WO2023002834A1 - Heat insulating film and heat insulating component - Google Patents

Heat insulating film and heat insulating component Download PDF

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Publication number
WO2023002834A1
WO2023002834A1 PCT/JP2022/026328 JP2022026328W WO2023002834A1 WO 2023002834 A1 WO2023002834 A1 WO 2023002834A1 JP 2022026328 W JP2022026328 W JP 2022026328W WO 2023002834 A1 WO2023002834 A1 WO 2023002834A1
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Prior art keywords
inorganic compound
heat
film
compound layer
inorganic
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PCT/JP2022/026328
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French (fr)
Japanese (ja)
Inventor
亮子 山野井
直樹 山川
陽介 田口
圭資 宮本
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アート金属工業株式会社
アクロス株式会社
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Publication of WO2023002834A1 publication Critical patent/WO2023002834A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/10—Pistons  having surface coverings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials

Definitions

  • the present invention relates to a heat shield film and a part (hereinafter referred to as "heat shield part") insulated by the formation of the heat shield film, for example, a heat shield film formed on the top surface of an engine piston , and a heat shielding component such as a piston on which the heat shielding film is formed.
  • a heat insulating film is formed on the top surface of the piston to improve thermal efficiency. Improvements are being made.
  • the thermal barrier film 70 is formed of inorganic coating layers 72 (72a, 72b) made of an inorganic material such as silica, zirconia, alumina, and ceria containing hollow particles 80a, 80b. (See FIG. 4 of Patent Document 1).
  • the high temperature such as the combustion chamber of the engine
  • the heat insulating layer formed on the top surface of the piston 102 is formed by the alumite layer 241, and on this heat insulating layer (alumite layer) 241, scale-like inorganic particles are dispersed in an inorganic compound formed from alkoxide as a protective layer. It is proposed to form an inorganic compound layer 243 composed of a reference).
  • the heat shield film 240 described in Patent Document 2 above the heat insulating layer 71 formed by the resin and the hollow particles 80 in Patent Document 1 is changed to an alumite layer 241, and in Patent Document 1, the hollow particles 80a and 80b
  • the inorganic coating layers 72 (72a, 72b) formed of an inorganic material with an inorganic compound layer (protective layer) 243 in which scale-like inorganic particles are dispersed in an inorganic compound formed from an alkoxide.
  • the inorganic compound layer 243 formed of alkoxide provided on the heat shield film 240 described in Patent Document 2 mentioned above is a liquid paint (a metal alkoxide solution containing inorganic particles) that becomes the inorganic compound layer 243 is applied to the piston 102.
  • the chemical reaction is caused by baking. Destruction such as cracks occurs.
  • the vacancies and microcracks generated in the inorganic compound layer 243 in this way become starting points for peeling of the inorganic compound layer 243 and the like.
  • the fuel that has penetrated into the microcracks further penetrates into the scaly inorganic particles and is retained in the inorganic particles. .
  • unburned loss the fuel loss associated with the discharge of unburned fuel.
  • the formation of the inorganic compound layer 243 on the top surface of the piston 102 which has an uneven surface due to the occurrence of microcracks, not only reduces the heat insulating properties of the heat insulating film 240 as described above, but also Abnormal explosion (knocking) is likely to occur on the top surface.
  • the heat shielding film 240 of Patent Document 2 which includes the inorganic compound layer 243, has high heat shielding properties and heat resistance. I haven't been able to.
  • the present invention has been made to solve the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a heat insulating film and a heat insulating component on which the heat insulating film is formed, which solves the various problems caused by cracks.
  • the heat shield film 10 of the present invention is In the heat shield film 10 formed on at least part of the surface of the heat shield target component 2, an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide; It is characterized by comprising a top coat 30 formed on the inorganic compound layer 20 and having a thickness of 0.5 to 30 ⁇ m and made of an organic-inorganic hybrid material composed of a mixture of metal alkoxide and resin. (Claim 1).
  • the surface of the top coat 30 preferably has a surface arithmetic mean height Sa defined in ISO 25178 of 0.1 to 1.5 ⁇ m, or an interface development area ratio Sdr of 0.01 to 1.5 (claim Item 2).
  • An anodized film layer 40 can be further provided under the inorganic compound layer 20 (Claim 3).
  • the heat shield part 1 of the present invention is formed by covering at least a part of the surface of the heat shield target part 2 with the heat shield film 10,
  • the heat shield film 10 is an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide;
  • a top coat 30 formed on the inorganic compound layer 20 and having a thickness of 0.5 to 30 ⁇ m and made of an organic-inorganic hybrid material composed of a mixture of a metal alkoxide and a resin is provided. (Claim 4).
  • the surface of the top coat 30 has a surface arithmetic mean height Sa defined in ISO25178 of 0.1 to 1.5 ⁇ m, or an interface developed area ratio Sdr of 0.01 to 1. 0.5 (claim 5).
  • an anodized film layer 40 can be further provided under the inorganic compound layer 20 (claim 6).
  • the part 2 to be heat-insulated can be an engine piston, preferably an engine piston made of an aluminum alloy (Claim 7).
  • the heat shielding film 10 of the present invention and the heat shielding component 1 on which the heat shielding film 10 is formed have the following remarkable effects.
  • the inorganic compound layer 20 could be covered with the topcoat 30 in a state in which the organic-inorganic hybrid material was impregnated in the pores 23 and microcracks generated in the inorganic compound layer 20.
  • the top coat 30 is an organic-inorganic mixture of metal alkoxides, such as silicon alkoxide, zirconium alkoxide, and titanium alkoxide, which are inorganic components, and resins, which are organic components such as alkylsilicate resins, silicone resins, and fluorine-based resins. Because it is made of a hybrid material, it has both the high hardness and high heat resistance of the metal alkoxide, which is an inorganic component, and the flexibility of the resin, which is an organic component. Breakage such as microcracks is less likely to occur even when used in .
  • the heat shielding component 1 provided with the heat shielding film 10 of the present invention is used in a high-temperature environment, peeling of the topcoat 30 is difficult to occur, and the voids 23 and microcracks occur in the inorganic structure.
  • the compound layer 20 is covered with the topcoat 30, and the organic-inorganic hybrid material constituting the topcoat 30 penetrates into the microcracks and the pores 23 and hardens, so that the pores 23 and the microcracks are used as starting points. It was possible to make it difficult to cause peeling of the inorganic compound layer 20 formed on the substrate.
  • the surface of the heat shield film 10 is smoothed by the formation of the top coat 30, the surface area becomes smaller than when the surface is uneven, resulting in heat exchange on the surface of the heat shield film 10. is less likely to occur, and the heat shielding properties of the heat shield film 10 can be improved.
  • the heat shield film 10 of the present invention when the heat shield film 10 of the present invention is formed on the top surface of the piston of the engine, the surface of the inorganic compound layer 20 is covered with the top coat 30, so that part of the fuel injected into the combustion chamber becomes inorganic. Since the compound layer 20 does not soak into the pores 23, microcracks, and scaly inorganic particles 22 and is not retained, the unburned loss can be reduced.
  • the top surface of the piston becomes a smooth surface, which makes it possible to suppress the occurrence of abnormal explosion (knocking) on the top surface of the piston.
  • FIG. 4 is a cross-sectional explanatory view showing another configuration example of the heat shield film of the present invention.
  • FIG. 10 of Patent Document 2 A cross-sectional SEM image ( ⁇ 2000) of the heat shield film of Example 1.
  • FIG. A cross-sectional SEM image ( ⁇ 2000) of the heat shield film of Comparative Example 1.
  • FIG. Cross-sectional explanatory drawing of the conventional thermal insulation film (corresponding to FIG. 4 of Patent Document 1).
  • Cross-sectional explanatory drawing of the conventional thermal insulation film corresponding to FIG. 10 of Patent Document 2.
  • the part 2 to be heat-insulated is the piston of the engine
  • the heat-insulating film 10 of the present invention is formed on the top surface of the piston to form the heat-insulating part 1 of the present invention.
  • the heat shielding film 10 of the present invention can be formed not only on engine pistons, but also on various articles requiring heat shielding, such as various machine parts used in high temperature environments.
  • the heat shielding component 1 of the present invention includes a heat shielding target component 2, which is a metal part such as an engine piston, and at least a portion of the surface of the heat shielding target component 2, such as In the piston described above, it is constituted by a heat insulating film 10 formed on the top surface.
  • the heat shield film 10 is a film formed on the surface of the heat shield part 2 in order to block heat conduction to the heat shield part 2, and is made of alkoxide. It includes at least an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 and a topcoat 30 formed from an organic-inorganic hybrid material that is a mixture of a metal alkoxide and a resin.
  • the heat shield film 10 in FIG. 1 is a two-layer structure heat shield film 10 formed of the inorganic compound layer 20 and the topcoat 30 described above, and FIG. , and an anodized film layer 40 formed under the inorganic compound layer 20.
  • the thermal barrier film 10 has a three-layer structure.
  • the part 2 to be heat-insulated is made of aluminum or an aluminum alloy, and the part 2 to be heat-insulated is subjected to anodization treatment in advance.
  • An anodized film layer (alumite layer) 40 may be formed in advance, and the inorganic compound layer 20 and the topcoat 30 may be formed on the anodized film layer (alumite layer) 40 .
  • Such an alumite layer 40 can be formed by anodic oxidation of aluminum using an acidic aqueous solution of sulfuric acid, oxalic acid, phosphoric acid, etc., and its film thickness ranges from 10 to 100 ⁇ m.
  • the adhesion between the inorganic compound layer 20 and the base material of the aluminum alloy piston can be improved.
