CN111554466B - Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof - Google Patents

Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof Download PDF

Info

Publication number
CN111554466B
CN111554466B CN202010418456.5A CN202010418456A CN111554466B CN 111554466 B CN111554466 B CN 111554466B CN 202010418456 A CN202010418456 A CN 202010418456A CN 111554466 B CN111554466 B CN 111554466B
Authority
CN
China
Prior art keywords
heat
wave
magnetic sheet
conducting
absorbing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010418456.5A
Other languages
Chinese (zh)
Other versions
CN111554466A (en
Inventor
刘立东
单震
朱航飞
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hengdian Group DMEGC Magnetics Co Ltd
Original Assignee
Hengdian Group DMEGC Magnetics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hengdian Group DMEGC Magnetics Co Ltd filed Critical Hengdian Group DMEGC Magnetics Co Ltd
Priority to CN202010418456.5A priority Critical patent/CN111554466B/en
Publication of CN111554466A publication Critical patent/CN111554466A/en
Application granted granted Critical
Publication of CN111554466B publication Critical patent/CN111554466B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
    • C09K5/14—Solid materials, e.g. powdery or granular
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/003—Light absorbing elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14708—Fe-Ni based alloys
    • H01F1/14733—Fe-Ni based alloys in the form of particles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14766—Fe-Si based alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14766—Fe-Si based alloys
    • H01F1/14791—Fe-Si-Al based alloys, e.g. Sendust
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets

Landscapes

  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Abstract

The invention belongs to the technical field of electromagnetic wave absorbing materials, and discloses a heat-conducting wave-absorbing composite magnetic sheet with a periodic structure and a preparation method thereof. The heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises a plurality of periodic units, wherein each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure unit; the wave-absorbing magnetic sheet comprises the following components in percentage by weight: high-molecular binder: 10% -25%, scaly soft magnetic alloy magnetic powder: 75-90% of the raw materials, and auxiliary materials: less than or equal to 1 percent; the heat conduction structure unit comprises the following components in percentage by weight: high-molecular binder: 20% -50%, heat-conducting medium: 50% -80%, auxiliary agent: less than or equal to 2 percent; wherein the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure unit is more than 8:1, and the area of the periodic unit is 40mm2～400mm2. The heat-conducting and wave-absorbing composite magnetic sheet heat-conducting structural units are periodically distributed in the wave-absorbing magnetic sheet and penetrate through the whole wave-absorbing magnetic sheet in the thickness direction, so that a smooth and developed heat-conducting/heat-dissipating channel is provided for the wave-absorbing magnetic sheet, and the heat conductivity coefficient and the heat-dissipating capacity of the wave-absorbing magnetic sheet are improved.

