Method for forming functional self-fluxing alloy coatings

Abstract

To provide a method for forming a functional self-fluxing alloy coating, capable of exhibiting excellent wear resistance, corrosion resistance and lubricity and suppressing the suppression effect of the adhesion and deposition of ash (clinker) for a long period of time.SOLUTION: A method for forming a functional self-fluxing alloy coating comprises: the thermal spray coating formation step of forming a self-fluxing alloy thermal spray coating on the surface of a base material; the lubricant composition impregnation step; the drying step of drying the thermal spray coating including the impregnated lubricant composition to remove the solvent and form a thermal spray coating including the solid lubricant particles; and the self-fluxing alloy remelting step of heating the thermal spray coating including the solid lubricant particles to remelt the self-fluxing alloy.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for forming a functional self-fluxing alloy coating, and more specifically, to a method for forming a self-fluxing alloy coating that is excellent in wear resistance and corrosion resistance, as well as in lubricity (sliding properties). [Background technology]

[0002] In waste incineration facilities and similar facilities, there is a problem in that ash (clinker) generated during the combustion of waste adheres to and accumulates in piping such as heat transfer tubes, reducing the heat transfer efficiency of the piping over time and accelerating the corrosion of the piping.

[0003] To solve these problems, Patent Document 1 discloses a method for forming a coating on the surface of a substrate constituting a combustion furnace structure, which includes a step of applying or spraying a slurry-like sliding material containing oxide ceramics, a compound having a layered crystalline structure, silicone, and an organic solvent as a topcoat formation step, and then firing the coating of the sliding material to form a film.

[0004] According to the method described in Patent Document 1, the coating formed by the topcoat, which is formed by a compound having a layered crystalline structure (for example, boron nitride), exhibits lubricity (sliding properties) that causes colliding ash particles to slip, and also improves the ability of attached ash to detach, thereby suppressing the adhesion and accumulation of ash.

[0005] However, in the coating formed by the method described in Patent Document 1, the topcoat that exhibits lubricity does not have sufficient corrosion resistance and wear resistance, so the effect of suppressing ash adhesion and accumulation is lost in a relatively short time due to corrosion and wear of the topcoat.

[0006] Patent Document 1 discloses a method of forming a two-layer coating by using a thermal spray coating of a nickel-chromium alloy with good corrosion resistance and wear resistance as a base coat, applying a sliding material to the surface of this base coat, and then firing the coating of the sliding material to laminate and form a top coat. However, even if the base coat is formed with a material that has good corrosion resistance and wear resistance, it is not possible to improve the corrosion resistance and wear resistance of the top coat.

[0007] On the other hand, the present inventors have proposed a method for forming a functional self-fluxing alloy film by applying a slurry-like composition containing self-fluxing alloy powder, solid lubricant particles, a binder resin, and a solvent to the surface of a substrate, and then heating the dried coating film after solvent removal to 1000-1200°C using a high-frequency induction heating device, thereby thermally decomposing and removing the binder resin, and sintering the self-fluxing alloy powder and solid lubricant particles (see Patent Document 2 below).

[0008] According to the formation method described in Patent Document 2, a film consisting of a single layer in which a self-fluxing alloy and solid lubricant particles coexist can be formed.

[0009] However, the method described in Patent Document 2, which involves sintering self-fluxing alloy powder and solid lubricant particles, fails to form a dense film, resulting in a porous film with high porosity. Consequently, the film formed by the method described in Patent Document 2 does not possess sufficient strength, and the expected improvement in corrosion resistance and wear resistance achieved by incorporating the self-fluxing alloy cannot be fully realized.

[0010] Furthermore, in order to ensure the required film thickness, it is necessary to repeatedly apply and dry the slurry-like composition, which presents problems from the standpoint of ease of application. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Patent No. 6982391 [Patent Document 2] Patent No. 6351070 [Overview of the project] [Problems that the invention aims to solve]

[0012] This invention was made based on the circumstances described above. The object of the present invention is to provide a method for forming a functional self-fluxing alloy coating that exhibits excellent wear resistance and corrosion resistance, as well as excellent lubricity (sliding properties), and that can suppress the adhesion and accumulation of ash (clinker) over a long period of time. [Means for solving the problem]