  • the heat shield film 10 of the present invention is not limited to the structure shown in FIGS. 1 and 2.
  • the heat shield film 10 having the structure shown in FIG. A configuration in which a known heat insulating layer such as a heat insulating layer made of an inorganic material is provided, and a known heat insulating layer such as a heat insulating layer made of an inorganic material in which the hollow particles are dispersed are provided between the alumite layer 40 and the inorganic compound layer 20 in FIG.
  • a configuration in which a heat insulating layer is provided may be employed, and various configurations can be employed as long as the configuration comprises at least the inorganic compound layer 20 and the topcoat 30 described above.
  • the inorganic compound layer 20 has a structure in which scale-like inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide, as described above. As shown in FIGS. 1 and 2, scale-like inorganic particles 22 arranged in parallel with the surface of the heat shielding target part 2 in the longitudinal direction are formed from an alkoxide with an inorganic compound 21 as a binder. It has a combined structure.
  • the inorganic compound 21 constituting the inorganic compound layer 20 is composed of a metal oxide formed from an alkoxide such as silicon alkoxide, zirconium alkoxide, aluminum alkoxide, and cerium alkoxide.
  • zirconium alkoxide is preferable because it has toughness and easily follows the elongation of the heat shielding target component 2, which is an aluminum alloy piston.
  • the inorganic compound 21 of the inorganic compound layer 20 is composed of a metal oxide formed from an alkoxide, water and alcohol are generated as by-products when the alkoxide is treated, but these can be easily removed by heat treatment. It is possible to
  • a binder having an amino group (—NH 2 ) is dispersed in the inorganic compound 21, and examples of such a binder include aminopropyltriethoxysilane, aminopropyltrimethoxysilane, and aminopropylmethyldimethoxysilane.
  • An amino-based coupling agent such as can be used.
  • the thickness of the inorganic compound layer 20 configured as above is 10 to 500 ⁇ m, preferably 10 to 200 ⁇ m.
  • Examples of the scale-like inorganic particles 22 dispersed in the inorganic compound 21 include mica, talc, and wollastonite. Any one of these may be used alone, or any of them may be used. It is also possible to use a mixture of two or all three types.
  • Mica, talc, and wollastonite do not melt even at high temperatures of about 1000°C, and have sufficient heat resistance.
  • scale-like refers to a shape with a thickness that is sufficiently small relative to the length, and in addition to plate-like and flake-like shapes, if the thickness is sufficiently small relative to the length, fibrous and needle-like shapes are also included in the scaly form here.
  • the size of the scale-like inorganic particles 22 dispersed in the inorganic compound layer 20 is preferably about 0.1 to 100 ⁇ m, more preferably about 1 to 20 ⁇ m in average particle size.
  • Such scale-like inorganic particles 22 are dispersed in the inorganic compound 21 so that 35 to 75 vol % of the inorganic compound layer 20 becomes the inorganic particles 22 .
  • the topcoat 30 formed on the inorganic compound layer 20 is a mixture of a metal alkoxide such as silicon alkoxide, zirconium alkoxide, and titanium alkoxide, and a resin having excellent heat resistance such as alkylsilicate resin, silicone resin, and fluorine resin. It is formed from an organic-inorganic hybrid material consisting of
  • the organic-inorganic hybrid material is impregnated into the pores 23 and microcracks generated in the inorganic compound layer 20. You can cover the top.
  • the heat shield film 10 having such a top coat 30 is formed on the top surface of the piston, the fuel penetrates into the pores 23 and cracks of the inorganic compound layer 20 and the scale-like inorganic particles 22.
  • the surface of the heat shield film 10 smooth, it is possible to prevent abnormal fuel combustion (knocking) from occurring on the top surface of the piston.
  • the film thickness of the top coat is preferably 0.5-30 ⁇ m, more preferably 0.5-10 ⁇ m.
  • the formation of the top coat 30 smoothes the surface of the heat shield film 10, which improves the heat shield performance due to the reduction in the surface area and prevents the occurrence of abnormal combustion (knocking) on the top surface of the piston. By preventing this, the fuel efficiency of the engine is improved.
  • the surface roughness of the top coat 30 is 0.1 to 1.5 ⁇ m in terms of surface arithmetic mean height Sa defined by ISO 25178, or 0.01 to 1.5 ⁇ m in terms of interface development area ratio Sdr. It is preferable to
  • the heat shield film 10 of the present invention described above uses the piston of the engine as a heat shield target component as described above, and by forming it on the top surface of this piston, as with the conventional heat shield film, It is possible to reduce the unburned loss while maintaining the effect of suppressing the heat release in the combustion chamber, and the formation of the heat shield film 10 with a smooth surface is due to the unevenness of the surface.
  • the conventional heat shield film which has a large surface area and facilitates heat exchange (thus, the heat shielding performance is low)
  • the heat shielding performance can be improved, and abnormal combustion (knocking) on the top surface of the piston can be prevented. can be suppressed to improve fuel efficiency.
  • the heat shield film 10 of the present invention is suitable for forming on the top surface of an engine piston, particularly a piston made of an aluminum alloy with good thermal conductivity.
  • the part (part to be heat-insulated) 2 for which heat is shielded by forming the heat-insulating film 10 of the present invention is not limited to the piston of the engine, but may be a mechanical part used in a high-temperature environment, such as an exhaust manifold. It can be applied to various mechanical parts that require heat insulation, such as exhaust system parts and EGR (exhaust gas recirculation).
  • EGR exhaust gas recirculation
  • thermal barrier films formed on the samples of Examples 1 and 2 and Comparative Examples 1 to 3 are as shown in Table 1 below.
  • each sample was held in a heated state of 350°C for 10 minutes, and then cooled by being immersed in water at room temperature.
  • oil absorption For the evaluation of oil absorption, drop n-hexadecane (low-viscosity oil similar to fuel) on the surface of the heat shield film and leave it for 3 minutes, then wipe it off with a paper cloth. After dropping and wiping off with a waste cloth, the weight change of each sample was measured as "oil absorption (mg)".
  • the surface was observed with a laser microscope using an objective lens with a magnification of 50 times.
  • the measurement was performed using a laser microscope (objective lens with a magnification of 50 times), and as roughness parameters, the surface arithmetic average height Sa defined by ISO25178 and the developed area ratio Sdr of the interface were measured.
  • Table 2 shows the results of the oil absorption test, surface/cross-section observation, and surface roughness measurement described above.
  • FIGS. 3 to 7 show the state of the heat shield film surface of each sample of Examples 1 and 2 and Comparative Examples 1 to 3, and cross-sectional SEM images of Example 1 and Comparative Example 1 are shown in FIGS. each shown.
  • FIG. 8 is a cross-sectional SEM image of the sample of Example 1, and although the cross-sectional SEM image of the sample of Example 2 is omitted, similar results were confirmed.
  • Comparative Example 2 As in Examples 1 and 2, a top coat formed of an organic-inorganic hybrid material was provided, and the oil absorption rate before thermal shock was 0.3%, which was higher than that of Examples 1 and 2. It is lower than that of the hot film, and the surface roughness is 0.12 in surface arithmetic average height Sa, and 0.03 in surface expansion area ratio Sdr, confirming that a smooth surface is obtained. rice field.
  • the film thickness of the top coat formed on the thermal barrier film of Comparative Example 2 was 50 ⁇ m, which is thicker than the film thickness of the top coats of Examples 1 and 2 (3 ⁇ m in Example 1 and 30 ⁇ m in Example 2). Therefore, it is considered that the residual stress in the film was increased by increasing the film thickness of the topcoat, and as a result, the film delaminated due to the thermal shock.
  • the thermal barrier film of Comparative Example 3 has a topcoat thickness of 5 ⁇ m, which is within the thickness range of the topcoat of the present invention, but the topcoat is formed only of an inorganic alkoxide metal (Zr alkoxide). It is different from the structure of the heat shield film of the present invention in that
  • the oil absorption rate before the thermal shock was already as high as 16.2%, and the surface roughness was 1.30 ⁇ m in surface arithmetic mean height Sa, but the developed area ratio Sdr of the interface was 4.07.
  • the top coat was peeled off by applying high and further thermal shock.
  • the film thickness of less than 3 ⁇ m (Example 1), which is the minimum value of the film thickness of the top coat in the above-mentioned test examples, was 0.00.
  • the film thickness of the top coat was changed in the range of 5 to 2 ⁇ m, and the changes in the appearance and oil absorption of the formed heat shield film were measured.
  • the film thickness of the top coat was determined based on cross-sectional observation.
  • Heat shield part 2 Heat shield target part (piston) REFERENCE SIGNS LIST 10 heat shield film 20 inorganic compound layer 21 inorganic compound 22 scaly inorganic particles 23 pores 30 top coat 40 anodized layer (alumite layer) 70 heat insulating film 71 heat insulating layer 72 (72a, 72b) inorganic coating layer 80, 80a, 80b hollow particles 102 piston 240 heat insulating film 241 heat insulating layer (alumite layer) 243 inorganic compound layer (protective layer)

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Abstract

Provided is a heat insulating film which, despite being provided with an inorganic compound layer, overcomes various problems that arise due to the occurrence of voids or microcracks in the inorganic compound layer. A heat insulating film (10) formed on at least a portion of the surface of a component 2 to be heat-insulated is formed from: an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide; and a top coat 30 that is formed on the inorganic compound layer 20, has a thickness of 0.5-30 µm, and is formed by an organic-inorganic hybrid material comprising a mixture of a metal alkoxide and a resin. By the formation of the top coat 30, voids 23 or microcracks in the inorganic compound layer 20 are filled by the organic/inorganic hybrid material, and the surface of the inorganic compound layer 20 is covered, whereby the heat insulating performance of the heat insulating film 10 is enhanced, and fuel efficiency of an engine is improved by forming the heat insulating film 10 on piston top surfaces of the engine.

