Manufacturing method of iron-aluminum alloy

Abstract

To provide a manufacturing method of an iron aluminum alloy capable of manufacturing an iron aluminum alloy stably and inexpensively.SOLUTION: A manufacturing method of an iron aluminum alloy includes: a raw material melting step of heating, under an inert atmosphere, a crucible in which a raw material with an iron particle layer and an aluminum particle layer sequentially stored in layers is arranged inside to melt the raw material; and an alloy synthesis step of maintaining, under the inert atmosphere, a temperature of the raw material after the raw material melting step to synthesize an alloy of iron and aluminum. A stoichiometric ratio of the iron and aluminum of the raw material is 45-55:45-55.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing an iron-aluminum alloy, and more particularly to a method for producing an iron-aluminum alloy having giant magnetostrictive properties. [Background technology]

[0002] Iron-aluminum alloys (hereinafter sometimes referred to as "FeAl alloys") are machineable, exhibit large magnetostriction of about 30 to 130 ppm, and are made from inexpensive raw materials. As such, they are suitable as materials for magnetostrictive vibration power generators and actuators, and have been attracting attention in recent years.

[0003] Known methods for synthesizing an FeAl alloy include a powder sintering synthesis method as disclosed in Patent Document 1 and a melting synthesis method as disclosed in Non-Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2818860 [Non-patent literature]

[0005] [Non-Patent Document 1] Honda, On the magnetostatic strain of Fe-Al alloys and the new magnetostrictive alloy "Alfer", Journal of the Japan Institute of Metals, Vol.12, No.7-12, pp.1-6, 1948. Summary of the Invention [Problem to be solved by the invention]

[0006] However, in previous methods for producing FeAl alloys, manufacturing conditions that would result in a high rate of success in alloying had not been established, and there were cases in which the alloy was obtained in each processing batch but not in others. As a result, there was a problem that the low rate of success in alloying resulted in high manufacturing costs.

[0007] Therefore, an object of the present invention is to provide a method for producing an iron-aluminum alloy, which can produce the iron-aluminum alloy stably and inexpensively. [Means for solving the problem]

[0008] In order to solve the above problems, the method for producing an iron-aluminum alloy of the present invention includes a raw material melting step of heating a crucible containing a raw material having an iron particle layer and an aluminum particle layer stacked in sequence under an inert atmosphere to melt the raw material, and an alloy synthesis step of maintaining the temperature of the raw material after the raw material melting step under an inert atmosphere to synthesize an alloy of iron and aluminum, wherein the stoichiometric ratio of iron to aluminum in the raw material is 45-55:45-55.

[0009] The raw material melting step may be a step of melting the raw material only by heating without stirring.

[0010] The raw material may be a raw material consisting of only one layer of iron particles packed in the bottom of the crucible and one layer of aluminum particles packed in the iron particle layer.

[0011] The raw material may be a raw material in which a plurality of the iron particle layers and a plurality of the aluminum particle layers are alternately laminated.

[0012] The raw material iron particles may have a particle size of 150 μm to 500 μm, and the raw material aluminum particles may have a particle size of 150 μm to 250 μm. Effect of the Invention

[0013] The present invention can provide a method for producing an iron-aluminum alloy, which can stably and inexpensively produce an iron-aluminum alloy. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of a raw material 4 in a crucible 1 in which an iron particle layer 2 and an aluminum particle layer 3 are laminated in this order. [Diagram 2] 1 is a schematic cross-sectional view showing an alloy production apparatus in a state in which a crucible is installed inside which is placed a raw material in which an iron particle layer and an aluminum particle layer are laminated in that order. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of a method for producing an FeAl alloy will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0016] The method for producing an iron-aluminum alloy of the present invention includes a raw material melting step and an alloy synthesis step.

[0017] [Raw material melting process] In this step, the crucible containing the raw materials is heated under an inert atmosphere to melt the raw materials.

[0018] <Raw materials> The raw materials used are iron particles and aluminum particles, and the raw materials in a state in which an iron particle layer filled with iron particles and an aluminum particle layer filled with aluminum particles are layered in sequence are melted in a crucible described below.

