JP2023130647A - Ni-based self-fluxing alloy - Google Patents

Abstract

To provide a Ni-based self-fluxing alloy from which a film 6 having excellent compactness, smoothness and corrosion resistance can be obtained.SOLUTION: A metal product 2 has a main part 4 and a film 6. A material of the film 6 is a Ni-based self-fluxing alloy. The Ni-based self-fluxing alloy contains Mo: 5.0 mass% or more and 30.0 mass% or less, B: 0.5 mass% or more and 4.0 mass% or less, Si: 0.5 mass% or more and 10.0 mass% or less, C: 0.01 mass% or more and 0.50 mass% or less, and one or more selected from a group consisting of Fe, Co, and Cu: 0.1 mass% or more and 10.0 mass% or less in total. The balance is Ni and unavoidable impurities.SELECTED DRAWING: Figure 1

Description

This specification discloses an alloy that has self-fusing properties. In particular, this specification discloses a self-fusing alloy in which the base metal is Ni.

Various Ni-based self-fluxing alloys are specified in "JIS H8303 2010". This Ni-based self-fluxing alloy is subjected to a thermal spraying method, an overlay welding method, a centrifugal casting method, etc. to obtain a film. This film covers the main part of the metal product. This film may be subjected to a remelting process. In the remelting process, the coating is heated and a liquid phase appears in the coating. This liquid phase solidifies upon cooling. Remelting treatment can increase the density of the film. Because of their low solidus or liquidus temperatures, Ni-based self-fluxing alloys are suitable for remelting treatment. An example of a Ni-based self-fluxing alloy is disclosed in JP-A-8-134569. Another example of a Ni-based self-fluxing alloy is disclosed in JP-A-2001-342530.

Japanese Patent Application Publication No. 8-134569 Japanese Patent Application Publication No. 2001-342530

Conventional Ni-based self-fluxing alloys contain B and Si. B and Si are easily oxidized. The metal oxide in the film is reduced by the oxidation of B and Si in the remelting process. This reduction reduces the amount of metal oxide in the coating. Furthermore, oxidation of B and Si produces borosilicate glass in the film. This borosilicate glass forms the surface of the film and closes the pores. B and Si contribute to densification, smoothing, and homogenization of the film.

Conventional Ni-based self-fluxing alloys also contain Cr. Cr combines with C to form carbide (Cr ₇ C ₃ ). Cr further combines with B to form boride (CrB). These carbides and borides are hard. The carbides and borides can contribute to the hardness and wear resistance of the coating. Cr also contributes to the corrosion resistance of the coating.

Cr combines with O to form an oxide (Cr ₂ O ₃ ). Since this oxide is stable, it is difficult to be reduced even by remelting treatment. This oxide remains in the film after the remelting treatment. This oxide impairs the denseness and smoothness of the film. Particularly, in coatings obtained by thermal spraying in which the distance between the thermal spraying machine and the object to be coated is long, the adverse effects of Cr oxide are large. The reason for this is that in thermal spraying over a long distance, the flight time of the molten metal is long, and therefore the oxidation of Cr progresses more during the flight.

Conventional coatings leave room for improvement. The applicant's intention is to provide a Ni-based self-fluxing alloy that can provide a film with excellent density, smoothness, and corrosion resistance.

The Ni-based self-fluxing alloy according to this embodiment is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total contains. The remainder is Ni and unavoidable impurities.

The present specification is also directed to powders. The material of this powder is a Ni-based self-fluxing alloy. This Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total contains. The remainder is Ni and unavoidable impurities.

This specification is also directed to products. This product has a film. The material of this film is a Ni-based self-fluxing alloy. This Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total contains. The remainder is Ni and unavoidable impurities.

A dense film with a smooth surface can be obtained from this Ni-based self-fluxing alloy.

FIG. 1 is a sectional view schematically showing a part of a metal product according to an embodiment. FIG. 2 is a conceptual diagram showing an example of a manufacturing method for the metal product shown in FIG.

Hereinafter, preferred embodiments will be described with reference to the drawings as appropriate.