Description

遮熱膜及び遮熱部品Heat shield film and heat shield parts
　本発明は，遮熱膜，及び，前記遮熱膜の形成によって遮熱された部品（本明細書において「遮熱部品」という。）に関し，例えばエンジンのピストンの頂面に形成する遮熱膜，及び，該遮熱膜が形成されたピストン等の遮熱部品に関する。 The present invention relates to a heat shield film and a part (hereinafter referred to as "heat shield part") insulated by the formation of the heat shield film, for example, a heat shield film formed on the top surface of an engine piston , and a heat shielding component such as a piston on which the heat shielding film is formed.
　燃費の向上等を目的として，エンジンの燃焼室内で発生した熱がピストン等を伝って放出されることにより生じる熱損失を低減すべく，ピストンの頂面に遮熱膜を形成して，熱効率を改善することが行われている。 In order to reduce the heat loss caused by the heat generated in the combustion chamber of the engine being released through the piston, etc., for the purpose of improving fuel efficiency, etc., a heat insulating film is formed on the top surface of the piston to improve thermal efficiency. Improvements are being made.
　このような遮熱膜として，後掲の特許文献１には，図１０に示すようにピストン１０２の頂面に中空粒子８０を埋設した樹脂から成る断熱層７１と，この断熱層７１の表面に形成された，中空粒子８０ａ，８０ｂを含むシリカ，ジルコニア，アルミナ，及びセリア等の無機材料から成る無機系被膜層７２（７２ａ，７２ｂ）から成る遮熱膜７０を形成する構成が提案されている（特許文献１の図４参照）。 As such a heat insulating film, as shown in FIG. A configuration has been proposed in which the thermal barrier film 70 is formed of inorganic coating layers 72 (72a, 72b) made of an inorganic material such as silica, zirconia, alumina, and ceria containing hollow particles 80a, 80b. (See FIG. 4 of Patent Document 1).
　また，上記特許文献１に記載の遮熱膜に設けられた樹脂製の断熱層７１や，中空粒子８０ａ，８０ｂを含む無機系被膜層７２（７２ａ，７２ｂ）では，エンジンの燃焼室等の高温環境下での耐熱性が不十分であり，無機系被膜層７２（７２ａ，７２ｂ）にクラックが生じる等して剥離しやすいことに鑑み，後掲の特許文献２では，図１１に示すように，ピストン１０２の頂面に形成する断熱層をアルマイト層２４１によって形成すると共に，この断熱層（アルマイト層）２４１上に，保護層としてアルコキシドから形成された無機化合物中に鱗片状の無機粒子が分散されて成る無機化合物層２４３を形成し，前述のアルマイト層２４１と無機化合物層（保護層）２４３から成る遮熱膜２４０を形成することを提案している（特許文献２の図１０，図１１参照）。 In addition, in the resin heat insulating layer 71 provided in the heat insulating film described in Patent Document 1 and the inorganic coating layers 72 (72a, 72b) containing the hollow particles 80a, 80b, the high temperature such as the combustion chamber of the engine In view of the fact that the heat resistance in the environment is insufficient and the inorganic coating layer 72 (72a, 72b) is easily peeled off due to cracks, etc., as shown in FIG. , the heat insulating layer formed on the top surface of the piston 102 is formed by the alumite layer 241, and on this heat insulating layer (alumite layer) 241, scale-like inorganic particles are dispersed in an inorganic compound formed from alkoxide as a protective layer. It is proposed to form an inorganic compound layer 243 composed of a reference).
日本国特許第６０６７７１２号公報Japanese Patent No. 6067712 日本国特許第６３３９１１８号公報Japanese Patent No. 6339118
　前掲の特許文献２に記載の遮熱膜２４０では，特許文献１において樹脂と中空粒子８０によって形成されていた断熱層７１をアルマイト層２４１に変更すると共に，特許文献１で中空粒子８０ａ，８０ｂと無機材料によって形成されていた無機系被膜層７２（７２ａ，７２ｂ）を，アルコキシドから形成された無機化合物中に鱗片状の無機粒子が分散された無機化合物層（保護層）２４３としたことで，特許文献１に記載の遮熱膜７０の弱点であった，耐熱性が低いという欠点を克服している。 In the heat shield film 240 described in Patent Document 2 above, the heat insulating layer 71 formed by the resin and the hollow particles 80 in Patent Document 1 is changed to an alumite layer 241, and in Patent Document 1, the hollow particles 80a and 80b By replacing the inorganic coating layers 72 (72a, 72b) formed of an inorganic material with an inorganic compound layer (protective layer) 243 in which scale-like inorganic particles are dispersed in an inorganic compound formed from an alkoxide, This overcomes the weak point of the heat shield film 70 described in Patent Document 1, namely low heat resistance.
　しかし，前掲の特許文献２に記載の遮熱膜２４０に設けられているアルコキシドから形成された無機化合物層２４３は，無機化合物層２４３となる液体塗料（無機粒子を含む金属アルコキシド溶液）をピストン１０２等の遮熱対象部品に塗布した後，焼成により化学反応を生じさせて形成していることから，成膜後の冷却による体積収縮によって無機化合物層２４３内に空孔が形成されると共に，マイクロクラック等の破壊が発生する。 However, the inorganic compound layer 243 formed of alkoxide provided on the heat shield film 240 described in Patent Document 2 mentioned above is a liquid paint (a metal alkoxide solution containing inorganic particles) that becomes the inorganic compound layer 243 is applied to the piston 102. After coating the parts to be heat-shielded, such as the heat shielding target parts, the chemical reaction is caused by baking. Destruction such as cracks occurs.
　また，このようなマイクロクラック等の破壊の発生は，無機化合物層２４３の焼成時のみならず，成膜後，高温環境下での使用によって加熱と冷却が繰り返されることによっても生じ得る。 In addition, such destruction such as microcracks can occur not only when the inorganic compound layer 243 is baked, but also when heating and cooling are repeated due to use in a high temperature environment after film formation.
　このようにして無機化合物層２４３に発生した空孔や，マイクロクラックの発生は，無機化合物層２４３の剥離等の起点等となる。 The vacancies and microcracks generated in the inorganic compound layer 243 in this way become starting points for peeling of the inorganic compound layer 243 and the like.
　また，マイクロクラックの発生によって無機化合物層２４３の表面が凹凸になり表面積が増大すれば，受熱面積が増え，熱移動量が増えることにより無機化合物層２４３に熱が伝わりやすくなるため遮熱膜としての機能が低下する。 In addition, if the surface of the inorganic compound layer 243 becomes uneven due to the occurrence of microcracks and the surface area increases, the heat receiving area increases and the amount of heat transfer increases. function deteriorates.
　特に，特許文献２の遮熱膜２４０をエンジンのピストン１０２の頂面に設ける構成では，無機化合物層２４３に空孔や，マイクロクラックが生じると，燃焼室内に噴射された燃料の一部が空孔やマイクロクラックに染み込んで，空孔やマイクロクラック内に保持される。 In particular, in the configuration in which the heat shield film 240 of Patent Document 2 is provided on the top surface of the engine piston 102, if holes or microcracks occur in the inorganic compound layer 243, part of the fuel injected into the combustion chamber becomes empty. It soaks into the pores and microcracks and is retained in the pores and microcracks.
　また，無機化合物層２４３に分散されている鱗片状の無機粒子は液体吸収性を有することから，マイクロクラックに染み込んだ燃料は更に鱗片状の無機粒子にも染み込んで，無機粒子中に保持される。 In addition, since the scaly inorganic particles dispersed in the inorganic compound layer 243 have liquid absorption properties, the fuel that has penetrated into the microcracks further penetrates into the scaly inorganic particles and is retained in the inorganic particles. .
　このようにして空孔やマイクロクラック，鱗片状の無機粒子等に保持された燃料は，エンジンの燃焼行程においても燃焼されず，未燃焼燃料として排気ガスと共に機外に排出されることで，燃料の損失（以下，このような未燃焼燃料の排出に伴う燃料損失を「未燃損失」という。）が増加する。 In this way, the fuel held in pores, microcracks, scale-like inorganic particles, etc. is not burned even in the combustion process of the engine, and is discharged outside the aircraft as unburned fuel together with the exhaust gas. (Hereinafter, the fuel loss associated with the discharge of unburned fuel is referred to as "unburned loss".) increases.
　また，マイクロクラックが発生して表面が凹凸となった無機化合物層２４３がピストン１０２の頂面に形成されることで，前述したように遮熱膜２４０の遮熱性が低下するだけでなく，ピストン頂面で異常爆発（ノッキング）が生じ易くなる。 In addition, the formation of the inorganic compound layer 243 on the top surface of the piston 102, which has an uneven surface due to the occurrence of microcracks, not only reduces the heat insulating properties of the heat insulating film 240 as described above, but also Abnormal explosion (knocking) is likely to occur on the top surface.
　その結果，頂面に特許文献２に記載の遮熱膜２４０を形成したピストン１０２をエンジンに搭載して行った「実機エンジン試験」では，遮熱膜２４０の形成により熱損失が低減されているにも拘わらず，十分な燃費の改善を得ることができなかった。 As a result, in an "actual engine test" in which the piston 102 with the heat shield film 240 described in Patent Document 2 was mounted on the engine, the heat loss was reduced by forming the heat shield film 240. In spite of this, a sufficient improvement in fuel efficiency could not be obtained.
