JP6917185B2 - Thermal radiation suppression film and covering member provided with it - Google Patents

Description

In the present invention, for example, a coating member that covers the surface of a high-temperature pipe as a high-temperature object laid in a thermal power generation facility and the like, and heat radiation suppression provided on the surface of a stainless steel foil as a coating base material constituting the coating member. It is an invention relating to a membrane. This heat radiation suppression film increases the reflectance in the infrared region, that is, reduces the emissivity and reduces the heat dissipation loss from the high temperature piping.

Conventionally, a laminated film in which ceramics are laminated in multiple layers has been studied as a film for suppressing radiant heat transfer. According to this laminated film, heat dissipation loss can be reduced by reflecting infrared rays. However, in such a laminated film of ceramics, since the reflection wavelength band of infrared rays is narrow and the reflectance is low, it is difficult to sufficiently suppress radiant heat transfer.

As a heat radiation suppressing film of this kind, for example, Patent Document 1 discloses a heat reflecting material. In this heat reflective material, _{two or more layers of A 2} Ti ₂ O ₇ as a titanium oxide-based material layer and two or more layers of an alumina-based material are alternately laminated, and the A ₂ Ti ₂ O ₇ layer is arranged on the outermost surface side. Is to be done. Rare earth elements such as yttrium (Y) and samarium (Sm) are used as A in the A ₂ Ti ₂ O _{7 layer.}

Japanese Unexamined Patent Publication No. 2014-55079

In the heat-reflecting material having the conventional structure described in Patent Document 1 described above, the reflectance of the heat-reflecting material has a wavelength of light of 0.3 to 0.7 μm (300 to 700 nm) and 1.0 to 1.4 μm (1000 to 1000 to). It was only high in the narrow wavelength range of 1400 nm), and its reflectance was as low as less than 50%. Therefore, there is a drawback that the emissivity of the surface of the base material cannot be sufficiently reduced and it is difficult to suppress the radiant heat transfer.

On the other hand, in general, various metals with high infrared reflectance such as gold, silver, and copper are also candidates that can suppress radiant heat transfer, but in a high temperature environment, deterioration due to evaporation and aggregation, and an atmosphere in which oxygen is present. Among them, there is a problem that the heat-resistant life is short because it is accompanied by oxidative deterioration and the like.

Therefore, an object of the present invention is to provide a heat radiation suppression film capable of remarkably suppressing radiant heat transfer of a high-temperature object and maintaining its effect for a long period of time, and a coating member provided with the same. ..

In order to achieve the above object, the heat radiation suppression film of the present invention is a heat radiation suppression film provided on the surface of a stainless steel coating substrate covering the high temperature object in order to suppress the radiant heat transfer of the high temperature object. A reflective film that reflects light via a barrier film that suppresses the migration of components is provided on the surface of the coating substrate, and an oxidation-suppressing film that suppresses oxidation of the reflective film is provided on the surface of the reflective film. Are laminated and configured.

Generally, the emissivity (%) is expressed by the following equation according to Kirchhoff's law.
Emissivity (%) = Absorption rate (%) = 100% -Reflectance (%) -Transmittance (%)
From this relationship, since the emissivity is low on the surface of the reflective film having high reflectance, the transfer of heat energy from the coating substrate side, that is, the radiant heat transfer is suppressed. Further, since the reflective film is covered with an oxidation-suppressing film, the oxidation of the reflective film is suppressed by blocking the permeation of oxygen, and the progress of deterioration of the reflective film is suppressed.

In addition, since a barrier film is provided between the reflective film and the coating base material, the transfer of both components between the component of the reflective film and the component of the coating base material is blocked, and the reaction of both components is blocked. Can be suppressed, and the function of the reflective film can be satisfactorily exhibited over a long period of time.

According to the heat radiation suppression film of the present invention, the radiant heat transfer of a high temperature object can be remarkably suppressed, and the effect can be maintained for a long period of time.