The metal product 2 shown in FIG. 1 has a main portion 4 and a coating 6. The metal product 2 shown in FIG. The film 6 covers the surface of the main portion 4. The film 6 may cover the entire surface of the main portion 4 or may cover a portion thereof. A typical material for the main portion 4 is a metal material. Various metallic materials are suitable for the main part 4. The coating 6 can be obtained by a thermal spraying method which will be explained in detail later. The coating 6 may be obtained by overlay welding, centrifugal casting, or the like. These methods use powders. The film 6 may be obtained through a remelting process which will be explained in detail later.

This powder is a collection of many particles. The material of these particles is a Ni-based self-fluxing alloy. This Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total contains. The remainder is Ni and unavoidable impurities.

As mentioned above, in conventional Ni-based self-fluxing alloys, Cr contributes to corrosion resistance. The Ni-based self-fluxing alloy according to this embodiment does not substantially contain Cr. On the other hand, this Ni-based self-fluxing alloy contains Fe, Co, or Cu. Fe, Co and Cu can each be dissolved in the Ni matrix. According to the knowledge obtained by the present inventor, Fe, Co, or Cu dissolved in the matrix contributes to the corrosion resistance of the coating 6. The film 6 containing Mo and containing Fe, Co, or Cu has excellent corrosion resistance even though it does not contain Cr. In other words, Fe, Co, and Cu can replace Cr from the viewpoint of corrosion resistance. This Ni-based self-fluxing alloy has particularly excellent corrosion resistance against acids. Even if the metal product 2 is placed in a hydrochloric acid environment or a sulfuric acid environment, the coating 6 is resistant to corrosion.

That is, in a Ni-based self-fluxing alloy in which corrosion resistance is a concern because it does not contain Cr, the present applicants have discovered that Fe, Co, and Cu supplement the corrosion resistance of Cr without interfering with the formation of borides and other phases. I discovered this for the first time. This is also clear from the fact that, as will be described later, when the Ni-based self-fluxing alloy does not contain any of Fe, Co, and Cu, its corrosion resistance against hydrochloric acid and sulfuric acid is insufficient.

The standard Gibbs energies of formation at 1000° C. for oxides of Cr, Mo, Fe, Co, and Cu are as follows.
_Cr2O3 : _-538kJ / _molO2
MoO3 : -284kJ/ _molO2
Fe3O4 : _-364kJ / _molO2
CoO: -289kJ/ _molO2
Cu2O : -152kJ/ _molO2
As is clear from these standard Gibbs energies of formation, oxides of Mo, Fe, Co, and Cu are thermally unstable compared to Cr oxide. Oxides of Mo, Fe, Co, and Cu are easily sublimated and easily reduced in the remelting process of the film 6. In the film 6 that does not substantially contain Cr and contains Mo, Fe, Co, or Cu, the amount of metal oxide remaining after the remelting treatment is small. This film 6 is dense.

In other words, the present applicants have found that in this Ni-based self-fluxing alloy, Fe, Co, or Cu is dissolved in the Ni matrix, which has the effect of increasing the corrosion resistance of the material and coating, and further provides deoxidation and sublimation effects. For the first time, I discovered that I could do it.

By reducing the oxides of Mo, Fe, Co, and Cu, B and Si combine with O. Borosilicate glass is produced in the film 6 by the oxides (B ₂ O ₃ and SiO ₂ ) obtained by this combination. This borosilicate glass emerges onto the surface of the coating 6. This borosilicate glass closes the pores and suppresses the roughness of the film. The film 6 that does not substantially contain Cr and contains Mo, Fe, Co, or Cu has excellent smoothness. When the metal product 2 is a mold, the surface of the molded product obtained from this mold is also smooth. In this molded article, deterioration in mechanical properties due to the rough surface of the molded article can be suppressed.

The composition of this Ni-based self-fluxing alloy will be explained in detail below.

[Molybdenum (Mo)]
Mo combines with C to form double carbide. Mo further combines with B to form a double boride. The double carbides and double borides can contribute to the hardness and wear resistance of the coating 6. In thermal spraying and the like, Mo combines with O to form an oxide (MoO ₃ ). This oxide is sublimed and reduced in the remelting process. Therefore, the amount of Mo oxide remaining in the film 6 after the remelting treatment is small. In this film 6, the denseness and smoothness are less likely to be inhibited due to Mo oxide. From the viewpoint of the hardness and wear resistance of the film 6, the Mo content is preferably 5.0% by mass or more, more preferably 8.3% by mass or more, and particularly preferably 10.8% by mass or more. When the content of Mo is excessive, an excessive amount of Mo double boride is generated. Excess Mo double boride inhibits the toughness of the film 6. Furthermore, when the powder is produced by atomization, excess Mo leads to nozzle blockage due to coarse borides. From the viewpoint of toughness and ease of handling, the content of Mo is preferably 30.0% by mass or less, more preferably 28.5% by mass or less, and particularly preferably 25.3% by mass or less.

