WO2022065656A1 - Procédé de fabrication d'un stratifié magnétoélectrique sur lequel est empilée une électrode magnétostrictive poreuse, et stratifié magnétoélectrique fabriqué au moyen dudit procédé - Google Patents

Procédé de fabrication d'un stratifié magnétoélectrique sur lequel est empilée une électrode magnétostrictive poreuse, et stratifié magnétoélectrique fabriqué au moyen dudit procédé Download PDF

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WO2022065656A1
WO2022065656A1 PCT/KR2021/009594 KR2021009594W WO2022065656A1 WO 2022065656 A1 WO2022065656 A1 WO 2022065656A1 KR 2021009594 W KR2021009594 W KR 2021009594W WO 2022065656 A1 WO2022065656 A1 WO 2022065656A1
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magnetostrictive
porous
layer
piezoelectric
laminate
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PCT/KR2021/009594
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English (en)
Korean (ko)
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양수철
노병일
송만성
장준하
박재한
유태규
김지수
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동아대학교 산학협력단
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N35/00—Magnetostrictive devices
    • H10N35/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/05—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes
    • H10N30/057—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes by stacking bulk piezoelectric or electrostrictive bodies and electrodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N35/00—Magnetostrictive devices

Definitions

  • the present invention relates to a method for manufacturing a magneto-electric laminate in which porous magnetostrictive electrodes are laminated, and to a magneto-electric laminate manufactured therefrom.
  • Magnetostriction is induced in the magnetostriction phase according to the change of the external magnetic field, including the magnetostrictive phase and the piezoelectric phase, and the strain caused by the induced magnetostriction is transferred to the piezoelectric phase and mechanical stress is applied to the piezoelectric phase. It has magnetoelectric characteristics that can obtain an output voltage by
  • the magnetoelectric complex has been applied to various fields such as an energy harvesting device, a high-sensitivity magnetic field sensor, an actuator, a memory device, and a drug delivery system due to the above-described magnetoelectric properties.
  • a magnetoelectric laminate including a piezoelectric layer having piezoelectricity and a magnetostrictive layer laminated on the piezoelectric layer and having magnetostriction is used.
  • the magnetoelectric laminate according to the prior art has been mainly manufactured by bonding a piezoelectric layer and a magnetostrictive layer using an epoxy adhesive.
  • the magnetoelectric laminate manufactured according to the prior art uses an epoxy adhesive
  • the cost for providing the epoxy adhesive and a process for applying and curing the epoxy adhesive must be accompanied, as well as the applied epoxy adhesive
  • magnetostriction of the magnetostrictive layer is prevented due to the strength of the epoxy adhesive, resulting in strain transmission loss to the piezoelectric layer, and thus the generated output voltage drops.
  • An object of the present invention is to solve the above problems, and a porous magnetostrictive layer and a piezoelectric layer do not need to be accompanied by a process for providing a separate electrode as well as not using an epoxy adhesive in the manufacture of a magnetoelectric laminate
  • An object of the present invention is to provide a method for manufacturing a magneto-electric laminate in which porous magnetostrictive electrodes are laminated, which can produce a magneto-electric laminate by hot pressing, and a magneto-electric laminate manufactured by the method.
  • a method for manufacturing a magnetoelectric laminate in which a porous magnetostrictive electrode is laminated comprising the steps of preparing a piezoelectric layer made of a piezoelectric material, preparing a porous magnetostrictive layer having magnetostrictive properties , laminating a porous magnetostrictive layer on a piezoelectric layer to prepare a magnetoelectric laminate, applying heat and pressure to the magnetoelectric laminate, and polarizing the magnetoelectric laminate.
  • a magneto-electric laminate in which a porous magnetostrictive electrode is laminated is a piezoelectric layer made of a piezoelectric material, a plurality of pores are formed therein, and the piezoelectric layer is laminated on at least one surface of the piezoelectric layer. It is characterized in that it includes a porous magnetostrictive layer inserted to a predetermined depth in the layer, and has a structure in which the piezoelectric layer is filled in pores as the porous magnetostrictive layer is inserted into the piezoelectric layer to a predetermined depth.
  • the method for manufacturing a magneto-electric laminate in which porous magnetostrictive electrodes are stacked according to an embodiment of the present invention according to the above configuration can expect the following effects.
  • the strain transmission loss due to the cured epoxy adhesive does not occur, and the strain transmission from the porous magnetostrictive layer to the piezoelectric layer can be effectively achieved.
  • a porous magnetostrictive layer used as a magnetostrictive phase can be used as an electrode without a separate electrode, the process and cost for providing a separate electrode do not occur, thereby improving economic efficiency and productivity in manufacturing a magnetoelectric laminate can be further improved.
  • FIG. 1 is a view for explaining a magnetoelectric laminate in which a porous magnetostrictive layer is stacked according to an embodiment of the present invention.
  • FIG. 2 is a flowchart illustrating a method of manufacturing a magneto-electric laminate in which a porous magnetostrictive layer is laminated according to an embodiment of the present invention.
  • 3A to 3B are images obtained by analyzing the surface of the magnetoelectric accumulation body according to Examples 1 and 2 using a scanning electron microscope.
  • 4A to 4B are images obtained by analyzing the cross-sections of the magnetoelectric laminates according to Examples 1 and 2 using EDS.