[0013] (1) The method for forming a functional self-fluxing alloy coating of the present invention comprises the steps of forming a thermal spray coating of a self-fluxing alloy on the surface of a substrate (hereinafter referred to as the "thermal spray coating formation step"), A step of impregnating the thermal spray coating with a lubricant composition containing solid lubricant particles and a solvent (hereinafter referred to as the "lubricant composition impregnation step"), A step of forming a thermal spray coating containing solid lubricant particles by drying the thermal spray coating impregnated with the lubricant composition to remove the solvent (hereinafter referred to as the "drying step"), The invention is characterized by including a step of heating the thermal spray coating containing the solid lubricant particles to remelt the self-fluxing alloy (hereinafter referred to as the "self-fluxing alloy remelting step").

[0014] According to this formation method, in the self-fluxing alloy remelting process, the thermal spray coating containing solid lubricant particles is heated to remelt the self-fluxing alloy, thereby forming a single-layer coating in which the self-fluxing alloy and solid lubricant particles coexist. This coating exhibits excellent wear resistance and corrosion resistance due to the self-fluxing alloy formed by the thermal spraying and remelting process, as well as excellent lubricity (sliding properties) due to the solid lubricant particles.

[0015] (2) In the method for forming the functional self-fluxing alloy coating of the present invention, it is preferable that the filling rate of the self-fluxing alloy in the sprayed coating is 65 to 85%, and the average particle size of the solid lubricant particles is 10 μm or less.

[0016] According to such a forming method, in the lubricant composition impregnation step, the lubricant composition can be efficiently impregnated into the sprayed coating without the solid lubricant particles being captured in the pores of the sprayed coating, and the solid lubricant particles can be uniformly dispersed inside the sprayed coating. As a result, a sufficient amount of solid lubricant particles for exhibiting lubricity can be uniformly contained in the coating formed through the drying step and the self-fluxing alloy remelting step.

[0017] (3) In the method for forming the functional self-fluxing alloy coating of the present invention, it is preferable that the concentration of the solid lubricant particles in the lubricant composition is 0.02 to 10% by weight.

[0018] According to such a forming method, in the lubricant composition impregnation step, the lubricant composition can be impregnated more efficiently.

[0019] (4) In the method for forming the functional self-fluxing alloy coating of the present invention, it is preferable that the base material is a component of a combustion furnace structure (forming a coating on the surface of a component of a combustion furnace structure).

Advantages of the Invention

[0020] According to the forming method of the present invention, a functional self-fluxing alloy coating can be formed that exhibits excellent wear resistance and corrosion resistance by the self-fluxing alloy and excellent lubricity (sliding property) by the solid lubricant particles. According to this functional self-fluxing alloy coating, the adhesion of ash (clinker) can be suppressed over a long period.

Brief Description of the Drawings

[0021] [Figure 1] It is a photograph showing a cross section of a functional self-fluxing alloy coating formed on the outer surface of a metal pipe using a low filling rate sprayed coating in Example 1. [Figure 2] This is a photograph showing a cross-section of a functional self-fluxing alloy coating formed on the outer surface of a metal pipe using a high-filling-rate thermal spray coating in Example 1. [Figure 3] This is a schematic diagram showing the general structure of a circulating water-tube boiler. [Figure 4] Figure 3 shows a photograph of the outer surface of a protector after it has been placed in the first stage piping of the evaporator tube of a circulating water-tube boiler, where (a) is the outer surface of the protector according to Example 2, and (b) is the outer surface of the protector according to Comparative Example 1. [Modes for carrying out the invention]

[0022] The method for forming the functional self-fluxing alloy coating of the present invention will be described in detail below. The present invention provides a method for forming a self-fluxing alloy by comprising: a thermal spray coating forming step of forming a thermal spray coating of a self-fluxing alloy on the surface of a substrate; a lubricant composition impregnation step of impregnating the thermal spray coating with a lubricant composition containing solid lubricant particles and a solvent; a drying step of drying the thermal spray coating impregnated with the lubricant composition to remove the solvent and form a thermal spray coating containing solid lubricant particles; and a self-fluxing alloy remelting step of heating the thermal spray coating containing solid lubricant particles to remelt the self-fluxing alloy.

[0023] In the present invention, examples of substrates (workpieces to be treated) for forming functional self-fluxing alloy coatings include metal materials used as components of combustion furnace structures, such as steel. The shape of the substrate is not particularly limited.

