JP2013059936A - Laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet of a novel composition making a graphite sheet as a base.SOLUTION: A laminated sheet 1 is such that a ceramics thermal spraying layer 21 formed by thermal spraying of ceramics is laminated on at least a portion of a graphite sheet 10. In the composition, the ceramics thermal spraying layer 21 can be laminated on at least one surface 11 in front and rear surfaces 11 and 12 of the graphite sheet 10. In addition, in the composition, the ceramics thermal spraying layer 21 can be laminated to an end face 13 along a thickness direction of the graphite sheet 10.

Description

  The present invention relates to a laminated sheet having a graphite sheet as a base.

  The graphite sheet has characteristics such as low density, high elasticity, and flexibility in addition to the characteristics inherent to graphite, such as heat resistance, chemical resistance, lubricity, and electrical conductivity. And, for example, it is used as a sealing material by utilizing its high elasticity, as a release material by utilizing lubricity and surface smoothness, as a heat conducting material and a heat dissipation material by utilizing high thermal conductivity, etc. Are used in various applications. Moreover, since it has various characteristics, it is considered that a new use is latent.

  As a graphite sheet, in addition to a single-phase graphite sheet, a laminated sheet obtained by laminating other materials using a graphite sheet as a base has been proposed. For example, a laminated sheet in which a resin thin film is laminated on a graphite sheet (for example, see Patent Document 1), a laminated sheet in which a metal foil is adhered to a graphite sheet (for example, see Patent Document 2), and a carbon fiber sheet is adhered to the graphite sheet. Further, a laminated sheet (Patent Document 3) on which metal plating is further applied has been proposed. In this way, by laminating other materials, new characteristics are added to the graphite sheet, so that it is expected that the range of selection of applications will be expanded.

  Then, this invention makes it a subject to provide the laminated sheet of the novel structure which makes a graphite sheet a base | substrate in view of said situation.

  In order to solve the above problems, the laminated sheet according to the present invention is “a ceramic sprayed layer formed by ceramic spraying is laminated on at least a part of the graphite sheet”. Further, the laminated sheet according to the present invention can be "a ceramic sprayed layer formed by ceramic spraying is laminated on at least one of the front and back surfaces of the graphite sheet".

  There has been no conventional laminated sheet in which a ceramic sprayed layer is laminated on a graphite sheet. Therefore, the laminated sheet of the present invention has a novel configuration as a laminated sheet having a graphite sheet as a substrate.

  In conventional laminated sheets in which a resin is laminated to laminate an electrical insulating layer on an electrically conductive graphite sheet, the excellent properties of the graphite sheet, such as heat resistance and chemical resistance, may be impaired by the resin. It was. On the other hand, in the present invention having the above configuration, an electrical insulating layer can be laminated on a graphite sheet with ceramics having excellent heat resistance and chemical resistance.

  Moreover, in order to reinforce the mechanical strength of the graphite sheet, the conventional laminated sheet in which the metal layers are laminated may not have sufficient heat resistance and cannot provide electrical insulation. On the other hand, in the present invention having the above configuration, the mechanical strength of the graphite sheet can be reinforced with ceramics having excellent heat resistance and low electrical conductivity.

  Furthermore, the conventional laminated sheet that used a resin adhesive (adhesive) to laminate other materials on the graphite sheet has heat resistance, chemical resistance, and mechanical strength due to the presence of the adhesive layer. There was a risk of damage. On the other hand, in the present invention having the above configuration, the layer laminated on the graphite sheet is a layer formed by thermal spraying of ceramics and does not require an adhesive. Disadvantages are avoided.

  Further, the graphite sheet has a high thermal conductivity in the plane direction, but has a low thermal conductivity in the thickness direction. For this reason, when a graphite sheet is used as a member that conducts and dissipates heat generated by the heating element, heat is dissipated mainly from the end face of the graphite sheet, which is inefficient. In contrast, ceramics generally have a thermal conductivity higher than the thermal conductivity in the thickness direction of the graphite sheet. Therefore, it is possible to dissipate heat conducted in the graphite sheet in the thickness direction by laminating the ceramic sprayed layer on at least one of the front and back surfaces of the graphite sheet.