　このように，無機化合物層２４３を備えた特許文献２の遮熱膜２４０は，高い遮熱性と耐熱性を有するものでありながら，空孔やマイクロクラックの発生によりその性能を十分に引き出すことができていない。 As described above, the heat shielding film 240 of Patent Document 2, which includes the inorganic compound layer 243, has high heat shielding properties and heat resistance. I haven't been able to.
　そこで，本発明は上記従来技術の欠点を解消するために成されたものであり，前述したように遮熱性と耐熱性に優れた無機化合物層を備えつつ，この無機化合物層に空孔やマイクロクラックが発生することにより生じる，前記各種の問題を解消した遮熱膜，及び，該遮熱膜が形成された遮熱部品を提供することを目的とする。 Therefore, the present invention has been made to solve the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a heat insulating film and a heat insulating component on which the heat insulating film is formed, which solves the various problems caused by cracks.
　以下に，課題を解決するための手段を，発明を実施するための形態で使用する符号と共に記載する。この符号は，特許請求の範囲の記載と，発明を実施するための形態の記載との対応を明らかにするためのものであり，言うまでもなく，本発明の技術的範囲の解釈に制限的に用いられるものではない。 Below, the means for solving the problems are described together with the symbols used in the mode for carrying out the invention. This code is for clarifying the correspondence between the description of the claims and the description of the mode for carrying out the invention, and needless to say, it is used restrictively to interpret the technical scope of the present invention. It is not something that can be done.
　上記目的を達成するために，本発明の遮熱膜１０は，
　遮熱対象部品２の少なくとも表面の一部上に成膜される遮熱膜１０において，
　アルコキシドから形成された無機化合物２１中に鱗片状の無機粒子２２が分散されて成る無機化合物層２０と，
　前記無機化合物層２０上に形成された，厚さ０．５～３０μmで，かつ，金属アルコキシドと樹脂との混合体から成る有機－無機ハイブリッド材によって形成されたトップコート３０を備えることを特徴とする（請求項１）。 In order to achieve the above object, the heat shield film 10 of the present invention is
In the heat shield film 10 formed on at least part of the surface of the heat shield target component 2,
an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide;
It is characterized by comprising a top coat 30 formed on the inorganic compound layer 20 and having a thickness of 0.5 to 30 μm and made of an organic-inorganic hybrid material composed of a mixture of metal alkoxide and resin. (Claim 1).
　前記トップコート３０の表面は，ＩＳＯ２５１７８に規定する面算術平均高さＳａで０．１～１．５μm，又は，界面の展開面積比Ｓｄｒで０．０１～１．５とすることが好ましい（請求項２）。 The surface of the top coat 30 preferably has a surface arithmetic mean height Sa defined in ISO 25178 of 0.1 to 1.5 μm, or an interface development area ratio Sdr of 0.01 to 1.5 (claim Item 2).
　前記無機化合物層２０の下層には，更に陽極酸化被膜層４０を設けることができる（請求項３）。 An anodized film layer 40 can be further provided under the inorganic compound layer 20 (Claim 3).
　また，本発明の遮熱部品１は，遮熱対象部品２の表面の少なくとも一部を遮熱膜１０で覆って成り，
　前記遮熱膜１０が，
　アルコキシドから形成された無機化合物２１中に鱗片状の無機粒子２２が分散されて成る無機化合物層２０と，
　前記無機化合物層２０上に形成された，厚さ０．５～３０μmで，かつ，金属アルコキシドと樹脂の混合体から成る有機－無機ハイブリッド材から形成されたトップコート３０を備えることを特徴とする（請求項４）。 In addition, the heat shield part 1 of the present invention is formed by covering at least a part of the surface of the heat shield target part 2 with the heat shield film 10,
The heat shield film 10 is
an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide;
A top coat 30 formed on the inorganic compound layer 20 and having a thickness of 0.5 to 30 μm and made of an organic-inorganic hybrid material composed of a mixture of a metal alkoxide and a resin is provided. (Claim 4).
　前記構成の遮熱部品１において，前記トップコート３０の表面は，ＩＳＯ２５１７８に規定する面算術平均高さＳａで０．１～１．５μm，又は，界面の展開面積比Ｓｄｒで０．０１～１．５であることが好ましい（請求項５）。 In the heat shielding component 1 having the above configuration, the surface of the top coat 30 has a surface arithmetic mean height Sa defined in ISO25178 of 0.1 to 1.5 μm, or an interface developed area ratio Sdr of 0.01 to 1. 0.5 (claim 5).
　また，前記無機化合物層２０の下層には，更に陽極酸化被膜層４０を設けることができる（請求項６）。 In addition, an anodized film layer 40 can be further provided under the inorganic compound layer 20 (claim 6).
　なお，前記遮熱対象部品２は，これをエンジン用ピストン，好ましくはアルミ合金製のエンジン用ピストンとすることができる（請求項７）。 The part 2 to be heat-insulated can be an engine piston, preferably an engine piston made of an aluminum alloy (Claim 7).
　以上で説明した本発明の構成により，本発明の遮熱膜１０及び該遮熱膜１０が形成された遮熱部品１では，以下の顕著な効果を得ることができた。 Due to the configuration of the present invention described above, the heat shielding film 10 of the present invention and the heat shielding component 1 on which the heat shielding film 10 is formed have the following remarkable effects.
　成膜の際に空孔２３やマイクロクラックが生じた前記無機化合物層２０上に，金属アルコキシドと樹脂との混合体である有機－無機ハイブリッド材から形成されたトップコート３０を０．５～３０μmの膜厚で設けることにより，無機化合物層２０に生じた空孔２３やマイクロクラック内に有機－無機ハイブリッド材を含浸させた状態で無機化合物層２０をトップコート３０で覆うことができた。 A top coat 30 made of an organic-inorganic hybrid material, which is a mixture of a metal alkoxide and a resin, is applied to a thickness of 0.5 to 30 μm on the inorganic compound layer 20 in which pores 23 and microcracks are generated during film formation. By providing a film thickness of , the inorganic compound layer 20 could be covered with the topcoat 30 in a state in which the organic-inorganic hybrid material was impregnated in the pores 23 and microcracks generated in the inorganic compound layer 20.
　このトップコート３０は，ケイ素アルコキシド，ジルコニウムアルコキシド，チタンアルコキシド等の，無機成分である金属アルコキシドと，アルキルシリケート樹脂，シリコーン樹脂，フッ素系樹脂などの有機成分である樹脂の混合体から成る有機－無機ハイブリッド材によって形成されているため，無機成分である金属アルコキシドが有する高硬度，高耐熱という性質と，有機成分である樹脂が有する柔軟性を併せ持っており，加熱と冷却が繰り返し行われる高温環境下での使用によってもマイクロクラック等の破壊が生じ難いものとなっている。 The top coat 30 is an organic-inorganic mixture of metal alkoxides, such as silicon alkoxide, zirconium alkoxide, and titanium alkoxide, which are inorganic components, and resins, which are organic components such as alkylsilicate resins, silicone resins, and fluorine-based resins. Because it is made of a hybrid material, it has both the high hardness and high heat resistance of the metal alkoxide, which is an inorganic component, and the flexibility of the resin, which is an organic component. Breakage such as microcracks is less likely to occur even when used in .
　その結果，本発明の遮熱膜１０を設けた遮熱部品１を高温環境下で使用した場合であっても，トップコート３０の剥離等が生じ難く，空孔２３やマイクロクラックが生じた無機化合物層２０がトップコート３０で覆われていると共に，トップコート３０を構成する有機－無機ハイブリッド材がマイクロクラックや空孔２３内に染み込んで硬化することで，空孔２３やマイクロクラックを起点とした無機化合物層２０の剥離等を生じ難くすることができた。 As a result, even when the heat shielding component 1 provided with the heat shielding film 10 of the present invention is used in a high-temperature environment, peeling of the topcoat 30 is difficult to occur, and the voids 23 and microcracks occur in the inorganic structure. The compound layer 20 is covered with the topcoat 30, and the organic-inorganic hybrid material constituting the topcoat 30 penetrates into the microcracks and the pores 23 and hardens, so that the pores 23 and the microcracks are used as starting points. It was possible to make it difficult to cause peeling of the inorganic compound layer 20 formed on the substrate.
　また，トップコート３０の形成によって遮熱膜１０の表面が平滑となることで，表面が凹凸形状となっている場合に比較して表面積が小さくなる結果，遮熱膜１０の表面での熱交換が起こり難くなり，遮熱膜１０の遮熱性を向上させることができた。 In addition, since the surface of the heat shield film 10 is smoothed by the formation of the top coat 30, the surface area becomes smaller than when the surface is uneven, resulting in heat exchange on the surface of the heat shield film 10. is less likely to occur, and the heat shielding properties of the heat shield film 10 can be improved.
　特に，本発明の遮熱膜１０をエンジンのピストン頂面に形成した場合には，無機化合物層２０の表面がトップコート３０によって覆われることで，燃焼室内に噴射された燃料の一部が無機化合物層２０の空孔２３やマイクロクラック，鱗片状の無機粒子２２に染み込んで保持されることがないため，未燃損失を低減することができた。 In particular, when the heat shield film 10 of the present invention is formed on the top surface of the piston of the engine, the surface of the inorganic compound layer 20 is covered with the top coat 30, so that part of the fuel injected into the combustion chamber becomes inorganic. Since the compound layer 20 does not soak into the pores 23, microcracks, and scaly inorganic particles 22 and is not retained, the unburned loss can be reduced.
　また，トップコート３０の形成によって，ピストンの頂面が平滑な面となることで，ピストン頂面における異常爆発（ノッキング）の発生についても抑制することができた。 In addition, by forming the top coat 30, the top surface of the piston becomes a smooth surface, which makes it possible to suppress the occurrence of abnormal explosion (knocking) on the top surface of the piston.
