JPH1068086A - Sealing agent for thermally sprayed coating film, and sealing treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute good sealing treatment without using any heating furnace or the like by using a sealing agent contg. specified fluorine compounds. SOLUTION: This sealing agent is prepd. by dissolving a fluorine surfactant and at least one kind selected from the group of perfluoro group-contg. organic silicon compounds into an organic solvent. The solvent is volatilized after the sealing agent is applied on the thermally sprayed coating film to leave the fluorine-contg. compounds behind. In this way, the sealing agent good in infiltration into the narrow pores of the coating film can be obtd. The sealing agent is applied by spraying using an ordinary spray gun, brushing, immersing or the like. Since the sprayed coating film is formed by laminating unstable grains, and is gradually changed by the influence of the air immediately after the film formation to lose its activity, the sealing treatment is executed promptly as possible after thermal spraying to prevent the disappearance of the activity. Moreover, a heating device or the like is unnecessitated in this sealing treatment, and the operation can simply be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment agent and a treatment method for sealing a thermal sprayed coating.

[0002]

2. Description of the Related Art A technique of spraying a metal or ceramic onto a surface of a base metal such as steel to improve heat resistance, abrasion resistance, or corrosion resistance is widely used. However, since the thermal spray coating is generally porous, gas and liquid diffuse or permeate to the substrate due to its pore structure,
There is a tendency that the performance of the thermal spray material itself, particularly the corrosion resistance, is inferior. Therefore, after the thermal spray coating is formed, some sealing treatment is performed. The same applies to the case of zinc spray coating, zinc / aluminum alloy spray coating, and aluminum spray coating which are general anti-corrosion spraying. These thermal sprayed materials have a sacrificial anticorrosion effect because they are base to steel without post-treatment, but also in this case, sealing treatment is performed in order to extend the service life and improve reliability.

[0003] As a sealing method, the following method is conventionally known. As one of the methods, there is a method of heating and melting a coating after spraying using a self-fluxing alloy. Literally, it is a clever method using self-flux (self-fluxing) property, and has the advantage that pores generated at the time of thermal spraying can be reduced by heating and melting. However, it is necessary to add a remelting step in a heating furnace after thermal spraying. In that case, there is a disadvantage that the product is thermally deformed. In addition, there is a method of re-melting a sprayed coating using a vacuum electron beam or a laser beam (Japanese Patent Application Laid-Open No. 61-104062). This method is excellent in that the heat resistance of the thermal spray material itself is not impaired, but there are restrictions on the shape and size of products that can be processed on the apparatus.

[0004] The most common sealing treatment method conventionally used is to spray a sealing treatment agent obtained by dissolving a synthetic resin such as an epoxy resin, an acrylic resin, a urethane resin, a phenol resin, or a fluororesin in an organic solvent. This is a method of applying to a film. However, in this method, the synthetic resin is only applied to the surface of the thermal spray coating and does not penetrate to the bottom of the pores. Therefore, the corrosion protection of the thermal spray coating was poor.

On the other hand, fluorine-containing silazane compounds have been known as coating materials for plastic materials and inorganic materials, particularly for glass surfaces (Japanese Patent Publication No. 3-19276, Japanese Patent Application Laid-Open No. 3-29037). It is disclosed that a fluorinated silazane compound forms a coating film having excellent weather resistance, such as water repellency, oil repellency, and releasability, on these substrates. However, there is no mention of the anticorrosion effect when the base material is a metal such as steel.

[0006] Like the fluorine-containing silazane compound, the fluorine-containing silane compound is also known as a coating agent for imparting water repellency, oil repellency, releasability and lubricity. Since the silane compound chemically reacts with Si-OH on the glass surface, various proposals have been made since ancient times, particularly as a coating agent for window glass and lenses. However, there is no disclosure of any anticorrosive action involving not only water but also permeation of ions, gases, and the like, and application of these coating agents to thermal spray coatings is not known.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing agent and a sealing method for a thermal sprayed coating which can be easily processed without requiring an apparatus such as a heating furnace.
SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing agent and a sealing method which have excellent permeability to a thermal sprayed coating and significantly improve corrosion resistance.