[0024] <Thermal spray coating formation process> The thermal spray coating process involves spraying self-fluxing alloy powder onto the surface of a substrate to form a thermal spray coating. Examples of thermal spraying methods include flame spraying, high-velocity flame spraying, and plasma spraying.

[0025] Examples of self-fluxing alloy powders to be sprayed onto the substrate surface include those specified in JIS H 8303 (Self-fluxing alloy spraying). The average particle size of the self-fluxing alloy powder is preferably 150 μm or less, and more preferably 35 to 125 μm.

[0026] A thermal spray coating formed by spraying self-fluxing alloy powder can be remelted to create a dense coating with excellent wear resistance and corrosion resistance.

[0027] The thickness of the thermal spray coating is preferably 0.5 to 5 mm, and more preferably 0.8 to 3 mm.

[0028] The filling rate of the self-fluxing alloy in the thermal spray coating is preferably 65-85%, and more preferably 70-80%. Here, "self-fluxing alloy filling rate" refers to the volume percentage occupied by the self-fluxing alloy in the thermal spray coating. When the bulk volume of the thermal spray coating is V, the weight of the self-fluxing alloy is W, and the true density of the self-fluxing alloy is ρ, it can be calculated as W / (V·ρ).

[0029] By having a filling rate of the self-fluxing alloy in the thermal spray coating of 65-85%, the strength, wear resistance, and corrosion resistance of the final functional self-fluxing alloy coating can be sufficiently ensured. Furthermore, in the lubricant composition impregnation step described later, a composition containing solid lubricant particles can be efficiently impregnated into the thermal spray coating, uniformly dispersing the solid lubricant particles within the thermal spray coating. This allows the functional self-fluxing alloy coating formed through the drying step and the self-fluxing alloy remelting step to contain a sufficient amount of solid lubricant particles to exhibit lubricity (sliding properties).

[0030] If the filling rate of the self-fluxing alloy is less than 65%, the final functional self-fluxing alloy coating may not have sufficient strength. Furthermore, the ease of application during thermal spray coating formation may be compromised, leading to a decrease in yield. On the other hand, if the filling rate of the self-fluxing alloy exceeds 85%, it becomes difficult to efficiently impregnate the thermal spray coating with a composition containing solid lubricant particles during the lubricant composition impregnation process.

[0031] In conventional methods for forming self-fluxing alloy coatings, in order to maintain a high adhesion efficiency of the self-fluxing alloy powder and to minimize the amount of pores remaining in the final self-fluxing alloy coating, the filling rate of the self-fluxing alloy in the thermal spray coating never falls below 85%, and is usually around 87-95%.

[0032] To reduce the self-fluxing alloy filling rate to 85% or less, this can be adjusted by increasing the flow rate and pressure of the powder supply device that makes up the thermal spraying system to increase the supply (discharge) amount of self-fluxing alloy powder beyond normal limits, or by reducing the flow rate of combustion gas and oxygen to reduce the heat output during thermal spraying beyond normal limits.

[0033] <Lubricant composition impregnation process> The lubricant composition impregnation step is a step in which the lubricant composition is impregnated into the thermal spray coating formed in the thermal spray coating formation step, thereby incorporating solid lubricant particles into the thermal spray coating.

[0034] The lubricant composition used in this process consists of solid lubricant particles and a solvent as essential components.

[0035] The solid lubricant particles contained in the lubricant composition are not particularly limited as long as they can impart lubricity (low coefficient of friction) to the surface of the film. Suitable examples include particles such as boron nitride (BN), molybdenum disulfide (MoS2), and graphite (C).

[0036] The average particle size of the solid lubricant particles is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 0.02 to 3 μm. Small-diameter solid lubricant particles with an average particle size of 10 μm or less are less likely to be trapped in the pores of the thermal spray coating. Therefore, the lubricant composition can be efficiently impregnated into the thermal spray coating (penetrating deep into the thickness direction of the thermal spray coating), and the solid lubricant particles can be uniformly dispersed inside the thermal spray coating. As a result, the coating formed after the drying process and the self-fluxing alloy remelting process described later can contain a sufficient amount of solid lubricant particles to exhibit lubricity (sliding properties).

[0037] The solvent contained in the lubricant composition is not particularly limited and may be an organic solvent or an aqueous solvent. Suitable organic solvents to be included in the lubricant composition include lower alcohols such as ethanol and isopropyl alcohol.

