux density 0.05T
10 mass% ferrite 90 mass% aluminum
After 8 hours of treatment, saturation magnetic flux density 0.02T

Changes in the holding force due to mechanical alloying of pure ferrite and a mixture of pure aluminum and ferrite are as follows.
In mechanical alloying of pure aluminum and ferrite mixture, when the weight ratio is 50:50 (indicated by Δ in the case of 52, 54, 58 AlFR), it stays relatively low in the case of 2 hours treatment, and is 8 hours. After the lapse of time, the mixture is in the highest state.
Next, when the weight ratio is 70:30 (indicated by ○ for 32, 34, and 38 AlFR), the mixture starts from the lowest state as a result of processing for 2 hours, and becomes the highest state after 4 hours. After 8 hours, the state becomes the next highest when the weight ratio is 50:50.
And in the case of a mixture when the weight ratio is 90:10 (indicated by □ in the case of 12, 14, 18 AlFR), the mechanical alloying is 2 hours, which is the highest among the three types of mixture, and thereafter , Has been in the lowest state.
The holding power is the highest in the case of pure ferrite. The holding power in the case of 50 mass% ferrite 50 mass% aluminum is the next highest.
In the case of 10 mass% ferrite and 90 mass% aluminum, the holding power is the lowest.
The mechanical alloying weight ratio of pure aluminum and ferrite mixture is 50:50, and the weight ratio of 90:10 is the lowest.
The holding force when mechanically alloying only pure ferrite is higher than the holding force when mechanically alloying pure aluminum and ferrite mixture.
Pure ferrite 8 hours later Holding power 11kA / m
50 mass% ferrite 50 mass% aluminum
8 hours later Holding power 5kA / m
30 mass% ferrite 70 mass% aluminum
8 hours later Holding power 4kA / m
10 mass% ferrite 90 mass% aluminum
8 hours holding power 3kA / m

Sintering is performed using a discharge plasma sintering method in a state where the Vickers hardness obtained by mechanical alloying of the pure aluminum and ferrite mixture is improved.
An apparatus for sintering a mixture obtained by mechanically alloying a pure aluminum and ferrite mixture is shown in FIG.
A mixture 1 obtained by mechanically alloying a pure aluminum and ferrite mixture is filled in a mold 21 and set in a discharge plasma sintering apparatus, and then sintered by a discharge plasma sintering method.

  The discharge plasma sintering apparatus includes a vacuum chamber 20, a pair of upper and lower pressure rams 24 and 25, a sintering power source 32 that generates a pulse voltage, and a hydraulic pressure press that drives the pressure rams 24 and 25 up and down. It has the drive mechanism 33 and the control part 31 which controls these.

The molding die 21 charged with the mechanically alloyed mixture 1 of the pure aluminum and ferrite mixture is set between the pressure rams 24 and 25 in the vacuum chamber 20.
The inside of the vacuum chamber 20 is degassed by the vacuum pump 22, and sintering is performed in a vacuum state (reduced pressure state) or in the vacuum chamber 20 with an inert gas atmosphere.
As a result, oxygen, nitrogen, water, etc. in the vacuum chamber 20 react with highly reactive components contained in the sintered object of the pure aluminum and ferrite mixture 1 to adversely affect the sintered body. Can be avoided.

  The control unit 31 controls the output of the sintering power supply 32 so that the material temperature detected by a temperature sensor (thermocouple) (not shown) installed in the molding die 21 matches a preset temperature increase curve. . Further, the control unit 31 controls the driving of the pressurization drive mechanism 33 and the vacuum pump 22.

  The pair of upper and lower first pressing elements 26 and second pressing elements 27 are fixed to the pressurizing rams 24 and 25, respectively, and are fed by power supply terminals (not shown) provided in the pressurizing rams 24 and 25. It is electrically connected to the power source 32 for sintering. The pressurizing drive mechanism 33 is operated to move the pressurizing rams 24 and 25 in directions approaching each other, and the first presser 26 and the second presser 27 fixed to the pressurizing rams 24 and 25 are finely powdered pure aluminum and ferrite. Compress mixture 1.

  It is preferable to interpose heat insulating materials 28 and 29 between the green compact of the fine powder pure aluminum and ferrite mixture 1 and the first pressing element 26 and the second pressing element 27, respectively. Thereby, when an electric current concentrates on the 1st presser 26 or the 2nd presser 27, from the heated 1st presser 26 or the 2nd presser 27 to the green compact of a fine powder pure aluminum and a ferrite mixture Heat diffusion is blocked, preventing local heating and high temperatures. Therefore, the temperature during sintering of the green compact of the fine powder pure aluminum and the ferrite mixture 1 is made uniform, and a homogeneous and high-quality sintered body can be obtained.