(A) is a cross-sectional view schematically showing a state in which a barrier film, a reflective film and an oxidation suppressing film are sequentially formed on the surface of the covering base material to form a heat radiation suppressing film in the embodiment, and (b) is a cross-sectional view schematically showing a state where the coating base material surface is formed. FIG. 5 is a cross-sectional view schematically showing a state in which a first barrier membrane, a second barrier membrane, a reflection film, and an oxidation suppression film are formed in this order to form a heat radiation suppression film. (A) is a cross-sectional view schematically showing a state in which a covering member is arranged on the outer periphery of a high-temperature pipe and a heat insulating material is arranged on the outer periphery of the covering member, and (b) is an enlarged cross-sectional view showing a portion 2b of (a). .. FIG. 5 is an X-ray diffraction pattern diagram in a state where a nickel silicide reflective film is formed on a quartz glass surface. The wavelength of light (μm) of a thermal radiation suppression film in which silica (SiO ₂ ) of the first barrier film, tungsten of the second barrier film, cobalt silicide of the reflection film, and silicon nitride of the oxidation suppression film are formed on the coating substrate. A graph showing the relationship between and reflectance (%). The graph which shows the relationship between the wavelength (μm) of light and the reflectance (%) when the heat radiation suppression film was heated to 700 degreeC for a predetermined time in Example 1. FIG. The graph which shows the relationship between the wavelength (μm) of light and the reflectance (%) when the heat radiation suppression film was heated to 750 ° C. for a predetermined time in Example 1. FIG. The graph which shows the relationship between the wavelength (μm) of light and the reflectance (%) when the heat radiation suppression film was heated to 800 degreeC for a predetermined time in Example 1. FIG. In the state shown in FIG. 5, a graph showing the relationship between the time (hr) for obtaining the time (lifetime) until the reflectance decreases by 10% and the reflectance (%). In the state shown in FIG. 6, a graph showing the relationship between the time (hr) for obtaining the time (lifetime) until the reflectance decreases by 10% and the reflectance (%). In the state shown in FIG. 7, a graph showing the relationship between the time (hr) for obtaining the time (lifetime) until the reflectance decreases by 10% and the reflectance (%). The result of the accelerated deterioration test (requiring the life of 5 years and the life of 10 years) regarding the durability of the thermal radiation suppression film of Example 1 is shown, and the temperature (the reciprocal of the absolute temperature T) and the time [the logarithm of the time t (hr)] are shown. A graph showing the relationship with. The result of the accelerated deterioration test (requiring the life of 5 years and the life of 10 years) regarding the durability of the thermal radiation suppression film of Example 2 is shown, and the temperature (the reciprocal of the absolute temperature T) and the time [the logarithm of the time t (hr)] are shown. A graph showing the relationship with. The result of the accelerated deterioration test (requiring the life of 5 years and the life of 10 years) regarding the durability of the thermal radiation suppression film of Example 3 is shown, and the temperature (the reciprocal of the absolute temperature T) and the time [the logarithm of the time t (hr)] are shown. A graph showing the relationship with. The result of the accelerated deterioration test (requiring the life of 5 years and the life of 10 years) regarding the durability of the thermal radiation suppression film of Example 4 is shown, and the temperature (the reciprocal of the absolute temperature T) and the time [the logarithm of the time t (hr)] are shown. A graph showing the relationship with. The result of the accelerated deterioration test (requiring the life of 5 years and the life of 10 years) regarding the durability of the thermal radiation suppression film of Example 5 is shown, and the temperature (the reciprocal of the absolute temperature T) and the time [the logarithm of the time t (hr)] are shown. A graph showing the relationship with.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.
As shown in FIG. 2A, for example, a covering member 12 for suppressing radiant heat transfer of the high temperature pipe 11 is arranged on the surface (outer peripheral surface) of the high temperature pipe 11 as a high temperature object in a thermal power plant facility. On the surface (outer peripheral surface) of the covering member 12, a heat insulating material (heat insulating material) 13 for suppressing heat dissipation from the high temperature pipe 11 is arranged. The covering member 12 is formed in a foil shape, and after being wound around the outer periphery of the high temperature pipe 11, the outer periphery of the covering member 12 is coated with the heat insulating material 13. The high temperature pipe 11 reaches a high temperature of 100 to 600 ° C. at the time of use, and it is required to suppress radiant heat transfer at such a high temperature and improve energy efficiency.