Description

Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof
Technical Field
The invention relates to the technical field of electromagnetic wave absorbing materials, in particular to a heat-conducting wave-absorbing composite magnetic sheet with a periodic structure and a preparation method thereof.
Background
The wave-absorbing magnetic sheet can solve the problems of electromagnetic compatibility and electromagnetic radiation of electronic products to a certain extent, and is more and more favored by electronic engineers due to simple use. The wave-absorbing magnetic sheet is mainly formed by compounding soft magnetic alloy magnetic powder and a polymer binder, and high-frequency electromagnetic clutter is lost by depending on mechanisms such as eddy current, magnetic hysteresis, resonance and the like of the soft magnetic alloy magnetic powder, so that electromagnetic energy is converted into heat energy to be dissipated. In order to improve the high-frequency absorption/magnetic shielding characteristics of the magnetic sheet, the flaky soft magnetic alloy magnetic powder is usually used as a filler, and the oriented arrangement of the flaky magnetic powder in a high polymer material is realized by utilizing a casting or calendering process, so that the magnetic sheet can obtain higher magnetic permeability and magnetic loss at high frequency.
Along with the high frequency and high integration of electronic products, the data transmission speed is faster and faster, the electromagnetic compatibility problem is more and more prominent, and meanwhile, the heat dissipation problem of components such as chips is more and more serious. The wave-absorbing magnetic sheet contains a large amount (more than 10% by weight) of high polymer materials, so that the heat conduction property is poor, generally 0.7-1.0W/(m.K), and therefore, how to solve the problems of electromagnetic compatibility and heat dissipation simultaneously provides challenges for electronic engineers. At present, the mainstream solution is to use the wave-absorbing magnetic sheet and the heat-dissipating material in a composite manner, that is, a layer of heat-conducting/heat-dissipating material such as foam, graphite film and the like is adhered on the surface of the wave-absorbing magnetic sheet, so that the problems can be solved to a certain extent. However, the effect of the scheme is limited because the wave-absorbing magnetic sheet has poor heat conduction property and cannot effectively transmit the heat generated by the electronic component to the heat conduction material, i.e. the problems of unclogged heat conduction channel and large heat resistance exist. Aiming at the problem, part of researchers add a heat-conducting medium into the traditional wave-absorbing plate to improve the heat conductivity of the wave-absorbing magnetic sheet. The method can improve the heat conduction characteristic of the wave-absorbing magnetic sheet to a certain extent, but has certain problems: the addition of the heat-conducting medium can cause the reduction of the filling amount of the soft magnetic alloy magnetic powder in the wave-absorbing magnetic sheet, thereby influencing the electromagnetic wave absorption and magnetic shielding properties of the magnetic sheet.
Disclosure of Invention
The invention aims to provide a heat-conducting wave-absorbing composite magnetic sheet with a periodic structure, overcomes the defects of the background technology, and provides a preparation method, so that the problem that the electromagnetic wave absorption/shielding and heat conduction of the traditional wave-absorbing magnetic sheet cannot be considered at the same time is effectively solved.
In order to achieve the aim of the invention, the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises a plurality of periodic units, wherein each periodic unit comprises two parts, namely a wave-absorbing magnetic sheet and a heat-conducting structure unit;
the wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 10 to 25 percent
Scaly soft magnetic alloy magnetic powder: 75 to 90 percent
Auxiliary materials: less than or equal to 1 percent
The heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 20 to 50 percent
A heat-conducting medium: 50 to 80 percent
Auxiliary agent: less than or equal to 2 percent
Wherein the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure unit is more than 8:1 and less than 15:1, and the area of the periodic unit is 40mm2～400mm2。
Furthermore, the polymer binder in the wave-absorbing magnetic sheet is required to be suitable for tape casting, and the system is not limited and comprises polyurethane, acrylic resin, epoxy resin, liquid nitrile rubber, ethyl cellulose, PVB and the like.
Further, the scaly soft magnetic alloy magnetic powder in the wave-absorbing magnetic sheet comprises but is not limited to Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Si-Al-Cr, Fe-Ni-Mo or Fe-Al, preferably Fe-Si-Al, Fe-Ni or Fe-Ni-Mo, the thickness of the magnetic powder is 0.5 mu m to 1.3 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is more than 40: 1.
furthermore, the auxiliary materials in the wave-absorbing magnetic sheet include but are not limited to an anti-settling agent, a coupling agent, a dispersing agent or a toughening agent, and the like, and one or more of the anti-settling agent, the coupling agent, the dispersing agent or the toughening agent can be not added or contained.
Furthermore, the requirement of the high-molecular adhesive in the heat-conducting structural unit is the same as or similar to the physical and chemical properties of the adhesive used for the wave-absorbing magnetic sheet, so that the wave-absorbing magnetic sheet unit and the heat-conducting structural unit can be well combined.
Further, the heat conducting medium in the heat conducting structural unit is a carbon-based material, including but not limited to graphite, graphene or graphene nanoplatelets.
Further, the auxiliary agent in the heat conducting structural unit includes, but is not limited to, a coupling agent, a dispersing agent, a leveling agent, an antifoaming agent, and the like, and one or more of the coupling agent, the dispersing agent, the leveling agent, or the antifoaming agent may be not added or may be included.
Further, the shape of the heat conduction structure unit is not limited, and regular shapes such as a circle, a square and a rectangle are preferred, so that the heat conduction structure unit is convenient to process.
Further, the invention also provides a preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, which comprises the following steps:
(1) preparing casting slurry of the wave-absorbing magnetic sheet part: uniformly mixing a high-molecular binder, a solvent, scaly soft magnetic alloy magnetic powder and auxiliary materials, and performing vacuum defoaming treatment to obtain uniform wave-absorbing magnetic sheet slurry suitable for casting;
(2) preparing the wave-absorbing magnetic sheet: coating the slurry prepared in the step (1) on a steel strip, drying the casting film, and taking the casting film off the steel strip after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes; the surface of the steel strip is of a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, and the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then carrying out defoaming treatment to obtain heat-conducting structural unit slurry with proper viscosity and uniform mixing;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the dried wave-absorbing magnetic sheets, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing a plurality of heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and carrying out hot pressing on the plurality of casting green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure.