  • 5A to 5C are graphs illustrating output voltages generated according to a magnetic field applied to the magneto-electric laminate 10 according to Examples 1 to 2 and Comparative Examples.
  • a method for manufacturing a magnetoelectric laminate in which a porous magnetostrictive electrode is laminated comprising the steps of: preparing a piezoelectric layer made of a piezoelectric material; preparing a porous magnetostrictive layer having magnetostrictive properties; manufacturing a magnetoelectric laminate by laminating a porous magnetostrictive layer on the piezoelectric layer, and applying heat and pressure to the magnetoelectric laminate; and polarizing the magnetoelectric laminate.
  • the magnetoelectric laminate is manufactured by laminating the porous magnetostrictive layer on the piezoelectric layer, and a pressure of 25 to 35 MPa is applied to the magnetoelectric laminate at a temperature of 130 to 150° C. for 25 to 35 minutes. will be applied while
  • the preparing of the porous magnetostrictive layer is to prepare a porous magnetostrictive layer including at least one selected from a ferromagnetic metal, a ferritic ceramics, a magnetostrictive alloy, and a magnetic shape memory alloy.
  • Preparing the piezoelectric layer may include: preparing a piezoelectric solution by adding a piezoelectric material to a solvent and mixing; manufacturing a film having a predetermined thickness using the piezoelectric solution and drying the film to prepare a piezoelectric layer; and heat-treating the piezoelectric layer.
  • the step of preparing the piezoelectric solution at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, polyvinylidene fluoride-tetrafluoroethylene and triglycine sulfate in 100 parts by weight of the solvent 10 to 30 parts by weight of the piezoelectric material containing
  • the preparing of the piezoelectric layer may further include applying a pressure of 25 to 35 MPa to the piezoelectric layer at a temperature of 130 to 150° C. for 25 to 35 minutes after the heat treatment.
  • the porous magnetostrictive layer prepared in the step of preparing the porous magnetostrictive layer has a plurality of pores formed therein and has a porosity of 50 to 99%.
  • the porous magnetostrictive layer prepared in the step of preparing the porous magnetostrictive layer has a plurality of pores formed therein, and the average diameter of the plurality of pores is 10 to 500 ⁇ m.
  • a magneto-electric laminate in which a porous magnetostrictive electrode is laminated is a piezoelectric layer made of a piezoelectric material, a plurality of pores are formed therein, and the piezoelectric layer is laminated on at least one surface of the piezoelectric layer. It is characterized in that it includes a porous magnetostrictive layer inserted to a predetermined depth in the layer, and has a structure in which the piezoelectric layer is filled in pores as the porous magnetostrictive layer is inserted into the piezoelectric layer to a predetermined depth.
  • the volume fraction of the porous magnetostrictive layer with respect to the total volume is 0.3 to 0.7.
  • the piezoelectric layer is made of the piezoelectric material, which is at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, polyvinylidene fluoride-tetrafluoroethylene, and triglycine sulfate.
  • the piezoelectric material is polyvinylidene fluoride having a weight average molecular weight of 180000 to 700000 g/mol.
  • the porous magnetostrictive layer is made of at least one selected from a ferromagnetic metal, a ferritic ceramics, a magnetostrictive alloy, and a magnetic shape memory alloy.
  • the method of manufacturing a magneto-electric laminate in which porous magnetostrictive electrodes are stacked according to an embodiment of the present invention includes time-series performing steps for manufacturing a magneto-electric laminate in which porous magnetostrictive electrodes are stacked according to another embodiment of the present invention do.
  • the method of manufacturing a magnetoelectric laminate in which porous magnetostrictive electrodes are stacked includes a piezoelectric layer preparation step (S100), a magnetostrictive layer preparation step (S200), a lamination step (S300) and and a polarization step (S400).
  • a magnetoelectric laminate 10 in which porous magnetostrictive electrodes are stacked includes a piezoelectric layer 100 and a porous magnetostrictive layer 200 .
  • a piezoelectric layer 100 made of a piezoelectric material is prepared (S100).
  • the piezoelectric layer 100 prepared in the piezoelectric layer preparation step (S100) is not limited as long as it is made of a piezoelectric material having piezoelectricity, but preferably, it may be a polymer having piezoelectricity, for example, polyvinylidene fluoride. , polyvinylidene fluoride-trifluoroethylene, polyvinylidene fluoride-tetrafluoroethylene, and may be one comprising at least one selected from triglycine sulfate.
  • the thickness of the piezoelectric layer 100 prepared in the piezoelectric layer preparation step S100 may be 100 to 1000 ⁇ m.
  • the thickness of the piezoelectric layer 100 prepared in the piezoelectric layer preparation step (S100) is less than 100 ⁇ m, the thickness of the piezoelectric layer 100 is thin and the mechanical strength of the magnetoelectric laminate 10 may be reduced, and a lamination step to be described later
  • the porous magnetostrictive layer 200 is laminated on the upper surface and the lower surface of the piezoelectric layer 100 in (S300)
  • the distance between the porous magnetostrictive layer 200 laminated on the upper and lower surfaces is too close, so that the magnetoelectricity in the polarization step (S400)
  • an electric field is applied to the laminate 10 , electricity flows between the porous magnetostrictive layers 200 , so that the dipoles in the magneto-electric composite 10 are not effectively aligned, so that the magnetoelectric properties of the magneto-electric laminate 10 are reduced.