  In addition, ceramics generally have low electrical conductivity, but there are various types of ceramics with high and low thermal conductivity. Therefore, various uses are possible by selecting the type of ceramics for forming the ceramic sprayed layer, or by combining ceramic sprayed layers of different types of ceramics. For example, in a graphite sheet, heat is conducted and dissipated by designing the arrangement of a portion where a ceramic sprayed layer made of ceramic with high thermal conductivity is laminated and a portion where a ceramic sprayed layer made of ceramic with low thermal conductivity is laminated. The route can be controlled.

  In addition to the above configuration, the laminated sheet according to the present invention can be "a ceramic sprayed layer formed by ceramic spraying is laminated on the end face along the thickness direction of the graphite sheet".

  Since the graphite sheet is relatively brittle, peeling occurs at the end face along the thickness direction, and the graphite powder may be detached and scattered. In the laminated sheet of this configuration, the end face along the thickness direction of the graphite sheet is laminated by the ceramic sprayed layer. Thereby, since the end surface of the graphite sheet is protected by the ceramic sprayed layer, peeling at the end surface is suppressed, and a situation where the graphite powder is detached and scattered can be avoided.

  As described above, as an effect of the present invention, a laminated sheet having a novel configuration using a graphite sheet as a base can be provided.

It is a longitudinal cross-sectional view of the lamination sheet of 1st embodiment of this invention. It is sectional drawing explaining use of the lamination sheet of FIG. It is a longitudinal cross-sectional view of the lamination sheet of 2nd embodiment of this invention. It is sectional drawing explaining use of the lamination sheet of FIG. It is a longitudinal cross-sectional view of the lamination sheet of 3rd embodiment of this invention. It is a longitudinal cross-sectional view explaining the structure and use of the lamination sheet of other embodiment. It is a longitudinal cross-sectional view explaining the structure and use of the laminated sheet of other embodiment.

  Hereinafter, specific embodiments of the present invention will be described. In the laminated sheet of the present embodiment, a ceramic sprayed layer is laminated on at least a part of the graphite sheet. The laminated sheet having such a structure can be manufactured by spraying ceramics on at least a part of the graphite sheet.

  The graphite sheet used as the base of the laminated sheet is a graphite sheet (expanded graphite sheet) obtained by abruptly heating graphite as an intercalation compound, gasifying the interlayer material to widen the layer spacing, and then rolling. It can be used. On the other hand, if the thickness of the graphite sheet is too thin, the strength is small and handling becomes difficult, whereas if it is too thick, flexibility is lost. Moreover, when a laminated sheet is used as a heat conducting member, the heat conduction resistance in the thickness direction increases as the graphite sheet becomes thicker. Therefore, if the thickness of the graphite sheet is 0.05 mm to 6.0 mm, it is suitable for general use, and if the thickness is 0.5 mm to 2.0 mm, it is more preferable, and the thickness is 0.5 mm. If it is -1.0mm, it is still more suitable.

  Ceramics used as the thermal spray material include aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, chromium oxide, mullite, spinel, and other oxide ceramics, as well as aluminum nitride, silicon nitride, boron nitride, silicon carbide, etc. Non-oxide ceramics can be exemplified.

As the thermal spraying method, a flame spraying method using a gas flame as a heat source is possible, but a plasma spraying method is desirable. In the plasma spraying method, since the sprayed material can be heated at a high temperature of 3000 ° C. or higher, it is suitable as a spraying method when a ceramic having a high melting point is the sprayed material. In plasma spraying, Ar gas, He gas, H ₂ gas, or a mixed gas thereof is used as a working gas, and a working gas is dissociated by applying a voltage to eject a high-temperature, high-speed plasma jet from a nozzle. And ceramic powder as a thermal spray material is supplied in this plasma jet, and it sprays on a graphite sheet. As a result, the melted / softened ceramic particles adhere to the surface of the graphite sheet and solidify / deposit to form a ceramic sprayed layer. Since the ceramic particles are crushed and flattened by thermal spraying, the ceramic particles in the ceramic sprayed layer can be distinguished from the ceramic particles in the ceramic layer other than the sprayed layer.

  In general, a treatment for roughening the surface of the material (base material) to be sprayed, such as a blast treatment, is necessary as a pretreatment for spraying. This is because the thermal spray layer is formed by mechanical contact between the particles of the thermal spray material and the surface of the substrate. By roughening the surface of the base material, the contact area between the thermal spray material and the base material is increased, and the anchor effect is exhibited by the unevenness of the base material surface, thereby improving the adhesion between the thermal spray material and the base material. JIS H 9302 (Ceramics spraying work standard) also describes that as a pretreatment for thermal spraying, a process of irregularly irregularizing the substrate such as threading and grooving, or a roughening process by projecting a blast material is performed. ing. The JIS also describes that adhesion is improved by spraying an undercoat agent prior to thermal spraying of the thermal spray material.

  However, as a result of the study by the present inventors, contrary to such a conventional method of thermal spraying, a graphite sheet without undergoing a process of roughening the surface of the graphite sheet and a process of spraying an undercoat agent on the graphite sheet. According to the manufacturing method of spraying ceramics, it has been found that it is possible to manufacture a laminated sheet having the above-described structure and having a high adhesion of the ceramic sprayed layer to the graphite sheet. Since the surface of the graphite sheet is very smooth (arithmetic mean roughness according to JIS B0601 is 5 μm to 6 μm), a laminated sheet with high adhesion of the ceramic sprayed layer to the graphite sheet can be obtained without roughening the surface. It is very interesting to be able to do it.

  Next, the structure of the lamination sheet of 1st embodiment is demonstrated. As shown in FIG. 1, the laminated sheet 1 is obtained by laminating a ceramic sprayed layer 21 on one of the front and back surfaces 11 of the graphite sheet 10. FIG. 1 does not accurately illustrate the relationship between the thickness of the graphite sheet 10 and the thickness of the ceramic sprayed layer 21. The same applies to other figures described later.

  With this configuration, one of the front and back surfaces of the electrically conductive graphite sheet 10 is electrically insulated by the ceramic sprayed layer 21 having excellent heat resistance, chemical resistance, and the like. Further, the mechanical strength of the graphite sheet 10 is reinforced by the ceramic sprayed layer 21.

  The laminated sheet 1 having the above configuration can be used for the following applications. For example, as shown in FIG. 2A, a ceramic sprayed layer 21 laminated on one surface 11 of the graphite sheet 10 is formed of ceramics (aluminum nitride, silicon carbide, etc.) having high thermal conductivity, and this ceramics. A heating element 71 such as an electronic component that is required to be electrically insulated is disposed so as to be in contact with the thermal spray layer 21. Thereby, the heat generated in the heating element 71 is conducted to the graphite sheet 10 through the ceramic sprayed layer 21. In the graphite sheet, the thermal conductivity in the plane direction (140 to 200 W / m · K) is much larger than the thermal conductivity in the thickness direction (3 to 5 W / m · K). The conducted heat is mainly conducted in the surface direction of the graphite sheet. In addition, the arrow in a figure shows the movement of heat typically.

  Further, as shown in FIG. 2 (b), a heating element 72 that is not required to be electrically insulated is disposed so as to contact one surface 11 of the graphite sheet 10, and the other side of the graphite sheet 10 is arranged. A ceramic sprayed layer 21 may be laminated on the surface 12. Here, the ceramic forming the ceramic sprayed layer 21 is a ceramic (aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, etc.) having higher thermal conductivity than the thermal conductivity in the thickness direction of the graphite sheet 10. Further, the thickness of the graphite sheet 10 is desirably smaller than that described with reference to FIG. As described above, the ceramic sprayed layer 21 with high thermal conductivity is laminated on at least one of the front and back surfaces 11 of the graphite sheet 10 that is difficult to dissipate heat in the thickness direction. The conducted heat is conducted in the surface direction of the graphite sheet 10 and is radiated in the thickness direction of the graphite sheet 10.