Further, the solvent in steps (1) and (3) is to ensure that the polymeric binder and the auxiliary materials/additives can be uniformly dispersed in the solvent, and therefore, the solvent is preferably a low-boiling solvent.
Further, the protruding height of the steel strip in the step (2) is 0.06 mm-0.12 mm.
Further, in order to facilitate film formation in the step (2), a release agent needs to be sprayed on the steel strip before casting, the type of the release agent is not limited, the quality of the cast film is not influenced, and the film formation is facilitated.
Further, the viscosity in the step (2) is suitably controlled to be 3000 to 5000 mPas. The viscosity is too high, so that slurry cannot be completely filled in through holes of the wave-absorbing magnetic sheet units, the wave-absorbing magnetic sheet parts in the final periodic units cannot be well combined with the interface of the heat-conducting structure, and certain air holes exist; the solvent amount is too much, the viscosity is too low, a large number of cavities can be formed in the heat conduction structure in the subsequent drying process, the density of the heat conduction layer can be influenced, and the heat conduction effect is finally influenced.
Compared with the prior art, the invention has the following advantages:
(1) compared with the traditional wave-absorbing magnetic sheet, the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure provided by the invention has the advantages that the heat-conducting structural units are periodically distributed in the wave-absorbing magnetic sheet and penetrate through the whole wave-absorbing magnetic sheet in the thickness direction, so that a smooth and developed heat-conducting/radiating channel is provided for the wave-absorbing magnetic sheet, and the heat conductivity coefficient and the heat-radiating capacity of the wave-absorbing magnetic sheet are greatly improved. Meanwhile, the electromagnetic wave absorption/shielding characteristics of the wave-absorbing magnetic sheet are not obviously changed by limiting the area ratio of the heat-conducting structure unit to the wave-absorbing magnetic sheet and the size of the periodic structure. Therefore, the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure has good wave-absorbing/shielding and heat-conducting/radiating performances.
(2) The carbon-based material is adopted as the heat-conducting medium in the heat-conducting structural unit, so that on one hand, the heat-conducting property of the material is greatly improved, meanwhile, the light weight of the material is facilitated, and the density of the whole material is reduced. More importantly, the carbon-based material has good electromagnetic wave absorption and shielding characteristics, so that the leakage of electromagnetic waves from the heat conduction channel is avoided, and the electromagnetic wave absorption and shielding effects of the wave-absorbing magnetic sheet are not obviously deteriorated.
(3) The invention takes a steel belt with a periodic structure as a base film, takes a tape casting process as a main process, and simultaneously assists in preparing the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure by a hot-pressing process. In the preparation process, the viscosity of the slurry of the heat-conducting structure unit is strictly limited, and the slurry cannot be completely filled in the through hole of the wave-absorbing magnetic sheet unit due to overlarge viscosity, so that the wave-absorbing magnetic sheet part in the final periodic unit cannot be well combined with the interface of the heat-conducting structure, and certain air holes exist; the solvent amount is too much, the viscosity is too low, a large number of cavities can be formed in the heat conduction structure in the subsequent drying process, the density of the heat conduction layer can be influenced, and the heat conduction effect is finally influenced.
Drawings
Fig. 1 is a schematic structural view of a heat-conducting and wave-absorbing composite magnetic sheet according to embodiment 1 of the present invention, in which 1 is a periodic unit, 2 is a heat-conducting structural unit, and 3 is a wave-absorbing magnetic sheet;
FIG. 2 is a schematic view of a steel strip according to the present invention having a surface with periodic asperities.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. It is to be understood that the following description is only illustrative of the present invention and is not to be construed as limiting the present invention.
The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
The indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the number clearly indicates the singular.
The technical features of the embodiments of the present invention may be combined with each other as long as they do not conflict with each other.
Example 1
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodic units, each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure, the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 10:1, and the area of each periodic unit is 300mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 13 percent of
Scaly soft magnetic alloy magnetic powder: 86.5 percent
Auxiliary materials: 0.5 percent
The high-molecular binder is polyurethane;
the scaly soft magnetic alloy magnetic powder is Fe-Si-Al, the average thickness of the magnetic powder is 0.9 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is 64: 1.
the auxiliary material is KH550 silane coupling agent.
(2) The heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 35 percent of
A heat-conducting medium: 64 percent
Auxiliary agent: 1 percent of
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent, scaly magnetic powder and auxiliary materials, and then carrying out vacuum defoaming treatment on the slurry to obtain wave-absorbing magnetic sheet slurry suitable for uniform casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the surface of the steel belt with the special structure is of a periodic rugged structure, the protruding parts correspond to the heat conducting structure unit parts, the groove parts correspond to the wave-absorbing magnetic sheet parts, and the protruding height is 0.08 mm. Before casting, the steel strip needs to be sprayed with an oily release agent;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structural unit slurry with certain viscosity;
the viscosity of the heat-conducting structural unit slurry is required to be controlled to be 3856 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the dried wave-absorbing magnetic sheets, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures; wherein the coating process is tape casting;
(5) repeating the steps (1) to (4), and preparing 5 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 5 cast green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.2 mm.
Comparative example 1