  • the piezoelectric layer 100 included in the magnetoelectric laminate 10 obtained in the lamination step S300 is a porous element. Magnetoelectricity of the magnetoelectric laminate 10 manufactured according to the embodiment of the present invention by applying excessive strain to the piezoelectric layer 100 during magnetostriction of the porous magnetostrictive layer 200 because the volume of the strain layer 200 is too large characteristics may be reduced.
  • the thickness of the piezoelectric layer 100 prepared in the piezoelectric layer preparation step (S100) exceeds 1000 ⁇ m, the thickness of the piezoelectric layer 100 is too thick, and even if the porous magnetostrictive layer 200 self-deforms, the piezoelectric layer 100 ), the strain may not be uniformly transmitted to the magneto-electrical properties of the magneto-electric laminate 10 may be deteriorated.
  • the piezoelectric layer 100 prepared in the piezoelectric layer preparation step (S100) may include polyvinylidene fluoride having a weight average molecular weight of 180,000 to 700,000 g/mol.
  • the molecular weight of polyvinylidene fluoride constituting the piezoelectric layer 100 is less than 180,000 g/mol, the molecular weight is low and the thermal stability of the piezoelectric layer 100 in the lamination step (S300) is lowered, and heat is applied to the piezoelectric layer 100 It may be excessively melted when applied, and if the molecular weight exceeds 700,000 g/mol, the thermal stability of the piezoelectric layer 100 is too high, so that even when heat and pressure are applied in the lamination step (S300), the porous magnetostrictive layer 200 forms the piezoelectric layer 100 ), the magnetoelectric properties of the magneto-electric laminate 10 may not be sufficiently penetrated.
  • the piezoelectric layer preparation step S100 may include a piezoelectric solution preparation step S110 , a piezoelectric layer formation step S120 , and a heat treatment step S130 .
  • the piezoelectric solution preparation step ( S110 ) may be to prepare a piezoelectric solution by adding a piezoelectric material to a solvent and mixing it.
  • the solvent is not limited as long as it can dissolve the piezoelectric material, but preferably, dimethylformamide (DMF), acetone, dimethylsulfoxide (DMSO), methylpi Rollidone (N-Methyl-2-pyrrolidone, NMP), Methyl Ethyl Ketone (MEK), Dimethylacetamide (DMAc), Tetrahydrofuran (THF), Hexamethylphosphoramide (Hexamethylphosphoramide) , HMPA) and triethyl phosphate, and more preferably, dimethylformamide (DMF).
  • DMF dimethylformamide
  • DMSO dimethylsulfoxide
  • NMP methylpi Rollidone
  • MEK Methyl Ethyl Ketone
  • DMAc Dimethylacetamide
  • THF Tetrahydrofuran
  • Hexamethylphosphoramide Hexamethylphosphoramide
  • HMPA Hexamethylphosphoramide
  • triethyl phosphate and more
  • the piezoelectric solution preparation step ( S110 ) may be to prepare a piezoelectric solution by adding 10 to 30 parts by weight of a piezoelectric material to 100 parts by weight of a solvent and mixing them.
  • the piezoelectric solution When the piezoelectric material to be mixed in the preparation of the piezoelectric solution is less than 10 parts by weight or exceeds 30 parts by weight, the piezoelectric solution has a low or high viscosity, so it may be difficult to form the piezoelectric layer 100 using the piezoelectric solution in the piezoelectric layer forming step (S120). .
  • the piezoelectric solution preparation step (S110) may be to prepare a piezoelectric solution by adding 15 to 25 parts by weight of the piezoelectric material to 100 parts by weight of the solvent and mixing them, and more preferably 20 parts by weight of the piezoelectric material to 100 parts by weight of the solvent. It may be to prepare a piezoelectric solution by adding and mixing.
  • the piezoelectric solution preparation step (S110) may be to prepare a piezoelectric solution by mixing a piezoelectric material in a solvent and stirring at 40 to 60° C. at 100 to 200 rpm for 5 to 10 hours using a stirrer.
  • the mixing temperature in the piezoelectric solution preparation step (S110) is less than 40°C, the temperature is low and the piezoelectric material may not be dissolved in the solvent.
  • the increase is meaningless and can lead to energy loss.
  • the stirring speed is less than 100 rpm, the stirring speed may not be effectively dissolved in the solvent, and if it exceeds 200 rpm, the stirring speed is too fast and the piezoelectric material may not be uniformly dissolved in the solvent.
  • the stirring speed is not limited to 100 to 200 rpm, and may vary depending on the physical properties of the piezoelectric solution.
  • the mixing time in the piezoelectric solution preparation step (S110) is less than 5 hours, the piezoelectric material may not be completely dissolved in the solvent. The productivity of the sieve 10 may be reduced.
  • the piezoelectric solution preparation step (S110) may be to prepare a piezoelectric solution by mixing a piezoelectric material in a solvent and stirring at 50° C. using a stirrer at 125 rpm for 5 hours.
  • the piezoelectric layer forming step ( S120 ) may be a step of manufacturing a film using the piezoelectric solution prepared in the piezoelectric solution manufacturing step ( S110 ), and drying the prepared film to prepare the piezoelectric layer 100 .