[0008]

According to the present invention, there is provided a method for sealing a thermal sprayed coating comprising at least one selected from the group consisting of a fluorine-based surfactant and a perfluoro group-containing organosilicon compound. Agent. The present invention relates to a method for sealing a thermal spray coating, which comprises applying a sealing agent to the thermal spray coating formed on the surface of a base metal such as steel.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Sealing Agent The sealing agent of the present invention is obtained by spraying a metal or ceramic such as aluminum, zinc, aluminum or zinc on the surface of a thermal sprayed coating, particularly a base metal such as steel. Sealing treatment can be performed by applying to the coating. The sealant for the thermal spray coating of the present invention contains at least one selected from the group consisting of a fluorine-based surfactant and a perfluoro group-containing organosilicon compound.

(1) Fluorinated Surfactant As the fluorinated surfactant, known anionic, cationic, nonionic and amphoteric fluorinated surfactants can be used. The fluorinated surfactants can be used alone or in combination of two or more. Anionic surfactants include carboxylate, sulfate, sulfonate, phosphate, phosphonate, phosphate and the like. Cationic surfactants include amino halide salts,
And quaternary ammonium salts. Nonionic surfactants include polyoxyethylene ether type, polyoxyethylene ester type, sorbitan ester type and the like. The amphoteric fluorinated surfactants include betaine type, imidazoline type and the like.

As the fluorine-based surfactant used in the present invention, an anionic fluorine-based surfactant, particularly a phosphate,
Phosphonates are preferred, and specifically, for example, fluorine-containing phosphonates represented by the following formula can be used.

[0012]

Embedded image

As the fluorinated surfactant, a surfactant containing a perfluoro group is preferred. Specifically, the following surfactants containing a perfluoro group can be used.
Rf represents a perfluoroalkyl group or a perfluoroalkenyl group. M represents a monovalent metal, for example, an alkali metal.

Anionic fluorinated surfactant RfCOOH RfCOOM Rf (CH ₂ CF ₂ ) _n CH ₂ COOH Rf (CH ₂ ) _n COONa RfCH = CH (CH ₂ ) _n COONa RfO (CH ₂ ) COOH RfCH ₂ CH ₂ OCH ₂ CH ₂ COOH RfOC ₆ H ₄ COONa

[0015] _{RfCH 2 CH 2 SCH 2 CH 2} COONa RfCONH (CH 2) 5 COONa RfSO 2 NH (CH 2) 3 N (CH 2 COONa) 2 RfSO 3 H C n F 2n + 1 SO 3 N (C 2 H _{5) 4 C n F 2n +} 1 CH 2 CH 2 SO 3 NH 4 C n F 2n + 1 (CH 2) n SO 3 Na C n F 2n + 1 C 6 H 4 SO 3 H C n F 2n + 1 OC ₆ H ₄ SO ₃ H

[0016] _{(C n F 2n + 1)} 3 OC (CH 2) 3 SO 3 K (CF 3) 2 C = C (CF 3) OC 6 H 4 SO 3 Na C 3n F 6n-1 OC 6 H 4 _{SO 3 K RfCONR (CH 2)} SO 3 Na RfCH 2 OSO 3 Na CF 3 (CF 2) n CH 2 CH 2 OP (O) (OH) 2 C 6 F 13 CH = C (CF 3) OPO (OH) _{2 F - (- CF (CF} 3) CFO-) n -CF (CF) CH
₂ CH ₂ CH ₂ SO ₃ H

The fluorinated cationic surfactant _{C n F 2n + 1 CH 2} CH 2 N + (CH 3) 2 C 2 H 5 l - C n F 2n + 1 CH 2 NH (CH 2) 2 N + ( CH ₃ ) ₃ Cl ⁻ (CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ N ^{+
_{(CH 3) 3 l - RfCONH}} (CH 2) 3 N + (CH 3) l - RfSO 2 NH (CH 2) 3 N + (CH 3) 3 l - C n F 2n + 1 SO 2 O (CH 2 ^{_{) n + (CH 3) 3}} l - C n F 2n + 1 (CH 2) n n + (CH 3) 3 Br -

Nonionic fluorinated surfactant CF ₃ (CF ₂ ) _n CH ₂ O (CH ₂ CH ₂ O) _m H RfCOOCH ₂ C (CH ₂ OH) ₃ CF ₃ CF ₂ (CF ₂ CF ₂ ) _m CH ₂ CH ₂ O (CH ₂ CH _{2
O) n H (CF 3)} 2 CFO (CH 2) 6 O (CH 2 CH 2 O) n H CF 3 CHFCF 2 CH 2 O [CH (CH ₃₎ CH ₂ O] _m H C _n F _{2n + 1} CH ₂ CH (OH) CH ₂ OC ₂ H ₅