  Next, the structure of the lamination sheet 2 of 2nd embodiment is demonstrated. As shown in FIG. 3, the laminated sheet 2 has a ceramic sprayed layer 21 laminated on one surface 11 of the front and back surfaces of the graphite sheet 10 and the other surface of the front and back surfaces of the graphite sheet 10. 12, a ceramic sprayed layer 22 is laminated. The ceramic forming the ceramic sprayed layer 21 and the ceramic forming the ceramic sprayed layer 22 can be the same type or different types.

  With this configuration, the front and back surfaces of the electrically conductive graphite sheet 10 are both electrically insulated by the ceramic sprayed layers 21 and 22 that are excellent in heat resistance, chemical resistance, and the like. Further, the mechanical strength of the graphite sheet 10 is further reinforced by sandwiching the graphite sheet 10 between the ceramic sprayed layers 21 and 22 from both sides.

  The laminated sheet 2 having the above configuration can be used for the following applications. For example, as shown in FIG. 4A, the ceramic sprayed layer 21 laminated on one surface 11 of the front and back surfaces of the graphite sheet 10 is formed of ceramics (aluminum nitride, silicon carbide, etc.) having high thermal conductivity. A heating element 71 that is required to be electrically insulated is disposed so as to be in contact with the ceramic sprayed layer 21. On the other hand, the ceramic sprayed layer 22 laminated on the other surface of the graphite sheet 10 is formed of ceramics (zirconium oxide or the like) having low thermal conductivity. Thereby, in the graphite sheet 10, the surface 12 opposite to the surface 11 on which the heating element 71 is disposed is also electrically insulated, and the heat conducted from the heating element 71 to the graphite sheet 10 is mainly made of graphite. Conduction is conducted in the surface direction of the sheet 10.

  Further, as shown in FIG. 4B, the ceramic sprayed layers 21 and 22b laminated on the front and back surfaces of the graphite sheet 10 are both formed of ceramics (aluminum nitride, silicon carbide, etc.) having high thermal conductivity. And the heat generating body 71 calculated | required to be electrically insulated is arranged so that one ceramic sprayed layer 21 may be contacted. In this case as well, it is desirable that the thickness of the graphite sheet 10 is small. In this way, while electrically insulating the front and back surfaces of the graphite sheet 10, heat generated in the heating element 71 disposed on the one surface 11 is conducted in the surface direction of the graphite sheet 10, Heat can be dissipated in the thickness direction of the graphite sheet 10.

  Next, the structure of the lamination sheet 3 of 3rd embodiment is demonstrated. As shown in FIG. 5, the laminated sheet 3 is obtained by laminating a ceramic sprayed layer 31 on the front and back surfaces 11 and 12 of the graphite sheet 10 and the end face 13 along the thickness direction. In other words, the ceramic sprayed layer 31 is laminated on the entire surface of the laminated sheet 3.