The difference of the comparative example of the embodiment 1 is that no heat conduction structural unit exists, namely 0.08mm casting film is cast on a flat steel strip, the components, the proportion and the process parameters are completely the same as those of the embodiment 1, and finally 5 pieces of casting film are hot-pressed to obtain 0.2mm wave-absorbing magnetic sheets.
Example 2
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodic units, each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure, the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 12:1, and the area of each periodic unit is 285mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 11 percent of
Scaly soft magnetic alloy magnetic powder: 89 percent
The high-molecular binder is polyurethane;
the scaly iron-based alloy magnetic powder is Fe-Si-Al, the average thickness of the magnetic powder is 0.8 mu m, and the diameter-thickness ratio (the diameter direction size and the thickness direction size) is 93: 1.
(2) the heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 25 percent of
A heat-conducting medium: 74 percent
Auxiliary agent: 1 percent of
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent and scaly magnetic powder, and then carrying out vacuum defoaming treatment on the slurry to obtain wave-absorbing magnetic sheet slurry suitable for uniform casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the surface of the steel strip with the special structure is a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part, the height of the convex part is 0.1mm, and an oily release agent needs to be sprayed on the steel strip before tape casting;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structural unit slurry with certain viscosity;
the viscosity of the heat-conducting structural unit slurry is controlled to be 4267 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the wave-absorbing magnetic sheets which are completely dried, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures; wherein the coating process is tape casting;
(5) repeating the steps (1) to (4), and preparing 5 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 5 casting green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.25 mm.
Comparative example 2
The difference of the comparative example of the embodiment 2 is that no heat conducting structural unit exists, namely 0.1mm casting film is cast on a flat steel strip, the components, the proportion and the process parameters are completely the same as those of the embodiment 2, and finally 5 pieces of casting film are hot-pressed to obtain 0.25mm wave-absorbing magnetic sheets.
The materials prepared in the embodiment 1 and the embodiment 2 and the comparative embodiment 1 and the comparative embodiment 2 are respectively tested for shielding performance, wave-absorbing performance (reflection loss), heat conductivity and density, in order to further test the heat dissipation effect of the magnetic sheet, an IC chip in a normal working state is selected as a research object, the wave-absorbing magnetic sheet is fixed on the surface of the chip, the surface of the wave-absorbing magnetic sheet is required to be directly and tightly attached to the surface of the chip, after 1 hour of working, the heat dissipation capability of the wave-absorbing magnetic sheet is evaluated by testing the temperature rise of the chip, and the test results are shown in Table 1.
TABLE 1 test results of materials prepared in examples 1-2 and comparative examples 1-2
Figure BDA0002495971060000091
Figure BDA0002495971060000101
The test results in table 1 show that the shielding performance and reflection loss of the example 1 and the comparative example 1 and the example 2 and the comparative example 2 are equivalent, which indicates that the addition of the heat-conducting medium unit does not significantly deteriorate the electromagnetic wave absorption and shielding performance of the wave-absorbing magnetic sheet, but significantly improves the heat conductivity and heat dissipation capacity, and simultaneously reduces the density of the wave-absorbing magnetic sheet, thereby facilitating the weight reduction of the material.
Example 3
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodic units, each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure, the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 12:1, and the area of each periodic unit is 200mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 12 percent of
Scaly soft magnetic alloy magnetic powder: 88 percent
The high-molecular binder is polyurethane;
the scaly soft magnetic alloy magnetic powder is Fe-Si-Al, the average thickness of the magnetic powder is 1.1 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is 103: 1.
(2) the heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 34 percent of
A heat-conducting medium: 64.5 percent
Auxiliary agent: 1.5 percent
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent, scaly magnetic powder and auxiliary materials, and then carrying out vacuum defoaming treatment on the slurry to obtain wave-absorbing magnetic sheet slurry suitable for uniform casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the surface of the steel strip with the special structure is a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part, the height of the convex part is 0.1mm, and an oily release agent needs to be sprayed on the steel strip before tape casting;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structural unit slurry with certain viscosity, wherein the viscosity of the heat-conducting structural unit slurry is required to be controlled at 3954 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the wave-absorbing magnetic sheet completely dried, wherein the coating process is casting, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing 4 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 4 cast green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.2 mm.
Comparative example 3
As a comparative example of example 3, the difference is that the ratio of the area of the wave-absorbing magnetic sheet to the area of the heat conducting structure is 7: 1.
Comparative example 4
As a comparative example of example 3, the difference is that the ratio of the area of the wave-absorbing magnetic sheet to the area of the heat conducting structure is 21: 1.
Comparative example 5
As an implementationComparative example of example 3, except that the area of the periodic unit is 38mm2。
Comparative example 6
As a comparative example of example 3, the difference is that the area of the periodic unit is 410mm2。
The materials prepared in example 3 and comparative examples 3-6 were tested for shielding property, wave-absorbing property (reflection loss), thermal conductivity and density, and in order to further test the heat dissipation effect of the magnetic sheet, an IC chip in a normal working state was selected as a research object, and the wave-absorbing magnetic sheet was fixed on the surface of the chip, and the surface of the wave-absorbing magnetic sheet was required to be directly and tightly attached to the surface of the chip, and after 1 hour of working, the heat dissipation capability of the wave-absorbing magnetic sheet was evaluated by testing the temperature rise of the chip, and the heat-conducting structural unit and the interface bonding condition with the wave-absorbing magnetic sheet unit were observed by a scanning electron microscope, and the test results are shown in table 2.
Table 2 test results of the materials prepared in example 3 and comparative examples 3 to 6
Figure BDA0002495971060000121