C _n F _{2n + 1} C ₂ H ₄ SO ₂ NH [CH ₂ CH
(CH ₂ OH) O] _n H C ₆ F ₅ (OCH ₂ CH ₂ ) ₁₀ OH C _n F _{2n + 1} CONH (CH ₂ CH ₂ O) _m H C _n F _{2n + 1} CONH (CH ₂ ) ₃ N _{(CH 2 CH 2 OH) 2} C n F 2n + 1 CH 2 CON (CH 2 CH 2 O) m CH 2 ] _{2 C n F 2n + 1 CH} 2 CH 2 SO 2 n (CH 3) CH 2 CH 2 OH

[0020] Amphoteric fluorosurfactants ^{_{RfOC 6 H 4 CH 2 N +}} (CH 3) 2 / CH 2 COO - RfCH 2 CH (OCOCH 3) CH 2 N + (CH 3) 2 CH
₂ COO ^-

(2) Perfluoro group-containing organosilicon compound As the perfluoro group-containing organosilicon compound, a per se known fluorinated silazane compound or fluorinated silane compound can be used. The perfluoro group-containing organosilicon compound can be used alone or in combination of two or more.

[Fluorine-Containing Silazane Compound] As the fluorine-containing silazane compound, a silazane compound containing a perfluoro group represented by the following general formula (I) can be used.

[(RfQ) _a Si (R ¹ ) _b (NR ² ) _2-0.5a-0.5b ] _n (I) In the general formula (I), R ¹ may be the same or different, A hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 1 carbon atoms;
0, more preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms. Examples of the unsubstituted or substituted monovalent hydrocarbon group corresponding to R ¹ include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; an alkenyl group such as a vinyl group and an allyl group; And aryl groups such as tolyl groups; cycloalkyl groups such as cyclohexyl groups; halogenated hydrocarbon groups in which some or all of the hydrogen atoms bonded to carbon atoms of these hydrocarbon groups have been substituted with halogen atoms.

R ² may be the same or different and is a hydrogen atom or an alkyl group, preferably a hydrogen atom. The alkyl group corresponding to R ² is, for example,
It is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group. Rf is
Each may be the same or different and have 1 to 1 carbon atoms
20 perfluoroalkyl groups or 5 to 3 carbon atoms
2 perfluoroalkyl ether group. Rf is
For example C _i F _{2i + 1} - perfluoroalkyl group represented by; F - (- CF (CF 3) CF 2 O-) j -CF (C
F ₃ ) — represents a perfluoroether group. i
Is an integer of 1 to 20, and j is an integer of 1 to 10.

Q represents —C _m H _2m — or —SO ₂ N
(R ³ ) a divalent organic group represented by C ₁ H _2l —. m is an integer of 2 to 4, l is an integer of 1 to 4, R ³ is 1 carbon atom.
To 4 alkyl groups. Divalent organic group which corresponds to Q, for example, -CH ₂ CH ₂ - group, -CH ₂ CH ₂ CH ₂ -
An alkylene group such as a group; —SO ₂ N (C ₃ H ₇ ) CH ₂ CH ₂
A CH ₂ — group. a is an integer of 1 to 3;
And a + b is an integer of 1 to 3.
n is an integer of 1 or more, usually an integer of 2 to 100.

The fluorine-containing silazane compound represented by the general formula (I) is disclosed in JP-B-3-19276 and JP-A-3-2276.
As shown in JP-A-90437, it can be produced by a method of reacting a silane compound with ammonia or a primary amine.

[Organopolysiloxane Copolymer Fluorinated Silazane Compound] In the present invention, if necessary, an organopolysiloxane, for example, a fluorinated silazane compound copolymerized with an organosiloxane represented by the following formula can also be used.

[0028]

Embedded image

Here, R ¹ may be the same or different and is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms.
More preferably, it is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms. Examples of the unsubstituted or substituted monovalent hydrocarbon group corresponding to R ¹ include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; an alkenyl group such as a vinyl group and an allyl group; And aryl groups such as tolyl groups; cycloalkyl groups such as cyclohexyl groups; halogenated hydrocarbon groups in which some or all of the hydrogen atoms bonded to carbon atoms of these hydrocarbon groups have been substituted with halogen atoms.

