JP2015183207A - Heating method of composite material using millimeter wave, and formation method of composite material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating method applicable to wide use, having a simple treatment process, capable of selecting easily a portion to be heated, and having inexpensive operation cost.SOLUTION: In a heating method of a composite material in an embodiment, a millimeter wave is irradiated to the composite material including a substrate layer and a heat-generating layer containing a heat-generating material generating heat by absorbing the millimeter wave, to thereby raise the temperature of the heat-generating layer by allow the heat-generating material to generate heat.

Description

  Embodiments of the present invention include a method of heating a composite material by irradiating a composite material including a heat generating layer with millimeter waves and increasing the temperature of the heat generating layer, and a method of forming a composite material using the same About.

  Conventionally, a technique for forming a film on the surface of a substrate or the like to protect it has been studied. However, there are cases where sufficient hardness and durability cannot be realized only by forming a coating such as a sprayed layer on the surface of a substrate or the like, and various improved techniques have been studied. For example, in Japanese Patent Laid-Open No. 5-13364 (Patent Document 1), a sprayed coating is formed using a specific material, and the diffusion of the sprayed coating to the base material and pressurization of the coating are performed using a pressurized electric resistance heating method. A technique for diffusing and densifying the sprayed film by sintering is disclosed.

  Japanese Patent Laid-Open No. 6-10112 (Patent Document 2) discloses that a porous film is formed on a surface of a substrate such as a roll by spraying ceramics or cermet, and the porous portion is impregnated with an inorganic coating agent. Further, a method of densifying and strengthening the coating with ceramics produced by further sealing treatment and, if necessary, firing treatment has been studied.

Japanese Patent Laid-Open No. 5-1364 JP-A-6-10112

  The present invention provides a heating method that can be applied to a wide range of uses, has a simple treatment process, and that it is easy to select a portion to be heated, and that has low operating costs.

  A method for heating a composite material according to an embodiment of the present invention irradiates a composite material comprising a base material layer and a heat generating layer containing a heat generating material that absorbs millimeter waves and generates heat, and radiates millimeter waves. The temperature of the heat generating layer is raised by causing the heat generating material to generate heat.

3 is a conceptual diagram for explaining a method of heating a composite material according to Example 1. FIG. In Example 1, it is explanatory drawing showing the state of the composite material before a heating. In Example 1, it is explanatory drawing showing the state of the composite material after a heating. 6 is a conceptual diagram for explaining a method of heating a composite material according to Example 2. FIG. In Example 2, it is explanatory drawing showing the state of the composite material before a heating. In Example 2, it is explanatory drawing showing the state of the composite material after a heating. 6 is a conceptual diagram for explaining a method of heating a composite material according to Example 3. FIG. In Example 3, it is explanatory drawing showing the state of the composite material before a heating. In Example 3, it is explanatory drawing showing the state of the composite material after a heating.

  The embodiment of the present invention will be described in detail as follows.

Millimeter wave heating In an embodiment of the present invention, a composite material is heated by irradiation with millimeter waves. In the present invention, such a heating method is called millimeter wave heating.

Composite Material In an embodiment of the present invention, the composite material comprises a base layer and a heat generating layer comprising a heat generating material that absorbs millimeter waves and generates heat. Moreover, the composite material which can be used in this invention may have comprised the other layer as needed. Examples of such composite materials include (i) a base material layer and a thermal spray layer composed of multiple layers on the base material layer, and an outermost surface layer of the thermal spray layer containing an exothermic material, ii) a base material layer, a multilayer coating on the base material layer, comprising a thermal spray layer comprising resin particles, and further comprising a metal plating layer on the thermal spray layer, and (iii) a base material layer, Examples thereof include a thermal spray layer composed of multiple layers on the base material layer, a resin spray layer containing resin particles, and a metal foil further provided on the thermal spray layer.

Base material layer In the embodiment of the present invention, the members constituting the base material layer of the composite material can be appropriately selected according to the use of the composite material. For example, a member made of metal or ceramics is used. Can be used. As the member made of metal, steel materials such as carbon steel and stainless steel, aluminum alloys, copper alloys, nickel alloys, and the like can be used. As the member made of ceramics, oxide ceramics such as Al ₂ O ₃ and MgO, ceramics such as SiC, nitride ceramics such as TiN, and composite oxides such as SiAlON can be used. In these, it is preferable to use members other than SiC as a base material layer.