[Boron (B)]
In alloys containing B, low solidus and low liquidus temperatures can be achieved. B can contribute to self-solubility in the remelting process. B can reduce metal oxides in the remelting process. Through this reduction, a film 6 with a small amount of remaining metal oxide and excellent density can be obtained. B combines with Mo to form a double boride. This double boride contributes to the hardness and wear resistance of the coating 6. Further, B exists in the matrix as Ni ₃ B, which is a pseudo-ternary eutectic structure, and contributes to the hardness and wear resistance of the coating 6. From these viewpoints, the content of B is preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and particularly preferably 1.0% by mass or more. If the content of B is excessive, excess double boride is produced. Excessive double boride impairs the toughness of the coating 6. Furthermore, if the powder is produced by atomization, excess B leads to nozzle blockage due to coarse borides. From these viewpoints, the content of B is preferably 4.0% by mass or less, more preferably 3.9% by mass or less, and particularly preferably 3.6% by mass or less.

[Silicon (Si)]
Low solidus and liquidus temperatures can be achieved with alloys containing Si. Si can contribute to self-solubility in the remelting process. Si can reduce metal oxides during the remelting process. Through this reduction, a film 6 with a small amount of remaining metal oxide and excellent density can be obtained. Further, Si exists in the matrix as Ni ₃ Si, which is a pseudo-ternary eutectic structure, and contributes to the hardness and wear resistance of the film 6. From these viewpoints, the Si content is preferably 0.5% by mass or more, more preferably 1.1% by mass or more, and particularly preferably 2.9% by mass or more. Excessive Si impairs the toughness of the film 6. From this viewpoint, the Si content is preferably 10.0% by mass or less, more preferably 9.3% by mass or less, and particularly preferably 8.2% by mass or less.

[Carbon (C)]
C contributes to high hardness of the coating 6. C dissolves in Ni, strengthens the base material, and increases hardness. Furthermore, when the powder is produced by atomization, C suppresses pores in the powder. The reason for this is presumed to be that C contributes to the deoxidization of the molten metal before atomization, and the gas component of this molten metal decreases. From a molten metal with a small amount of gas components, a powder with few pores generated by gasification of this gas component during the solidification process can be obtained. A dense film 6 can be obtained from a powder with few pores. From these viewpoints, the content of C is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and particularly preferably 0.04% by mass or more. Excessive C impairs the toughness of the film 6. From this point of view, the content is preferably 0.50% by mass or less, more preferably 0.48% by mass or less, and particularly preferably 0.32% by mass or less.

A raw material with high purity has a low C content, but the cost of this raw material is high. On the other hand, although the cost of a raw material with low purity is low, this raw material has a high C content. A highly pure raw material may be dissolved, and C may be further actively added thereto. A raw material with low purity may be used, and C derived from this raw material may remain in the Ni-based self-fluxing alloy. The Ni-based self-fluxing alloy may contain both actively added C and raw material-derived C. The Ni-based self-fluxing alloy may contain only either actively added C or raw material-derived C. In either case, a high-quality film 6 can be obtained as long as the total content of C is within the above range.

[Iron (Fe)]
Fe may be dissolved in the Ni matrix. According to the knowledge obtained by the present inventors, Fe dissolved in the matrix contributes to the corrosion resistance of the coating 6. The film 6 containing Mo and Fe has excellent corrosion resistance even though it does not contain Cr. In other words, Fe can replace Cr from the viewpoint of corrosion resistance. Fe dissolved in the Ni matrix can also contribute to the strength of the film 6. Fe can form oxides, which can be reduced and sublimed in the remelting process. The amount of oxides remaining in the film 6 after the remelting treatment is small. This film 6 is dense. In addition, this film 6 is less likely to be damaged due to cracks originating from Fe precipitates. From these viewpoints, the content of Fe is preferably 0.1% by mass or more, more preferably 1.7% by mass or more, and particularly preferably 2.1% by mass or more. From the viewpoint of the toughness of the film 6, the content of Fe is preferably 10.0% by mass or less.