[0038] The concentration of solid lubricant particles in the lubricant composition is preferably 0.02 to 10% by weight, and more preferably 0.2 to 2% by weight.

[0039] When the concentration of solid lubricant particles is less than 0.02% by weight, a large amount of composition (solvent) is required to incorporate a predetermined amount of solid lubricant particles into the thermal spray coating, which is undesirable from the viewpoint of production efficiency. On the other hand, when the concentration of solid lubricant particles exceeds 10% by weight, it may be difficult to efficiently impregnate the lubricant composition into the thermal spray coating.

[0040] The lubricant composition is in the form of a slurry or liquid.

[0041] By applying a lubricant composition containing solid lubricant particles with an average particle size of 10 μm or less to the surface of a thermal spray coating (preferably a thermal spray coating with a self-fluxing alloy filling rate of 65-85%), the lubricant composition can be impregnated (penetrated) into the thermal spray coating. The method for applying the lubricant composition to the surface of the thermal spray coating is not particularly limited and may include spraying, immersion, or using application means such as brushes or rollers.

[0042] <Drying process> The drying process involves drying the thermal spray coating impregnated with the lubricant composition to remove the solvent, thereby forming a thermal spray coating containing solid lubricant particles. Here, the drying temperature is set to 100°C or lower, preferably between 10 and 70°C. As for the drying method, the substrate on which the thermal spray coating containing solid lubricant particles has been formed can be left in the atmosphere, but compressed air or hot air may also be blown onto the thermal spray coating. The drying time varies depending on the proportion of solvent in the film-forming composition and the drying conditions, but it is usually 1 to 10 minutes.

[0043] <Remelting process for self-fluxing alloys> The self-fluxing alloy remelting process is a step in which the thermal spray coating containing solid lubricant particles obtained in the drying process is heated to remelt the self-fluxing alloy.

[0044] The heating temperature in this process is usually 900°C or higher, preferably 950 to 1100°C, and the heating time during which this temperature is maintained is, for example, 5 to 200 seconds. The heat treatment can preferably be carried out by high-frequency induction heating, but is not limited to this.

[0045] This self-fluxing alloy remelting process forms a dense film (functional self-fluxing alloy film) containing solid lubricant particles on the surface of the substrate. This film exhibits excellent wear resistance and corrosion resistance due to the self-fluxing alloy, as well as excellent lubricity (sliding properties) due to the solid lubricant particles. Herein, the thickness of the functional self-fluxing alloy film formed by the formation method of the present invention is usually 0.45 to 4.5 mm, and preferably 0.7 to 2.7 mm. Furthermore, the functional self-fluxing alloy coating formed by the method of the present invention is strong, has good adhesion to the substrate, and also has good density. [Examples]

[0046] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. stomach.

[0047] In the following Example 1, a metal pipe [carbon steel pipe for machine structures (STKM13A)] with an outer diameter of 38.1 mm, a wall thickness of 3.5 mm, and a length of 600 mm was used as the base material. Furthermore, in Example 2 and Comparative Example 1 below, a metal pipe (SUS316L) with an outer diameter of 60.5 mm, a wall thickness of 5.5 mm, and a length of 1000 mm was used as the base material. Furthermore, as the self-fluxing alloy powder material, we used self-fluxing alloy powder with a particle size of 35 to 125 μm, corresponding to JIS H 8303 2.14A.

[0048] <Example 1> (1) Thermal spray coating process: (1-1) Formation of low-fill-rate thermal spray coating: A 2.0 mm thick thermal spray coating was formed on the outer surface of a metal pipe (a 400 mm coating area excluding the 100 mm ends) by flame spraying self-fluxing alloy powder under the following conditions: powder discharge rate = 20-21 Lbs / Hr, acetylene gas flow rate = 18 flow%, oxygen gas flow rate = 30 flow%, peripheral speed = 40 m / min, and pitch = 5 mm / s. The filling rate of the self-fluxing alloy in the thermal spray coating, calculated from the bulk volume of the formed thermal spray coating, the weight of the self-fluxing alloy (weight change of the test material before and after thermal spraying), and the true density of the self-fluxing alloy, was 70.0% (porosity = 30.0%).