Heat generation layer In the embodiment of the present invention, the heated composite material includes a heat generation layer including a heat generating material that absorbs millimeter waves and generates heat. The exothermic layer can include the exothermic material in any form, but typically the exothermic layer is in the form of a solid dispersion in which the exothermic material is dispersed in the carrier, or the exothermic layer is It has a film-like structure composed only of exothermic materials.

  In the embodiment of the present invention, the thickness of the heat generating layer can be arbitrarily set according to the use of the composite material, but is preferably 50 to 500 μm, and more preferably 100 to 300 μm.

Exothermic material The exothermic material that absorbs millimeter waves and generates heat needs to be an assembly of positive and negative dipoles. When such a material is irradiated with a high-frequency millimeter wave, the polarization of the dipole cannot follow the frequency, and is subject to friction with surrounding molecules, resulting in an exothermic phenomenon. The phenomenon in which energy is consumed inside the heat-generating material due to this friction is called dielectric loss. Silicon carbide SiC can be applied as the heat generating material.

Heat generation amount P (W / m ³ ) per unit volume by millimeter wave, millimeter wave frequency f (MHz), vacuum permittivity ε ₀ , exothermic material dielectric constant ε _r , exothermic material dielectric When the loss angle is δ and the electric field strength of millimeter waves is E (V / m), it is expressed by the following equation. In the expression, ε ₀ ε _r tan δ represents a dielectric loss factor. In general, the higher the value of the dielectric loss factor, the higher the millimeter wave absorption.

P (W / m ³ ) = 2πfε ₀ ε _r tan δE ²

  In this specification, the dielectric loss factor can be a numerical value measured using a perturbation method under conditions of a temperature of 25 ° C. and a frequency of 1 GHz.

  In one embodiment of the present invention, the heat generating layer includes a heat generating material and a carrier. The exothermic material is fine particles dispersed in the carrier.

  In the embodiment of the present invention, when the exothermic material has a fine particle shape, the average particle size is preferably 10 to 500 nm, and more preferably 20 to 100 nm. When the average particle diameter is within this range, the amount of heat generated by absorption of millimeter waves increases, and heating can be performed effectively. In the embodiment of the present invention, the average particle diameter is measured by a laser diffraction particle size distribution measuring apparatus.

  As said exothermic material used for embodiment of this invention, a metal, a metal oxide, a metal nitride, a metal carbide, a metal boride, carbon etc. can be used individually or in mixture, for example. Moreover, as a metal, the metal selected from the group which consists of iron, nickel, copper, and those alloys can be used. As the metal oxide, a metal oxide selected from the group consisting of alumina, zirconia, and a mixture thereof can be used. As the metal nitride, a metal nitride selected from the group consisting of silicon nitride, aluminum nitride, and a mixture thereof can be used. Moreover, silicon carbide can be used as the metal carbide. Moreover, a metal boride can be used. For example, high-purity alumina having a purity of 98% or more, for example, is not suitable as a heat-generating material because it does not absorb millimeter waves and passes through.

Carrier In one embodiment of the present invention, the heat generating layer is a solid dispersion in which a heat generating material is dispersed in a carrier. As the carrier, a material that does not absorb or shield millimeter waves should be used. Specifically, a metal oxide such as zirconia, a self-fluxing alloy having a nickel group, a cobalt group, or the like can be used as a support. The carrier for dispersing the heating element is not only a carrier but also a sprayed layer as a surface functional layer on the substrate. That is, the zirconia layer acts as a heat shielding layer for the substrate and is also used as a carrier. The zirconia layer generates heat by millimeter waves, but if a substance that absorbs millimeter waves more easily than zirconia (for example, stainless steel particles as a heat generating material) is present, the millimeter waves can be concentrated on the heat generating material.