[Cobalt (Co)]
Co can be dissolved in the Ni matrix. According to the knowledge obtained by the present inventor, Co dissolved in the matrix contributes to the corrosion resistance of the coating 6. The film 6 containing Mo and Co has excellent corrosion resistance even though it does not contain Cr. In other words, Co can replace Cr from the viewpoint of corrosion resistance. Co dissolved in the Ni matrix can also contribute to the strength of the film 6. Co can form oxides, which can be reduced and sublimed in the remelting process. The amount of oxides remaining in the film 6 after the remelting treatment is small. This film 6 is dense. In addition, this film 6 is less likely to be damaged due to cracks originating from Co precipitates. From these viewpoints, the content of Co is preferably 0.1% by mass or more, more preferably 1.3% by mass or more, and particularly preferably 1.9% by mass or more. From the viewpoint of the toughness of the film 6, the Co content is preferably 10.0% by mass or less.

[Copper (Cu)]
Cu can be dissolved in the Ni matrix. According to the knowledge obtained by the present inventors, Cu dissolved in the matrix contributes to the corrosion resistance of the film 6. The film 6 containing Mo and Cu has excellent corrosion resistance even though it does not contain Cr. In other words, Cu can replace Cr from the viewpoint of corrosion resistance. Cu dissolved in the Ni matrix can also contribute to the strength of the film 6. Cu can promote the formation of carbides and borides to stabilize the composition. Cu can form oxides, which can be reduced and sublimed in the remelting process. The amount of oxides remaining in the film 6 after the remelting treatment is small. This film 6 is dense. In addition, this film 6 is less likely to be damaged due to cracks originating from Cu precipitates. From these viewpoints, the content of Cu is preferably 0.1% by mass or more, more preferably 1.9% by mass or more, and particularly preferably 2.5% by mass or more. From the viewpoint of the toughness of the film 6, the content of Cu is preferably 10.0% by mass or less.

[Fe, Co and Cu]
As mentioned above, each of Fe, Co, and Cu can contribute to the corrosion resistance and denseness of the coating 6. Embodiments of the Ni-based self-fluxing alloy suitable for the coating 6 are listed below.
(a) Embodiment containing Fe and not substantially containing Co and Cu (b) Embodiment containing Co but substantially not containing Fe and Cu (c) Embodiment containing Cu and substantially not containing Fe and Co (d) A mode containing Fe and Co, but not substantially containing Cu. (e) A mode containing Fe and Cu, but not substantially containing Co. (f) A mode containing Co and Cu, Embodiment that does not substantially contain Fe (g) Embodiment that contains Fe, Co, and Cu The total content TC (Total content) of Fe, Co, and Cu is preferably 0.1% by mass or more, and 1.9% by mass or more. is more preferable, and 2.5% by mass or more is particularly preferable. From the viewpoint of the toughness of the coating 6, this total content TC is preferably 10.0% by mass or less.

[Nickel (Ni)]
The base material of this alloy is Ni. Ni can contribute to the low melting point of the alloy. Ni can further contribute to the corrosion resistance and toughness of the coating 6. From these viewpoints, the Ni content is preferably 50% by mass or more, particularly preferably 55% by mass or more.

[impurities]
This Ni-based self-fluxing alloy contains inevitable impurities. An example of an unavoidable impurity is Cr. The content of Cr in this Ni-based self-fluxing alloy is extremely small. Therefore, even if this alloy is subjected to thermal spraying or the like, almost no Cr oxide is generated. A film 6 with excellent density can be obtained from this alloy. From the viewpoint of compactness, the content of Cr in this alloy is preferably 0.010% by mass or less, particularly preferably 0.005% by mass or less.

[Solidus temperature]
From the viewpoint of ease of forming the film 6, the solidus temperature of the Ni-based self-fluxing alloy is preferably 1000°C or lower, more preferably 985°C or lower, and particularly preferably 975°C or lower.

[Liquidus temperature]
From the viewpoint of ease of forming the film 6, the liquidus temperature of the Ni-based self-fluxing alloy is preferably 1250°C or lower, more preferably 1200°C or lower, and particularly preferably 1190°C or lower.