The material of the high-temperature pipe 11 is not particularly limited, and may be carbon steel, stainless steel, alloy steel, or the like, as well as silica, alumina, or the like. As the high temperature object, various materials in fields such as steel, automobiles, and aerospace are applied in addition to the high temperature pipe 11. The heat insulating material 13 is formed to a thickness of several tens of mm by a ceramic fiber or the like which is a heat insulating material for high temperature.

As shown enlarged in FIG. 2B, the coating member 12 is configured by providing a heat radiation suppression film 15 on the surface of a stainless steel foil 14 as a coating base material, and the foil 14 is on the inner peripheral side, that is, on the inner peripheral side. It is arranged on the high temperature pipe 11 side, and the heat radiation suppressing film 15 is arranged on the outer peripheral side, that is, on the heat insulating material 13 side. By arranging the covering member 12 on the outer periphery of the high temperature pipe 11 in this way, the radiant heat transfer of the high temperature pipe 11 can be effectively suppressed. If the stainless steel foil 14 and the heat radiation suppression film 15 constituting the covering member 12 are arranged upside down on the inner and outer circumferences, the performance of the heat radiation suppression film 15 deteriorates and its function cannot be exhibited, and the amount of radiant heat transfer increases. Is not preferable.

As the stainless steel of the coating base material, austenitic stainless steel is preferable because it can be formed into a foil shape, its shape can be easily maintained, and its stability at high temperature is high, and specifically, SUS304, SUS316L and the like are preferable. Used. SUS304 contains iron as a main component, nickel 8 to 11% by mass, chromium 18 to 20% by mass, and the like. SUS316L contains iron as a main component and contains 12 to 16% by mass of nickel, 16 to 18% by mass of chromium, 2 to 3% by mass of molybdenum, and the like.

The thickness of the stainless steel foil 14 is preferably 1 to 100 μm, more preferably 10 to 25 μm. The stainless steel foil 14 having a thickness of less than 1 μm is difficult to manufacture, while the stainless steel foil 14 having a thickness of more than 100 μm is less flexible and the manufacturing cost is increased.

As shown in FIG. 1A, the thermal radiation suppression film 15 is provided with a reflection film 17 that reflects light via a barrier film 16 that suppresses the migration (diffusion) of components on the surface of the foil 14. An oxidation-suppressing film 18 that suppresses the oxidation of the reflective film 17 is laminated on the surface of the reflective film 17.

As shown in FIG. 1 (b), the thermal radiation suppression film 15 uses the barrier film 16 of the thermal radiation suppression film 15 shown in FIG. 1 (a) with the first barrier film 16a on the reflection film 17 side. It is formed by laminating the second barrier film 16b on the foil 14 side.

The reflective film 17 is preferably a non-oxide metal silicide among the metal silicides, and the non-oxide metal silicide is preferably cobalt silicide (CoSi ₂ ) or nickel silicide (NiSix). Here, x of nickel silicide is 1 to 2.

As shown in the X-ray diffraction pattern result of FIG. 3, when the reflective film 17 is formed on the surface of the barrier membrane 16 by the simultaneous sputtering method using nickel and silicon (silicon), NiSi is used as the nickel silicide showing the highest reflectance. It was shown that two types, _{2 and NiSi, were mixed.} Therefore, x of the nickel silicide (NiSix) is in the range of 1 to 2.

These metal silicides can increase the reflectance of light on the surface of the foil 14, and in particular, increase the reflectance of light in a wide range of infrared regions having a wavelength of 1 to 25 μm (1000 to 25000 nm) to 90% or more. Can be done. That is, the emissivity can be suppressed to 10% or less, and the radiant heat transfer can be remarkably suppressed.

Specifically, the reflective film 17 is formed according to a conventional method of a sputtering method (direct sputtering method) or a simultaneous sputtering method. For example, when cobalt silicide is formed by the simultaneous sputtering method, cobalt and silicon (silicon) are targeted, and sputtering is performed with an inert gas such as argon to react cobalt and silicon (silicon) to form a cobalt silicide film. Can be formed on the barrier film 16.