  In the embodiment of the present invention, the amount of the exothermic material in the exothermic layer having a form in which the exothermic material is dispersed in the carrier is 5 to 30% by weight based on the weight of the entire layer including the exothermic material. Preferably, 10 to 15% by weight is more preferable. When the blending amount of the exothermic material is within this range, millimeter wave heating proceeds efficiently.

  In one embodiment of the present invention, the heat generating layer can be formed by spraying a heat generating layer forming material in which a heat generating material is dispersed in a carrier such as a thermal spray material on the surface of the substrate. Here, before and after thermal spraying of the heat generating layer forming material, a thermal spray material that does not include the heat generating material is sprayed to form a multilayer structure, and any of the layers forming the structure is a heat sprayed layer. A layer can be formed. In other words, it is possible to place a heat-generating material only in a specific layer of the thermal spray layer formed from the thermal spray material, and to raise only the temperature of the layer and the layer adjacent to the layer when irradiated with millimeter waves. . In the sprayed layer having such a multilayer structure, when the outermost layer is a heat generating layer, the vicinity of the surface can be selectively heated. According to such an embodiment, since only the vicinity of the outermost surface of the composite material can be selectively sintered, it is possible to form a sprayed layer having a high hardness near the surface and a low hardness in a portion away from the surface. it can. As a result, when the entire composite material formed is viewed, the surface is hard, and the portion adjacent to the base material in the sprayed layer is relatively low in hardness. it can. In addition, by directly forming the heat generation layer on the surface of the substrate and irradiating millimeter waves, diffusion bonding can proceed at the interface between the sprayed layer and the adjacent substrate, and the mutual adhesion can be improved. A composite material in which peeling between the base material and the sprayed layer hardly occurs can be produced.

  In the embodiment of the present invention, the heat generating layer may be composed of a porous material and a heat generating material filled in the pores of the porous material. In this case, the porous material functions as the carrier described above. Further, the substrate surface may be a porous layer. In this case, the surface of the base material filled with the heat generating material also functions as the heat generating layer. A heat generating layer comprising a combination of such a porous material and a heat generating material is required by filling the pores of the porous layer with a paste or composition in which the heat generating material is dispersed in an appropriate solvent. It can be formed by drying according to.

  In another embodiment of the present invention, the heat generating layer may have a film-like structure composed only of a heat generating material. For example, the exothermic material itself may constitute a heat generating layer having a film-like structure. In such an embodiment, the heat generating layer can be a metal plating layer. As the metal used for the plating treatment, a metal selected from the group consisting of nickel, silver, copper, and tin can be used. The plating treatment can be performed by any method, for example, an electroplating method, a hot dipping method, or the like.

  In the embodiment of the present invention, the heat generating layer can be a layer comprising a metal foil. As the metal used for the metal foil, a metal selected from the group consisting of nickel, silver, copper, and tin can be used. It is preferable to dispose a high-purity alumina plate having extremely high millimeter wave permeability on the metal foil and fix the metal foil.

Other Layers In the embodiment of the present invention, the composite material may include one or more arbitrary layers in addition to the base material layer and the heat generating layer. For example, an intermediate layer can be provided between the base material layer and the heat generating layer for the purpose of improving adhesion or a protective layer can be provided on the surface of the composite material. It is also possible to provide a layer to be processed that is deformed or modified by heat conducted from the heat generating layer.

  Specifically, a sprayed layer can be provided between the base material layer and the heat generating layer. When such a composite material is irradiated with millimeter waves, the exothermic material in the heat generating layer generates heat, and the temperature of the heat generating layer rises. Next, the adjacent sprayed layer is heated by the heated heating layer. When the thermal spray layer includes resin particles, the resin particles can be evaporated by heating the thermal spray layer.

Millimeter wave Millimeter wave refers to an electromagnetic wave having a frequency of 20 to 300 GHz. In addition, millimeter wave heating refers to heating using an electromagnetic wave in the millimeter wave band, and the object to be heated itself generates heat by an electric field of millimeter waves. For example, a dielectric is heated by a magnetic field by dielectric heating, and a metal is heated by resistance. In the embodiment of the present invention, the millimeter wave frequency is preferably 10 to 50 GHz, and more preferably 20 to 30 GHz. Using millimeter waves with a frequency in such a range is advantageous in that the heat-generating material can efficiently generate heat.