  • the method of manufacturing the film in the piezoelectric layer forming step S120 is not limited as long as it is a method capable of manufacturing the film using the piezoelectric solution, but preferably, the film may be manufactured by casting the piezoelectric solution on a substrate.
  • the piezoelectric layer forming step (S120) may be to prepare a piezoelectric layer by drying the film prepared using the piezoelectric solution at 20 to 30° C. for 10 to 14 hours to remove the solvent contained in the film.
  • drying temperature of the film in the piezoelectric layer forming step (S120) is less than 20 °C or the drying time is shorter than 10 hours, the solvent may not be completely removed from the film, and if the drying temperature exceeds 30 °C or the drying time is longer than 14 hours If the temperature and time are sufficient, further increases in temperature and time may not be meaningful.
  • the piezoelectric layer forming step ( S120 ) may be to prepare the piezoelectric layer 100 by drying the film prepared using the piezoelectric solution at 25° C. for 12 hours to remove the solvent contained in the film.
  • the heat treatment step (S130) may be to heat the piezoelectric layer 100 obtained in the piezoelectric layer forming step (S120) to remove the solvent and voids remaining in the piezoelectric layer 100 obtained in the piezoelectric layer forming step (S120). .
  • the piezoelectric layer 100 obtained in the piezoelectric layer forming step (S120) is heated at a heating start temperature of 190 to 210° C. at a temperature increase rate of 8 to 12° C. per minute for 5 to 10 minutes. may be doing
  • the heating start temperature in the heat treatment step (S130) is less than 190 °C, the temperature is low, the removal of the solvent and voids present in the piezoelectric layer 100 may not be effectively made, and if it exceeds 210 °C, the heating completion temperature is high, so the piezoelectric Layer 100 may be damaged by heat.
  • the finally achieved heat treatment temperature is lowered as the temperature increase rate is low, so that the removal of the solvent and the voids present in the piezoelectric layer 100 may not be effectively made,
  • the heat treatment temperature finally achieved increases as the temperature increase rate is fast, and thus the piezoelectric layer 100 may be damaged by heat.
  • the heat treatment time in the heat treatment step (S130) is less than 8 minutes, the heat treatment time is short, so the solvent and voids present in the piezoelectric layer 100 may not be completely removed. It may have been sufficiently performed that further heat treatment may not be meaningful.
  • the heat treatment step (S130) is to heat the piezoelectric layer 100 obtained in the piezoelectric layer forming step (S120) at a heating start temperature of 210° C. for 10 minutes at a temperature increase rate of 10° C. per minute. there is.
  • the piezoelectric layer preparation step (S100) of the method for manufacturing a magnetoelectric laminate in which a porous magnetostrictive layer is stacked according to an embodiment of the present invention may further include a compression step (S140) after the heat treatment step (S130).
  • the compression step (S140) may be to apply a pressure of 25 to 35 MPa to the piezoelectric layer 100 obtained in the heat treatment step (S130) at a temperature of 130 to 150 °C and hold the pressure for 25 to 35 minutes.
  • the compression step ( S140 ) may be for polarizing the piezoelectric layer 100 by applying heat and pressure to the piezoelectric layer 100 to transform the crystal structure of the piezoelectric material constituting the piezoelectric layer 100 .
  • the piezoelectric material constituting the piezoelectric layer 100 is polyvinylidene fluoride
  • polyvinylidene fluoride is generally known to improve piezoelectricity as the ratio of the ⁇ crystal structure increases
  • the compression step (S140) When the piezoelectric layer 100 is made of polyvinylidene fluoride, heat and pressure are applied to the piezoelectric layer 100 to transform the crystal structure of polyvinylidene fluoride to increase the ratio of the ⁇ crystal structure.
  • a porous magnetostrictive layer 200 having magnetostrictive properties is prepared (S200).
  • the magnetostrictive layer preparation step S200 may be to prepare the porous magnetostrictive layer 200 made of at least one selected from a ferromagnetic metal, a ferritic ceramics, a magnetostrictive alloy, and a magnetic shape memory alloy.
  • the ferromagnetic metal may include nickel (Ni), cobalt (Co) and iron (Fe), and the ferritic ceramics are Fe 3 O 4 , NiFe 2 O 4 , MnFe 2 O 4 , (Ni,Zn)Fe 2 O 4 , (Mn,Zn)Fe 2 O 4 , CoFe 2 O 4 and ⁇ -Fe 2 O 3 , and magnetostrictive alloys may include Terfenol-D, Gafenol, Samfenol-D, Metglas and FeCoB.
  • the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) may be made of nickel, and when the porous magnetostrictive layer 200 is made of nickel, nickel can also act as an electrode, such as silver paste A process for forming an electrode may be reduced by using a separate electrode material.
  • the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step ( S200 ) may have a plurality of pores formed therein, and may have a porosity of 50 to 99% as the plurality of pores are formed therein.
  • the porous magnetostrictive layer 200 can penetrate into the piezoelectric layer 100 as pores are formed therein, As the porous magnetostrictive layer 200 penetrates into the piezoelectric layer, the piezoelectric layer 100 may be filled in pores formed in the porous magnetostrictive layer 200 .
  • the porous magnetostrictive layer 200 and the piezoelectric layer 100 are combined, so that even without using an epoxy adhesive, the porous magnetostrictive layer 200 ) and the piezoelectric layer 100 may maintain a state in which they are bonded to each other.
  • the strain due to magnetostriction of the porous magnetostrictive layer 200 can be effectively transferred to the piezoelectric layer 100 .
  • the porosity of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) is less than 50%, the number of pores inside is small, and the pores inside the piezoelectric layer 100 and the porous magnetostrictive layer 200 are not sufficiently filled.
  • the magnetostrictive layer 200 and the piezoelectric layer 100 may not be effectively bonded.
  • the contact area between the porous magnetostrictive layer 200 and the piezoelectric layer 100 may be reduced, so that the magnetoelectric properties of the magnetoelectric laminate 10 may be deteriorated.
  • the porosity of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) exceeds 99%, excessive pores are formed inside the porous magnetostrictive layer 200, and the magnetoelectric laminate 10 in the laminating step (S300) ), when heat and pressure are applied, it may not be able to withstand it, and the pores formed inside the porous magnetostrictive layer 200 may not be maintained.
  • the porosity of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) may be 75 to 99%, more preferably 90 to 99%, and most preferably 95%. there is.
  • the average diameter of the plurality of pores formed inside the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step S200 may be 10 to 500 ⁇ m.
  • the average diameter of the pores formed inside the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) is less than 10 ⁇ m, the size of the pores is small and the piezoelectric layer is placed in the pores inside the porous magnetostrictive layer when compressed in the laminating step (S300). (100) may be difficult to fill.
  • the porous magnetostrictive layer 200 and the piezoelectric layer 100 are formed as the size of the pores becomes too large.
  • the strain may not be uniformly transferred to the entire piezoelectric layer 100 during magnetostriction of the porous magnetostrictive layer 200, and the alignment of the dipoles in the magnetoelectric laminate 10 in the polarization step (S400) to be described later. If this is not done, the polarization may not be performed effectively.
  • the average diameter of the pores formed therein may be 135 to 375 ⁇ m, more preferably 190 to 310 ⁇ m, most preferably For example, it may be 250 ⁇ m.
  • the thickness of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step S200 may be 500 to 3000 ⁇ m.
  • the thickness of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) is less than 500 ⁇ m, the mechanical strength of the porous magnetostrictive layer 200 may drop, and the porous magnetostrictive layer 200 and the piezoelectric layer 100 Since the contact area is small, the magnetoelectric properties of the magneto-electric laminate 10 may be deteriorated.
  • the thickness of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) exceeds 3000 ⁇ m, the porous magnetostrictive layer 200 and the piezoelectric layer ( When stacking 100) and compressing it, the porous magnetostrictive layer 200 protrudes to the outside of the piezoelectric layer 100 , so that a portion not in contact with the piezoelectric layer 100 may be excessively generated.
  • the thickness of the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step (S200) may be 1125 to 2375 ⁇ m, more preferably, 1430 to 2060 ⁇ m, and most preferably, 1600 ⁇ m. there is.
  • the magnetoelectric laminate 10 is manufactured by laminating the porous magnetostrictive layer 200 prepared in the magnetostrictive layer preparation step S200 on at least one surface of the piezoelectric layer 100 prepared in the piezoelectric layer preparation step S100, and the manufactured magnetic Heat and pressure are applied to the electrical laminate 10 and compressed (S300).
  • the magnetoelectric laminate 10 is manufactured by laminating the porous magnetostrictive layer 200 on the upper and lower surfaces of the piezoelectric layer 100, and heat and heat to the manufactured magnetoelectric laminate 10 are applied. It may be compressed by applying pressure.
  • a porous magnetostrictive layer 200 is laminated on the upper and lower surfaces of the piezoelectric layer 100 to prepare a magnetoelectric laminate 10, and heat and pressure are applied to the manufactured magnetoelectric laminate 10 to As it is compressed, the porous magnetostrictive layer 200 may penetrate into the piezoelectric layer 100 , and accordingly, the piezoelectric layer 100 is filled in the pores formed in the porous magnetostrictive layer 200 , and the porous magnetostrictive layer 200 . A contact area between the piezoelectric layer 100 and the piezoelectric layer 100 may increase.
  • the porous magnetostrictive layer 200 and the piezoelectric layer 100 can be bonded without using an epoxy adhesive, and the porous magnetostrictive layer
  • the contact area between 200 and the piezoelectric layer 100 increases, a magnetic field is applied to the magneto-electric laminate 10 and the porous magnetostrictive layer 200 undergoes magnetostriction, and the resulting strain is effectively applied to the piezoelectric layer 100 . can be transmitted.
  • a porous magnetostrictive layer 200 is laminated on the upper and lower surfaces of the piezoelectric layer 100 to prepare a magneto-electric laminate 10, and a magneto-electric laminate manufactured at a temperature of 130 to 150 ° C. 10) may be a step of compressing the piezoelectric layer 100 and the porous magnetostrictive layer 200 by applying a pressure of 25 to 35 MPa and maintaining the pressure for 25 to 35 minutes.
  • the compression temperature when the compression temperature is less than 130 °C, the temperature is low, so that the porous magnetostrictive layer 200 cannot effectively penetrate into the inside of the piezoelectric layer 100, so that the piezoelectric layer 100 in the pores inside the porous magnetostrictive layer 200 ) may not be sufficiently filled, and when it exceeds 150° C., the temperature is too high, and the piezoelectric layer 100 or the porous magnetostrictive layer 200 may be altered to deteriorate physicochemical properties.
  • the pressure is less than 25 MPa during compression in the lamination step (S300), the pressure is low, so that the porous magnetostrictive layer 200 does not effectively penetrate into the inside of the piezoelectric layer 100, so that the piezoelectric layer 100 in the pores inside the porous magnetostrictive layer 200.
  • This may not be sufficiently filled, and if it exceeds 35 MPa, the pressure is too strong, and damage and breakage may occur in the porous magnetostrictive layer 200 or the piezoelectric layer 100 .
  • the compression time in the lamination step (S300) is less than 25 minutes, the time for the porous magnetostrictive layer 200 to penetrate into the piezoelectric layer 100 may be insufficient, and if it exceeds 35 minutes, the porous magnetostrictive layer 200 is sufficiently formed into the piezoelectric layer (100) Penetrating into the interior, further compression is meaningless, and the productivity of the magnetoelectric laminate 10 may be reduced.
  • the magnetoelectric laminate 10 is manufactured by laminating the porous magnetostrictive layer 200 on the upper and lower surfaces of the piezoelectric layer 100, and the magnetoelectric laminate manufactured at a temperature of 140° C. It may be a step of compressing the piezoelectric layer 100 and the porous magnetostrictive layer 200 by applying a pressure of 30 MPa to the sieve 10 and maintaining the pressure for 30 minutes.
  • the magnetoelectric laminate 10 is manufactured by laminating the porous magnetostrictive layer 200 on at least one surface of the piezoelectric layer 100, and heat and When compressed by applying pressure, the volume of the piezoelectric layer 100 and the porous magnetostrictive layer 200 may be reduced as heat and pressure are applied.
  • the volume fraction of the porous magnetostrictive layer 200 with respect to the total volume of the magnetoelectric laminate 10 in the magnetoelectric laminate 10 obtained by being compressed as heat and pressure are applied in the lamination step S300 is 0.3 to 0.7 can be
  • the volume fraction of the porous magnetostrictive layer 200 with respect to the total volume of the magnetoelectric laminate 10 is the piezoelectric layer 100 prepared in the piezoelectric layer preparation step S100 and the porous prepared in the magnetostrictive layer preparation step S200. This may be due to the thickness of the magnetostrictive layer 200 .
  • the volume fraction of the porous magnetostrictive layer 200 with respect to the total volume of the magnetoelectric laminate 10 of the magnetoelectric laminate 10 obtained in the lamination step S300 is less than 0.3, compared to the thickness of the piezoelectric layer 100, Since the thickness of the strain layer 200 is too thin, the strain is not uniformly transmitted to the piezoelectric layer 100 during the magnetostriction of the porous magnetostrictive layer 200, so the magnetoelectric properties of the magnetoelectric laminate 10 according to the embodiment of the present invention This can fall.
  • the volume fraction of the porous magnetostrictive layer 200 with respect to the total volume of the magnetoelectric laminate 10 of the magnetoelectric laminate 10 obtained in the lamination step S300 exceeds 0.7, a strain is uniformly applied to the piezoelectric layer 100 Since the amount of the porous magnetostrictive layer 200 for transfer is already sufficient, any increase in the volume of the porous magnetostrictive layer 200 is meaningless, and the strain applied to the piezoelectric layer 100 during magnetostriction of the porous magnetostrictive layer 200 . This can be excessive.
  • the volume fraction of the porous magnetostrictive layer 200 with respect to the total volume of the magnetoelectric laminate 10 in the magnetoelectric laminate 10 obtained by being compressed as heat and pressure are applied in the lamination step S300 is 0.4 to 0.6 can be
  • the porous magnetostrictive layer 200 may be inserted to a predetermined depth in the piezoelectric layer 100 , and accordingly, the magnetoelectric laminate 10 according to an embodiment of the present invention is a piezoelectric layer 100 .
  • the porous magnetostrictive layer 200 may have a structure filled with pores formed inside.
  • Polarization step (S400) is 30 kV / mm to 50 kV / mm intensity in the magnetoelectric laminate 10 obtained in the lamination step (S300) to align the dipoles of the piezoelectric layer 100 included in the magnetoelectric laminate 10 . It may be to apply an electric field of
  • the dipole of the piezoelectric layer 100 may not be effectively aligned because the intensity of the electric field is weak. Since electricity flows (electrical short), dipole alignment of the piezoelectric layer 100 may not be achieved.
  • the piezoelectric layer 100 may effectively generate an output voltage.
  • the magnetoelectric laminate in which the porous magnetostrictive electrode is laminated and the magnetoelectric laminate 10 prepared therefrom according to the present invention can compress the piezoelectric phase and the magnetostrictive phase without using an epoxy adhesive, as well as a porous magnetostrictive layer ( As the 200 ) penetrates into the piezoelectric layer 100 , the contact area between the porous magnetostrictive layer 200 and the piezoelectric layer 100 increases, so that the magnetoelectric properties of the magnetoelectric laminate 10 can be improved.