The thickness of the reflective film 17 is preferably 150 to 300 nm from the viewpoint of increasing the reflectance. If the thickness of the reflective film 17 is less than 150 nm, sufficient reflectance cannot be obtained or the strength of the reflective film 17 cannot be ensured, which is not preferable. On the other hand, when the thickness of the reflective film 17 exceeds 300 nm, the reflectance cannot be expected to be improved to match the thickness of the reflective film 17, and the manufacturing cost is increased, which is not preferable.

The oxidation-suppressing film 18 suppresses the permeation of oxygen and suppresses the oxidation of the reflection film 17 to protect it. Among the compounds constituting the oxidation-inhibiting film 18, high oxygen barrier property is preferably nitride from the viewpoint of excellent oxidation inhibiting effect of the reflective film 17, in particular silicon nitride (Si 3 _{N 4)} are preferable among the nitride thereof .. The oxidation-suppressing film 18 can exhibit the oxidation resistance of the heat radiation-suppressing film 15 in a high temperature region of 600 ° C. or higher.

The oxidation-suppressing film 18 is formed according to a conventional method of a direct sputtering method or a reactive sputtering method. For example, when a silicon nitride film is formed by a reactive sputtering method, a silicon nitride film is formed on the reflective film 17 by targeting silicon, flowing nitrogen gas to perform sputtering, and reacting silicon with nitrogen to form a silicon nitride film. can do.

The thickness of the oxidation-suppressing film 18 is preferably 10 to 100 nm. When the thickness of the oxidation-suppressing film 18 is thinner than 10 nm, it is not preferable because a sufficient oxidation-suppressing action cannot be obtained or the strength of the oxidation-suppressing film 18 cannot be ensured. On the other hand, when the thickness of the oxidation-suppressing film 18 is thicker than 100 nm, not only the oxidation-suppressing action corresponding to the thickness of the oxidation-suppressing film 18 cannot be obtained and the manufacturing cost increases, but also the reflective film 17 is increased. It is not preferable because the reflectance is lowered when the laminated body is formed with.

The barrier film 16 can maintain the function of the reflective film 17 for a long period of time, and the life of the heat radiation suppressing film 15 can be extended to, for example, 600 ° C., preferably 5 years or more, and more preferably 10 years or more. can.

_{The material constituting the barrier film 16 is a silica (SiO 2} ) film or a silica film and a metal compound in order to suppress the reaction between the component of the stainless steel foil 14 and the component of the reflective film 17. Membranes or silica membranes and metal membranes are preferred. _{Chromium oxide (Cr 2} O ₃ ) or the like is preferable as the metal compound, and tungsten (W) or the like is preferable as the metal. As the material constituting the barrier membrane 16, a material different from the material constituting the oxidation suppression film 18 is preferably used. The barrier membrane 16 is usually composed of one or two layers depending on the material. Specifically, the barrier membrane 16 is composed of one layer of silica only, the first barrier membrane 16a is composed of two layers of silica, the second barrier membrane 16b is composed of two layers of tungsten, and the first barrier membrane 16a is silica. The second barrier membrane 16b may be composed of two layers of chromium oxide.

The barrier film 16 is formed according to a conventional method of a direct sputtering method or a reactive sputtering method. The thickness of the barrier membrane 16 is preferably 10 to 100 nm. When the thickness of the barrier film 16 is less than 10 nm, a sufficient reaction suppressing action between the component of the reflective film 17 and the component of the stainless steel foil 14 cannot be obtained, or the strength of the barrier film 16 can be ensured. It is not preferable because it does not exist. On the other hand, when the thickness of the barrier membrane 16 exceeds 100 nm, a reaction suppressing action commensurate with the thickness of the barrier membrane 16 cannot be obtained, or the manufacturing cost increases, which is not preferable.

A coating member 12 is obtained by providing the heat radiation suppression film 15 configured as described above on the outer surface of the stainless steel foil 14, and the coating member 12 is wound around the high temperature pipe 11 to cover the high temperature pipe 11. Radiant heat transfer (radiance rate) can be reduced, heat dissipation loss can be reduced, and energy efficiency can be improved. Here, the emissivity (%) is calculated by the following formula based on Kirchhoff's law.