　その結果，本発明の遮熱膜１０をエンジンのピストン頂面に形成することで，該ピストンを搭載したエンジンの燃費を改善することができた。 As a result, by forming the heat shield film 10 of the present invention on the top surface of the piston of the engine, it was possible to improve the fuel efficiency of the engine equipped with the piston.
本発明の遮熱膜の一構成例を示す断面説明図。BRIEF DESCRIPTION OF THE DRAWINGS Cross-sectional explanatory drawing which shows one structural example of the thermal insulation film of this invention. 本発明の遮熱膜の別の構成例を示す断面説明図。FIG. 4 is a cross-sectional explanatory view showing another configuration example of the heat shield film of the present invention. 実施例１の遮熱膜表面のレーザ顕微鏡像（×５０）。A laser microscope image (×50) of the surface of the heat shield film of Example 1. FIG. 実施例２の遮熱膜表面のレーザ顕微鏡像（×５０）。A laser microscope image (×50) of the surface of the heat shield film of Example 2. FIG. 比較例１の遮熱膜表面のレーザ顕微鏡像（×５０）。A laser microscope image (×50) of the surface of the heat shield film of Comparative Example 1. FIG. 比較例２の遮熱膜の表面像（マイクロスコープによるデジタルカメラ画像）（×５０）。A surface image of the heat shield film of Comparative Example 2 (digital camera image obtained by a microscope) (×50). 比較例３の遮熱膜表面のレーザ顕微鏡像（×５０）。A laser microscope image (×50) of the surface of the heat shield film of Comparative Example 3. FIG. 実施例１の遮熱膜の断面ＳＥＭ像（×２０００）。A cross-sectional SEM image (×2000) of the heat shield film of Example 1. FIG. 比較例１の遮熱膜の断面ＳＥＭ像（×２０００）。A cross-sectional SEM image (×2000) of the heat shield film of Comparative Example 1. FIG. 従来の遮熱膜の断面説明図（特許文献１の図４に対応）。Cross-sectional explanatory drawing of the conventional thermal insulation film (corresponding to FIG. 4 of Patent Document 1). 従来の遮熱膜の断面説明図（特許文献２の図１０に対応）。Cross-sectional explanatory drawing of the conventional thermal insulation film (corresponding to FIG. 10 of Patent Document 2).
　次に，本発明の実施形態につき添付図面を参照しながら以下説明する。 Next, an embodiment of the present invention will be described below with reference to the accompanying drawings.
　なお，以下の説明では，遮熱対象部品２をエンジンのピストンとし，このピストンの頂面に本発明の遮熱膜１０を形成して本発明の遮熱部品１を形成した例について説明するが，本発明の遮熱膜１０は，エンジンのピストンのみならず，高温環境下で使用される各種の機械部品等，遮熱を必要とする各種の物品に対し形成することができる。 In the following explanation, an example will be described in which the part 2 to be heat-insulated is the piston of the engine, and the heat-insulating film 10 of the present invention is formed on the top surface of the piston to form the heat-insulating part 1 of the present invention. The heat shielding film 10 of the present invention can be formed not only on engine pistons, but also on various articles requiring heat shielding, such as various machine parts used in high temperature environments.
〔遮熱部品及び遮熱膜の全体構造〕
　本発明の遮熱部品１は，図１及び図２に示すように，エンジンのピストンなどの金属製の部品である遮熱対象部品２と，この遮熱対象部品２の表面の少なくとも一部分，例えば前述のピストンにあってはその頂面形成された遮熱膜１０によって構成されている。 [Overall structure of heat shield parts and heat shield film]
As shown in FIGS. 1 and 2, the heat shielding component 1 of the present invention includes a heat shielding target component 2, which is a metal part such as an engine piston, and at least a portion of the surface of the heat shielding target component 2, such as In the piston described above, it is constituted by a heat insulating film 10 formed on the top surface.
　この遮熱膜１０は，図１及び図２に示すように，遮熱対象部品２に対する熱伝導を遮断するために，遮熱対象部品２の表面に形成される膜であり，アルコキシドから形成された無機化合物２１中に，鱗片状の無機粒子２２が分散され成る無機化合物層２０と，金属アルコキシドと樹脂との混合体である有機－無機ハイブリッド材から形成されたトップコート３０を少なくとも含む。 As shown in FIGS. 1 and 2, the heat shield film 10 is a film formed on the surface of the heat shield part 2 in order to block heat conduction to the heat shield part 2, and is made of alkoxide. It includes at least an inorganic compound layer 20 in which scaly inorganic particles 22 are dispersed in an inorganic compound 21 and a topcoat 30 formed from an organic-inorganic hybrid material that is a mixture of a metal alkoxide and a resin.
　図１の遮熱膜１０は，前述した無機化合物層２０とトップコート３０で形成された二層構造の遮熱膜１０であり，図２は，無機化合物層２０とトップコート３０に加え，更に，無機化合物層２０の下層に形成された陽極酸化被膜層４０を有する，三層構造の遮熱膜１０である。 The heat shield film 10 in FIG. 1 is a two-layer structure heat shield film 10 formed of the inorganic compound layer 20 and the topcoat 30 described above, and FIG. , and an anodized film layer 40 formed under the inorganic compound layer 20. The thermal barrier film 10 has a three-layer structure.
　図２に示すように，無機化合物層２０の下層に陽極酸化被膜層４０を設ける場合，遮熱対象部品２をアルミニウムやアルミニウム合金製とし，この遮熱対象部品２に対し予め陽極酸化処理を行って陽極酸化被膜層（アルマイト層）４０を形成しておくと共に，この陽極酸化被膜層（アルマイト層）４０上に前述の無機化合物層２０とトップコート３０を形成するものとしても良い。 As shown in FIG. 2, when the anodized film layer 40 is provided on the lower layer of the inorganic compound layer 20, the part 2 to be heat-insulated is made of aluminum or an aluminum alloy, and the part 2 to be heat-insulated is subjected to anodization treatment in advance. An anodized film layer (alumite layer) 40 may be formed in advance, and the inorganic compound layer 20 and the topcoat 30 may be formed on the anodized film layer (alumite layer) 40 .
　このようなアルマイト層４０は，硫酸，シュウ酸，リン酸などから成る酸性水溶液を使用してアルミニウムをアノード酸化させることにより形成することができ，その膜厚の範囲は１０～１００μmである。 Such an alumite layer 40 can be formed by anodic oxidation of aluminum using an acidic aqueous solution of sulfuric acid, oxalic acid, phosphoric acid, etc., and its film thickness ranges from 10 to 100 μm.
　このように，無機化合物層２０の下層にアルマイト層４０を設けることで，無機化合物層２０と，アルミニウム合金製のピストンの母材との密着性を向上させることができる。 By providing the alumite layer 40 under the inorganic compound layer 20 in this manner, the adhesion between the inorganic compound layer 20 and the base material of the aluminum alloy piston can be improved.
　なお，本発明の遮熱膜１０は，図１及び図２に示す構成に限定されず，図２に示す構成の遮熱膜１０において，アルマイト層４０に代えて，例えば中空粒子を分散させた無機材料から成る断熱層等の既知の断熱層を設ける構成や，図２におけるアルマイト層４０と無機化合物層２０の間に，前述した中空粒子を分散させた無機材料から成る断熱層等の既知の断熱層を設ける構成を採用するものとしても良く，少なくとも前述した無機化合物層２０とトップコート３０を備える構成であれば，各種構成が採用可能である。 The heat shield film 10 of the present invention is not limited to the structure shown in FIGS. 1 and 2. In the heat shield film 10 having the structure shown in FIG. A configuration in which a known heat insulating layer such as a heat insulating layer made of an inorganic material is provided, and a known heat insulating layer such as a heat insulating layer made of an inorganic material in which the hollow particles are dispersed are provided between the alumite layer 40 and the inorganic compound layer 20 in FIG. A configuration in which a heat insulating layer is provided may be employed, and various configurations can be employed as long as the configuration comprises at least the inorganic compound layer 20 and the topcoat 30 described above.
〔無機化合物層〕
　本発明の遮熱膜１０を構成する層のうち，前述の無機化合物層２０は，前述したように，アルコキシドから形成された無機化合物２１中に，鱗片状の無機粒子２２が分散された構造を有するものであり，図１及び図２に示すように，長手方向を遮熱対象部品２の表面と平行に配置された鱗片状の無機粒子２２が，アルコキシドより形成された無機化合物２１をバインダとして結合された構造を備えている。 [Inorganic compound layer]
Among the layers constituting the heat shield film 10 of the present invention, the inorganic compound layer 20 has a structure in which scale-like inorganic particles 22 are dispersed in an inorganic compound 21 formed from an alkoxide, as described above. As shown in FIGS. 1 and 2, scale-like inorganic particles 22 arranged in parallel with the surface of the heat shielding target part 2 in the longitudinal direction are formed from an alkoxide with an inorganic compound 21 as a binder. It has a combined structure.
　無機化合物層２０を構成する無機化合物２１は，ケイ素アルコキシド，ジルコニウムアルコキシド，アルミニウムアルコキシド，セリウムアルコキシドのようなアルコキシドから形成された金属酸化物により構成されている。 The inorganic compound 21 constituting the inorganic compound layer 20 is composed of a metal oxide formed from an alkoxide such as silicon alkoxide, zirconium alkoxide, aluminum alkoxide, and cerium alkoxide.