[0049] (1-2) Formation of high-fillness thermal spray coating: Except for changing the acetylene gas flow rate to 28 flow% and the oxygen gas flow rate to 40 flow% under the same conditions as in (1-1) above, a 2.0 mm thick thermal spray coating was formed by flame spraying the self-fluxing alloy powder. The filling rate of the self-fluxing alloy in the formed thermal spray coating was 88.1% (porosity = 11.9%).

[0050] (2) Lubricant composition impregnation process: (2-1) Preparation and preparation of lubricant composition: As a lubricant composition, a slurry "LSL-170-20-IPA" (manufactured by MARUKA Corporation, concentration of boron nitride particles = 19.87% by weight) containing boron nitride particles with an average particle size of 0.05 μm dispersed in IPA was prepared. This was then used as the "lubricant composition (L 100 )"

[0051] Furthermore, the above slurry "LSL-170-20-IPA" is diluted with ethanol to a weight ratio of 2 to obtain a lubricant composition (L 50 Prepare a solution and dilute it 10 times to make a lubricant composition (L 10 A solution was prepared, diluted 20 times to prepare lubricant composition (L5), and diluted 100 times to prepare lubricant composition (L1).

[0052] (2-2) Lubricant composition impregnation process: On the surface of the low-filling-density thermal spray coating and the high-filling-density thermal spray coating formed in the above thermal spray coating formation process, a lubricant composition (L 100 ), lubricant composition (L 50 ), lubricant composition (L 10 The lubricant compositions (L5) and (L1) were applied to each thermal spray coating using a brush (application area = 50 mm), thereby impregnating each thermal spray coating with the lubricant composition.

[0053] (3) Drying process: The solvents constituting the lubricant compositions were completely removed by leaving the metal pipes, each impregnated with a lubricant composition (low-filling-density thermal spray coating and high-filling-density thermal spray coating), in the atmosphere for 5 minutes.

[0054] (4) Self-fluxing alloy remelting process: After the drying process described above, each of the thermal spray coatings (low-filling thermal spray coating and high-filling thermal spray coating) containing boron nitride particles formed on the outer surface of the metal tube was heated to 1050°C at a heating rate of approximately 100°C / second using a high-frequency induction heating device, and the self-fluxing alloy was remelted by heating at this temperature for 20 seconds. Subsequently, by cooling to room temperature over 30 minutes, a functional (lubricating) self-fluxing alloy coating approximately 1.7 mm thick was formed on the outer surface of the metal tube.

[0055] <Dispersibility of boron nitride particles in functional self-fluxing alloy coatings> The cross-section of the self-fluxing alloy film formed in Example 1 was visually observed to assess the dispersion state of boron nitride particles. The evaluation criteria are as follows. The results are shown in Fig. 1, Fig. 2 and Table 1 below.

[0056] (Evaluation Criteria) 「◎」: Boron nitride particles are uniformly dispersed throughout the self-fluxing alloy coating. 「○」: Boron nitride particles are dispersed throughout the self-fluxing alloy coating, but there is a slight bias. 「△」: Boron nitride particles are only partially observed and the amount is small. 「×」: Boron nitride particles are hardly observed.

[0057] Here, Fig. 1 is a cross-section of a coating formed using a low filling rate sprayed coating (filling rate of self-fluxing alloy = 70.0%) in the lubricant composition impregnation step, and Fig. 2 is a cross-section of a coating formed using a high filling rate sprayed coating (filling rate of self-fluxing alloy = 88.1%). Also, in Fig. 1 and Fig. 2, (a) is a coating formed by impregnating the lubricant composition (L 100 ), (b) is a coating formed by impregnating the lubricant composition (L 50 ), (c) is a coating formed by impregnating the lubricant composition (L 10 ), (d) is a coating formed by impregnating the lubricant composition (L5), and (e) is a coating formed by impregnating the lubricant composition (L1). In Fig. 1 and Fig. 2, the white-looking parts in the coating are boron nitride particles.

[0058] [Table 1]

[0059] As shown in Fig. 1, it can be visually confirmed that boron nitride particles are dispersed and contained in the coating formed using the low filling rate sprayed coating. As shown in Fig. 2, although it could not be visually confirmed that boron nitride particles were dispersed and contained in the coating formed using the high filling rate sprayed coating, it was confirmed by observation with an electron microscope that boron nitride particles were contained.