Rf may be the same or different and is a perfluoroalkyl group having 1 to 20 carbon atoms or a perfluoroalkyl ether group having 5 to 32 carbon atoms. Rf is, for example, C _i F _{2i + 1} - perfluoroalkyl group represented by; F - (- CF (CF 3) CF 2
_{O-) j -CF (CF 3)} - is a perfluoroether group represented by. i is an integer of 1 to 20, and j is an integer of 1 to 10. Q is, -C _m H _2m - or -SO ₂ N (R ³⁾
It is a divalent organic group represented by C _l H _2l- . m is 2-4
, L is an integer of 1 to 4, and R ³ is an alkyl group having 1 to 4 carbon atoms. Divalent organic group which corresponds to Q, for example, -CH ₂ CH ₂ - group, -CH ₂ CH ₂ CH ₂ - alkylene groups such _{as; -SO 2 N (C 3 H} 7) CH 2 CH 2 CH _{A 2} -group. p and q are each an integer of 0 to 200.

[Fluorine-containing silane compound] As the fluorine-containing silazane compound, a silane compound having a perfluoro group represented by the following general formula (II) can be used.

(RfQ) _a SiR (R ⁴ ) _4-a (II) In the general formula (II), R ⁴ may be the same or different and each represents -H, -CH ₃ , -OCH ₃ ,- OC
₂ H ₅ or —Cl. Rf may be the same or different, and is a perfluoroalkyl group having 1 to 20 carbon atoms or a perfluoroalkyl ether group having 5 to 32 carbon atoms. Rf is, for example, C _i
A perfluoroether group represented by F _{2i +} 1-;
_{CF (CF 3) CF 2 O-} ) j -CF (CF 3) - is a perfluoroether group represented by. Where i is 1-2
An integer of 0 and j is an integer of 1 to 10.

Q is —C _m H _2m — or —SO ₂ N
(R ³ ) a divalent organic group represented by C ₁ H _2l —. m is an integer of 2 to 4, l is an integer of 1 to 4, R ³ is 1 carbon atom.
To 4 alkyl groups. Divalent organic group which corresponds to Q, for example, -CH ₂ CH ₂ - group, -CH ₂ CH ₂ CH ₂ -
An alkylene group such as a group; —SO ₂ N (C ₃ H ₇ ) CH ₂ CH ₂
A CH ₂ — group. a is an integer of 1 to 3. Specific examples of the fluorine-containing silane compound represented by the general formula (II) include the following fluorine-containing silane compounds.

NC ₆ F ₁₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ CF ₃ CF ₂ CF ₂ C (CF ₃ ) ₂ CH ₂ CH ₂ CH ₂ Si (C
_{H 3) 2 Cl n-C} 8 F 17 -SO 2 N (C 3 H 7) CH 2 CH 2 CH 2 Si
_{(OCH 3) 3 F - (} - CF (CF 3) CF 2 O-) 2 -CF (CF 3) C
H ₂ CH ₂ Si (C ₂ H ₅ ) Cl ₂

When a sealing agent containing a chlorosilane-based fluorine-containing silane compound is used, the chlorosilane-based fluorine-containing compound reacts with moisture or the like to generate hydrogen chloride during the coating operation and at the time of natural drying after the coating. Therefore, when generation of hydrogen chloride is not preferable, generation of hydrogen chloride can be prevented by using an alkoxysilane-based fluorine-containing compound.

Method for producing pore-treating agent The pore-treating agent of the present invention is obtained by converting at least one fluorine-containing compound selected from the group consisting of a fluorine-containing surfactant and a perfluoro group-containing organosilicon compound into an organic solvent. It can be produced by dissolving. As the organic solvent, an organic compound capable of dissolving the fluorine-containing compound and volatilizing the fluorine-containing compound after applying the pore-treating agent to the sprayed coating can be used.

By completely dissolving the fluorine-containing compound in the organic solvent, it is possible to produce a pore-sealing agent having good permeability to the pores in the thermal spray coating. By properly selecting and using one or a mixture of two or more organic solvents having good solubility, a pore-sealing agent in which the fluorine-containing compound is completely dissolved can be produced. Examples of the organic solvent include alcohols such as methanol, ethanol and isopropanol; ketones such as acetone and methyl ethyl ketone; aromatic solvents such as benzene, toluene and xylene; esters such as ethyl acetate and butyl acetate; Do
Fluorinated solvents such as meta (or para) xylene hexafluoride can be used.

The concentration of the fluorine-containing compound in the sealing agent of the present invention varies depending on various conditions such as the type of the base metal and the thermal spraying material, the thermal spraying method, the thickness of the thermal spray coating, and the porosity.
The standard is 1 to 30% by weight, preferably 0.5 to 10% by weight. To the sealing agent of the present invention, if necessary, a synthetic resin such as an epoxy resin, a urethane resin, or a silicone resin may be added for the purpose of strengthening a film formed on the surface of the thermal spray coating by the sealing agent. Can also. Further, a dye soluble in an organic solvent may be added for the purpose of coloring, or other additives may be blended.

Sealing Treatment Method The sealing treatment can be performed by applying the sealing agent of the present invention to the sprayed coating. The sealing agent can be applied to the thermal spray coating by a known application method, for example, spraying with a spray gun, brushing or dipping. The thermal spray coating is a coating formed by laminating unstable particles, unlike general stable metals.It changes every moment, immediately after the formation of the coating, under the influence of environmental conditions in the atmosphere. It loses its activity. Therefore, by performing the sealing treatment of the thermal spray coating as soon as possible after thermal spraying, the loss of the activity of the thermal spray coating can be suppressed.

[0040]

The sealant of the present invention is excellent in permeability, efficiently shuts the pore surface inside the sprayed coating from the external environment, improves the anticorrosion effect, and can greatly extend the life of the coating. . In particular, by using the sealing agent of the present invention for sealing a metal sprayed coating having a sacrificial anticorrosion effect formed on the surface of a base metal such as steel, the service life of the sprayed coating is extended, and the reliability is increased. Can be improved. The sealing treatment method of the present invention does not require a heating device or the like, and the operation is simple.

[0041]

The present invention will be described below with reference to examples.

Example 1 [Preparation of a pore-treating agent] 1 g of a fluorine-containing zinc phosphonate represented by the following formula was added to meta-xylene hexafluoride 99
g, to prepare a 1% by weight sealing agent.

[0043]

Embedded image

[Preparation of Sealed Sample Plate] 150 × 5
Using a steel sheet of 0 × 3 mm as a base material and blasting, aluminum was sprayed to a thickness of 120 μm, and the above-mentioned sealing agent was brush-applied immediately to perform sealing.

[Salt Spray Test] A 1000-hour salt spray test was carried out on the thus prepared sample plate subjected to sealing in accordance with the method specified in JIS Z2371. The sample surface was good with almost no occurrence of white rust due to the sacrificial anticorrosive action of aluminum. Table 1 shows the results.

Example 2 Example 1 except that the concentration of the sealing agent was 10% by weight.
Preparation of a sealed sample plate and a salt spray test were performed in the same manner as described above. Table 1 shows the results.

Example 3 Using the same potassium salt of a fluorinated phosphonic acid having the same structure as that of Example 1 in the anion portion, it was dissolved in isopropanol,
A weight percent sealant was prepared. Preparation of a sealed sample and a salt spray test were performed in the same manner as in Example 1 except that the sealing agent was used. Table 1 shows the results.

Example 4 n was placed in a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer.
After charging 15 g of —C ₈ F ₁₇ CH ₂ CH ₂ SiCl _{3 and} 200 g of trichlorotrifluoroethane, the ammonia gas cooled to 5 ° C. in an ice bath and dried with stirring was heated to a liquid temperature of 2 ° C.
Blowing was carried out gradually over 4 hours so as to keep the temperature at 0 ° C or less. Then, the blowing of the ammonia gas was stopped, and the mixture was heated under reflux for 30 minutes to remove the dissolved ammonia gas. After cooling, the by-produced ammonium chloride was separated by filtration, and the solvent was distilled off from the filtrate by an evaporator. A white solid was obtained.

The obtained white solid was diluted with meta-xylene hexafluoride to 1% by weight to prepare a pore-sealing agent. Preparation of a sealed sample plate and a salt spray test were performed in the same manner as in Example 1 except that the sealing agent was used. The sample surface was good with almost no occurrence of white rust due to the sacrificial anticorrosive action of aluminum. Table 1 shows the results.

Example 5 Example 4 except that the concentration of the sealing agent was 10% by weight.
Preparation of a sealed sample plate and a salt spray test were performed in the same manner as described above. Table 1 shows the results.

Example 6 C ₈ F ₁₇ SO ₂ N (C ₂ H ₅ ) CH ₂ CH ₂ CH ₂ Si (OC
The fluorine-containing silane compound represented by H ₃ ) ₃ was diluted in toluene to prepare a 1% by weight sealing agent. Except for using the sealing agent, a sealed sample plate was prepared and a salt spray test was performed in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 An aluminum sprayed plate was prepared in the same manner as in Example 1.
It was subjected to a salt spray test without any sealing treatment. as a result,
White rust was generated on the entire surface of the sample, and the aluminum sprayed coating was clearly worn by the sacrificial corrosion protection.
Table 1 shows the results.

Comparative Example 2 An aluminum sprayed plate produced in the same manner as in Example 1 was sealed using a sealing agent "Super Seal 21" (acrylic two-liquid curing type) for thermal spray coatings manufactured by Daiichi Metco Co., Ltd. After the hole treatment, curing was further performed in a dryer at 80 ° C. for 2 hours to prepare a sample plate for sealing treatment. A salt spray test was carried out in the same manner as in Example 1 using the prepared sealed sample plate. White rust equivalent to that in the non-sealing treatment (Comparative Example 1) was generated. Table 1 shows the results.

[0054]

Table 1 Pore Sealant Result Example 1 1%-Fluorine-containing zinc phosphonate salt solution Almost free from white rust Example 2 10%-Fluorine-containing zinc phosphonate salt solution Almost free from white rust Example 3 1% -Potassium fluorinated phosphonate solution with almost no white rust Example 4 1%-Fluorine-containing silazane compound solution Almost without white rust Example 5 10%-Fluorine-containing silazane compound solution Almost without white rust Example 6 1% -Fluorine-containing silane compound solution Almost no white rust Comparative Example 3 Untreated White rust generated on the entire surface Comparative Example 2 Acrylic two-part curing type sealing agent for thermal spray coating White rust generated on the entire surface

Claims (8)

[Claims] 1. A sealing agent for a thermal spray coating, comprising at least one fluorine-containing compound selected from the group consisting of a fluorine-based surfactant and a perfluoro group-containing organosilicon compound. 2. The method of claim 1, wherein the fluorine-containing surfactant contains a surfactant containing a perfluoro group. 3. The thermal spray coating according to claim 1, which comprises a silazane compound as the perfluoro group-containing organosilicon compound. 4. The sealing agent according to claim 3, wherein the silazane compound is a fluorine-containing silazane compound represented by the following general formula (I). [(RfQ) _a Si (R ¹ ) _b (NR ² ) ² _-0.5a-0.5b ] _n (I) In the general formula (I), R ¹ may be the same or different, and may be a hydrogen atom or R ² is an unsubstituted or substituted monovalent hydrocarbon group; R ² may be the same or different and is a hydrogen atom or an alkyl group;
f is the same or different and is a perfluoroalkyl group having 1 to 20 carbon atoms or a perfluoroalkyl ether group having 5 to 32 carbon atoms;
Is, -C _m H _2m - or ^{_{-SO 2 N (R 3) C}} l H 2l - is a divalent organic group represented, m is an integer of 2 to 4, l is 1
An integer of 4, R ³ is an alkyl group having 1 to 4 carbon atoms; a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b is an integer of 1 to 3 N is an integer of 1 or more; 5. The thermal spray coating according to claim 1, further comprising a silane compound as the perfluoro group-containing organosilicon compound. 6. The sealing agent according to claim 5, wherein the silane compound is a fluorine-containing silane compound represented by the following general formula (II). (RfQ) _a Si (R ⁴ ) _4-a (II) In the general formula (II), R ⁴ may be the same or different and each represents —H, —CH ₃ , —OCH ₃ , or —OC.
₂ H _5, be either -Cl; Rf, which may be each the same or different and may be a perfluoroalkyl ether group of a perfluoroalkyl group or a carbon atoms 5 to 32 carbon atoms from 1 to 20 ; Q is, -C _m H _2m -
Or ^{_{-SO 2 N (R 3) C}} l H 2l - is a divalent organic group represented, m is an integer of 2 to 4, l is an integer of 1 to 4, R ³
Is an alkyl group having 1 to 4 carbon atoms; a is an integer of 1 to 3; 7. A thermal spray coating, wherein the thermal spray coating formed on the surface of the base metal is subjected to a sealing treatment by applying the sealing agent according to any one of claims 1 to 6. Sealing method. 8. The method according to claim 7, wherein the base metal is steel.