　特に、ジルコニウムアルコキシドはじん性があり，アルミ合金製のピストンである遮熱対象部品２の伸びに追従しやすく好ましい。 In particular, zirconium alkoxide is preferable because it has toughness and easily follows the elongation of the heat shielding target component 2, which is an aluminum alloy piston.
　このように，無機化合物層２０の無機化合物２１は，アルコキシドから形成された金属酸化物によって構成されるため，アルコキシドを処理した際に副産物として水やアルコールが生じるものの，これらは熱処理により容易に除去することが可能である。 Thus, since the inorganic compound 21 of the inorganic compound layer 20 is composed of a metal oxide formed from an alkoxide, water and alcohol are generated as by-products when the alkoxide is treated, but these can be easily removed by heat treatment. It is possible to
　これにより異物が残存することを抑制できるので，耐熱性を向上させることが可能である。 As a result, it is possible to suppress the remaining foreign matter, so it is possible to improve the heat resistance.
　無機化合物２１中には，アミノ基（－ＮＨ２）を有する結合剤が分散されており，このような結合剤としては，アミノプロピルトリエトキシシランや，アミノプロピルトリメトキシシラン，アミノプロピルメチルジメトキシシランなどのアミノ系のカップリング剤を使用することができる。 A binder having an amino group (—NH 2 ) is dispersed in the inorganic compound 21, and examples of such a binder include aminopropyltriethoxysilane, aminopropyltrimethoxysilane, and aminopropylmethyldimethoxysilane. An amino-based coupling agent such as can be used.
　このようなアミノ系カップリング剤の添加は，金属アルコキシド溶液である塗料（鱗片状の無機粒子を含まない）１００mass％に対して０．１mass％～１０mass％添加する。 The addition of such an amino-based coupling agent is 0.1 mass% to 10 mass% with respect to 100 mass% of paint (not including scale-like inorganic particles), which is a metal alkoxide solution.
　以上のように構成された無機化合物層２０の厚さは，１０～５００μmであり，好ましくは，１０～２００μmである。 The thickness of the inorganic compound layer 20 configured as above is 10 to 500 μm, preferably 10 to 200 μm.
　前述の無機化合物２１中に分散される鱗片状の無機粒子２２としては，マイカ，タルク，及びウォラストナイトを挙げることができ，これらはいずれか一種を単独で使用しても良く，または，いずれか二種，又は三種全てを混ぜ合わせて使用するものとしても良い。 Examples of the scale-like inorganic particles 22 dispersed in the inorganic compound 21 include mica, talc, and wollastonite. Any one of these may be used alone, or any of them may be used. It is also possible to use a mixture of two or all three types.
　マイカ，タルク，及びウォラストナイトは，いずれも１０００℃程度の高温下においても溶融等が生じず，十分な耐熱性を有している。 Mica, talc, and wollastonite do not melt even at high temperatures of about 1000°C, and have sufficient heat resistance.
　ここで鱗片状とは，長さに対し厚みが十分に小さい形状を言い，板状や片状のものの他，長さに対し厚みが十分に小さな形状であれば，繊維状，針状のものも，ここでいう鱗片状に含まれる。 Here, scale-like refers to a shape with a thickness that is sufficiently small relative to the length, and in addition to plate-like and flake-like shapes, if the thickness is sufficiently small relative to the length, fibrous and needle-like shapes are also included in the scaly form here.
　無機化合物層２０に分散させる鱗片状の無機粒子２２のサイズは，平均粒径において好ましくは０．１～１００μm程度であり，より好ましくは１～２０μm程度である。 The size of the scale-like inorganic particles 22 dispersed in the inorganic compound layer 20 is preferably about 0.1 to 100 μm, more preferably about 1 to 20 μm in average particle size.
　このような鱗片状の無機粒子２２を，無機化合物層２０のうちの３５～７５vol％が無機粒子２２となるように無機化合物２１中に分散させる。 Such scale-like inorganic particles 22 are dispersed in the inorganic compound 21 so that 35 to 75 vol % of the inorganic compound layer 20 becomes the inorganic particles 22 .
　このような鱗片状の無機粒子の添加により，無機化合物層２０の剥離を抑制することができ，高温環境下においても高い遮熱性を確保することができる。 By adding such scaly inorganic particles, it is possible to suppress peeling of the inorganic compound layer 20 and ensure high heat shielding properties even in a high-temperature environment.
〔トップコート〕
　上記無機化合物層２０上に形成されるトップコート３０は，ケイ素アルコキシド，ジルコニウムアルコキシド，チタンアルコキシド等の金属アルコキシドと，アルキルシリケート樹脂，シリコーン樹脂，フッ素系樹脂などの耐熱性に優れた樹脂の混合体から成る，有機－無機ハイブリッド材から形成されている。 [top coat]
The topcoat 30 formed on the inorganic compound layer 20 is a mixture of a metal alkoxide such as silicon alkoxide, zirconium alkoxide, and titanium alkoxide, and a resin having excellent heat resistance such as alkylsilicate resin, silicone resin, and fluorine resin. It is formed from an organic-inorganic hybrid material consisting of
　このトップコート３０は，膜厚０．５～３０μｍの範囲で形成することにより，無機化合物層２０に生じた空孔２３やマイクロクラックに有機－無機ハイブリッド材を染み込ませた状態で無機化合物層２０上を覆うことができる。 By forming the top coat 30 in a thickness range of 0.5 to 30 μm, the organic-inorganic hybrid material is impregnated into the pores 23 and microcracks generated in the inorganic compound layer 20. You can cover the top.
　これにより空孔２３やマイクロクラックが発生した無機化合物層２０を補強することができると共に，遮熱膜１０の表面が平坦化されることで，遮熱膜１０の遮熱性を向上させることができる。 This makes it possible to reinforce the inorganic compound layer 20 in which the pores 23 and microcracks are generated, and to flatten the surface of the heat shield film 10, thereby improving the heat shielding property of the heat shield film 10. .
　また，このようなトップコート３０を備えた遮熱膜１０をピストンの頂面に形成する場合には，無機化合物層２０の空孔２３やクラック，鱗片状の無機粒子２２に対して燃料が染み込むことを防止することができると共に，遮熱膜１０の表面が平滑となることで，ピストンの頂面における燃料の異常燃焼（ノッキング）の発生について防止することができる。 In addition, when the heat shield film 10 having such a top coat 30 is formed on the top surface of the piston, the fuel penetrates into the pores 23 and cracks of the inorganic compound layer 20 and the scale-like inorganic particles 22. In addition, by making the surface of the heat shield film 10 smooth, it is possible to prevent abnormal fuel combustion (knocking) from occurring on the top surface of the piston.
　このトップコート３０は，膜厚が薄くなるほど無機化合物層２０に対する燃料染み込みの効果が低くなり，また，膜厚が厚くなる程，内部応力が高まってクラックや剥離等が生じ易くなる等，トップコート３０を良好な状態に維持することが難しくなる。 The thinner the film thickness of the top coat 30 is, the lower the effect of fuel penetration into the inorganic compound layer 20 is. It becomes difficult to maintain 30 in good condition.
　よって，トップコートの膜厚は，０．５～３０μmとすることが好ましく，より好ましくは０．５～１０μmである。 Therefore, the film thickness of the top coat is preferably 0.5-30 μm, more preferably 0.5-10 μm.
　なお，前述のようにトップコート３０の形成により遮熱膜１０の表面が平滑となることで，表面積の減少に伴う遮熱性能の向上や，ピストン頂面での異常燃焼（ノッキング）の発生を防止して，エンジンの燃費の改善が行われる。 As described above, the formation of the top coat 30 smoothes the surface of the heat shield film 10, which improves the heat shield performance due to the reduction in the surface area and prevents the occurrence of abnormal combustion (knocking) on the top surface of the piston. By preventing this, the fuel efficiency of the engine is improved.
　このような観点より，トップコート３０の表面粗さは，ＩＳＯ２５１７８で規定する面算術平均高さＳａで０．１～１．５μm，又は，界面の展開面積比Ｓｄｒで０．０１～１．５とすることが好ましい。 From this point of view, the surface roughness of the top coat 30 is 0.1 to 1.5 μm in terms of surface arithmetic mean height Sa defined by ISO 25178, or 0.01 to 1.5 μm in terms of interface development area ratio Sdr. It is preferable to
〔遮熱対象部品〕
　以上で説明した本発明の遮熱膜１０は，前述したようにエンジンのピストンを遮熱対象部品とし，このピストンの頂面に形成することで，従来の遮熱膜と同様，ピストンを介した燃焼室内の熱放出を抑制するという効果を維持しつつ，未燃損失を低減することができると共に，表面が平滑に形成された遮熱膜１０の形成は，表面が凹凸に形成されていたために表面積が広く熱交換を行い易く（従って，遮熱性が低く）なっていた従来の遮熱膜に比較して，遮熱性能を向上させることができ，また，ピストン頂面における異常燃焼（ノッキング）を抑制して，燃費を改善することができるものとなっている。 [Parts subject to heat insulation]
The heat shield film 10 of the present invention described above uses the piston of the engine as a heat shield target component as described above, and by forming it on the top surface of this piston, as with the conventional heat shield film, It is possible to reduce the unburned loss while maintaining the effect of suppressing the heat release in the combustion chamber, and the formation of the heat shield film 10 with a smooth surface is due to the unevenness of the surface. Compared to the conventional heat shield film, which has a large surface area and facilitates heat exchange (thus, the heat shielding performance is low), the heat shielding performance can be improved, and abnormal combustion (knocking) on the top surface of the piston can be prevented. can be suppressed to improve fuel efficiency.
　このように，本発明の遮熱膜１０は，エンジンのピストン，特に，熱伝導性の良いアルミ合金製のピストンの頂面に形成するに適している。 Thus, the heat shield film 10 of the present invention is suitable for forming on the top surface of an engine piston, particularly a piston made of an aluminum alloy with good thermal conductivity.