[0019] Fig. 1 shows a schematic cross-sectional view of raw material 4 in a state where an iron particle layer 2 and an aluminum particle layer 3 are layered in this order in a crucible 1. In the case of Fig. 1(a), raw material 4 is a raw material consisting of only one iron particle layer 2 packed in the bottom 1a of crucible 1 and one aluminum particle layer 3 packed in the iron particle layer. In the present invention, raw material 4 can be obtained by arranging the iron particle layer 2 and the aluminum particle layer 3 in this manner.

[0020] 1(b) and (c), the raw material 4 is a raw material in which a plurality of iron particle layers 2 and a plurality of aluminum particle layers 3 are alternately laminated. In the present invention, the raw material 4 can be obtained by arranging the iron particle layers 2 and the aluminum particle layers 3 in this manner.

[0021] Furthermore, in the present invention, it is important that the raw material is in a state in which an iron particle layer and an aluminum particle layer are laminated in that order, and the particle size of the raw material is not limited. For example, a raw material in which the iron particles have a particle size in the range of 150 μm to 500 μm and the aluminum particles have a particle size in the range of 150 μm to 250 μm can be used.

[0022] (stoichiometric ratio of iron and aluminum) In order to produce an iron-aluminum alloy, the ratio of iron to aluminum is important. In the present invention, it is ideal to set the stoichiometric ratio of iron and aluminum in the raw materials to Fe:Al=50:50, but if this is difficult, it is possible to produce an iron-aluminum alloy in the range of Fe:Al=45-55:45-55.

[0023] (crucible) The crucible 1 is preferably made of a material that has low chemical reactivity with iron, aluminum, and iron-aluminum alloys and a melting point higher than that of the raw material. Examples of crucibles that satisfy these conditions include alumina crucibles, and magnesia crucibles, boron nitride crucibles, etc. may also be used.

[0024] (Heating conditions) In the raw material melting process, the raw materials are heated in an inert atmosphere such as an argon gas atmosphere or a nitrogen gas atmosphere to prevent the raw materials from oxidizing. In addition, to melt iron and aluminum, the raw materials must be heated to above their melting points, for example, to about 1550°C.

[0025] The raw material melting step can be a step of melting the raw material only by heating without stirring. By melting the raw material in a state where the iron particle layer and the aluminum particle layer are laminated in order by heating only, it is possible to reliably produce an iron-aluminum alloy. In the raw material melting step, for example, if the raw material is melted with electromagnetic stirring or a physical tool is inserted into the raw material molten liquid to stir the raw material, there is a risk that iron and aluminum will not be alloyed.

[0026] [Alloy synthesis process] This process is a process for synthesizing an alloy of iron and aluminum by maintaining the temperature of the raw materials after the raw material melting process in an inert atmosphere. For example, the temperature of the raw materials can be maintained at about 1550°C in an inert atmosphere such as an argon gas atmosphere or a nitrogen gas atmosphere to alloy the iron and aluminum. The time for which the raw material temperature is maintained is the time until the iron and aluminum are alloyed, and can be, for example, about 3 hours to 20 hours, depending on the amount of raw materials.

[0027] (Other processes) The method for producing the iron-aluminum alloy of the present invention may include other steps in addition to the raw material melting step and the alloy synthesis step, such as a cooling step for cooling the iron-aluminum alloy after the alloy synthesis step, and a removal step for removing the alloy from the crucible after the cooling step.

[0028] (Alloy manufacturing equipment 100) Hereinafter, an alloy production apparatus 100 will be described as an example of an apparatus capable of producing an FeAl alloy based on the production method of the present invention. Fig. 2 is a cross-sectional schematic diagram showing the alloy production apparatus 100 in a state in which a crucible 1 is installed in which a raw material 4 having an iron particle layer 2 and an aluminum particle layer 3 laminated in that order is placed.

[0029] In the alloy manufacturing apparatus 100 shown in FIG. 2, a cylindrical carbon resistance heater 5 is disposed inside a cylindrical insulating material 6, forming a hot zone. The temperature in the hot zone can be controlled by appropriately adjusting the power input to the resistance heater 5. The crucible 1 can be placed in the hot zone by placing the crucible 1 on the crucible base 8. The crucible 1 with the open upper side may be covered with a dust-fall prevention lid (not shown) to prevent dust from falling into the crucible 1. The alloy manufacturing apparatus 100 has a chamber 7 disposed outside the insulating material 6, and the chamber 7 can be adjusted to an inert atmosphere by introducing an inert gas such as argon or nitrogen. A thermocouple (not shown) for measuring the temperature of the bottom of the crucible 1 is disposed on the crucible base 8, and the temperature of the raw material 4 in the crucible 1 can be indirectly grasped by measuring the temperature of the crucible 1 with the thermocouple.