  • the epoxy adhesive is not used, there is no need for a process for applying and curing them, so the manufacturing process of the magnetoelectric laminate 10 can be shortened, and the cost for providing the epoxy adhesive can also be saved. Economical efficiency of the manufactured magnetoelectric laminate 10 can be improved.
  • a piezoelectric solution was prepared by adding 2 g of a piezoelectric material to 8 g of a solvent and mixing by stirring at 125 rpm at 50° C. for 5 hours.
  • Dimethylformamide (DMF) was used as the solvent, and polyvinylidene fluoride having a weight average molecular weight of 534,000 g/mol was used as the piezoelectric material.
  • a film having a thickness was prepared by using the solution casting method on a glass substrate having a thickness of 2 mm, and the prepared film was dried at 25° C. for 12 hours to prepare a piezoelectric layer 100 .
  • the prepared piezoelectric layer 100 was heat-treated at 210° C. for 10 minutes at a temperature increase rate of 10° C. per minute.
  • a porous magnetostrictive layer 200 having magnetostrictive properties was prepared, but containing nickel, and pores having a diameter of a diameter were formed therein, so that the porosity was 95%, and a thickness of 1600 ⁇ m was prepared.
  • a magnetoelectric laminate 10 was manufactured by laminating a porous magnetostrictive layer 200 on both sides of the piezoelectric layer 100, and a pressure of 30 MPa was applied in the vertical direction to the magnetoelectric laminate 10 at 140° C. held for a minute. Thereafter, the pressure applied to the magneto-electric laminate 10 was released, and an electric field having an intensity of 45 kv/mm was applied to the magneto-electric laminate 10 at room temperature to polarize it.
  • Example 1 Prior to (3) hot press and polarization of Example 1, a pressure of 30 MPa was applied to the piezoelectric layer 100 prepared in (1) at 140° C. for 30 minutes until polarization in the same manner as in Example 1 A completed magnetoelectric laminate 10 was prepared.
  • a piezoelectric layer 100 was prepared in the same manner as in Example 1 (1) preparing the piezoelectric layer. Thereafter, in the same manner as in Example 2, a pressure of 30 MPa was applied to the piezoelectric layer 100 prepared in (1) at 140° C. for 30 minutes.
  • Test Example 1 is for analyzing the surface of the magnetoelectric laminate 10 manufactured according to an embodiment of the present invention, and the magnetoelectric laminate 10 according to Examples 1 and 2 was subjected to a scanning electron microscope (Scanning Electron Microscopy). , SEM) and EDS (Energy Dispersive Spectrometer).
  • FIGS. 4A and 4B are images analyzed using SEM of the surface of the magnetoelectric laminate 10 according to Examples 1 and 2, respectively, and FIGS. 4A and 4B are images according to Examples 1 and 2, respectively. It is an image analyzed using EDS of the cross-section of the magnetoelectric laminate.
  • the piezoelectric layer 100 is filled in the pores of the porous magnetostrictive layer 200 of the magnetoelectric laminate 10 according to Example 1, and the porous magnetostrictive layer 200 is the piezoelectric layer 100 . ), it can be confirmed that it has penetrated into the interior of the
  • the piezoelectric layer 100 is formed in the pores of the porous magnetostrictive layer 200 . It can be seen that the filling and the porous magnetostrictive layer 200 penetrate into the piezoelectric layer 100 .
  • Test Example 2 is to compare the magnetoelectric properties of Examples 1 and 2 and Comparative Example 1, and the output voltage generated by applying a magnetic field to the magnetoelectric laminates according to Examples 1 and 2 and Comparative Example 2 is measured. did
  • a bias magnetic field was applied to the magneto-electric laminates according to Examples 1 to 2 and Comparative Example 1, and the DC magnetic field was The intensity was varied from -1000 to 1000 Oe.
  • 5A, 5B, and 5C are graphs illustrating output voltages generated as a result of applying a bias magnetic field to the magneto-electric laminates according to Examples 1 to 2 and Comparative Example 1;
  • Example 1 Example 2 comparative example Output voltage (mV/cm) 1.88 2.27 1.13
  • the magneto-electric laminate according to the comparative example shows the highest value of the magneto-electrical output voltage when the intensity of the bias magnetic field is around 300 Oe, whereas the magneto-electric laminate according to Example 2 (10) confirms that a similar magnetoelectric output voltage value can be obtained when the strength of the applied bias magnetic field is near 0 Oe.
  • the magneto-electric laminate according to the comparative example can generate a magneto-electrical output voltage only when a DC magnetic field having a predetermined strength is applied, whereas the magneto-electric laminate 10 according to Example 2 has a high magnetic field even when a DC magnetic field is not applied.
  • the magneto-electric stack 10 according to the second embodiment artificially generates a DC magnetic field when constructing a device such as an energy harvester. This is a result confirming that the device can be more easily configured without the need for an external power source such as an electromagnetic magnet because it does not need to be applied.
  • the output voltage of the magneto-electric laminate 10 according to Example 1 is somewhat lower than the output voltage of the magneto-electric laminate 10 according to the second embodiment.
  • the method of manufacturing a magnetoelectric laminate according to an embodiment of the present invention prepares the magnetoelectric laminate 10 by hot pressing the piezoelectric layer 100 and the porous magnetostrictive layer 200, so that the piezoelectric layer 100 is prepared.