Among them, the heat conductive unit of comparative example 5 was difficult to mold, and the heat conductive unit had significant air holes. It can be known from the comparison of the experimental results of the embodiment 3, the comparative embodiment 3 and the comparative embodiment 4 in the table 2 that the ratio of the area of the wave-absorbing magnetic sheet to the area of the heat-conducting structural unit in the periodic unit has important influence on the electromagnetic wave absorption/shielding, the heat-conducting performance and the heat-radiating property of the heat-conducting wave-absorbing magnetic sheet, the heat-conducting coefficient and the heat-radiating capacity can be influenced by the high area ratio, the electromagnetic wave absorption/shielding deterioration can be caused by the low area ratio, and the heat-conducting and heat-radiating properties are not obviously improved.
The comparison of the experimental results of the comparative example 5 and the comparative example 6 shows that the too small area of the structural unit can cause the too small size of the heat-conducting structural unit, so that the heat-conducting structural unit is not easy to form, and the observation of a scanning electron microscope shows that the interface between the heat-conducting structural unit and the wave-absorbing magnetic sheet has air holes and cavities, which causes the reduction of electromagnetic wave absorption/shielding and heat conduction/heat dissipation; and the area of the periodic unit is too large, and the heat conduction and heat dissipation effects of the wave-absorbing magnetic sheet are slightly poor. Therefore, the area of the periodic unit and the ratio of the area of the wave-absorbing magnetic sheet to the area of the heat-conducting structural unit need to be controlled within a certain range.
Example 4
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodic units, each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure, the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 10:1, and the area of each periodic unit is 280mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 12 percent of
Scaly soft magnetic alloy magnetic powder: 88 percent
The high-molecular binder is polyurethane;
the scaly soft magnetic alloy magnetic powder is Fe-Ni, the average thickness of the magnetic powder is 1.2 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is 109: 1.
(2) the heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 41 percent
A heat-conducting medium: 58.1 percent
Auxiliary agent: 0.9 percent
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent, scaly magnetic powder and auxiliary materials, and then carrying out vacuum defoaming treatment on the slurry to obtain wave-absorbing magnetic sheet slurry suitable for uniform casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the steel belt with the special structure is of a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part, the height of the convex part is 0.1mm, and an oily release agent needs to be sprayed on the steel belt before tape casting;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structure unit slurry with certain viscosity, wherein the viscosity of the heat-conducting structure unit slurry is required to be controlled at 4534 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the wave-absorbing magnetic sheet completely dried, wherein the coating process is casting, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing 4 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 4 cast green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.2 mm.
Comparative example 7
As a comparative example of example 4, except that the heat transfer medium was boron nitride, the average particle size was 3.1 μm.
Comparative example 8
As a comparative example of example 4, except that the heat transfer medium was aluminum nitride, the average particle size was 5.2 μm.
The materials prepared in example 4, comparative example 7 and comparative example 8 were tested for shielding property, wave-absorbing property (reflection loss), thermal conductivity and density, and in order to further test the heat dissipation effect of the magnetic sheet, an IC chip in a normal working state was selected as a research object, the wave-absorbing magnetic sheet was fixed on the surface of the chip, the surface of the wave-absorbing magnetic sheet was required to be directly and tightly attached to the surface of the chip, and after 1 hour of working, the heat dissipation capability of the wave-absorbing magnetic sheet was evaluated by testing the temperature rise of the chip, and the test results are shown in table 3.
TABLE 3 test results of materials prepared in example 4 and comparative examples 7 to 8
Figure BDA0002495971060000151
As can be seen from comparison of the experimental results of example 4, comparative example 7, and comparative example 8 in table 3, the filling of other non-carbon heat-conducting media in the heat-conducting structural unit can also achieve good heat-conducting and heat-dissipating effects, but the shielding performance and the wave-absorbing performance of the magnetic sheet are seriously attenuated.
Example 5
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodic units, each periodic unit comprises a wave-absorbing magnetic sheet and a heat-conducting structure, the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 10:1, and the area of each periodic unit is 190mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 15 percent of
Scaly soft magnetic alloy magnetic powder: 85 percent of
The high-molecular binder is polyurethane;
the scaly soft magnetic alloy magnetic powder is Fe-Si-Al, the average thickness of the magnetic powder is 0.9 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is 88: 1.
(2) the heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 39 percent of
A heat-conducting medium: 60 percent of
Auxiliary agent: 1 percent of
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent, scaly magnetic powder and auxiliary materials, and then carrying out vacuum defoaming treatment on the slurry to obtain uniform wave-absorbing magnetic sheet slurry suitable for tape casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the surface of the steel strip with the special structure is a periodic rugged structure, the size and the shape of the convex part correspond to the heat conducting structure unit part, the size and the structure of the groove part correspond to the wave-absorbing magnetic sheet part, the height of the convex part is 0.1mm, and an oily release agent needs to be sprayed on the steel strip before tape casting;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structural unit slurry with certain viscosity, wherein the viscosity of the heat-conducting structural unit slurry is required to be controlled at 4152 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the wave-absorbing magnetic sheet completely dried, wherein the coating process is casting, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing 4 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 4 cast green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.2 mm.
Comparative example 9
As a comparative example of example 5, except that the thermally conductive structural unit paste viscosity was 2934 mPas.
Comparative example 10
As a comparative example of example 5, the difference is that the thermally conductive building block paste viscosity is 5071 mPas.