[Manufacture of powder]
The powder is preferably obtained by an atomization method. Gas atomization method, disk atomization method, water atomization method, centrifugal atomization method, etc. are employed. Preferred atomization methods are gas atomization method and disk atomization method. The powder obtained by atomization may be subjected to mechanical milling or the like.

[Formation of film]
Typically, the coating 6 is formed by a thermal spraying method. An example of a thermal spraying method is shown in FIG. In this thermal spraying method, a powder made of a Ni-based self-fluxing alloy is heated in a thermal spraying machine 8. This heating brings the powder particles into a molten or semi-molten state. The particles 10 are sprayed onto the main portion 4 (ie, the object to be coated), as shown in FIG. The particles 10 fly and collide with the main part 4. After the collision, the particles 10 solidify and form a solidified layer. Since the particles 10 are continuously sprayed, the particles 10 also collide with the coagulated layer and solidify, thereby growing the coagulated layer. In this way, the film 6 is formed. During flight, the particles 10 are exposed to the atmosphere between the thermal spray machine 8 and the main part 4 . As a result, some of the metal elements in the Ni-based self-fluxing alloy are oxidized, and metal oxides are formed in the coating 6. The coating 6 may be formed by a method other than thermal spraying. Examples of methods other than thermal spraying include overlay welding and centrifugal casting. Since the solidus temperature of the Ni-based self-fluxing alloy is low, damage to the main portion 4 can be suppressed in either method.

[Remelting process]
The film 6 may be subjected to a remelting treatment. In the remelting process, the coating 6 is heated until it reaches a temperature equal to or higher than the solidus temperature. This heating generates a liquid phase in the film 6. The film 6 is in a solid-liquid mixed state. This liquid phase solidifies and the film 6 is re-formed. The remelting treatment increases the denseness of the film 6. During the remelting process, some of the metal oxide is reduced and disappears. The preferred temperature to be achieved in the remelting process is in the range of 1000°C to 1200°C.

[Spraying distance]
In FIG. 2, the symbol L1 represents the spraying distance. The spray distance L1 is the distance between the tip 12 of the spray machine 8 and the main portion 4. In thermal spraying in which the thermal spraying distance L1 is long, the time during which the molten particles 10 are exposed to the atmosphere is long. By thermal spraying with a long thermal spraying distance L1, a coating 6 containing many metal oxides can be formed. The Ni-based self-fluxing alloy according to this embodiment does not substantially contain Cr and contains Fe, Co, or Cu. Therefore, many metal oxides are reduced and disappear by the remelting process. Even in thermal spraying with a long thermal spraying distance L1, a high-quality coating 6 can be obtained by using the Ni-based self-fluxing alloy powder according to the present embodiment. Thermal spraying with a large spraying distance L1 is also superior in safety. The normal thermal spraying distance is generally 300 mm or less, but the Ni-based self-fluxing alloy according to the present embodiment has a good coating 6 even when the thermal spraying distance L1 is 350 mm or more, 400 mm or more, and even about 500 mm. can be formed.

[Production method]
The present specification is also directed to a method of manufacturing metal product 2. This manufacturing method is
(1) The material is a Ni-based self-fluxing alloy, and this Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total a step of preparing a powder containing Ni and the remainder being Ni and unavoidable impurities;
(2) heating this powder to 600° C. or higher and 800° C. or lower using a thermal spraying machine 8 and spraying particles 10 of this powder onto the main portion 4 to obtain a coating 6 laminated on the main portion 4;
and (3) a step of subjecting the film 6 to remelting treatment.

Hereinafter, the effects of the Ni-based self-fluxing alloy according to Examples will be clarified, but the scope disclosed in this specification should not be interpreted to be limited based on the description of these Examples.

[Example 1]
Raw materials having the composition shown in Table 1 were charged into a refractory crucible. This raw material was induction melted in argon gas to obtain a molten metal. This molten metal was taken out from the nozzle of the crucible, and high-pressure nitrogen gas was sprayed onto it to obtain a powder. This powder was classified using a sieve, and the particle size was adjusted to 45 μm or more and 125 μm or less. On the other hand, a columnar main part made of SUS304 and having a size of 50 mm was prepared. The powder was subjected to gas flame spraying to form a film with a thickness of 1 mm on the surface of the main part. The main part and the coating were placed in an electric furnace and kept at a temperature of 940° C. for 30 minutes. This film was air-cooled to obtain the metal product of Example 1.

[Example 2-19 and Comparative Examples 1-7 and 10-12]
Metal products of Example 2-19 and Comparative Examples 1-7 and 10-12 were obtained in the same manner as in Example 1 except that the compositions were as shown in Tables 1 and 2 below.

[Comparative Examples 8 and 9]
Atomization was attempted in the same manner as in Example 1 except that the composition was as shown in Table 2 below. Atomization was stopped because the molten metal blocked the nozzle.

[Solidus temperature and liquidus temperature]
Using a thermal analyzer (DTA), the solidus temperature and liquidus temperature of the powder were measured under the following conditions.
Amount of powder: 20mg
Atmosphere: After evacuation, flow argon gas at 200 ml/min Temperature increase rate: 20°C/min Start temperature: Room temperature Reached temperature: 1500°C (held for 5 minutes)
Cooling rate: -20°C/min Of the exothermic peaks seen in the DTA signal during cooling, the temperature at which heat generation begins at the highest temperature is the liquidus temperature, and the temperature at which heat generation ends at the lowest temperature is the solidus temperature. be. The results are shown in Tables 1 and 2 below.

[Folding strength]
A copper substrate was placed in an arc melting apparatus. Powder was set on this copper base material. After evacuating the inside of the arc melting device, the powder was arc melted in an argon gas atmosphere to obtain an ingot. During arc melting, the ingot was rotated from front to back 10 times or more to suppress uneven distribution of the composition. The ingot was subjected to heat treatment under the following conditions.
Atmosphere: Argon gas Temperature: 950℃
Holding time: Holding for 24 hours Cooling: Furnace cooling A test piece was obtained from this ingot and subjected to a bending test in accordance with the provisions of JIS Z 2248 to obtain bending strength (3-point bending strength). The results are shown in Tables 1 and 2 below.

[Corrosion resistance]
A test piece with a size of 10 x 14 x 4 mm was obtained from an ingot obtained by the same method as the bending test. This test piece was subjected to a corrosion resistance test under conditions 1 and 2 below.
Condition 1
Corrosion liquid: 10% hydrochloric acid aqueous solution Temperature: 40℃
Time: 10 hours Condition 2
Corrosion liquid: 10% sulfuric acid aqueous solution Temperature: 40℃
Time: 10 hours The corrosion rates obtained are shown in Tables 1 and 2 below.

[Hardness]
A test piece was cut out from the film after the remelting treatment, and the cross section was polished. The Vickers hardness of this cross section was measured when the load was 2.94N. The average values of the 10 measurements are shown in Tables 1 and 2 below.

[Density rate]
A test piece was cut out from the film after the remelting treatment, and the cross section was polished. An optical microscopic image (magnification: 25 times) of this cross section was obtained. The image of the 0.5 x 0.5 mm zone was binarized into powder-filled areas and void areas using public domain image processing software ``Image J 1.45''. The density ratio (100×(AB)/A) was calculated from the image area (A) and the area of the void portion (B). The average values of density obtained from the images of No. 6 are shown in Tables 1 and 2 below.

Each of the alloys shown in Tables 1 and 2 contains unavoidable impurities.

As shown in Tables 1 and 2, the alloys according to each example are excellent in various performances. From these evaluation results, the superiority of this Ni-based self-fluxing alloy is clear.

The alloys described above are suitable for mechanical parts and the like. This alloy is particularly suitable for coating boiler tubes, heating barrels, sleeves, molds, etc.

2...Product 4...Main part 6...Coating 8...Thermal spray machine 10...Particles 12...Tip

Claims (3)

Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total Contains
A Ni-based self-fluxing alloy in which the balance is Ni and unavoidable impurities. The material is a Ni-based self-fluxing alloy,
The above Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total Contains
Powder, the balance being Ni and unavoidable impurities. It has a film,
The material of the film is a Ni-based self-fluxing alloy,
The above Ni-based self-fluxing alloy is
Mo: 5.0% by mass or more and 30.0% by mass or less,
B: 0.5% by mass or more and 4.0% by mass or less,
Si: 0.5% by mass or more and 10.0% by mass or less,
C: 0.01% by mass or more and 0.50% by mass or less, and one or more selected from the group consisting of Fe, Co, and Cu: 0.1% by mass or more and 10.0% by mass or less in total Contains
A product in which the balance is Ni and unavoidable impurities.

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