  Furthermore, it is preferable to interpose a carbon sheet between the heat insulating materials 28 and 29, the green compact of the pure aluminum and ferrite mixture 1, the first pressing element 26, and the second pressing element 27.

  In the discharge plasma sintering, a pulse voltage is applied through the first pressing element 26 and the second pressing element 27 to heat the compression energization system. When the temperature of the sintering system reaches a predetermined temperature, the temperature is maintained for a certain time to form a composite.

The sintering temperature can be appropriately adopted. In this invention, it carried out in the range of 673-1073K. Usually, sintering temperature can be performed in the range of about 600-1200K. If it is 600K or less, the effect of sintering may not be obtained sufficiently. If it exceeds 1200K, sintering may proceed too much and may not be appropriate. Sintering the mechanically alloyed mixture of pure aluminum and ferrite mixture under conditions where the sintering temperature and processing time were changed with the recognition that the sintering temperature should not decompose the ferrite powder, A sintered body is obtained.
The processing time is required from about 20 minutes to about 1 hour.
If the pressure was in the range of 40-60 MPa, there was no problem and the pressure was about 49 MPa.
With respect to the sintered body when the mixed powder is solidified and formed by a discharge plasma sintering apparatus, the state of change in Vickers hardness by changing the sintering time is as shown in FIG. Moreover, the result of having measured the sintering temperature at the time of processing a mixed powder into a bulk material with a discharge plasma sintering apparatus, the saturation magnetic flux density, and the retention strength is as showing in FIG.

The measurement results of Vickers hardness are as follows.
The Vickers hardness according to the change of the sintering time of the mixture showing the result when the 10 mass% ferrite 90 mass% aluminum mixture is sintered is as follows.

The relationship between the sintering temperature and the saturation magnetic flux density in the case where 10 mass% ferrite 90 mass% aluminum is mechanically alloyed for 4 hours is as follows.
The relationship between the sintering temperature and the saturation magnetic flux density is 0.028T at the sintering temperature of 773K, the maximum is about 0.005T at 873 to 973K, and is 0 at 1073K.

  When mechanically alloyed with 10 mass% ferrite and 90 mass% aluminum for 4 hours, the results of the holding force are as follows: 8 kA / m at 673 K, 6 kA / m at 973 K, and 92 kA / m at 1073 K, the maximum.

  When the sintering temperature is determined by measuring the sintering temperature, the saturation magnetic flux density, and the holding force, numerical values for the saturation magnetic flux density and the holding force can be obtained, and the structural material having magnetism can be clarified. The saturation magnetic flux density and coercive force when 873 to 973K are employed are apparent from FIG. In this case, the saturation magnetic flux density and the holding force indicate that the structure material has magnetism.

Specific examples of the present invention are shown below as examples. The present invention is not limited by this example.
The measuring method of Vickers hardness which is a high specific strength aluminum functional material having magnetism obtained in the present invention is as follows.
The Vickers hardness was measured by polishing the surface of the solidified material, then using a Vickers hardness tester to perform a test load of 1 kg, a holding time of 15 seconds, and measuring 7 times to obtain an average value thereof.
The method for measuring the saturation magnetic flux density and the coercive force are as follows.
The measurement of the saturation magnetization Ms and the coercive force Hc of the sample Tokyo Kogyo Co., Ltd. of vibrating sample magnetometer VSM5 ^- 15: Using the (VSM Vibrating Sample Magnetometer). It was determined by measuring MH curves in a magnetic field of 800 kA / m and 40 kA / m. The vibrating sample magnetometer is a magnetic flux in a detection coil placed outside by vibrating a sample magnetized at pole piece intervals of an electromagnet up and down at a constant amplitude of about 80 Hz with an amplitude of about 0.1 to 0.2 nm. And an induced electromotive force is generated in proportion to the magnetization value of the sample due to the electromagnetic induction phenomenon. The magnetization value of the sample can be measured by the magnitude of this induced electromotive force. During measurement, a magnetic field of 800 kA / m is applied to the powder Ni standard sample to calibrate the magnetization value. Further, at the time of measurement, the weight of each powder sample was set to about 5.0 ± 5% mg, and measurement was performed by attaching it to a sample holder between pole pieces of an electromagnet.
The VSM measurement of the SPS material was performed by processing the sample to 4 × 6 mm and a thickness of 1 mm, attaching it to the tip of a transparent rod, and attaching it to the sample holder between the pole pieces of the electromagnet.

(1) Preparation of raw material The purity of pure aluminum was 99.7% by weight or more of aluminum, 0.10% by weight or less of silicon, 0.20% by weight or less of iron, and 0.02% by weight or less of other components. .
The particle size distribution of the granules was a maximum particle size of 100 μm, and 90% or more was 60 μm or less. (FIG. 1).
The average particle diameter of the ferrite was 1.8 μm.

(2) Mechanical alloying The results of measuring the hardness of the mechanical alloying of ferrite, pure aluminum and ferrite mixture for 2 to 8 hours are shown in FIG.
In mechanical alloying of pure aluminum and ferrite mixture, when the weight ratio is 50:50, the resulting mixture has the highest Vickers hardness, and when it is 90:10, the resulting mixture has the lowest Vickers hardness. .
10 mass% ferrite 90 mass% aluminum Vickers hardness 8 hours treatment
150HV
30 mass% Ferrite 70 mass% Aluminum Vickers hardness 8 hours treatment
190HV
50 Mass% Ferrite 50 mass% Aluminum Vickers hardness 8 hours treatment
275HV
Pure ferrite Vickers hardness 8 hours treatment
80HV

The manufacturing method of mechanical milling and a sintered compact is as follows.
(1) A 10 mass% ferrite 90 mass% aluminum mixture was mechanically alloyed for 4 hours to obtain a mixture.
(2) Production of Sintered Body A 10 mass% ferrite 90 mass% aluminum mixture was mechanically alloyed for 4 hours, and the mixture was sintered at temperatures of 673K, 773K, 873K, 973K, and 1073K.
The measurement results of Vickers hardness are as shown in FIG.
The results for the case of mechanical alloying of 10 mass% ferrite 90 mass% aluminum for 4 hours are as follows.
It can be seen that sintered bodies up to sintering temperatures of 873K and 973K have the second highest Vickers hardness because alumina is produced, and can be used as a structural material.
The result is that the hardness is different between the upper side and the lower side of the SPS bulk material. The hard side is named hard side and the low hardness side is named soft side.
The results of the sintering temperature and the saturation magnetic flux density when mechanically alloyed with 10 mass% ferrite and 90 mass% aluminum for 4 hours are as shown in FIG.
The relationship between the sintering temperature and the saturation magnetic flux density is 0.028T at the sintering temperature 773K, the maximum is about 0.005T at 873K to 973K, and is 0 at 1073K.

  When mechanically alloyed with 10 mass% ferrite and 90 mass% aluminum for 4 hours, the results of the holding force are as follows: 8 kA / m at 673 K, 6 kA / m at 973 K, and 92 kA / m at 1073 K, the maximum.

It is a figure which shows the particle size distribution of powdery aluminum. The figure which measured hardness about the result of mechanically alloying a ferrite, pure aluminum, and a ferrite mixture. The figure which shows the relationship of the saturation magnetic flux density by mechanical alloying of ferrite, pure aluminum, and a ferrite mixture, and the relationship of coercive force. The figure which shows a discharge plasma sintering apparatus. The hardness measurement result of a sintered compact (bulk material) when the mixed powder is solidified and formed by a discharge plasma sintering apparatus. Measurement results of sintering temperature, saturation magnetic flux density and coercive force when the mixed powder is processed into a sintered body (bulk material) with a discharge plasma sintering apparatus.

1: Mechanical alloying product of fine powder pure aluminum and ferrite mixture or ferrite 20: Vacuum chamber 21: Molding die 22: Vacuum pump 24: Pressurization ram 25: Pressurization ram 26: First presser 27: First 2 presser 28: heat insulating material 29: heat insulating material 31: control unit 32: power source for sintering 33: pressure drive mechanism

Claims (6)

  A pure aluminum and ferrite mixture with improved hardness, obtained by mechanically alloying powdered pure aluminum and ferrite.   2. The pure aluminum / ferrite mixture with improved hardness according to claim 1, wherein a weight ratio of the powdery pure aluminum and ferrite is 90-50 to 10-50.   A method for producing a pure aluminum and ferrite mixture having improved hardness, characterized by mechanically alloying powdered pure aluminum and ferrite.   4. The method for producing a pure aluminum / ferrite mixture with improved hardness according to claim 3, wherein the weight ratio of the powdery pure aluminum and ferrite is 90-50 to 10-50.   An aluminum and ferrite sintered solidified product obtained by spark plasma sintering the pure aluminum and ferrite mixture having improved hardness according to claim 1 or 2.   A method for producing a solidified sintered body of aluminum and ferrite, characterized in that after the pure aluminum and ferrite mixture having improved hardness according to claim 3 or 4 is produced, discharge plasma sintering is performed.