The materials prepared in example 5, comparative example 9 and comparative example 10 were tested for their shielding properties, wave-absorbing properties (reflection loss), thermal conductivity and density, and in order to further test the heat dissipation effect of the magnetic sheet, an IC chip in a normal working state was selected as the subject of study, and the wave-absorbing magnetic sheet was fixed on the surface of the chip, and the surface of the wave-absorbing magnetic sheet was required to be directly and tightly attached to the surface of the chip, and after 1 hour of working, the heat dissipation ability of the wave-absorbing magnetic sheet was evaluated by testing the temperature rise of the chip, and the heat-conducting structural unit and the interface bonding condition with the wave-absorbing magnetic sheet unit were observed by a scanning electron microscope, with the test results shown in table 4.
Table 4 test results of materials prepared in example 5 and comparative examples 9 to 10
Figure BDA0002495971060000171
Figure BDA0002495971060000181
Wherein, the heat-conducting structure unit and the interface joint part of the heat-conducting structure unit and the wave-absorbing magnetic sheet in the comparative example 9 have obvious air holes, and the heat-conducting structure unit in the comparative example 10 has obvious air holes. As can be seen from comparison of the test results of example 5 and comparative examples 9 to 10 in Table 4, when the viscosity of the slurry for preparing the heat conductive structural unit in the periodic structure is too high or too low, voids or pores are generated, resulting in a decrease in the heat conductive and heat dissipating ability of the magnetic sheet. Therefore, the slurry viscosity of the heat conductive structural unit needs to be controlled within a certain range.
Example 6
A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure comprises a plurality of periodsThe periodic unit comprises two parts of a wave-absorbing magnetic sheet and a heat-conducting structure, wherein the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure is 13:1, and the area of the periodic unit is 310mm2。
(1) The wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 10.5 percent
Scaly soft magnetic alloy magnetic powder: 89 percent
Auxiliary materials: 0.5 percent
The high-molecular binder is polyurethane;
the scaly soft magnetic alloy magnetic powder is Fe-Si-Al, the average thickness of the magnetic powder is 1.1 mu m, and the diameter-thickness ratio (the size in the diameter direction and the size in the thickness direction) is 103: 1.
(2) the heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 29 percent
A heat-conducting medium: 69.2 percent
Auxiliary agent: 1.8 percent
The binder is polyurethane;
the heat-conducting medium is a graphite microchip;
the auxiliary agent is KH550 silane coupling agent.
The heat conducting structure is circular.
The preparation method of the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure comprises the following steps:
(1) preparing casting slurry: uniformly mixing a high-molecular binder, an absolute ethyl alcohol solvent, scaly magnetic powder and auxiliary materials, and then carrying out vacuum defoaming treatment on the slurry to obtain wave-absorbing magnetic sheet slurry suitable for uniform casting;
(2) preparing the wave-absorbing magnetic sheet: coating the uniformly mixed slurry on a specially designed steel belt, drying the casting film, and taking the casting film off the steel belt after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes;
the surface of the steel strip with the special structure is a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part, the height of the convex part is 0.1mm, and an oily release agent needs to be sprayed on the steel strip before tape casting;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then defoaming the slurry to obtain uniformly-mixed heat-conducting structure unit slurry with certain viscosity, wherein the viscosity of the heat-conducting structure unit slurry is required to be controlled at 3178 mPas;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the wave-absorbing magnetic sheet completely dried, wherein the coating process is casting, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing 4 heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) and (3) carrying out hot pressing on the 4 cast green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure, wherein the compression amount of the magnetic sheet is 50%, and the thickness of the final composite magnetic sheet is 0.2 mm.
Comparative example 11
As a comparative example of example 6, except that the height of the steel strip protrusion was 0.05mm, 8 heat conductive and wave absorbing composite magnetic sheet cast green sheets having a periodic structure were prepared, and the 8 cast green sheets were hot pressed with a magnetic sheet compression of 50% and a final composite magnetic sheet thickness of 0.2 mm.
Comparative example 12
As a comparative example of example 6, except that the height of the steel strip protrusion was 0.13mm, 3 heat conductive and wave absorbing composite magnetic sheet cast green sheets having a periodic structure were prepared, the 3 cast green sheets were hot pressed, the compression amount of the magnetic sheet was 50%, and the thickness of the final composite magnetic sheet was 0.195 mm.
The materials prepared in example 6, comparative example 11 and comparative example 12 were tested for their shielding properties, wave-absorbing properties (reflection loss), thermal conductivity and density, and in order to further test the heat dissipation effect of the magnetic sheet, an IC chip in a normal working state was selected as the subject of study, the wave-absorbing magnetic sheet was fixed on the surface of the chip, and the surface of the wave-absorbing magnetic sheet was required to be directly and tightly attached to the surface of the chip, and after 1 hour of working, the heat dissipation ability of the wave-absorbing magnetic sheet was evaluated by testing the temperature rise of the chip, with the test results shown in table 5.
TABLE 5 test results of the materials prepared in example 6 and comparative examples 11 to 12
Figure BDA0002495971060000201
Among them, the cast sheet of comparative example 11 was less likely to be filmed and easily broken. As can be seen from the comparison of the test results of the example 6, the comparative example 11 and the comparative example 12 in the table 3, the too small protrusion height of the steel strip can result in too thin thickness of the wave-absorbing magnetic sheet casting green sheet, difficult film formation and easy fracture; the height of the steel strip protrusion is too large, and after the thickness of the casting green sheet is too large, the ordered arrangement degree of the flaky magnetic powder in the binder is poor, and finally the shielding and wave absorbing performance of the magnetic sheet is poor. Therefore, the height of the protrusion of the steel strip needs to be controlled within a certain range.
It will be understood by those skilled in the art that the foregoing is only exemplary of the present invention, and is not intended to limit the invention, which is intended to cover any variations, equivalents, or improvements therein, which fall within the spirit and scope of the invention.