Emissivity (%) = Absorption rate (%) = 100% -Reflectance (%) -Transmittance (%)
The transmittance of the heat radiation suppression film 15 is substantially 0.
Next, the action of the heat radiation suppression film 15 configured as described above will be described.

When a high-temperature fluid is circulated in the high-temperature pipe 11 of a thermal power plant, a part of the thermal energy of the high-temperature fluid is lost from the surface of the high-temperature pipe 11 due to radiant heat. However, in the present embodiment, as shown in FIGS. 2A and 2B, the covering member 12 is wound around the outer peripheral surface of the high temperature pipe 11 to be covered. The covering member 12 is composed of a stainless steel foil 14 on the high temperature pipe 11 side and a heat radiation suppressing film 15 on the outer surface thereof. Further, the heat radiation suppression film 15 is configured by laminating a barrier film 16, a reflection film 17, and an oxidation suppression film 18 from the foil 14 side. In the heat radiation suppression film 15, for example, the barrier film 16 is composed of a silica film or a silica film, a tungsten film or a silica film, and a chromium oxide film, and the reflection film 17 is a cobalt silicide film or a nickel silicide film. It is formed and the oxidation suppression film 18 is composed of a film of silicon nitride.

Then, the heat energy of the high-temperature fluid in the high-temperature pipe 11 is transferred to the pipe wall of the high-temperature pipe 11, and is heat-conducted from the outer surface of the pipe wall to the heat radiation suppression film 15 via the foil 14 of the covering member 12. .. At this time, most of the heat energy is largely reflected by the reflective film 17 in the thermal radiation suppression film 15 based on the characteristics of cobalt silicide or nickel silicide, and its reflectance reaches 90% or more. In other words, the emissivity of the reflective film 17 is 10% or less, the radiant heat transfer is significantly suppressed, and the heat dissipation loss can be significantly reduced.

Further, the barrier film 16 described above is provided on the foil 14 side of the reflective film 17. Therefore, the diffusion of the component between the component of the reflective film 17 and the component of the foil 14 is suppressed. As a result, the reaction between the components of the reflective film 17 such as cobalt silicide and nickel silicide and the components of the stainless steel constituting the foil 14 is suppressed, and the function of the reflective film 17 can be continuously exhibited for a long period of time. ..

In addition, since the oxidation-suppressing film 18 made of silicon nitride or the like is provided on the reflection film 17, the oxidation-suppressing film 18 blocks the permeation of oxygen in the atmosphere, and the reflection film 17 is oxidized. It can be suppressed. As a result, deterioration of the reflective film 17 due to oxidation is suppressed, and the life of the heat radiation suppressing film 15 is extended.

The effects exhibited by the above embodiments are summarized below.
(1) In the heat radiation suppression film 15 of this embodiment, a reflection film 17 is provided on the surface of the stainless steel foil 14 via a barrier film 16 that suppresses the migration of components, and the surface of the reflection film 17 is oxidized. The oxidation-suppressing film 18 for suppressing is laminated.

Therefore, the heat energy from the foil 14 side is largely reflected by the reflective film 17, and radiant heat transfer is suppressed. Moreover, since the reflective film 17 is covered with the oxidation-suppressing film 18, the oxidation of the reflective film 17 is suppressed, and the progress of its deterioration is suppressed.

Further, since the barrier film 16 is provided between the reflective film 17 and the foil 14, the transfer of the component of the reflective film 17 and the component of the foil 14 is blocked, and the reaction of both components can be suppressed. The function of the reflective film 17 can be maintained for a long period of time.

Therefore, according to the heat radiation suppression film 15 of this embodiment, the radiant heat transfer of the high temperature pipe 11 can be remarkably suppressed, and the heat resistant life is preferably 5 years or more at 600 ° C. and more preferably 10 years or more at 600 ° C. Can be extended. As a result, for example, the efficiency of fuel (energy) utilization in a thermal power plant can be significantly improved.

(2) The coating base material is an austenitic stainless steel foil 14. Therefore, good flexibility and strength can be exhibited as the covering member 12 that covers the high temperature pipe 11.
(3) The reflective film 17 is composed of a non-oxide metal silicide film, and the barrier film 16 is composed of a silica film or a silica film and a metal compound film or a silica film and a metal film, and is oxidized. The inhibitory film 18 is composed of a nitride film.

Therefore, the reflectance of the heat radiation suppression film 15 can be increased to, for example, 90% or more by the reflective film 17. Further, excellent oxygen barrier properties are exhibited based on the properties of the nitrides constituting the oxidation suppression film 18, and the oxidation of the reflection film 17 in a high temperature region of 600 ° C. or higher can be suppressed to improve its durability. In addition, the barrier film 16 can effectively shield the migration of the non-oxide metal silicide component and the austenitic stainless steel component, suppress the reaction of both components, and maintain the function of the reflective film 17 for a long period of time. be able to.

(4) When the coating base material is the foil 14 of SUS304, the reflective film 17 is composed of a cobalt silicide film, and the barrier film 16 is a silica film and a tungsten film or a silica film and a chromium oxide film. The oxidation-suppressing film 18 is composed of a silicon nitride film. Alternatively, the reflective film 17 is composed of a nickel silicide film, the barrier film 16 is composed of a silica film or a silica film and a tungsten film, and the oxidation suppression film 18 is composed of a silicon nitride film.

Therefore, the barrier film 16 can inhibit the reaction between the cobalt silicide and the components of SUS304, and the function of the cobalt silicide as the reflective film 17 can be well maintained, and the silicon nitride which is the oxidation suppressing film 18 can be maintained. As a result, the oxidation of the reflective film 17 can be suppressed and its durability can be improved.

(5) When the coating base material is a SUS316L foil, the reflective film 17 is composed of a cobalt silicide film, the barrier film 16 is composed of a silica film and a chromium oxide film, and an oxidation inhibitory film. Reference numeral 18 is composed of a film of silicon nitride.

Therefore, the barrier film 16 can inhibit the reaction between the cobalt silicide and the components of SUS316L, and the function of the cobalt silicide as the reflective film 17 can be well maintained, and the silicon nitride film 18 is used to suppress the oxidation. Oxidation of the reflective film 17 can be suppressed to improve its durability.

(6) The covering member 12 covers the high-temperature pipe 11 in order to suppress the radiant heat transfer of the high-temperature pipe 11, and the above-mentioned heat radiation suppression film 15 is provided on the surface of the stainless steel foil 14. It is composed of.

Therefore, the radiant heat transfer from the high temperature pipe 11 can be easily suppressed by simply covering the high temperature pipe 11 with the covering member 12 provided on one side of the stainless steel foil 14 for the heat radiation suppression film 15, and energy utilization. Efficiency can be increased over a long period of time.

Hereinafter, the embodiment will be described in more detail with reference to examples.
(Example 1)
In Example 1, under the conditions shown below, a tungsten film was formed as the second barrier membrane 16b on the surface of the coated substrate by a conventional method of a direct sputtering method, and the first surface was formed on the surface by a conventional method of a reactive sputtering method. A silica film was formed as the barrier film 16a. Further, a cobalt silicide film is formed on the reflective film 17 as a reflection film by a conventional method of simultaneous sputtering, and a silicon nitride film is formed as an oxidation suppression film 18 on the cobalt silicide film as an oxidation suppression film 18 by a conventional method of a reactive sputtering method to suppress thermal radiation. A film 15 was provided to obtain a covering member 12.

Coating base material: SUS304 foil 14 as stainless steel, thickness 10 μm
Second barrier membrane 16b: Tungsten film, thickness 50 nm
First barrier membrane 16a: silica film, thickness 50 nm
Reflective film 17: Cobalt Silicide film: 230 nm thick
Oxidation suppression film 18: Silicon nitride film, thickness 60 nm
With respect to the coating member 12 in which the thermal radiation suppression film 15 is formed on the surface of the foil 14 of the SUS304, the reflectance (%) is changed by changing the wavelength (μm) of light according to a conventional method using a spectroscope and a detector. Was measured. The result is shown in FIG. From the obtained reflectance measurement result, the change in the emissivity (%) with respect to the wavelength (μm) of light can be obtained (radiance (%) = 100% −reflectivity (%)).

From the results shown in FIG. 4, the reflectance reaches about 60% at a wavelength of 1 μm (1000 nm), the reflectance reaches about 85% at a wavelength of 2 μm, and the reflectance is maintained at about 95% until the wavelength reaches 25 μm thereafter. rice field.

Next, the heat radiation suppression film 15 of Example 1 was subjected to an accelerated deterioration test by the following method to evaluate the durability of the heat radiation suppression film 15.
First, as shown in FIG. 5, the foil 14 of SUS304 provided with the heat radiation suppression film 15 on the surface is placed in a heating furnace and heated to 700 ° C. (973K) in the air, and after 1 hour, The relationship between the wavelength (nm) of light and the reflectance (%) after 100 hours, 750 hours, and 900 hours was determined.

Similarly, as shown in FIG. 6, the foil 14 of SUS304 provided with the heat radiation suppression film 15 on the surface is heated to 750 ° C. (1023K) in a heating furnace, and the wavelength of light (nm) after a lapse of a predetermined time is determined. The relationship with the reflectance (%) was calculated. Further, in the same manner, as shown in FIG. 7, the foil 14 of SUS304 provided with the heat radiation suppression film 15 on the surface is heated to 800 ° C. (1073K) in a heating furnace, and the wavelength of light (nm) after a lapse of a predetermined time. The relationship between and the reflectance (%) was calculated.

Then, at each heating temperature, the time (life) until the reflectance decreased by 10% was measured. That is, when the heating temperature was 700 ° C., as shown in FIG. 8, the reflectance decreased from about 86% to about 76%, and the life was 820 hours (hr). At a heating temperature of 750 ° C., as shown in FIG. 9, the reflectance decreased from about 86% to about 76%, and the life was 71 hours. At a heating temperature of 800 ° C., as shown in FIG. 10, the reflectance decreased from about 85% to about 75%, and the life was 15.5 hours.

Next, the straight line showing the correlation is extrapolated by the relationship (Arrhenius plot) between the reciprocal of the absolute temperature [1000 / T (that is, 1000 / K)] and the logarithm [log (t)] of the time t (hr). Therefore, the life at 600 ° C. was obtained, and the result is shown in FIG.

From the result of FIG. 11, the life of the heat radiation suppressing film 15 in the high temperature region of 600 ° C. was 11.1 years.
(Example 2)
In Example 1, thermal radiation is radiated onto the foil 14 of SUS304 in the same manner as in Example 1 except that the first barrier film 16a uses a silica film and the second barrier film 16b uses a chromium oxide film as the barrier film 16. The restraining film 15 was formed to obtain a covering member 12.

Then, in the same manner as in Example 1, the thermal radiation suppression film 15 was subjected to an accelerated deterioration test at 700 ° C., 750 ° C. and 800 ° C. Based on the results of each accelerated aging test, the relationship between the reciprocal of absolute temperature [1000 / T (ie, 1000 / K)] and the logarithm of time t (hr) [log (t)] is shown in FIG.

From the results of FIG. 12, the life of the heat radiation suppressing film 15 in the high temperature region of 600 ° C. was 6.5 years.
(Example 3)
In Example 1, heat radiation is suppressed on the foil 14 of SUS304 in the same manner as in Example 1 except that a nickel silicide film (thickness 230 nm) is used as the reflective film 17 and a silica film is used as the barrier film 16. A film 15 was formed to obtain a covering member 12.

Then, in the same manner as in Example 1, the thermal radiation suppression film 15 was subjected to an accelerated deterioration test at 700 ° C., 750 ° C. and 800 ° C. Based on the results of each accelerated aging test, the relationship between the reciprocal of absolute temperature [1000 / T (ie, 1000 / K)] and the logarithm of time t (hr) [log (t)] is shown in FIG.

From the result of FIG. 13, the life of the heat radiation suppressing film 15 in the high temperature region of 600 ° C. was 11.5 years.
(Example 4)
In Example 3, heat radiation is suppressed on the foil 14 of SUS304 in the same manner as in Example 3 except that the first barrier film 16a uses a silica film and the second barrier film 16b uses a tungsten film as the barrier film 16. A film 15 was formed to obtain a covering member 12.

Then, in the same manner as in Example 3, the thermal radiation suppression film 15 was subjected to an accelerated deterioration test at 700 ° C., 750 ° C. and 800 ° C. Based on the results of each accelerated aging test, the relationship between the reciprocal of absolute temperature [1000 / T (ie, 1000 / K)] and the logarithm of time t (hr) [log (t)] is shown in FIG.

From the result of FIG. 14, the life of the heat radiation suppressing film 15 in the high temperature region of 600 ° C. was 7.0 years.
(Example 5)
In Example 1, SUS316L foil 14 (thickness 10 μm) was used as the coating base material, the first barrier film 16a was a silica film, and the second barrier film 16b was a chromium oxide film as the barrier film 16. In the same manner as in Example 1, a heat radiation suppression film 15 was formed on the foil 14 of SUS316L to obtain a covering member 12.

Then, in the same manner as in Example 1, the thermal radiation suppression film 15 was subjected to an accelerated deterioration test at 700 ° C., 750 ° C. and 800 ° C. Based on the results of each accelerated aging test, the relationship between the reciprocal of absolute temperature [1000 / T (ie, 1000 / K)] and the logarithm of time t (hr) [log (t)] is shown in FIG.

From the result of FIG. 15, the life of the heat radiation suppressing film 15 in the high temperature region of 600 ° C. was 6.9 years.
It is also possible to modify the embodiment as follows to embody it.

-As the barrier membrane 16 constituting the heat radiation suppression film 15, it is also possible to reverse the laminated structure of the first barrier membrane 16a and the second barrier membrane 16b. For example, silica as the first barrier membrane 16a may be arranged on the stainless steel foil 14 side, and chromium oxide as the second barrier membrane 16b may be arranged on the reflection film 17 side.

A heat radiation suppression film 15 may be provided on both sides of the stainless steel foil 14 to form the covering member 12.
The barrier film 16, the reflective film 17, or the oxidation-suppressing film 18 shown in Examples 1 to 5 may be formed by a direct sputtering method or the like.

In the configuration of the thermal radiation suppression film 15 shown in FIGS. 1A and 1B, the barrier film 16, the reflection film 17, and the oxidation suppression film 18 are further laminated on the oxidation suppression film 18 on the outermost surface. It may be configured.

11 ... High temperature piping as a high temperature object, 12 ... Coating member, 14 ... Stainless steel foil as a coating base material, 15 ... Thermal radiation suppression film, 16 ... Barrier membrane, 16a ... First barrier membrane, 16b ... Second barrier Membrane, 17 ... Reflective membrane, 18 ... Antioxidant membrane

Claims (5)

A heat radiation suppression film provided on the surface of a stainless steel coating base material that covers a high temperature object in order to suppress radiant heat transfer of the high temperature object.
A reflective film that reflects light via a barrier film that suppresses the migration of components is provided on the surface of the coating substrate, and an oxidation-suppressing film that suppresses oxidation of the reflective film is laminated on the surface of the reflective film. It is composed and
The coating base material is a heat radiation suppression film which is a foil of austenitic stainless steel. The reflective film is composed of a non-oxide metal silicide film, the barrier film is composed of a silica film or a silica film and a metal compound film or a silica film and a metal film, and the oxidation suppression film is a nitride film. The heat radiation suppression film according to claim 1 , which is composed of the above-mentioned film. When the coating base material is a SUS304 foil, the reflective film is composed of a cobalt silicide film, and the barrier film is composed of a silica film and a tungsten film or a silica film and a chromium oxide film. The oxidation-suppressing film is composed of a silicon nitride film, or the reflective film is composed of a nickel silicide film, the barrier film is composed of a silica film or a silica film and a tungsten film, and the oxidation-suppressing film is composed of a silica film. The heat radiation suppression film according to claim 2 , which is composed of a silicon nitride film. When the coating base material is a SUS316L foil, the reflective film is composed of a cobalt silicide film, the barrier film is composed of a silica film and a chromium oxide film, and the oxidation suppression film is a silicon nitride film. The heat radiation suppression film according to claim 2. The heat radiation according to any one of claims 1 to 4 , which is a coating member that covers the high-temperature object in order to suppress radiant heat transfer of the high-temperature object, and is provided on the surface of stainless steel as the coating base material. A covering member provided with an inhibitory film.

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