The output of the millimeter wave irradiated to the composite material is, for example, 1 to ² kW / cm ² .

  In the embodiment of the present invention, the irradiation time of the millimeter wave to the composite material is not particularly limited, but is preferably changed as appropriate according to the composite material to be obtained. In general, the irradiation time is preferably 1 to 60 minutes, more preferably 1 to 5 minutes.

Millimeter-wave heating device In an embodiment of the present invention, millimeter-wave heating can be performed using a millimeter-wave heating device. The configuration of the millimeter wave heating device is not particularly limited. For example, it is possible to use a millimeter-wave heating device that includes a millimeter-wave oscillator that generates a millimeter-wave to irradiate an object to be heated, a waveguide for transmitting the millimeter-wave to a desired position, and a heating furnace that contains an unheated object. it can.

  Irradiation of the composite material with millimeter waves may be performed under any condition in the air, in an inert atmosphere, or in vacuum. However, by performing irradiation in an inert atmosphere or in vacuum, oxidation of the composite material is performed. Can be prevented. For this reason, what the said heating furnace can seal is preferable. A heating furnace may consist of a metal container arrange | positioned so that a composite material may be covered. A vacuum chamber or the like can also be applied.

Formation of Composite Material Comprising Layer Dense on Surface In an embodiment of the present invention, a composite material comprising a base material layer and a thermal spray layer containing a heat generating material on the surface is irradiated with millimeter waves. The heat-generating material in the sprayed layer can be heated to increase the temperature of the surface of the sprayed layer, thereby densifying the material. As a result, a composite material having a densified layer on the surface can be obtained.

  For example, when a composite material comprising a base material layer and a thermal spray layer, of which the outermost layer is a heat generating layer, is irradiated with millimeter waves, the heat generating material in the heat generating layer generates heat, Since the temperature of the heat generating layer rises, the sintering of the layer proceeds and the hardness of the outermost surface can be increased. On the other hand, since the other layers of the sprayed layer do not contain an exothermic material, the progress of the sintering is small and the low hardness state can be maintained. As a result, since the hardness of the layer existing between the outermost layer and the base material is low, peeling between the base material layer and the sprayed layer due to the thermal expansion of the base material layer can be prevented.

In addition, when a composite material including a base material layer and a thermal spray layer in which the base material layer includes a multilayer, and the layer in direct contact with the base material layer is a heating layer, the base material layer and the thermal spray layer are irradiated. In some cases, diffusion bonding can be promoted at the interface between the two and the mutual adhesion can be improved. Even in this case, the progress of the sintering of the sprayed layer containing no heat generating material is small, and the hardness can be lowered.
When it is going to obtain the composite material which has the above structures, 1-60 minutes are preferable and, as for irradiation time, 1-5 minutes are more preferable.

Forming a composite material having a porous spray layer A millimeter wave is applied to a composite material including a base material layer, a heat generation layer, and a thermal spray layer including resin particles formed in the vicinity of the heat generation layer. The porous thermal spray layer can be formed by elevating the temperature of the heat generating layer and evaporating the resin particles contained in the thermal spray layer that has received the heat. As a result, a composite material comprising a porous sprayed layer can be obtained.

For example, when a millimeter wave is irradiated to a base material layer, a thermal spray layer comprising resin particles thereon, and a composite material having a heat generating layer thereon, the heat generating material in the heat generating layer is generated by the millimeter wave. Heat is generated and the heating layer rises in temperature. Next, this heat is received by the thermal spray layer adjacent to the heat generating layer, and the resin particles in the thermal spray layer are evaporated. As a result, pores are formed at the locations where the resin particles of the thermal spray layer were present, and a composite material comprising the porous thermal spray layer is obtained. In such a case, the resin can be selected from arbitrary ones, and examples thereof include polyethylene terephthalate (hereinafter sometimes referred to as PET), polyethylene, polypropylene, polystyrene, melamine resin, and phenol resin.
When it is going to obtain the composite material which has the above structures, 1-60 minutes are preferable and 1-5 minutes are preferable for irradiation time.

Applications of composite materials These composite materials can be applied to various fields. Specifically, abradable seal parts used for various sliding parts or gas turbine rotor gas seal parts. It can be used when creating In addition, embodiment is an illustration and the range of invention is not limited to them.

  An embodiment of the present invention will be described below with reference to FIGS.

Example 1
The first embodiment will be described with reference to FIGS. First, stainless steel (SUS304) having a size of 5 cm × 5 cm and a thickness of 10 mm was prepared as the base material layer 101.

  Next, zirconia (zirconia / 8% yttria (ZrO2 / 8% Y2O3)), manufactured by New Metals End Chemicals Corporation, Inc.) is sprayed on the surface of the base material layer 101 three times, and consists of three layers. A sprayed layer 102 having a thickness of 0.3 mm was provided.

  Further, the surface of the sprayed layer 102 is made of zirconia in which silver (NAG-32-2, manufactured by Daiken Chemical Manufacturing and Sales Co., Ltd.) having an average particle diameter of about 50 nm is mixed. 10% by weight of silver was sprayed to provide a heat-generating layer 103 having a thickness of 0.1 mm.

  The composite material 100 including the base material layer 101, the sprayed layer 102, and the heat generating layer 103 was disposed on the stage 105 in the heating furnace 104. After the inside of the heating furnace 104 was evacuated, the millimeter wave 107 having a frequency of 28 GHz was irradiated from the millimeter wave oscillator through the millimeter wave waveguide 106 at an output of 2 kW for 15 minutes. FMW-10-28 manufactured by Fuji Radio Industry Co., Ltd. was used as the millimeter wave heating device. By irradiation with the millimeter wave 107, the silver nanoparticles contained in the heat generating layer 103 are heated, and the temperature of the entire heat generating layer 103 is increased to advance the sintering of the heat generating layer 103. As a result, as shown in FIG. 3, the composite material including the heat generation layer 103 with high hardness and the thermal spray layer 102 with low hardness that can prevent peeling from the layer due to expansion of the base material layer 101. 110 was obtained.

Example 2
The second embodiment will be described with reference to FIGS. First, a nickel-based alloy (Inconel 600, manufactured by Niraco) having a size of 3 cm × 3 cm and a thickness of 5 mm was prepared as the base material layer 201.

Next, a CoNiCrAlY alloy containing PET resin particles 203 (Mitsui PET ^™ , manufactured by Mitsui Chemicals, Inc.) was sprayed on the surface of the base material layer 201 to provide a 0.2 mm thick sprayed layer 202.

  Furthermore, nickel was (molten) plated on the surface of the sprayed layer 202 to provide a nickel plating layer 204 having a thickness of about 5 μm.

  The composite material 200 including the base material layer 201, the thermal spray layer 202 including the PET resin particles 203, and the nickel plating layer 204 was disposed on the stage 105 in the heating furnace 104. After evacuating the inside of the heating furnace 104, a millimeter wave 107 having a frequency of 28 GHz was irradiated from a millimeter wave oscillator (not shown) for 15 minutes at an output of 2 kW through a waveguide 106 (see FIG. 4).

  The nickel plating layer 204 was heated and heated by irradiation with the millimeter wave 107. As a result, heat was transferred from the plating layer 204 to the surface of the thermal spray layer 202 adjacent to the plating layer, and the PET resin particles 203 contained in the thermal spray layer 202 were decomposed and removed by the heat, and pores 205 were formed. Further, heating was continued, the nickel plating layer was evaporated by self-heating, and disappeared from the sprayed layer 202. As a result, a composite material 206 having a porous sprayed layer 202 was obtained (see FIGS. 5 and 6).

  The third embodiment will be described with reference to FIGS. First, a nickel base alloy (Inconel 600, manufactured by Nilaco Corporation) having a size of 3 cm × 3 cm and a thickness of 5 mm was prepared as the base material layer 301.

Next, a CoNiCrAlY alloy containing PET resin particles 303 (Mitsui PET ^™ , manufactured by Mitsui Chemicals, Inc.) was sprayed on the surface of the base material layer 301 to provide a sprayed layer 302 having a thickness of 0.3 mm.