[0030] (Production example using alloy production apparatus 100) Hereinafter, as an example of the manufacturing method of the present invention, a manufacturing example using the alloy manufacturing apparatus 100 will be described.

[0031] A raw material 4 is placed in a crucible 1 as shown in Fig. 1. In Fig. 2, the raw material 4 having an iron particle layer 2 and an aluminum particle layer 3 laminated thereon is placed in the crucible 1 in the manner shown in Fig. 1(a).

[0032] Next, the crucible 1 is placed on the crucible base 8, and an inert gas such as argon or nitrogen is flowed into the chamber 7 to prepare the chamber 7 in an inert atmosphere.

[0033] Next, the heater 5 is operated to increase the temperature of the crucible 1 and perform the raw material melting step and the alloy synthesis step. After the raw material 4 is melted and the alloy synthesis is completed, the output of the heater 5 is reduced to solidify all the melt.

[0034] Next, after confirming that the temperature inside the chamber 7 has reached approximately room temperature, the crucible 1 containing the synthesized FeAl alloy is removed from the crucible base 8, and the synthesized FeAl alloy is then taken out from the crucible 1. EXAMPLES

[0035] Examples of the present invention will be specifically described below with reference to comparative examples, but the present invention is not limited to these examples.

[0036] [Example 1] First, particulate Fe raw material (purity: 99.9%) with a particle size of 150 μm to 500 μm and particulate Al raw material (purity: 99.99%) with a particle size of 150 μm to 250 μm were weighed out so that the stoichiometric ratio of iron to aluminum was 50:50.

[0037] Then, in a crucible 1 made of dense alumina with an inner diameter of 12 mm and a height of 100 mm, the entire amount of the Fe raw material prepared in advance was filled into the bottom of the crucible 1a to form an iron particle layer 2, and the entire amount of the Al raw material prepared was filled on top of the iron particle layer 2 to form an aluminum particle layer 3, thereby forming a raw material 4 (Figure 1(a)).

[0038] Next, the crucible 1 filled with the raw material 4 was placed on a crucible base 8 made of porous alumina, as shown in FIG.

[0039] Next, argon gas was introduced into the chamber 7 of the alloy manufacturing apparatus 100, and the inside of the chamber 7 was adjusted to an inert atmosphere at atmospheric pressure. In addition, the temperature of the raw material 4 was set to 1550°C by the carbon resistance heater 5, and the raw material 4 was heated from room temperature to 1550°C over 12 hours to melt the raw material 4 (raw material melting step). After the temperature rise was completed and the temperature in the synthesis furnace reached 1550°C, the temperature was maintained for 6 hours to synthesize the FeAl alloy (alloy synthesis step). Note that in the raw material melting step and the alloy synthesis step, the molten raw material 4 was not stirred by inserting a physical jig into it, nor was it stirred electromagnetically.

[0040] After the alloy synthesis process, the output of the resistance heater 5 was stopped over 30 minutes, and the crucible 1 was allowed to cool naturally to room temperature after the output was stopped. Thereafter, the sample was collected from the crucible 1. It took 8 hours from the stop of the output of the resistance heater 5 until the temperature of the crucible 1 reached 75°C.

[0041] The sample taken out of the crucible 1 was a FeAl alloy with a diameter of 12 mm and a length of 25 mm. The obtained FeAl alloy was cut and the inside of the alloy was observed, but no abnormalities were found that could be confirmed by the naked eye. In addition, the cross section of the sample was observed by SEM-EDX, and it was confirmed that iron and aluminum were uniformly distributed.

[0042] [Example 2] 1(b), the method of charging the raw materials into the crucible 1 was as follows: half of the Fe raw material prepared in advance was filled into the bottom of the crucible 1 to form an iron particle layer 2, half of the Al raw material prepared was filled on the iron particle layer 2 to form an aluminum particle layer 3, the remaining half of the Fe raw material prepared was filled on the aluminum particle layer 3 to form an iron particle layer 2, and the remaining half of the Al raw material prepared was filled on the iron particle layer 2 to form an aluminum particle layer 3, thereby forming a raw material 4. Aside from the aspect of raw material 4, the FeAl alloy was produced in the same manner as in Example 1.

[0043] After the synthesis operation was completed, the sample taken out of the crucible 1 was a FeAl alloy with a diameter of 12 mm and a length of 25 mm. The obtained FeAl alloy was cut and the inside of the alloy was observed, but no abnormalities were found that could be confirmed by the naked eye. The cross section of the sample was also observed by SEM-EDX, and it was confirmed that iron and aluminum were uniformly distributed.

[0044] [Reference example 1] Instead of forming the iron particle layer 2 and the aluminum particle layer 3 on the raw material 4, the entire amount of the Fe raw material and the entire amount of the Al raw material prepared in advance were uniformly mixed in a SUS container to prepare a mixture, and then the mixture was filled into the crucible 1. Otherwise, the FeAl alloy was produced in the same manner as in Example 1.

[0045] After the synthesis operation was completed, the sample taken out of the crucible 1 was a FeAl alloy with a diameter of 12 mm and a length of 25 mm. The obtained FeAl alloy was cut and the inside of the alloy was observed, but no abnormalities were found that could be confirmed by the naked eye. The cross section of the sample was also observed by SEM-EDX, and it was confirmed that iron and aluminum were uniformly distributed.

[0046] [Comparative Example 1] The method of charging the raw materials into the crucible 1 was such that the entire amount of the Al raw material prepared in advance was charged into the bottom of the crucible 1 to form the aluminum particle layer 3, and the entire amount of the Fe raw material prepared was charged onto the aluminum particle layer 3 to form the iron particle layer 2. That is, the iron particle layer 2 was laminated on the aluminum particle layer 3. Otherwise, the manufacturing work of the FeAl alloy was carried out in the same manner as in Example 1.

[0047] After the synthesis was completed, the sample was taken out of the crucible 1. The iron particle layer 2 and the aluminum particle layer 3 were found to have been solidified in layers and were not alloyed.

[0048] Table 1 shows the test results of Examples 1 and 2, Reference Example 1 and Comparative Example 1.

[0049] [Table 1]

[0050] In the cases of Examples 1 and 2 and Reference Example 1, a FeAl alloy could be produced, whereas in the case of Comparative Example 1, alloying did not occur and a FeAl alloy could not be produced.

[0051] (summary) From the above, it is clear that the present invention can provide a method for producing an iron-aluminum alloy, which can stably and inexpensively produce an iron-aluminum alloy. [Explanation of symbols]

[0052] 1 crucible 2. Iron particle layer 3 Aluminum particle layer 4 Raw materials 5 Heater 6. Insulation 7. Chambers 8 Crucible pedestal 100 Alloy manufacturing equipment

Claims

1. A method for producing a sintered body comprising the steps of: placing a raw material having an iron particle layer and an aluminum particle layer laminated thereon in a crucible; a raw material melting step of heating the crucible under an inert atmosphere to melt the raw material; an alloy synthesis step of synthesizing an alloy of iron and aluminum by maintaining the temperature of the raw materials after the raw material melting step in an inert atmosphere; Including, The stoichiometric ratio of iron and aluminum in the raw material is 45-55:45-55; Manufacturing method of iron-aluminum alloy.

2. The method for producing an iron-aluminum alloy according to claim 1 , wherein the raw material melting step is a step of melting the raw material only by heating without stirring.

3. 3. The method for producing an iron-aluminum alloy according to claim 1, wherein the raw material is a raw material consisting of only one layer of iron particles filled at the bottom of the crucible and one layer of aluminum particles filled in the iron particle layer.

4. The method for producing an iron-aluminum alloy according to claim 1 or 2, wherein the raw material is a raw material in which a plurality of the iron particle layers and a plurality of the aluminum particle layers are alternately laminated.

5. The method for producing an iron-aluminum alloy according to any one of claims 1 to 4, wherein the raw material iron particles have a particle size of 150 μm to 500 μm, and the raw material aluminum particles have a particle size of 150 μm to 250 μm.

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