　もっとも，本発明の遮熱膜１０の形成によって遮熱を行う部品（遮熱対象部品）２は，エンジンのピストンに限定されず，高温環境下で使用される機械部品，例えば、エキゾーストマニホールド等の排気系システム部品やEGR（exhaust gas recirculation：排気再循環）等，遮熱が必要とされる各種の機械部品に適用可能である。 However, the part (part to be heat-insulated) 2 for which heat is shielded by forming the heat-insulating film 10 of the present invention is not limited to the piston of the engine, but may be a mechanical part used in a high-temperature environment, such as an exhaust manifold. It can be applied to various mechanical parts that require heat insulation, such as exhaust system parts and EGR (exhaust gas recirculation).
１．評価試験
　本発明の遮熱膜に対する評価試験結果について以下に説明する。
〔評価対象〕
　SUS304製の試験片に，本発明の遮熱膜を形成した試料（実施例１，実施例２）と，比較例の遮熱膜を形成した試料（比較例１～３：但し，比較例１のみアルミ合金製の試験片を使用）について，それぞれ試験と評価を行った。 1. Evaluation Test The evaluation test results for the heat shield film of the present invention are described below.
[Evaluation target]
Samples in which the heat insulating film of the present invention was formed on a test piece made of SUS304 (Examples 1 and 2) and samples in which the heat insulating film of the comparative example was formed (Comparative Examples 1 to 3: However, Comparative Example 1 Only aluminum alloy specimens were used) were tested and evaluated.
　実施例１，２及び比較例１～３の各試料に形成した遮熱膜は，下記の表１に示す通りである。 The thermal barrier films formed on the samples of Examples 1 and 2 and Comparative Examples 1 to 3 are as shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
〔試験・観察方法〕
（１）吸油試験
　遮熱膜を形成した後，そのままの状態の各試料と，熱衝撃を加えた後の各試料をそれぞれ試験対象とした。 [Test/observation method]
(1) Oil absorption test After forming the heat shield film, each sample in the state as it is and each sample after applying thermal shock were subjected to the test.
　前述の熱衝撃として，各試料を３５０℃の加熱状態に１０分間保持した後，常温の水に浸漬して冷却する処理を行った。 As the thermal shock described above, each sample was held in a heated state of 350°C for 10 minutes, and then cooled by being immersed in water at room temperature.
　吸油性の評価は，遮熱膜の表面にｎ－ヘキサデカン（燃料に見立てた低粘性のオイル）を滴下して３分間放置した後，紙製のウエスで拭き取り，オイルの滴下前と，オイルの滴下後，更にウエスで拭き取った後の各試料の重量変化を『吸油量（mg）』として測定した。 For the evaluation of oil absorption, drop n-hexadecane (low-viscosity oil similar to fuel) on the surface of the heat shield film and leave it for 3 minutes, then wipe it off with a paper cloth. After dropping and wiping off with a waste cloth, the weight change of each sample was measured as "oil absorption (mg)".
　測定した吸油量を，オイル滴下前の遮熱膜の重量で割って得た値（×１００）を『吸油率（％）』として求めた。 The value (x 100) obtained by dividing the measured oil absorption by the weight of the heat shield film before the oil was dripped was obtained as the "oil absorption (%)".
（２）表面及び断面観察
　熱衝撃を与えた後の，実施例１，２及び比較例１～３の各試料の遮熱膜の表面を観察すると共に，実施例１及び２と，比較例１の断面を観察した。 (2) Observation of surface and cross section After applying thermal shock, the surface of the heat shield film of each sample of Examples 1 and 2 and Comparative Examples 1 to 3 was observed. Observed the cross section of
　表面観察はレーザ顕微鏡により，倍率５０倍の対物レンズによって行った。 　The surface was observed with a laser microscope using an objective lens with a magnification of 50 times.
　また，断面観察は，走査電子顕微鏡（ＳＥＭ）を使用し，倍率２０００倍として行った。 In addition, cross-sectional observation was performed using a scanning electron microscope (SEM) at a magnification of 2000 times.
（３）表面粗度の測定
　遮熱膜を形成した後，熱衝撃を加える前の実施例１，２及び比較例１～３の試料の表面粗さを測定した。 (3) Measurement of Surface Roughness The surface roughness of the samples of Examples 1 and 2 and Comparative Examples 1 to 3 was measured after the heat shield film was formed and before the thermal shock was applied.
　測定は，レーザ顕微鏡（倍率５０倍の対物レンズ）を使用して行い，粗さパラメータとして，ＩＳＯ２５１７８で規定する面算術平均高さＳａと，界面の展開面積比Ｓｄｒをそれぞれ測定した。 The measurement was performed using a laser microscope (objective lens with a magnification of 50 times), and as roughness parameters, the surface arithmetic average height Sa defined by ISO25178 and the developed area ratio Sdr of the interface were measured.
〔試験・観察結果〕
　前述した吸油試験，表面・断面観察，面粗度測定の各結果を下記の表２に示す。 [Test/observation results]
Table 2 below shows the results of the oil absorption test, surface/cross-section observation, and surface roughness measurement described above.
　また，実施例１，２及び比較例１～３の各試料の遮熱膜表面の状態を図３～図７に，実施例１と比較例１の断面ＳＥＭ像を，図８及び図９にそれぞれ示す。 3 to 7 show the state of the heat shield film surface of each sample of Examples 1 and 2 and Comparative Examples 1 to 3, and cross-sectional SEM images of Example 1 and Comparative Example 1 are shown in FIGS. each shown.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
〔考察〕
　実施例１及び２の試料は，熱衝撃を加える前後のいずれの状態においても吸油率が低く，亀裂の発生等も確認できず，面粗度についても面算術平均高さＳａ，界面の展開面積比Ｓｄｒ共に，１．５を大きく下回るものとなっていた。 [Discussion]
In the samples of Examples 1 and 2, the oil absorption rate was low in any state before and after the thermal shock was applied, and the occurrence of cracks could not be confirmed. Both the ratios Sdr were significantly below 1.5.
　また，図８に示すように，ＳＥＭによる断面観察の結果，有機－無機ハイブリッド材が染み込むことにより，無機化合物層内の空孔が埋められていることが確認された。 In addition, as shown in Fig. 8, as a result of cross-sectional observation by SEM, it was confirmed that the holes in the inorganic compound layer were filled by the permeation of the organic-inorganic hybrid material.
　なお，図８は実施例１の試料の断面ＳＥＭ像であり，実施例２の試料の断面ＳＥＭ像については掲載を省略するが，同様の結果が確認されている。 Note that FIG. 8 is a cross-sectional SEM image of the sample of Example 1, and although the cross-sectional SEM image of the sample of Example 2 is omitted, similar results were confirmed.
　一方，トップコートが設けられておらず，無機化合物層が表面に直接露出している比較例１の遮熱膜では，吸油率が熱衝撃前で１７．９％，熱衝撃後で１９．５％といずれも高く，また，表面及び断面観察の結果，無機化合物層にマイクロクラックの発生（図５参照）と，多数の空孔の発生（図９参照）が確認されていると共に，面粗度も，面算術平均高さＳａで１．６４μm，界面の展開面積比Ｓｄｒで４．２６と粗いものとなっていた。 On the other hand, in the heat shield film of Comparative Example 1, in which the inorganic compound layer was directly exposed on the surface without the topcoat, the oil absorption was 17.9% before the thermal shock and 19.5% after the thermal shock. As a result of observation of the surface and cross section, the occurrence of microcracks in the inorganic compound layer (see Figure 5) and the occurrence of many holes (see Figure 9) were confirmed, and the surface roughness The surface arithmetic average height Sa was 1.64 μm, and the developed area ratio Sdr of the interface was 4.26, which were rough.
　以上の結果から，無機化合物層上にトップコートを設けた本発明の遮熱膜の優位性が確認された。 From the above results, the superiority of the heat shield film of the present invention, which has a top coat on the inorganic compound layer, was confirmed.
　また，比較例２では，実施例１，２と同様，有機－無機ハイブリッド材によって形成したトップコートを設けており，熱衝撃前の吸油率は０．３％と，実施例１，２の遮熱膜よりも低くなっていると共に，面粗度も，面算術平均高さＳａで０．１２，界面の展開面積比Ｓｄｒで０．０３と，平滑な表面が得られていることが確認された。 In addition, in Comparative Example 2, as in Examples 1 and 2, a top coat formed of an organic-inorganic hybrid material was provided, and the oil absorption rate before thermal shock was 0.3%, which was higher than that of Examples 1 and 2. It is lower than that of the hot film, and the surface roughness is 0.12 in surface arithmetic average height Sa, and 0.03 in surface expansion area ratio Sdr, confirming that a smooth surface is obtained. rice field.
　しかし，比較例２の試料に設けた遮熱膜では，熱衝撃を加えることでトップコートに剥離が生じ（図６参照），高温環境下での使用に耐え得ないものであることが確認された。 However, with the thermal barrier film provided on the sample of Comparative Example 2, the topcoat peeled off when subjected to thermal shock (see Fig. 6), and it was confirmed that the film could not withstand use in a high-temperature environment. rice field.
　比較例２の遮熱膜に形成したトップコートの膜厚は５０μmと，実施例１，２のトップコートの膜厚（実施例１で３μm，実施例２で３０μm）に比較して厚くなっており，トップコートの膜厚をこのように厚いものとしたことで膜内の残留応力が高まった結果，熱衝撃を加えることで剥離したものと考えられる。 The film thickness of the top coat formed on the thermal barrier film of Comparative Example 2 was 50 μm, which is thicker than the film thickness of the top coats of Examples 1 and 2 (3 μm in Example 1 and 30 μm in Example 2). Therefore, it is considered that the residual stress in the film was increased by increasing the film thickness of the topcoat, and as a result, the film delaminated due to the thermal shock.