  Further, a nickel metal foil 304 having a thickness of 10 μm was disposed on the surface of the sprayed layer 302, and a high-purity alumina plate 305 (thickness 2 mm) was disposed on the foil. As the high-purity alumina plate, SAPPHAL (Saffal: trade name) purity 99.97% manufactured by Covalent Materials Co., Ltd. was used. Since this level of high-purity alumina material hardly absorbs millimeter waves, it was used as a fixing material for nickel foil.

  The composite material 300 including the base material layer 301, the thermal spray layer 302 including the PET resin particles 303, and the nickel metal foil 304 was disposed on the stage 105 in the heating furnace 104. After the inside of the heating furnace 104 was evacuated, a millimeter wave 107 having a frequency of 28 GHz was irradiated for 15 minutes at a power of 1 kW from a millimeter wave oscillator (not shown) through a waveguide 106 (see FIG. 7).

  The layer 304 made of nickel metal foil was heated and heated by irradiation with the millimeter wave 107. As a result, heat was transferred from the layer 304 made of nickel metal foil to the surface of the adjacent sprayed layer 302, and the PET resin particles 303 contained in the sprayed layer 302 were decomposed and removed by the heat to form pores 306. Further, heating was continued, the layer 304 made of nickel metal foil was evaporated by self-heating, and disappeared from the sprayed layer 302. The alumina plate 35 was removed, and as a result, a composite material 307 including a porous sprayed layer 302 was obtained (see FIGS. 8 and 9).

DESCRIPTION OF SYMBOLS 100: Composite material 101 before millimeter wave irradiation 101: Base material layer 102: Thermal spray layer 103: Heat generation layer 104: Heating furnace 105: Stage 106: Waveguide 107: Millimeter wave 108: Heat generation layer 109 which sintering advanced by heating : Interface 110: Composite material after millimeter wave irradiation 200: Composite material before millimeter wave irradiation 201: Base material layer 202: Thermal spray layer 203: PET resin particles 204: Plating layer 205: Pore 206: Composite material after millimeter wave irradiation 300: Composite material before millimeter wave irradiation 301: Base material layer 302: Thermal spray layer 303: PET resin particle 304: Metal foil 305: High-purity alumina plate 306: Pore 307: Composite material after millimeter wave irradiation

Claims (11)

  The heat generating layer is formed by irradiating a composite material comprising a base material layer and a heat generating layer including a heat generating material that absorbs millimeter waves and generating heat to cause the heat generating material to generate heat. A method for heating a composite material, characterized in that the temperature of the composite material is raised.   The method according to claim 1, wherein a frequency of the millimeter wave is 10 to 50 GHz.   The method according to claim 1 or 2, wherein the millimeter wave irradiation is performed under vacuum conditions.   The method according to any one of claims 1 to 3, wherein the exothermic material is fine particles having an average particle diameter of 10 to 500 nm.   The method according to claim 1, wherein the exothermic material is metal particles.   6. The method of claim 5, wherein the metal particles comprise a metal selected from the group consisting of iron, nickel, copper, and alloys thereof.   The method according to any one of claims 4 to 6, wherein the heat generating layer comprises a solid dispersion in which the fine particles are dispersed in a carrier.   The method according to claim 1, wherein the heat generating layer is a metal plating layer.   The method according to claim 1, wherein the heat generating layer is a layer comprising a metal foil.   The sprayed layer is formed by irradiating a composite material comprising a base material layer and a sprayed layer containing a heat-generating material that absorbs millimeter waves and generating heat to cause the heat-generating material to generate heat. The method of forming a composite material comprising a densified layer on the surface, wherein the temperature is raised and densified.   A composite material comprising: a base material layer; a heat generation layer including a heat generating material that absorbs millimeter waves and generates heat; and a sprayed layer including resin particles formed in the vicinity of the heat generation layer. Irradiating millimeter waves to generate heat in the exothermic material, the temperature of the exothermic layer is increased, and the resin particles contained in the thermal spray layer are evaporated to form a porous thermal spray layer. A method for forming a composite material comprising a porous sprayed layer.

Images