  • the compression step (S140) is not performed to increase the ratio of the ⁇ crystal structure of polyvinylidene fluoride, the ratio of the ⁇ crystal structure of the piezoelectric layer 100 is increased by the heat and pressure applied in the lamination step (S300). It is a result confirming that the magneto-electric laminate 10 having magneto-electric properties above the level can be manufactured.
  • the magnetoelectric laminate 10 in which the porous magnetostrictive layer is laminated according to an embodiment of the present invention does not use an epoxy adhesive, but the piezoelectric layer 100 and the porous magnet
  • the piezoelectric layer 100 is filled in the pores inside the porous magnetostrictive layer 200 by laminating the strained layer 200 and then compressing it by applying heat and pressure so that the porous magnetostrictive layer 200 penetrates into the piezoelectric layer 100 .
  • the magnetoelectric laminate 10 having magnetoelectric properties can be manufactured.
  • the porous magnetostrictive layer 200 used as a magnetostrictive phase can be used as an electrode, so a process for providing a separate electrode And there is an effect that does not require a cost.
  • the present invention can provide a method for manufacturing a magnetoelectric laminate having excellent economic efficiency, productivity, and magnetoelectric properties by not using an epoxy adhesive in bonding a porous magnetostrictive layer having magnetostrictive properties and a piezoelectric layer having piezoelectricity. It can be used in energy harvesting fields that require a magnetoelectric laminate with excellent electrical properties.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'un stratifié magnétoélectrique sur lequel est empilée une électrode magnétostrictive poreuse, le procédé comprenant les étapes consistant : à préparer une couche piézoélectrique constituée d'un matériau piézoélectrique ; à préparer une couche magnétostrictive poreuse présentant une magnétostriction ; à fabriquer un stratifié magnétoélectrique par empilement d'une couche magnétostrictive poreuse sur la couche piézoélectrique et à appliquer de la chaleur et de la pression au stratifié magnétoélectrique ; et à polariser le stratifié magnétoélectrique. La présente invention concerne un stratifié magnétoélectrique sur lequel est empilée une électrode magnétostrictive poreuse, le stratifié magnétoélectrique comprenant : une couche piézoélectrique constituée d'un matériau piézoélectrique ; et une couche magnétostrictive poreuse dans laquelle est formée une pluralité de pores et qui est empilée sur au moins une surface de la couche piézoélectrique à insérer dans la couche piézoélectrique à une profondeur prédéterminée, la couche piézoélectrique étant introduite dans les pores lorsque la couche magnétostrictive poreuse est insérée dans la couche piézoélectrique à la profondeur prédéterminée.
PCT/KR2021/009594 2020-09-22 2021-07-23 Procédé de fabrication d'un stratifié magnétoélectrique sur lequel est empilée une électrode magnétostrictive poreuse, et stratifié magnétoélectrique fabriqué au moyen dudit procédé WO2022065656A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115605070A (zh) * 2022-09-30 2023-01-13 深圳市汇顶科技股份有限公司（Cn） 压电聚合物溶液的制备方法及其应用

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0826786A1 (fr) * 1995-12-05 1998-03-04 Honda Giken Kogyo Kabushiki Kaisha Matiere magnetostrictive et procede de preparation
WO2010110423A1 (fr) * 2009-03-26 2010-09-30 並木精密宝石株式会社 Capteur magnétique composite piézoélectrique/magnétostrictif
KR101447561B1 (ko) * 2013-06-03 2014-10-10 한국기계연구원 에너지 하베스트 소자용 자기전기 복합재료 적층체 및 그 제조방법
KR102042638B1 (ko) * 2019-01-31 2019-11-08 전남대학교산학협력단 압전성 고분자를 이용한 압전 필름 제조방법

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101536973B1 (ko) 2014-01-28 2015-07-22 한국기계연구원 단결정 압전 섬유 포함 복합체 및 이를 포함하는 자기전기 복합재료 적층체

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0826786A1 (fr) * 1995-12-05 1998-03-04 Honda Giken Kogyo Kabushiki Kaisha Matiere magnetostrictive et procede de preparation
WO2010110423A1 (fr) * 2009-03-26 2010-09-30 並木精密宝石株式会社 Capteur magnétique composite piézoélectrique/magnétostrictif
KR101447561B1 (ko) * 2013-06-03 2014-10-10 한국기계연구원 에너지 하베스트 소자용 자기전기 복합재료 적층체 및 그 제조방법
KR102042638B1 (ko) * 2019-01-31 2019-11-08 전남대학교산학협력단 압전성 고분자를 이용한 압전 필름 제조방법

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHOI MOON, KO KYUJIN, YANG SU: "Structural Effects of Magnetostrictive Materials on the Magnetoelectric Response of Particulate CZFO/NKNLS Composites", MATERIALS, vol. 12, no. 1053, pages 1 - 9, XP055914000, DOI: 10.3390/ma12071053 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115605070A (zh) * 2022-09-30 2023-01-13 深圳市汇顶科技股份有限公司（Cn） 压电聚合物溶液的制备方法及其应用
CN115605070B (zh) * 2022-09-30 2023-12-26 深圳市汇顶科技股份有限公司 压电聚合物溶液的制备方法及其应用

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