[0060] <Example 2> (1) Thermal spray coating process: A thermal spray coating with a thickness of 1.5 mm and a filling rate of 70.0% of the self-fluxing alloy powder (low-filling-rate thermal spray coating) was formed on a metal pipe (SUS316L) by flame spraying.

[0061] (2) Lubricant composition impregnation process: A lubricant composition was prepared by diluting a slurry "LSL-170-20-IPA," which contains boron nitride particles dispersed in IPA, 100 times with ethanol, and applying it to the surface of the thermal spray coating formed in the above thermal spray coating formation process (application area = 500 mm), thereby impregnating the thermal spray coating with each component of the lubricant composition.

[0062] (3) Drying process: The metal pipe having a thermal spray coating impregnated with the lubricant composition as described above was left in the atmosphere for 5 minutes to completely remove the solvent constituting the lubricant composition.

[0063] (4) Self-fluxing alloy remelting process: After the drying process described above, the thermal spray coating containing boron nitride particles formed on the outer surface of the metal tube was heated to 1050°C at a heating rate of approximately 100°C / second using a high-frequency induction heating device, and the self-fluxing alloy was remelted by heating at this temperature for 20 seconds. Subsequently, by cooling to room temperature over 60 minutes, a functional self-fluxing alloy coating with a thickness of approximately 1.2 mm was formed on the outer surface of the metal tube.

[0064] <Comparative Example 1> A self-fluxing alloy powder was flame-sprayed onto a metal pipe (SUS316L) to form a sprayed coating with a thickness of 1.5 mm and a self-fluxing alloy filling rate of 88.1% (high-filling-rate sprayed coating). Subsequently, in the same manner as in Example 2(4), the formed sprayed coating was heated to remelt the self-fluxing alloy, thereby forming a self-fluxing alloy coating with a thickness of approximately 1.2 mm on the outer surface of the metal pipe.

[0065] <Effect of suppressing the adhesion and accumulation of ash (clinker)> Each of the metal tubes that had a self-fluxing alloy coating formed in Example 2 and Comparative Example 1 was cut lengthwise using a laser cutting machine to form halved metal tubes, which were then installed as protectors to protect the evaporator tubes of a circulating water-tube boiler, as shown in Figure 3. In Figure 3, 1 is a drum, 3 is a circulation pump, 5 is an evaporator tube, and 7 is a protector installed in the first stage of the evaporator tube 5 (the split metal tube made by splitting a metal tube with a self-fluxing alloy coating formed on it in Example 2 or Comparative Example 1). The combustion gases cause the ambient temperature in the first stage to reach 800-1000°C.

[0066] After continuously operating a circulating water-tube boiler equipped with the protectors according to Example 2 and Comparative Example 1 for six months, the protectors were recovered and the outer surface on which the self-fluxing alloy coating had formed was observed. The results are shown in Figure 4. In Figure 4, the white substance is clinker (ash). As shown in Figure 4(a), there is almost no clinker adhering to the outer surface of the protector according to Example 2. In contrast, as shown in Figure 4(b), significant clinker deposition is observed on the outer surface of the protector according to Comparative Example 1. [Explanation of Symbols]

[0067] 1 Drum 3. Circulation pump 5 Evaporator tube 7 Protector

Claims

1. A process for forming a self-fluxing alloy thermal spray coating on the surface of a substrate, A step of impregnating the thermal spray coating with a lubricant composition containing solid lubricant particles selected from boron nitride, molybdenum disulfide, and graphite, and a solvent, A step of forming a thermal spray coating containing solid lubricant particles by drying the thermal spray coating impregnated with the lubricant composition to remove the solvent, A step of heating the thermal spray coating containing the solid lubricant particles to remelt the self-fluxing alloy, A method for forming a functional self-fluxing alloy coating, including the coating.

2. A method for forming a functional self-fluxing alloy coating according to claim 1, wherein the filling rate of the self-fluxing alloy in the thermal spray coating is 65 to 85%, and the average particle size of the solid lubricant particles is 10 μm or less.

3. The method for forming a functional self-fluxing alloy film according to claim 2, wherein the concentration of the solid lubricant particles in the lubricant composition is 0.02 to 10% by weight.

4. A method for forming a functional self-fluxing alloy coating according to any one of claims 1 to 3, wherein the substrate is a component of a combustion furnace structure.

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