  With this configuration, the entire surface of the electrically conductive graphite sheet 10 is electrically insulated by the ceramic sprayed layer 31 having excellent heat resistance and chemical resistance. Further, by covering the end face 13 of the graphite sheet 10 with the ceramic sprayed layer 31, it is possible to avoid the possibility that the graphite powder is detached from the end face 13 and scattered. In the ceramic sprayed layer 31, a sprayed layer laminated on one surface 11 of the front and back surfaces of the graphite sheet 10, a sprayed layer laminated on the other surface 12 of the front and back surfaces of the graphite sheet 10, and It is also possible to vary the type of ceramic forming each of the thermal spray layers laminated on the end face 13.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, in the above, a laminated sheet in which the ceramic sprayed layer is entirely laminated on at least one of the front and back surfaces 11 and 12 and the end surface 13 of the graphite sheet 10 is illustrated. However, the present invention is not limited to this, and the ceramic sprayed layer may be partially laminated on at least one of the front and back surfaces 11 and 12 and the end surface 13 of the graphite sheet 10. For example, as shown in FIG. 6A, the ceramic sprayed layer 24 made of ceramics having high thermal conductivity is formed on the graphite sheet 10 only in the portion where the heating element 71 that is required to be electrically insulated is disposed. It can be set as the lamination sheet 4 of the laminated structure.

  Moreover, as shown in FIG.6 (b), the part except the part by which the heat generating body 72 which is not calculated | required electrically insulated is arrange | positioned in one surface 11 in the front and back of the graphite sheet 10 A laminated sheet in which a ceramic sprayed layer 25 made of ceramic having low thermal conductivity is laminated, and the ceramic sprayed layer 25 is laminated on one of the other surface 12 and the end surface 13 of the front and back surfaces of the graphite sheet 10. 5 can be set. With this configuration, the heat generated in the heating element 72 can be mainly dissipated from the one end face (the right end face in the drawing) by transmitting the inside of the graphite sheet 10 in the surface direction.

  Furthermore, in the above, the case where the ceramic sprayed layer formed from the same kind of ceramics is laminated on a certain surface of the graphite sheet 10 is illustrated. However, the present invention is not limited to this, and in the ceramic sprayed layer laminated on one surface of the graphite sheet 10, the type of ceramics forming the ceramic sprayed layer can be partially varied. For example, as shown in FIG. 7, the ceramic sprayed layer 26 laminated on the surface 12 opposite to the surface 11 on which the heating element 72 is disposed in the graphite sheet 10 is formed by thermal spraying of ceramics having low thermal conductivity. The laminated sheet 6 can be divided into a layer 26a and a layer 26b formed by thermal spraying of ceramics having high thermal conductivity. By setting it as such a structure, the area | region where the heat which generate | occur | produced in the heat generating body 72 is easy to be thermally radiated from the surface 12 can be limited.

  The partial ceramic spraying can be performed by masking a portion of the graphite sheet that is not sprayed. Further, by performing thermal spraying performed by masking a plurality of times with different types of ceramics, it is possible to partially form a ceramic sprayed layer having different types of ceramics.

In the above, the thermal conductivity of several types of ceramics has been described in comparison with the thermal conductivity of the graphite sheet. The thermal conductivity of these ceramics is as follows.
Aluminum nitride: about 150 (W / m · K)
Silicon carbide: about 60 (W / m · K)
Aluminum oxide: about 32 (W / m · K)
Silicon nitride: about 20 (W / m · K)
Zirconium oxide: About 3 (W / m · K)

  Moreover, although the example which uses a laminated sheet as a member which conducts heat and dissipates heat was mainly mentioned and demonstrated above, the use of the laminated sheet of this invention is not limited to this. For example, the present invention can be applied to a sealing material that requires heat resistance and chemical resistance as well as electrical insulation.

1, 2, 3, 4, 5, 6 Laminated sheet 10 Graphite sheets 21, 22, 22b, 23, 24, 25, 26 Ceramic sprayed layer

Japanese Patent No. 2935771 Japanese Patent Publication No. 6-5109 Japanese Patent No. 3069398

Claims (3)

A laminated sheet, wherein a ceramic sprayed layer formed by ceramic spraying is laminated on at least a part of a graphite sheet. The laminated sheet according to claim 1, wherein a ceramic sprayed layer formed by ceramic spraying is laminated on at least one of the front and back surfaces of the graphite sheet. The laminated sheet according to claim 1 or 2, wherein a ceramic sprayed layer formed by thermal spraying of ceramics is laminated on an end face along the thickness direction of the graphite sheet.

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