　以上の結果から，本発明の遮熱膜におけるトップコートの膜厚を３０μm以下とすることの有効性が確認された。 From the above results, the effectiveness of setting the film thickness of the top coat in the heat shield film of the present invention to 30 μm or less was confirmed.
　比較例３の遮熱膜は，トップコートの膜厚については５μmと本発明のトップコートの膜厚の範囲内であるが，トップコートが無機材料であるアルコキシド金属（Ｚｒアルコキシド）のみによって形成されている点で，本発明の遮熱膜の構成とは異なる。 The thermal barrier film of Comparative Example 3 has a topcoat thickness of 5 μm, which is within the thickness range of the topcoat of the present invention, but the topcoat is formed only of an inorganic alkoxide metal (Zr alkoxide). It is different from the structure of the heat shield film of the present invention in that
　この構成では，熱衝撃前の吸油率において既に１６．２％と高く，面粗度については面算術平均高さＳａで１．３０μmであったが，界面の展開面積比Ｓｄｒは４．０７と高く，更に，熱衝撃を与えることでトップコートは剥離した。 In this configuration, the oil absorption rate before the thermal shock was already as high as 16.2%, and the surface roughness was 1.30 μm in surface arithmetic mean height Sa, but the developed area ratio Sdr of the interface was 4.07. The top coat was peeled off by applying high and further thermal shock.
　以上の結果から，トップコートの材質として，有機－無機ハイブリッド材を採用した本発明の遮熱膜の優位性が確認された。 From the above results, the superiority of the thermal barrier film of the present invention, which uses an organic-inorganic hybrid material as the material of the top coat, was confirmed.
２．トップコートの膜厚の下限値の確認
　トップコートの膜厚の下限値を求めるべく，前掲の試験例におけるトップコートの膜厚の最小値である３μm（実施例１）未満である膜厚０．５～２μmの範囲でトップコートの膜厚を変化させて，形成される遮熱膜の外観の変化と吸油率の変化を測定した。 2. Confirmation of the lower limit of the film thickness of the top coat In order to determine the lower limit of the film thickness of the top coat, the film thickness of less than 3 µm (Example 1), which is the minimum value of the film thickness of the top coat in the above-mentioned test examples, was 0.00. The film thickness of the top coat was changed in the range of 5 to 2 μm, and the changes in the appearance and oil absorption of the formed heat shield film were measured.
　測定は熱負荷をかける前の試料と，熱負荷後の試料の双方に対して行い，外観の観察は，肉眼及び顕微鏡により遮熱膜（トップコート）の表面を観察し，顕微鏡を使用してもクラックが確認できないものを「○」，顕微鏡ではクラックが確認されたが肉眼ではクラックが確認できないものを「△」，肉眼でクラックが確認できたものを「×」とそれぞれ評価した。 Measurements are performed on both the sample before applying heat load and the sample after heat load. When no cracks were observed, the evaluation was given as "○", when the cracks were observed under a microscope but not observed with the naked eye, "△", and when the cracks were observed with the naked eye, "X".
　なお，トップコートの膜厚は断面観察に基づいて把握した。 The film thickness of the top coat was determined based on cross-sectional observation.
　試験結果を，下記の表３に示す。 The test results are shown in Table 3 below.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　以上の結果，トップコートの膜厚が０．５μm～２μmの範囲についてもクラックの発生がなく，かつ，吸油率の低い遮熱膜が得られており，遮熱膜に設けるトップコートの膜厚として，０．５μmの比較的薄い膜厚の形成であっても有効であることが確認された。 As a result, cracks did not occur even when the film thickness of the top coat was in the range of 0.5 μm to 2 μm, and a heat insulating film with a low oil absorption rate was obtained. As such, it was confirmed that even a relatively thin film thickness of 0.5 μm is effective.
　１　遮熱部品
　２　遮熱対象部品（ピストン）
　１０　遮熱膜
　２０　無機化合物層
　２１　無機化合物
　２２　鱗片状の無機粒子
　２３　空孔
　３０　トップコート
　４０　陽極酸化被膜層（アルマイト層）
　７０　遮熱膜
　７１　断熱層
　７２（７２ａ，７２ｂ）　無機系被膜層
　８０，８０ａ，８０ｂ　中空粒子
　１０２　ピストン
　２４０　遮熱膜
　２４１　断熱層（アルマイト層）
　２４３　無機化合物層（保護層）

  1 Heat shield part 2 Heat shield target part (piston)
REFERENCE SIGNS LIST 10 heat shield film 20 inorganic compound layer 21 inorganic compound 22 scaly inorganic particles 23 pores 30 top coat 40 anodized layer (alumite layer)
70 heat insulating film 71 heat insulating layer 72 (72a, 72b) inorganic coating layer 80, 80a, 80b hollow particles 102 piston 240 heat insulating film 241 heat insulating layer (alumite layer)
243 inorganic compound layer (protective layer)

Claims (7)

  1. 　遮熱対象部品の少なくとも表面の一部上に成膜される遮熱膜において，
    　アルコキシドから形成された無機化合物中に鱗片状の無機粒子が分散されて成る無機化合物層と，
    　前記無機化合物層上に形成された，厚さ０．５～３０μmで，かつ，金属アルコキシドと樹脂との混合体から成る有機－無機ハイブリッド材によって形成されたトップコートを備えることを特徴とする遮熱膜。     In the heat shield film formed on at least part of the surface of the part to be heat shielded,
    an inorganic compound layer in which scaly inorganic particles are dispersed in an inorganic compound formed from an alkoxide;
    A shield characterized by comprising a top coat formed on the inorganic compound layer and having a thickness of 0.5 to 30 μm and made of an organic-inorganic hybrid material composed of a mixture of a metal alkoxide and a resin. hot film.
  2. 　前記トップコートの表面が，ＩＳＯ２５１７８に規定する面算術平均高さＳａで０．１～１．５μm，又は，界面の展開面積比Ｓｄｒで０．０１～１．５である，請求項１記載の遮熱膜。 2. The method according to claim 1, wherein the surface of the topcoat has an area arithmetic mean height Sa defined in ISO25178 of 0.1 to 1.5 μm, or an interface developed area ratio Sdr of 0.01 to 1.5. Thermal insulation film.
  3. 　前記無機化合物層の下層に更に陽極酸化被膜層を備えることを特徴とする請求項１又は２記載の遮熱膜。 The heat shield film according to claim 1 or 2, further comprising an anodized film layer under the inorganic compound layer.
  4. 　遮熱対象部品の表面の少なくとも一部を遮熱膜で覆って成る遮熱部品において，
    　前記遮熱膜が，
    　アルコキシドから形成された無機化合物中に鱗片状の無機粒子が分散されて成る無機化合物層と，
    　前記無機化合物層上に形成された，厚さ０．５～３０μmで，かつ，金属アルコキシドと樹脂の混合体から成る有機－無機ハイブリッド材から形成されたトップコートを備えることを特徴とする遮熱部品。     In a heat shielding part that covers at least part of the surface of the part to be heat shielded with a heat shielding film,
    The heat shield film is
    an inorganic compound layer in which scaly inorganic particles are dispersed in an inorganic compound formed from an alkoxide;
    A heat shield characterized by comprising a top coat formed on the inorganic compound layer and having a thickness of 0.5 to 30 μm and made of an organic-inorganic hybrid material composed of a mixture of metal alkoxide and resin. parts.
  5. 　前記トップコートの表面が，ＩＳＯ２５１７８に規定する面算術平均高さＳａで０．１～１．５μm，又は，界面の展開面積比Ｓｄｒで０．０１～１．５である，請求項４記載の遮熱部品。 5. The surface of the topcoat according to claim 4, wherein the surface arithmetic mean height Sa defined in ISO 25178 is 0.1 to 1.5 μm, or the interface development area ratio Sdr is 0.01 to 1.5. Heat insulation parts.
  6. 　前記無機化合物層の下層に更に陽極酸化被膜層を備えることを特徴とする請求項４又は５記載の遮熱部品。 The heat shielding component according to claim 4 or 5, further comprising an anodized film layer under the inorganic compound layer.
  7. 　前記遮熱対象部品が，エンジン用ピストンである請求項４～６いずれか１項記載の遮熱部品。

          The heat shielding part according to any one of claims 4 to 6, wherein the heat shielding target part is an engine piston.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5950084A (en) * 1982-09-13 1984-03-22 旭化成株式会社 Ceramic laminate and manufacture
JPH04239078A (en) * 1991-01-11 1992-08-26 Ube Ind Ltd Heat-resistant coating composition
JPH11255883A (en) * 1998-03-09 1999-09-21 Orient Chem Ind Ltd Organic-inorganic hybrid polymer material and its preparation
WO2016163244A1 (en) * 2015-04-08 2016-10-13 アイシン精機株式会社 Vehicle machine part and piston

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5950084A (en) * 1982-09-13 1984-03-22 旭化成株式会社 Ceramic laminate and manufacture
JPH04239078A (en) * 1991-01-11 1992-08-26 Ube Ind Ltd Heat-resistant coating composition
JPH11255883A (en) * 1998-03-09 1999-09-21 Orient Chem Ind Ltd Organic-inorganic hybrid polymer material and its preparation
WO2016163244A1 (en) * 2015-04-08 2016-10-13 アイシン精機株式会社 Vehicle machine part and piston

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