Claims (9)

1. A preparation method of a heat-conducting wave-absorbing composite magnetic sheet with a periodic structure is characterized by comprising the following steps:
(1) preparing casting slurry of the wave-absorbing magnetic sheet part: uniformly mixing a high-molecular binder, a solvent, scaly soft magnetic alloy magnetic powder and auxiliary materials, and performing vacuum defoaming treatment to obtain uniform wave-absorbing magnetic sheet slurry suitable for casting;
(2) preparing the wave-absorbing magnetic sheet: coating the slurry prepared in the step (1) on a steel strip, drying the casting film, and taking the casting film off the steel strip after the solvent is completely volatilized to obtain the wave-absorbing magnetic sheet unit with a plurality of through holes; the surface of the steel strip is of a periodic rugged structure, the size and the shape of the convex part correspond to those of the heat conducting structure unit part, and the size and the shape of the groove part correspond to those of the wave-absorbing magnetic sheet part;
(3) preparing heat-conducting structure unit slurry: firstly, uniformly mixing a heat-conducting medium, a solvent, an auxiliary agent and a high-molecular binder, and then carrying out defoaming treatment to obtain heat-conducting structural unit slurry with proper viscosity and uniform mixing;
(4) preparing a heat conduction structural unit: uniformly coating the prepared slurry of the heat-conducting structure unit in the step (3) in through holes of the dried wave-absorbing magnetic sheets, and then drying to obtain single heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(5) repeating the steps (1) to (4), and preparing a plurality of heat-conducting wave-absorbing composite magnetic sheet cast green sheets with periodic structures;
(6) carrying out hot pressing on the plurality of casting green sheets to finally obtain the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure;
the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure unit is more than 8:1 and less than 15:1, and the area of the periodic unit is 40mm2～400mm2。
2. The method for preparing the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure according to claim 1, wherein the height of the protrusions of the steel strip in the step (2) is 0.06mm to 0.12 mm.
3. The method for preparing the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure according to claim 1, wherein the viscosity in the step (2) is controlled to be 3000-5000 mPas.
4. The heat-conducting and wave-absorbing composite magnetic sheet with the periodic structure obtained by the preparation method of the heat-conducting and wave-absorbing composite magnetic sheet with the periodic structure according to claim 1, wherein the heat-conducting and wave-absorbing composite magnetic sheet with the periodic structure comprises a plurality of periodic units, and the periodic units comprise two parts, namely wave-absorbing magnetic sheets and heat-conducting structural units;
the wave-absorbing magnetic sheet comprises the following components in percentage by weight:
high-molecular binder: 10 to 25 percent
Scaly soft magnetic alloy magnetic powder: 75 to 90 percent
Auxiliary materials: less than or equal to 1 percent
The heat conduction structure unit comprises the following components in percentage by weight:
high-molecular binder: 20 to 50 percent
A heat-conducting medium: 50 to 80 percent
Auxiliary agent: less than or equal to 2 percent
Wherein the area ratio of the wave-absorbing magnetic sheet to the heat-conducting structure unit is more than 8:1 and less than 15:1, and the area of the periodic unit is 40mm2～400mm2。
5. The heat-conducting wave-absorbing composite magnetic sheet with the periodic structure according to claim 4, wherein the wave-absorbing magnetic sheet and the polymer binder in the heat-conducting structural unit are one or more of polyurethane, acrylic resin, epoxy resin, liquid nitrile rubber, ethyl cellulose or PVB.
6. A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure according to claim 4, wherein the scaly soft magnetic alloy magnetic powder in the wave-absorbing magnetic sheet is one or more of Fe-Si, Fe-Si-Al, Fe-Si-Cr, Fe-Si-Al-Cr, Fe-Ni-Mo or Fe-Al, the thickness of the magnetic powder is 0.5 μm to 1.3 μm, and the ratio of the diameter to the thickness is more than 40: 1.
7. the heat-conducting wave-absorbing composite magnetic sheet with the periodic structure as claimed in claim 4, wherein the auxiliary materials in the wave-absorbing magnetic sheet are one or more of anti-settling agent, coupling agent, dispersing agent or toughening agent.
8. The heat-conducting wave-absorbing composite magnetic sheet with the periodic structure as claimed in claim 4, wherein the auxiliary agent in the heat-conducting structural unit is one or more of a coupling agent, a dispersing agent, a leveling agent or a defoaming agent.
9. A heat-conducting wave-absorbing composite magnetic sheet with a periodic structure according to claim 4, wherein the shape of the heat-conducting structural units is circular, square or rectangular.
CN202010418456.5A 2020-05-18 2020-05-18 Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof Active CN111554466B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010418456.5A CN111554466B (en) 2020-05-18 2020-05-18 Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010418456.5A CN111554466B (en) 2020-05-18 2020-05-18 Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof

Publications (2)

Publication Number Publication Date
CN111554466A CN111554466A (en) 2020-08-18
CN111554466B true CN111554466B (en) 2021-07-23

Family

ID=72001932

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010418456.5A Active CN111554466B (en) 2020-05-18 2020-05-18 Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof

Country Status (1)

Country Link
CN (1) CN111554466B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111952034B (en) * 2020-09-01 2022-04-15 赣州嘉通新材料有限公司 High-temperature-resistant high-thermal-conductivity sintered neodymium-iron-boron permanent magnet and preparation method thereof
CN112867377A (en) * 2020-12-16 2021-05-28 苏州驭奇材料科技有限公司 Heat-conducting wave absorber and preparation method and application thereof
CN113573552B (en) * 2021-07-26 2022-09-06 横店集团东磁股份有限公司 Magnetic shielding structure for wireless charging and manufacturing method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105007704A (en) * 2014-04-24 2015-10-28 苏州驭奇材料科技有限公司 Composite heat-dissipation wave-absorbing film
KR20160136226A (en) * 2015-05-18 2016-11-29 주식회사 이녹스 Composite sheet with EMI shield and heat radiation and Manufacturing method thereof
CN107880798A (en) * 2017-11-29 2018-04-06 横店集团东磁股份有限公司 A kind of heat conduction wave absorbing patch and preparation method thereof
CN108909113A (en) * 2018-08-24 2018-11-30 深圳市飞鸿达科技有限公司 A kind of thermally conductive noise suppression sheet and preparation method thereof
CN209022558U (en) * 2018-08-24 2019-06-25 深圳市飞鸿达科技有限公司 A kind of thermally conductive noise suppression sheet

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4798341B2 (en) * 2005-03-14 2011-10-19 Ｔｄｋ株式会社 Rare earth magnet sintering method
US7952322B2 (en) * 2006-01-31 2011-05-31 Mojo Mobility, Inc. Inductive power source and charging system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105007704A (en) * 2014-04-24 2015-10-28 苏州驭奇材料科技有限公司 Composite heat-dissipation wave-absorbing film
KR20160136226A (en) * 2015-05-18 2016-11-29 주식회사 이녹스 Composite sheet with EMI shield and heat radiation and Manufacturing method thereof
CN107880798A (en) * 2017-11-29 2018-04-06 横店集团东磁股份有限公司 A kind of heat conduction wave absorbing patch and preparation method thereof
CN108909113A (en) * 2018-08-24 2018-11-30 深圳市飞鸿达科技有限公司 A kind of thermally conductive noise suppression sheet and preparation method thereof
CN209022558U (en) * 2018-08-24 2019-06-25 深圳市飞鸿达科技有限公司 A kind of thermally conductive noise suppression sheet

Also Published As

Publication number Publication date
CN111554466A (en) 2020-08-18

Similar Documents

Publication Publication Date Title
CN111554466B (en) Heat-conducting wave-absorbing composite magnetic sheet with periodic structure and preparation method thereof
CN109664567B (en) Thin-sheet type heat-conducting wave-absorbing composite material and preparation method thereof
CN111589675B (en) High-thermal-conductivity electromagnetic wave absorption composite sheet and preparation method thereof
US10736237B2 (en) Heat sink, preparation method therefor, and communications device
JP6815152B2 (en) Hexagonal Boron Nitride Primary Particle Aggregates
CN111534016B (en) Electronic packaging material with heat conduction and electromagnetic shielding performance and preparation method thereof
KR101248385B1 (en) Hybrid composition with enhanced emi shielding and heat-releasing, and ink, sheet, and composition for injection using same
WO2014196496A1 (en) Resin-impregnated boron nitride sintered body and use for same
KR20150111469A (en) Electromagnetic wave shielding sheet, and the preparation method for the same
KR101552636B1 (en) Heat-conducting sheet and manufacturing method thereof
KR102645530B1 (en) Multifunctional composite film having heat dissipation and electronmagnetic shielding/absorption cpapticy and method for manufacturing thereof
CN111492474A (en) Insulating radiating fin
JP6285155B2 (en) Heat dissipation member and its use
TW200908871A (en) Sheet for prevention of electromagnetic wave interference, flat cable for high-frequency signal, flexible print substrate, and method for production of sheet for prevention of electromagnetic wave interference
CN118201337B (en) Wave-absorbing radiator, manufacturing method thereof and electronic equipment
CN114106564B (en) Oriented heat conduction gel, preparation method and application thereof
CN110746782A (en) High-performance wave-absorbing heat-conducting silica gel gasket convenient for die cutting and laminating and preparation method thereof
KR101900528B1 (en) ElECTROMAGNETIC WAVE SHIELDING SHEET AND THE PREPARATION METHOD FOR THE SAME
CN110117484B (en) Preparation method of heat-conducting silicone gel composite sheet with directionality
CN116456706A (en) Wave-absorbing heat-dissipating member and application thereof in electronic equipment
KR101531630B1 (en) Thin-heat film and heat-radiation sheet comparing the same
CN111303626A (en) Flexible insulating radiating fin of 5G antenna and preparation process thereof
KR20210084007A (en) Core-shell hybrid structured heat dissipating particles, and composites comprising the same
CN114644908B (en) Tough high-heat-conductivity film and preparation method thereof
CN111674115B (en) Artificial graphite flake high-orientation arranged heat conducting sheet and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant