KR20220031447A - Coated body and manufacturing method thereof - Google Patents

Abstract

The present invention is to provide a coated body in which an alloy coating layer having improved mechanical and chemical properties, particularly oxidation resistance, wear resistance and corrosion resistance at high temperatures, on a base material. A coated body according to one aspect of the present invention includes a base material and an alloy coating layer provided in at least one section on the base material, wherein the alloy coating layer includes a first tissue area in which the ratio of an amorphous phase is 5 to 49 vol% and a second tissue area that is divided by a boundary from the first tissue area and has a higher ratio of the amorphous phase than the first tissue area.

Description

Coated body and coating body manufacturing method {Coated body and manufacturing method thereof}

One aspect of the present invention relates to a coating body and a method for manufacturing the coating body, and more particularly, to a coating body having excellent oxidation resistance and excellent abrasion resistance and corrosion resistance, which can be utilized for various purposes, and a method for manufacturing the same.

An amorphous alloy is an alloy in which the metal atoms contained in the alloy are not crystalline but have a disordered and chaotic structure. Due to difficulties and limitations in that manufacturing is difficult and costly, there are few commercialized cases so far.

In order to manufacture an amorphous alloy material, two conditions must be satisfied. An alloy composition with high amorphous forming ability is required, and a rapid cooling rate of the molten alloy is required. That is, rapid cooling of the molten alloy material is required, and even if the cooling is rapid, if the amorphous forming ability of the composition itself is low, the amorphous phase is not formed in many cases.

In particular, when an alloy powder made of an amorphous alloy is used to form a product, for example, a coating body or a molded body with an amorphous alloy powder, a sufficient cooling rate is often not obtained in the process of cooling after the alloy powder is melted. Crystallization is mainly made, and there is a problem in that the proportion of amorphous material is rapidly reduced, making it difficult to manufacture application products that utilize the characteristics of amorphous alloy materials.

Due to these problems, the amorphous ratio is lowered when a molded body is manufactured using an amorphous alloy or a coating layer is formed, and the desired properties of the product are not obtained or the density is not excellent, so that the corrosion resistance is lowered, and foreign substances are easily penetrated. This is happening.

Accordingly, there is a need for research on an alloy coating layer capable of maintaining a high amorphous ratio and improving microstructure and mechanical properties, and a coating body formed of the alloy coating layer.

Republic of Korea Patent Registration No. 10-0723167

It is an object of the present invention to provide a coating in which an alloy coating layer having improved mechanical and chemical properties, particularly oxidation resistance at high temperature, wear resistance and corrosion resistance, is provided on a base material.

In addition, another object of the present invention is to provide a coating body comprising an alloy coating layer having a long lifespan and efficient due to low porosity and high hardness, which causes a small amount of wear due to friction on the surface, and less oxidation due to wear on the surface.

One aspect of the present invention is

base material; and

Including; an alloy coating layer provided in at least one section on the base material;

The alloy coating layer,

A first tissue region in which the proportion of the amorphous phase is 5 to 49% by volume, and

A coating body comprising a second tissue region separated by a boundary from the first tissue region and having an amorphous phase ratio higher than the amorphous phase ratio of the first tissue region,

The alloy coating layer includes a boride,

The size of the individual particle phase of the boride included in the first tissue region is preferably larger than the size of the individual particle phase of the boride included in the second tissue region,

Preferably, the volume of the second tissue region is 1.4 to 10 times the volume of the first tissue region,

It is preferable that the first tissue region is a powder laminate, and the second texture region is a melt spray body.

In addition, the alloy coating layer is

with respect to 100 parts by weight of iron,

17.22 to 58.23 parts by weight of chromium;

1.2 to 26.1 parts by weight of molybdenum,

0.12 to 6.22 parts by weight of niobium, and

It is preferable to include 0.12 to 6.63 parts by weight of boron,

At least a portion of the niobium or molybdenum is preferably included in a solid solution in the iron,

The boride may be a boride containing at least one of iron and chromium or a boride of niobium.

At this time, the thickness of the alloy coating layer is preferably 0.05 to 0.3 mm,

The alloy coating layer preferably includes a semi-amorphous (Metamorphic) alloy,

It is preferable that the Vickers hardness of the alloy coating layer is 600 to 900 Hv,

It is preferable that the ratio of the oxide region of the alloy coating layer is 2.50% or less,

It is preferable that the porosity of the alloy coating layer is 0.001 to 5%.

In addition, the size of the individual particle phase of the boride included in the first tissue region is preferably 1.1 to 30 times the size of the individual particle phase of the boride included in the second tissue region.

Another aspect of the present invention is

A method for manufacturing a coating body by forming an alloy coating layer on a base material, the method comprising:

The alloy powder is thermally sprayed at a speed of 600 to 2,200 m/s at a temperature of 3,000 to 18,000 ℃,

a first tissue region formed by stacking the alloy powder and having an amorphous phase ratio of 5 to 49% by volume; and

a second structure region formed by melt-spraying the alloy powder and having a higher ratio of amorphous phase than the ratio of the amorphous phase of the first tissue region; It is good to form the alloy coating layer comprising a,

The alloy powder

with respect to 100 parts by weight of iron,

17.22 to 58.23 parts by weight of chromium;

1.2 to 26.1 parts by weight of molybdenum,

0.12 to 6.22 parts by weight of niobium, and

It is preferable that the powder contains 0.12 to 6.63 parts by weight of boron,

The alloy coating layer includes a boride,

Preferably, the size of the individual particle phase of the boride included in the second tissue region is larger than the size of the individual particle phase of the boride included in the first tissue region.

The coating body, which is an aspect of the present invention, includes an alloy coating layer comprising iron, chromium, molybdenum, and niobium, the corresponding metal atoms are included in a specific weight ratio, and molybdenum or niobium is included in a solid solution form in the iron-based alloy. Therefore, it is possible to obtain an alloy coating layer containing an iron-based alloy having excellent high temperature oxidation resistance and corrosion resistance.

At this time, when boron is included, the amorphous forming performance of the iron-based alloy is improved, and a composite structure in which the ceramic phase is dispersed in the iron-based alloy including the amorphous phase can be obtained. , has the advantage of having abrasion resistance.

In addition, the alloy coating layer includes a first tissue region containing a portion of the alloy powder that is not completely melted and a second region region that is completely melted and laminated on the base material to be cooled, has a similar structure to the alloy powder and has oxidation resistance The first tissue region with excellent hardness, hardness, etc. and the second tissue region with excellent corrosion resistance and abrasion resistance are strongly bonded to each other to form a coating layer, which has a high ratio of amorphous phase after melting and has a structure in which fine boride is dispersed. An alloy coating layer having a composite structure having both excellent properties of the first and second tissue regions can be obtained.

In addition, the alloy coating layer included in one aspect of the present invention includes a semi-amorphous alloy (metamorphic) alloy including a ceramic phase dispersed in an iron-based matrix, and has a structure similar to that of a ceramic-reinforced composite, thereby providing strength compared to a simple single-phase alloy coating layer, It has excellent elasticity and is amorphous without melting on the wear surface to form an amorphous region, so the friction coefficient is reduced and thus the wear resistance is excellent.

In addition, since the second tissue region is included in a higher volume fraction than the first tissue region, the boundary region between the first tissue region and the second tissue region and the amount of oxide are reduced, and the first tissue region and the second tissue region are reduced on the surface of the alloy coating layer. Since the bonding between the tissue regions is strong, it is possible to solve the problem that the first tissue region is separated from the coating layer by friction.

1 is a view taken with an electron microscope of a cross section of an alloy powder prepared by using a metal composition for alloy according to an aspect of the present invention.
2 is a graph showing the particle size distribution of the alloy powder manufactured using the alloy metal composition according to some embodiments of the present invention.
3 is a view showing the results of XRD analysis of the alloy powder according to some embodiments of the present invention.
4 is a view showing an electron probe microanalyzer (EPMA) analysis results of the alloy powder according to some embodiments of the present invention.
5 is a graph showing the oxidation characteristics of the alloy powder according to some embodiments of the present invention.
6 is a photograph taken with an electron microscope of the surface of the coating body according to another aspect of the present invention.
7 is a photograph of the microstructure of the surface of the coating layer according to some embodiments of the present invention.
8 is a graph showing the porosity and the oxidation region ratio of the alloy coating layer of the coating body according to some embodiments of the present invention.
9 shows the Vickers hardness of the alloy coating layer of the coating body according to some embodiments of the present invention.
10 and 11 are diagrams analyzing crystals of the alloy coating layer of the coating body according to some embodiments of the present invention.

Prior to describing the present invention in detail below, it is to be understood that the terminology used herein is for the purpose of describing specific embodiments and is not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise stated.

Throughout this specification and claims, unless stated otherwise, the term comprise, comprises, comprising is meant to include the stated object, step or group of objects, and steps, and any other object. It is not used in the sense of excluding a step or a group of objects or groups of steps.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

In the present specification, the alloy (alloy) is broadly interpreted as meaning including a material containing a solid solution containing two or more metals in addition to an alloy containing one or more metal elements in a general sense and an alloy containing a crystalline structure and an amorphous structure, and , The iron-based alloy means an alloy containing iron as a main component and one or more non-ferrous metals, an alloy containing crystalline iron, an alloy containing an amorphous phase, and a material containing a solid solution of iron and other atoms. is used as

In the present specification, the powder laminate means a structure formed while maintaining the powder form in at least one part when processing or coating a powder metal or alloy in a spray method. The powder laminate can be obtained when the powder is not completely melted but collided and laminated due to temperature conditions or powder composition, even when cold spraying or other thermal spraying methods are used among the thermal spraying methods.

In the present specification, the molten spray means all or most of the metal or alloy is melted and sprayed when processing or coating various types of metals or alloys such as powder or wire by spraying, and loses its shape during collision or lamination It means a structure that spreads widely. Since the melt injection body does not contain most of the original shape, a molded body or coating having no or unclear boundaries and a low porosity can be obtained.

In the present specification, the particle size means an average particle size of a particle phase having a specific crystal structure or containing a specific material, and the particle size may be measured as a diameter or an average value of a major axis and a minor axis according to the geometric shape of the particle phase.

The metal composition for alloy of one aspect of the present invention is a composition comprising iron (Fe), chromium (Cr), molybdenum (Mo), niobium (Nb), boron (B) and carbon (C).

A preferred embodiment of the metal composition for alloy, which is an aspect of the present invention, is a metal composition for an iron-based alloy, and since the metal composition for alloy contains iron as a metal constituting the alloy, it has the advantages of improving the rigidity of the alloy and excellent economic efficiency.

Chromium contained in the alloy metal composition is included to improve physical or chemical properties such as wear resistance and corrosion resistance of the alloy prepared from the alloy metal composition.

Chromium may be included in an amount of 17.22 to 58.23 parts by weight, preferably 18.32 parts by weight to 44.25 parts by weight, and more preferably 21.96 parts by weight to 34.11 parts by weight based on 100 parts by weight of iron in the alloy metal composition.

Specifically, chromium is preferably included in an amount of 14.5 to 29 wt%, preferably 15 to 25 wt%, more preferably 17 to 22 wt% in the alloy metal composition.

When chromium is included out of the corresponding range, the amorphous formation ability of the formed alloy is lowered, so that the ratio of the amorphous phase is reduced, or there is a problem in that corrosion resistance or wear resistance is deteriorated.

Molybdenum is used to improve the wear resistance and corrosion resistance of the alloy produced from the alloy metal composition as well as the friction resistance.

Molybdenum may be included in an amount of 1.2 to 26.10 parts by weight, preferably 2.44 parts by weight to 19.47 parts by weight, and more preferably 4.52 parts by weight to 12.40 parts by weight based on 100 parts by weight of iron in the alloy composition.

Specifically, molybdenum is preferably included in an amount of 1 to 13 wt%, preferably 2 to 11 wt%, more preferably 3.5 to 8 wt% in the alloy composition.

When molybdenum is included outside the corresponding range, the amorphous forming ability of the alloy to be formed is lowered, so that the ratio of the amorphous phase is reduced, or physical and chemical properties such as wear resistance, corrosion resistance, and friction resistance may be deteriorated.

Niobium improves the high-temperature stability of the alloy manufactured from the alloy metal composition, does not react with oxygen or other highly reactive elements, and does not react or corrode with most chemicals, so that the alloy is It makes it possible to have excellent oxidation resistance at high temperatures, and it can also play the role of a beta phase stabilizer in a metal composition for alloys.

Niobium may be included in an amount of 0.12 to 6.22 parts by weight, preferably 0.61 parts by weight to 5.31 parts by weight, and more preferably 1.29 parts by weight to 3.10 parts by weight based on 100 parts by weight of iron in the alloy composition.

Specifically, niobium is preferably included in an amount of 0.1 to 3.1 wt%, preferably 0.5 to 3 wt%, more preferably 1 to 2 wt% in the alloy composition. When the content of niobium is out of the corresponding range, problems such as promotion of oxidation reaction and deterioration of abrasion due to deterioration of high-temperature stability may occur.

Boron plays a role in improving the amorphous forming ability of the alloy by causing mismatch and efficient packing through the difference in atomic size with metal atoms in the alloy metal composition. Boron may be included in an amount of 0.12 to 6.63 parts by weight, preferably 0.61 to 5.31 parts by weight, and more preferably 1.29 to 3.88 parts by weight based on 100 parts by weight of iron in the alloy composition.

Specifically, it is good that boron is included in an amount of 0.1 to 3.3 wt%, preferably 0.5 to 3 wt%, more preferably 1 to 2.5 wt% in the alloy composition.

Like boron, carbon plays a role in improving the amorphous formation ability of the alloy by making mismatch and efficient packing through the atomic size difference with metal atoms in the alloy metal composition. This is considered to be due to the difference in atomic size, packing ratio, deep eutactic and reaction entropy of the elements including the amorphous formation ability.

Carbon may be included in an amount of 0.12 to 3.61 parts by weight, preferably 0.12 to 2.65 parts by weight, and more preferably 0.13 to 1.55 parts by weight, based on 100 parts by weight of iron in the alloy metal composition.

Specifically, it is good that carbon is included in the alloy composition in an amount of 0.1 to 1.8 wt%, preferably 0.1 to 1.5 wt%, and more preferably 0.1 to 1.0 wt%.

When carbon and boron are out of the corresponding range, there is a problem in that the amorphous forming ability of the metal composition for alloy is lowered, so that an alloy that does not contain an amorphous phase or has a low ratio of an amorphous phase included therein may be obtained.

An embodiment of the present invention contains 17.22 to 58.23 parts by weight of chromium, 1.2 to 26.1 parts by weight of molybdenum, 0.12 to 6.22 parts by weight of niobium, 0.12 to 6.63 parts by weight of boron, and 0.12 to 3.61 parts by weight of carbon, based on 100 parts by weight of iron Disclosed is a metal composition for an alloy made by

Preferably, the metal composition for alloy contains 18.32 to 44.25 parts by weight of chromium, 2.44 to 19.47 parts by weight of molybdenum, 0.61 to 5.31 parts by weight of niobium, 0.61 to 5.31 parts by weight of boron, and 0.12 to 2.65 parts by weight of carbon, based on 100 parts by weight of iron. It can include wealth.

Further, more preferably, based on 100 parts by weight of iron, 21.96 to 34.11 parts by weight of chromium, 4.52 to 12.40 parts by weight of molybdenum, 1.29 to 3.10 parts by weight of niobium, 1.29 to 3.88 parts by weight of boron, and 0.13 to 1.55 parts by weight of carbon. A metal composition for use may be provided.

At this time, the alloy metal composition includes tungsten (W), cobalt (Co), yttrium (Y), silicon (Si), manganese (Mn), aluminum (Al), zirconium (Zr), phosphorus (P), nickel ( Ni), scandium (Sc) and other unavoidable impurities may be further included, and the additionally included elements may be included in a lower weight ratio than the aforementioned iron, chromium, molybdenum, boron and carbon.

When the metal composition for alloy contains silicon, silicon is preferably included in an amount of 0.2 parts by weight or less, preferably 0.1 parts by weight or less, and more preferably 0.05 parts by weight or less, based on 100 parts by weight of iron, and in the metal composition for alloying. 0.5 times or less, preferably 0.3 times or less, more preferably 0.1 times or less compared to the weight of carbon included, but preferably included in an amount of less than 0.1 times, when the metal composition for alloy does not contain silicon and Fe-Cr-Mo- Even a metal composition for a hexa-membered alloy of Nb-BC is understood to be a preferred metal composition for an alloy described in the present invention.

In the alloy metal composition of the present invention, the weight of chromium contained may be 3 to 5 times the weight of molybdenum, preferably 3.5 to 4.75 times, more preferably 3.75 to 4.25 times.

When the weight of chromium contained in the metal composition for alloy is higher than the weight of molybdenum, and specifically, when the ratio of the included weight satisfies the above range, the metal composition for alloy has excellent amorphous formation ability, oxidation resistance, wear resistance, An advantageous effect of improving chemical and mechanical properties such as hardness can be obtained.

Since the metal composition for alloy according to the present invention includes the elements according to the above-described composition, it has the advantage of excellent amorphous forming ability to form an amorphous phase.

Another aspect of the present invention is an alloy powder prepared from the aforementioned alloy metal composition. The alloy powder preferably has the same composition as the metal composition for alloy described above, but may further include some other composition by cooling or oxidation, and may include an amorphous phase due to the amorphous forming ability of the metal composition for alloy.

The alloy powder can be manufactured by variously changing the particle size and shape according to the use and application method such as 3D printing, powder metallurgy, injection, mold or thermal spray coating, and the particle size and shape are not limited, but, for example, 1 to 150 It has a particle size distribution of ㎛, preferably has a particle size distribution of 10 to 100㎛, alloy powder that can be used for thermal spray coating is preferably 10 to 54㎛, preferably 16 to 43㎛, metal injection The alloy powder that can be used for (MIM) is preferably fine powder having a particle size of 20 μm or less, preferably 5 to 16 μm.

In addition, as alloy powder that can be used for 3D printing, fine powder having a particle size of 20 μm or less may be preferred in the case of the Powder Bed Fusion method, and in the Direct Energy Deposit (DED) method, etc. Coarse powder having a particle size of 150 to 430 μm, preferably 50 to 100 μm may be preferred, and in the case of an alloy powder that can be used for laser cladding, an alloy powder having a coarse particle size is preferred. An alloy powder having a particle diameter similar to that of the DED method may be used.

When the particle size distribution and average particle diameter of the alloy powder are out of the corresponding range, there is a problem in that it is difficult to obtain a uniform quality when applying the alloy powder, and the work efficiency is lowered.

At this time, the alloy powder can be prepared by various methods and well-known techniques that can be employed by those skilled in the art, for example, water atomizing or gas atomizing method.

Here, the atomizing method is a powder manufacturing method in which gas or water is sprayed to split into small particles when the molten metal composition for alloy is dropped, and the alloy powder in the state of fragmented droplets is rapidly cooled to produce alloy powder. . Since the atomizing method corresponds to a well-known technique in the metal powder technical field, a detailed description thereof is omitted.

The alloy powder prepared according to an embodiment of the present invention includes an iron-based alloy including an α-Fe phase having a body-centered cubic structure (BCC) crystal structure, A ceramic phase dispersed in the iron-based alloy, for example, a boride containing at least one of iron, chromium, and niobium, or a phase containing carbide may be included.

In addition, as a meaning including all of iron boride, chromium boride, iron and chromium boride, a) iron, chromium-based boride, b) chromium, iron-based boride, c) Fe-Cr-based boride, or d) Compositions that can be included in the present invention are described using the terms Fe, Cr-based borides.

Chromium, which is an element included in the alloy powder, is not dissolved in the iron-based alloy and is mostly contained in a ceramic phase in the form of boride, and the iron-chromium-based boride ratio contained in the alloy powder may be within 30 to 90%, preferably Preferably, it may be within 35 to 85%, and more preferably, it may be within 40 to 80%.

At this time, the borides of molybdenum and niobium are not included in the alloy powder or are included in an undetectable level even if they are included, and molybdenum and niobium included in the alloy powder may be dissolved in the iron-based alloy to form a solid solution.

The alloy powder may include an amorphous or metallic glass (metallic glass) phase due to the compositional characteristics of the metal composition for alloying, and may include a ceramic compound such as boride or carbide therein.

At this time, the alloy powder has an in-situ characteristic, and such a microstructure and crystal structure can be obtained by being formed or reconfigured inside itself due to the compositional characteristics of the alloy powder.

The alloy powder according to an embodiment of the present invention has the above composition, and since the iron-based alloy includes an amorphous phase, it has excellent oxidation resistance, so the amount of oxidation and the oxidation rate according to the increase in temperature are low, and the temperature point at which rapid oxidation is made is high characterized in that

Specifically, the alloy powder is prepared from an alloy composition that can include an amorphous phase due to excellent amorphous formation ability even using a conventional atomizing method, and the amorphous phase may be included in at least a partial region of the alloy powder.

Due to the alloy composition and phase distribution of the alloy powder, the alloy powder prepared according to an embodiment of the present invention has excellent oxidation resistance. In general, in the case of alloy powder, when the temperature is increased, the metal is oxidized to form an oxide, and the weight of the powder increases. It has a point of rapid increase.

Another aspect of the present invention is a coating body in which an alloy coating layer formed from the above-described alloy metal composition or alloy powder is provided on a base material.

The base material (母材) is an object on which the coating layer is formed, and the material and shape thereof are not limited.

The alloy coating layer is provided on the base material and serves to improve physical and chemical performance on the surface of the base material and protect the base material.

The alloy coating layer may have the same composition as the metal composition or alloy powder for alloys described above, and specifically, 17.22 to 58.23 parts by weight of chromium, preferably 18.32 to 44.25 parts by weight, more preferably based on 100 parts by weight of iron. is included in an amount of 21.96 to 34.11 parts by weight.

In addition, it contains 1.2 to 26.1 parts by weight of molybdenum, preferably 2.44 to 19.47 parts by weight, and more preferably 4.52 to 12.40 parts by weight based on 100 parts by weight of iron.

Further, niobium is included in an amount of 0.12 to 6.22 parts by weight, preferably 0.61 to 5.31 parts by weight, and more preferably 1.29 to 3.10 parts by weight based on 100 parts by weight of iron.

In addition, boron may be included in an amount of 0.12 to 6.63 parts by weight, preferably 0.61 to 5.31 parts by weight, and more preferably 1.29 to 3.88 parts by weight based on 100 parts by weight of iron.

In addition, carbon may be included in an amount of 0.12 to 3.61 parts by weight, preferably 0.12 to 2.65 parts by weight, and more preferably 0.13 to 1.55 parts by weight, based on 100 parts by weight of iron.

The alloy coating layer may further include additional additives and unavoidable impurities in addition to the above-mentioned elements, and in this case, the total of the additional additives is 0.5 parts by weight or less, preferably 0.1 parts by weight or less, based on 100 parts by weight of iron. it's good

The method of forming the alloy coating layer is not limited, for example, a thermal spray coating method such as high-speed flame spraying (HVOF), plasma spraying, laser spraying, or various well-known coating methods such as laser cladding. It can be formed through, sputtering (sputtering), electrolytic plating, electroless plating, etc. can be used any coating method that can be employed by those skilled in the art, but it is preferable to use a thermal spraying method such as high-speed flame spraying Do.

When the thermal spray coating method is used, an alloy coating layer in which the alloy powder is mainly physically bonded can be obtained, and when the cladding coating method is used, an alloy coating layer in which the alloy powder is mainly chemically bonded can be obtained.

At this time, the thickness of the alloy coating layer is preferably formed in the range of 0.05 to 0.3 mm, preferably 0.075 to 0.125 mm.

Hereinafter, as a specific example, an alloy coating layer formed by coating the above-mentioned alloy powder on a base material by a thermal spraying method, for example, a high-speed flame spraying (HVOF) or a plasma spraying method, will be described.

The alloy coating layer according to an embodiment of the present invention may be provided from the above-mentioned alloy powder, and an iron-based alloy and ceramic phase containing alpha iron (α-Fe) having a body-centered cubic structure (BCC), for example, Fe and Cr It consists of a boride containing at least any one or more of a boride or a boride of niobium.

In addition, in the formation of the alloy coating layer from the alloy powder, the first structure region, which is a region that does not completely melt among the alloy powder or alloy powder, but collides with the base material, and the completely molten alloy powder and alloy powder in the coating process A second tissue region formed by laminating or attaching a partial region on the base material is included in the alloy coating layer.

In this case, the first tissue region and the second tissue region are adjacent to or in contact with each other, and the second tissue region is provided around the first tissue region or the first tissue region is dispersed in the second tissue region. and a boundary region may be formed at an interface between the first tissue region and the second tissue region.

The first texture region is a powder laminate, and may include a part of the alloy powder form, and the size of the crystal phase and the individual particle phase of the boride included in the first texture region is the crystal phase and the individual particle phase of the boride included in the alloy powder. appear similar to the size of

In the second tissue region, the molten powder is cooled and formed as a molten spray, so the shape of the powder is not observed, the structure or ratio of the alloy powder and the crystal, and the size of individual grain phases of the ceramic phase can be changed, and the first texture region A boundary is formed at the interface between the and the second tissue region and can be distinguished.

The first tissue region and the second tissue region may be identified with an electron microscope (SEM, TEM), an electron diffraction pattern analyzer, or an electron probe X-ray microanalyzer.

In the iron-based alloy constituting the alloy coating layer, Fe (BCC) is used to mean including body-centered cubic iron crystals or crystalline iron-based alloys, and includes alpha iron.

The iron-based alloy in which the ceramic phase is dispersed in the alloy coating layer refers to an iron-based alloy containing alpha iron or at least one of chromium, molybdenum, and niobium, and the iron-based alloy may include a crystalline alloy and an amorphous alloy at the same time, and chromium , Molybdenum, and niobium include a case in which at least one or more is included in the form of a solid solution.

The alloy coating layer includes both a crystalline phase and an amorphous phase, and has high temperature oxidation resistance, wear resistance and corrosion resistance, including an iron-based alloy containing at least one of chromium, molybdenum, and niobium in the form of a solid solution, and a ceramic phase dispersed in the iron-based alloy. great.

The alloy coating layer may be made of a semi-amorphous alloy (metamorphic) in which molybdenum and niobium are added to an Fe-Cr-B-based alloy.

Semi-amorphous alloy has the advantage of having a similar level of wear resistance and corrosion resistance while supplementing the difficult problem of manufacturing and processing an amorphous alloy, and by adding molybdenum and niobium, it improves oxidation resistance and corrosion resistance at high temperatures.

Hereinafter, the first and second tissue regions constituting the alloy coating layer will be described in detail.

The first structure region is a structure formed by collision or adhesion of a part or the entire powder of the alloy powder that is not completely melted on the base material when the alloy coating layer is formed using the alloy powder.

The first structure region includes a partial structure of powder in the alloy coating layer, or a spherical boundary, and is a structure containing a high fraction of Fe, Cr-based ceramic phase, for example, boride therein. In the case of forming an alloy coating layer using an alloy powder, a part of the powder that is not completely melted or partially melted is cooled on the surface of the base material or the alloy coating layer formed on the base material, and at this time, cooling in a state in which thermal energy is not sufficiently supplied Therefore, the internal structure of the alloy powder, rearrangement of crystals, amorphization, etc. are not actively performed, and it can also be expressed as an unmelted powder.

The first tissue region includes a ceramic phase including at least one of iron and chromium, for example, a boride, and the volume fraction of the boride may be within 30 to 90%, preferably 35 to 85 %, more preferably 40 to 80%.

In addition, boride may be included in a fraction similar to that of the alloy powder used in the manufacture of the alloy coating layer, or about 10% of the boride fraction of the alloy powder, and it is also possible to include boride of 70% or less.

Specifically, the first tissue region includes an iron-based alloy mainly containing BCC phase alpha iron and a boride phase therein, wherein the boride phase means a region in which individual boride particles are distributed.

The boride phase of the first structure region includes Fe, Cr-based boride, and in this case, the fraction of Fe, Cr-based boride, for example, Cr ₂ B, (Cr, Fe) ₂ B, etc. is the initial alloy powder. may be similar to, preferably 30 to 90%, preferably 40 to 85%, more preferably 40 to 80%, and niobium (Nb) can be finely and evenly distributed in the iron-based alloy , it can be observed that the distribution of niobium is similar to that of Fe element.

At this time, the size of individual particle phases of Fe and Cr-based boride among the ceramic phases included in the alloy coating layer may be 50 μm or less, preferably 2 μm or less, and more preferably 300 nm to 800 nm.

On the other hand, the iron-based alloy of the first structure region may include at least one portion of an amorphous phase or a region including metallic glass, and both the amorphous phase and the ceramic phase (boride, carbide, or boron carbide, etc.) It is good to include

The second tissue region is a tissue formed by cooling the entire molten powder or a part of the powder in the alloy powder when forming the alloy coating layer using the alloy powder and then cooling it on the base material. Since it is formed by being laminated or attached to the surface of the base material or the first tissue region, it is a tissue that does not contain the form of alloy powder or does not have a specific shape, and can be distinguished by a boundary existing between it and the first tissue region.

During coating, all or part of the alloy powder is melted, or changes in bonding such as decomposition of compounds inside due to thermal energy, and microstructure changes such as reorganization or amorphization of crystals occur and then cool to form a coating layer.

The powder that has undergone these changes loses its shape and deforms or disperses when it collides with the base material or alloy coating layer to form a second tissue region, and it is preferable that the second tissue region included in the alloy coating layer have a higher volume fraction than the first texture region. , the ratio is preferably in the range of 1.4 to 10 times, preferably 2 to 8 times.

The properties of the second tissue region can be controlled by the formation method of the coating layer, temperature conditions, flight distance of alloy powder, flight time and speed, particle size of alloy powder, composition of alloy powder, etc., high temperature, long flight distance, The ratio of the second tissue region may be increased under the conditions of a long flight time and a fast powder jetting speed.

The second structure region may include an iron-based alloy and a ceramic phase dispersed in the iron-based alloy, and elements such as iron, chromium, niobium, boron, and carbon are evenly distributed to almost include coarse crystals with large grain sizes It includes structures that are distributed in microscopic tissues without

Unlike the first texture region, the second texture region includes a fine ceramic phase or a fine crystalline structure compared to the alloy powder. The ceramic phase, such as Fe, Cr-based boride, contained in the second tissue region may have an individual particle phase size of 10 μm or less, preferably 1 μm or less, more preferably 300 nm or less, and is included in the first tissue region. The size of the individual particle phase of the Cr-based boride included in the second tissue region may be smaller than the size of the individual particle phase of the Fe, Cr-based boride.

In addition, the size of the individual boride particle phase included in the first tissue region is 1.1 to 30 times, preferably 1.5 to 10 times, more preferably 1.7 times the size of the boride individual particle phase in the second tissue region. It is good to be 5 to 5 times.

When Nb boride is formed in the ceramic phase and Nb is not included in Fe in the form of a solid solution, the size ratio of the individual particle phases of iron and chromium-based boride contained in the first and second tissue regions is out of the corresponding range. In this case, there is a problem in that the amorphous formation ability of the first and second tissue regions is reduced, and the physical properties of the alloy coating layer may be deteriorated.

In addition, the iron-based alloy of the second structure region is made to include at least a portion of the region including the amorphous phase. The volume ratio of the amorphous phase of the alloy coating layer may be 5 to 49%, preferably 13 to 40%. The proportion of amorphous content included in the first tissue region may be 5 to 49%, preferably 13 to 40%. In this case, the ratio of the amorphous phase included in the first tissue region may be lower than or equal to the ratio of the amorphous phase included in the second tissue region, and the ratio of the amorphous phase in the second tissue region is higher than the ratio of the amorphous phase in the first tissue region. A large one is preferable, and specifically, the ratio of the amorphous phase may be more than 1.0 times or less than 3 times, preferably 1.1 times to 2 times.

If the ratio of the amorphous phase between the first tissue region and the second tissue region is out of the corresponding range, the ratio of the amorphous phase of the overall alloy coating layer is lowered. Since the proportion of the ceramic phase such as the cargo phase is relatively reduced, there may be a problem in that hardness or wear resistance properties are deteriorated.

In the alloy coating layer of the present invention, a first tissue region and a second tissue region are separated from each other by a boundary, and in this case, the boundary may include a boundary region or a boundary surface. The boundary region or boundary surface is formed outside or on the surface of the first or second texture region, and is mainly formed in the process of forming the alloy coating layer from the alloy powder.

The boundary region may include Fe and Cr-based oxides, and Fe and Cr-based oxides are mainly formed during processes such as HVOF and plasma spraying in which powder is deposited on a base material in the atmosphere. For example, when powder is flown in a high-temperature thermal spraying process, the surface of the powder is oxidized during flight by inflight oxidation by thermal energy to generate oxide. In this case, the oxide may be included in the boundary region.

At this time, the generated oxide may be formed on the surface of the first tissue region or the surface of the second tissue region to be included in the alloy coating layer, and the adhesive force between the first tissue region or between the first tissue region and the second tissue region in the alloy coating layer (adhesion strength) and may act as a factor reducing mechanical properties such as wear resistance or hardness of the alloy coating layer.

On the other hand, the first tissue region does not receive a high temperature or is not sufficiently melted, so that the structure of the alloy powder is maintained at a high ratio inside, and the Fe-based boride contained in the alloy powder is decomposed by thermal energy in the process of forming the coating layer. Because it is not decomposition, it contains boride in a relatively high proportion compared to the molten powder structure.

For example, in the second tissue region, Fe, Cr-based borides are decomposed by a high temperature, so borides having relatively small individual particle sizes may exist, and the boride is decomposed and included in the entire second tissue region. The ratio of the boride phase is relatively lower than that of the first tissue region, and the ratio of the amorphous phase or the metallic glass structure may be relatively increased due to the effect of improving the amorphous formation performance by decomposed boron or chromium.

The alloy coating layer according to an embodiment of the present invention is characterized in that it includes a solid solution formed by dissolving at least one of molybdenum and niobium included in the composition of the alloy as a solid solution in the iron-based alloy. That is, molybdenum or niobium may be included as a solid solution in an iron-based alloy mainly containing iron in a relatively large proportion without forming a separate additional phase, and iron-molybdenum solid solution, iron-niobium solid solution or iron- Molybdenum and niobium solid solution may be included as an iron-based alloy of the alloy coating layer.

Due to the formation of such a solid solution, the ratio of molybdenum or niobium boride or carbide in the alloy coating layer decreases compared to the ratio of niobium boride or carbide in the alloy powder, and , molybdenum or niobium is uniformly dispersed with iron element in a solid solution, so that an amorphous phase can be formed more easily, the ratio of the amorphous region of the alloy coating layer is increased, the effect of improving the amorphous forming performance can be obtained, and the high level of niobium Oxidation at high temperatures can be effectively prevented due to thermal stability.

The alloy coating layer of an embodiment of the present invention is manufactured from alloy powder, and has improved amorphous forming performance including B and Cr obtained by thermally decomposing Fe and Cr-based boride contained in the alloy powder, and has a higher amorphous phase than the alloy powder can have a ratio of

The ratio of the amorphous phase included in the alloy coating layer can be controlled differently depending on the composition of the alloy and the coating conditions. Hereinafter, plasma spraying and HVOF spraying processes as examples of thermal spraying will be described in detail.

When the alloy coating layer is formed by the plasma spraying method, the temperature of the heat source is higher than that of the HVOF spraying, which causes the alloy powder to pass through the plasma gun and collide on the base material to form the coating layer with a large temperature difference (delta T). ) appears, and a relatively high cooling rate can be obtained in plasma spraying compared to HVOF spraying.

In addition, the flight speed of the powder is faster in HVOF thermal spraying. In the case of plasma thermal spraying, since the alloy powder is exposed to a higher temperature than HVOF thermal spraying for a long time, the decomposition of iron and chromium-based boride phases can occur more easily inside the alloy powder.

At this time, the iron-chromium-boron-based semi-amorphous alloy material has sufficient thermal energy and kinetic energy, the iron-chromium-based boride is decomposed to improve the amorphous forming performance of the system, and an alloy coating layer is formed. An advantageous effect of increasing the ratio of the amorphous phase in the coating layer can be obtained.

On the other hand, when the alloy coating layer according to this aspect of the present invention is formed by the HVOF method in which the temperature of the heat source is low and the flight speed of the powder is fast during the process, the temperature and time for oxidation in the coating process are insufficient, and the temperature and time of the alloy powder are insufficient. It has excellent oxidation resistance and has a low ratio of oxides and boundary regions included in the alloy coating layer, and has high bonding strength at the interface between the first tissue region and the second tissue region surrounding the first tissue region, resulting in mechanical properties This can have excellent advantages.

The alloy coating layer according to an embodiment of the present invention has excellent mechanical properties of the finally obtained alloy coating layer due to excellent alloy composition characteristics and amorphous formation ability according to the composition.

The mechanical properties of the alloy coating layer are interpreted in a broad sense including hardness, abrasion resistance, corrosion resistance, etc. In general, when forming a coating layer using alloy powder, heat generated by oxides or wear in the particle boundary area or microstructure of the coating layer Oxides formed from the oxides are worn by external force or force to induce cracks, and the cracks easily propagate along the grain boundaries, causing the coating layer to expand along the interface of the first tissue region and peeling of the coating layer may occur.

With respect to the alloy coating layer formed by the thermal spraying method according to the embodiment of the present invention, the oxidation resistance of the alloy coating layer can be expressed as the ratio of the oxidation region, and the ratio of the oxidation region is calculated from the oxide scale fraction. can be

The ratio of the oxidation region of the alloy coating layer may be 2.50% or less, preferably 0.001 to 0.5%, and more preferably 0.02 to 0.2%. If the ratio of the oxidation region is out of the corresponding range, problems such as a change in physical properties due to oxidation of the coating layer and a decrease in the lifespan of the coating layer may occur.

In addition, the alloy coating layer formed by the thermal spraying method according to an embodiment of the present invention has a composite structure in which amorphous regions of different crystal structures and different ratios, and a structure in which ceramic phases of different sizes are dispersed, thus having low porosity, wear resistance, It has excellent physical properties such as corrosion resistance and excellent oxidation resistance.

The alloy coating layer may have a lower porosity, but specifically may be in the range of 0.001 to 5%, preferably in the range of 0.001 to 4%, and more preferably in the range of 0.01 to 3.9%. When the porosity is higher than the corresponding range, there are problems in that the surface area is widened, corrosion resistance is lowered, and abrasion resistance and hardness are lowered.

Due to the above characteristics, the alloy coating layer according to the present invention has excellent hardness and wear resistance.

The hardness of the alloy coating layer is 600 to 900 Hv in terms of Vickers hardness, preferably 610 to 800 Hv, and more preferably 700 to 800 Hv. If the hardness of the alloy coating layer is out of the corresponding range, the coating layer may be destroyed or the lifespan may be reduced due to insufficient physical properties.

In addition, the alloy coating layer of the coating body according to an embodiment of the present invention includes the excellent properties of the iron-based semi-amorphous alloy, and as wear progresses on the wear surface, the alloy on the surface does not melt in the solid phase but becomes amorphous. It has a characteristic that the coefficient of friction gradually decreases, and the surface with the reduced coefficient of friction increases the amorphous ratio and has better hardness and wear resistance.

The alloy coating layer according to one aspect of the present invention may be formed on various types of base materials to provide various coatings, and may be applied without limitation if the excellent wear resistance, heat resistance, and oxidation resistance of the alloy coating layer are required.

For example, when an alloy coating layer is applied to the surface of a brake disc used in automobiles, an alloy coating layer containing an amorphous phase and a ceramic phase, which has excellent durability and hardness, and less generation of fine dust due to friction may be provided. , a brake disc having a low production cost and excellent productivity by replacing the conventional tungsten carbide (WC) coating layer with a coating layer or an alloy coating layer formed thereon can be provided.

In particular, since the alloy coating layer is made of an iron-based alloy, when an iron-based alloy or cast iron is used as the base material of the brake disc, the difference in the coefficient of thermal expansion between the base material and the alloy coating layer can be minimized. There is an advantage in that peeling of the coating layer or damage at the interface is prevented.

At this time, the coefficient of thermal expansion (a) of the alloy coating layer is similar to the coefficient of thermal expansion (b) of the brake base material, and the ratio (a/b) may be 0.85 times to 1.15 times, preferably 0.9 times to 1.1 times.

In addition, due to the advantage of a small difference in the coefficient of thermal expansion, the brake body may not include a bonding layer between the formation of the coating layer when the alloy coating layer is formed, and even when the heat treatment process is not included when the coating layer is formed, a uniform thickness and Since the coating layer can be formed directly on the surface of the brake body, the production process is simplified, thereby increasing productivity and reducing costs.

The brake disc or coating body with the alloy coating layer according to the present invention has a microstructure including an amorphous phase and a ceramic phase, and it is easy to adhere to a metal base material such as a cast iron-based material, an iron-based alloy, an aluminum alloy, and a base material of a ceramic component It has excellent physical and chemical properties such as abrasion resistance, oxidation resistance, and corrosion resistance while having high deposition efficiency.

Another aspect of the present invention is a method for preparing a coating body. The coating body manufacturing method includes a method of forming an alloy coating layer in a thermal spray method by using the alloy powder having the above-described characteristics on the base material, and in this case, the alloy coating layer is the same alloy as the above-mentioned alloy coating layer. It is preferable that it is a coating layer, and in the following, the same contents with respect to the above-described alloy powder and alloy coating layer are omitted.

The base material used in manufacturing the coating is not limited, and alloy powder can be used with high-speed flame spray (HVOF), plasma spray, vacuum plasma spray (VPS), or cold spray methods. is not limited and can be used, but a suitable thermal spraying method may be selected depending on the field and purpose of application of the coating, and it is preferable to use the ultrafast flame spraying or plasma spraying method.

Ultra-high-speed flame spraying uses the flame generated by mixing oxygen and fuel as a heat source. Plasma spraying uses reverse polarity arc to obtain ultra-high temperature plasma from ionized inert gas and transferring it to use. Vacuum plasma spraying uses a vacuum It is a method to prevent oxidation by performing plasma spraying in an atmosphere.

The spraying temperature and speed may vary depending on the spraying method, and ultra-high-speed flame spraying has a wide temperature range, so both low and high temperatures are possible, and the spraying speed is fast. Do.

In the method for manufacturing a coating body according to an embodiment of the present invention, it is preferable to use a method of spraying the alloy powder at a temperature of 3,000 to 18,000 ℃ at a speed of 600 to 2,200 m/s to form an alloy coating layer.

More specifically, as a condition for high-speed flame spraying (HVOF) among thermal spraying, the temperature is preferably 3,000 to 4,300 °C, preferably 3,100 to 3,300 °C, and the powder spraying speed at this time is 2,000 to 2,200 m/s is good.

In addition, as a condition for plasma spraying the alloy powder, it is preferable that the temperature be 15,000 to 18,000° C., and at this time, the powder spraying speed is preferably 600 to 700 m/s.

If the temperature is too low, the alloy powder is not sufficiently melted, so that the coating is made in a manner close to cold spray, and the ratio of the second tissue area decreases, so that the wear resistance can be reduced, and the porosity can be increased. , if the temperature is too high, a problem in which a lot of oxides are formed during coating may occur.

In the method for manufacturing a coating body according to an embodiment of the present invention, when the flame temperature of the thermal spray coating method used to form the alloy coating layer is T (°C) and the injection speed of the alloy powder is v (m/s), the melting The injection energy (E) of a particle can be expressed as the sum of the internal energy proportional to the temperature and the kinetic energy proportional to the square of the velocity.

Injection energy (E) = T + (v ² * 10 ^-3 ) (T is flame temperature [℃], v is powder injection speed [m/s])

The injection energy may vary depending on the thermal spraying method, and even the same method may be obtained differently depending on the thermal spraying conditions.

The value of the injection energy preferably satisfies the range of 7,000 to 17,000, and when the value of the injection energy satisfies the corresponding range, the volume of the second tissue region in the alloy coating layer formed by thermal spraying the alloy powder in the corresponding method is the first tissue region It can be obtained in 1.4 to 10 times the volume.

If the temperature of the powder is too low or the injection speed is slow, the value of the equation becomes too small, the ratio of the second tissue region may be lower than 1.4 times the volume of the first tissue region, and the temperature of the powder is too high or If the jetting speed is too fast, on the contrary, there may be a problem in that the ratio of the second tissue area increases.

When the coating body is formed by coating the alloy powder, which is another aspect of the present invention, by the thermal spraying method as described above, the volume of the second tissue region formed on the formed alloy coating layer is 1.4 to 10 times that of the first tissue region, preferably It can be obtained in the range of 2 to 8 times, a higher ratio of amorphous phase compared to the first tissue region is obtained in the second tissue region, and the size of individual particle phases of boride in the second tissue region is that of the first tissue region. The effect of being smaller than the size of the individual particle phase of the boride can be obtained.

Hereinafter, preferred examples are presented to aid the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention. , it is natural that such changes and modifications fall within the scope of the appended claims.

<Example>

Examples 1 to 7: Preparation of alloy powder

After the materials were weighed to have a predetermined composition and melted to obtain a metal composition for alloy, the alloy powder was prepared by supplying it to an atomizer in a nitrogen gas atmosphere and cooling the fragmented molten metal droplets, which are shown in Table 1 below. summarized and shown.

Examples 8 to 9, 12 to 13, 16: Formation of alloy coating layer using HVOF method

Using the alloy powder of Examples 1 to 4 and 7, using an Oerlikon Metco Diamond Jet series HVOF gas fuel spray system, oxygen and propane gas were used as fuels, and the injection distance was 30 cm. An alloy coating layer was formed by HVOF, High velocity oxygen fuel spray) method. The apparatus and conditions used at this time are described in detail below.

- DJ Gun HVOF -

[Conditions] Gun type: Hybrid, Air cap: 2701, LPG Flow 160 SCFH, LPG Pressure 90 PSI, Oxygen flow 550 SCFH, Oxygen Pressure 150 PSI, Air flow 900 SCFH, Air Pressure 100 PSI, Nitrogen flow 28 SCFH, Nitrogen Pressure 150 PSI, Gun speed: 100 m/min, Gun pitch: 3.0mm, Feeder rate 45 g/min, Stand-off distance: 250mm

Examples 10 to 11, 14 to 15: Formation of alloy coating layer using plasma spraying method

Examples 1 to 2, using the alloy powder of 5 to 6 using a plasma spraying device (Metco 9MC Plasma Spray controller, 9MB spray gun), current (current) 700A, power (Power) 53Kw, distance (Distance) 350mm, An alloy coating layer was formed by plasma spraying under the conditions of a speed of 300 and a spot size of 10 mm.

<Comparative example>

Comparative Examples 1 to 3: Preparation of alloy powder

Iron 48.05 g, chromium 44.73 g, boron 6.36 g, carbon 0.13 g, and silicon 0.73 g are weighed and melted to obtain a metal composition for alloy, which is then supplied to an atomizer in a nitrogen gas atmosphere for atomization and split molten metal solution The alloy powder of Comparative Example 1 was prepared by cooling the mixture, and alloy powders of Comparative Examples 2 and 3 were prepared in the same manner as in Comparative Example 1 using the alloy metal composition prepared in a predetermined composition.

It is summarized and shown in Table 1 below.

Comparative Examples 4 to 9: Formation of alloy coating layer

The alloy powders of Comparative Examples 1 to 3 were coated in the same manner as in Examples 8 and 10 to obtain alloy coating layers of Comparative Examples 4 to 9.

The alloy composition and powder average diameter of Examples 1 to 7 and Comparative Example 1 are shown in Table 1 below, and the coating layer forming method, thickness, and used alloy powder of Examples 8 to 16 and Comparative Examples 4 to 9 are summarized in Table 2 was indicated.

division alloy composition powder average diameter
(μm) steel
(g) chrome
(g) molybdenum
(g) niobium
(g) boron
(g) carbon
(g) silicon
(g) Example 1 100 27.55 6.89 4.82 2.75 0.55 0 33.1 Example 2 100 28.23 7.06 2.47 2.82 0.56 0 33.1 Example 3 100 17.22 26.10 0.12 6.63 0.12 0 31.9 Example 4 100 58.23 1.2 6.22 0.12 3.61 0 34.0 Example 5 100 21.96 4.52 1.29 3.88 0 0 33.8 Example 6 100 18.32 19.47 0.61 0 2.65 0 35.0 Example 7 100 44.25 2.44 5.31 0 0 0 32.8 Comparative Example 1 100 86.10 0 0 12.24 0.25 1.40 31.2 Comparative Example 2 100 16.49 27.74 6.78 0 3.96 0 32.6 Comparative Example 3 100 60.52 1.0 0.1 7.71 0.1 0 32.4

division Coating method Coating layer thickness (㎛) alloy powder used Example 8 HVOF 215.0 Example 1 Example 9 HVOF 425.1 Example 2 Example 10 plasma 228.2 Example 1 Example 11 plasma 388.3 Example 2 Example 12 HVOF 207.8 Example 3 Example 13 HVOF 432.5 Example 4 Example 14 plasma 224.1 Example 5 Example 15 plasma 391.7 Example 6 Example 16 HVOF 308.6 Example 7 Comparative Example 4 HVOF 223.3 Comparative Example 1 Comparative Example 5 plasma 278.0 Comparative Example 1 Comparative Example 6 HVOF 196.4 Comparative Example 2 Comparative Example 7 plasma 441.0 Comparative Example 2 Comparative Example 8 HVOF 227.9 Comparative Example 3 Comparative Example 9 plasma 376.2 Comparative Example 3

<Experimental example>

Experimental Example 1: Analysis of particle size of alloy powder

The particle size of the alloy powder of Examples 1 and 2 was analyzed, and the cross section of the powder was observed with an electron microscope (SEM). 1 is a view showing the results of observing the powder cross section of Example 3 and Comparative Example 1, FIG. 2 is a graph showing the results of particle size analysis.

As shown in Figs. 1 (a) and 2 (a), the alloy powder of Example 1 is a spherical powder having a particle size distribution of 11.2 to 81.1, and Figs. 1 (b) and 2 (b). As shown in, it can be seen that the alloy powder of Experimental Example 2 is a spherical powder having a particle size distribution of 11.2 to 81.2.

Experimental Example 2: XRD crystal analysis of alloy powder

The alloy powders of Example 3 and Comparative Example 1 were observed by XRD analysis, and the results are shown in FIG. 3 .

In Example 3 and Comparative Example 1, Fe, Cr, and Fe-based boride having a body-centered cubic (bcc) structure were commonly detected.

Experimental Example 3: Microstructure observation of alloy powder

The alloy powders of Example 2 and Comparative Example 1 were observed using an electron probe microanalyzer (EPMA) analyzer to obtain the same results as in FIG. 4 .

In Example (b) and Comparative Example (a), it can be confirmed that iron-based alloys containing alpha iron (BCC) and Cr and Cr-based boride phases exist inside the spherical powder.

Experimental Example 4: Evaluation of oxidation properties of alloy powder

After putting 50 g of the alloy powder of Experimental Examples 1 and 2 and Comparative Examples 1 to 3 into an Al2O3 pot, using Rigaku's TG-DTA 8122 equipment, the heating rate was 10°C/min, the final temperature (stop temperature) The result of Experimental Examples 1, 2 and Comparative Example 1 was obtained by setting the temperature to 1200 ℃, heating from room temperature to 1200 ℃, observing the change in the mass of the powder, and measuring the temperature at which the oxide weight rapidly increased due to the rapid increase in oxidation. It is shown as a graph in FIG. 5, and the temperature at which rapid oxidation occurs was recorded.

The oxide weights of the alloy powders of Examples 1 and 2 and Comparative Examples 1 to 3 (weight after oxidation test - initial powder weight of 50 g) were measured to be 5.23 mg, 1.25 mg, 3.30 mg, 3.42 mg, and 3.56 mg, respectively, at 1200 ° C. , calculated as 0.0105%, 0.0025%, 0.0066%, 0.0068%, and 0.0071%, respectively, relative to the weight of the initial powder, and the powders of Comparative Examples 1 to 3 were rapidly oxidized at 1044 ° C., 1042 ° C., and 1039 ° C., Example 1 Abrupt oxidation occurred at 1009 ° C. and 1075 ° C. in Example 2, indicating that the powder of Example 2 had the best oxidation resistance than other powders.

The less the oxide weight compared to the initial powder weight of 50 g, the better the oxidation resistance, and preferably 0.007% or less, preferably 0.005% or less, more preferably 0.003% or less or 0.0025% or less.

Experimental Example 5: Observation of surface structure and structure of alloy coating layer

The surface structures of the alloy coating layers of Examples 8 to 11 and Comparative Examples 4 to 5 were analyzed using a field emission electron microscope (Fe-SEM, Field Emission Scanning Electron Microscope, Tescan, MIRA 3), an electron probe X-ray micro analyzer (EPMA, Electron Probe) It was observed using an X-ray Microanalyzer, Joel JXA-8500F) and an electron microscope FE_TEM (FEI, TALOS F200X), and it is shown in FIG. 6 .

As a result of observation, the coatings of Examples 8 and 9 and Comparative Example 4 had relatively few pores in the coating layer, and peeling from the base material was not observed.

7 is a photograph taken of the surface structure of the alloy coating layer and the boundary of particles. In the coating layers of Examples 8 and 9 and Comparative Example 4, fine pores at a level of 1 μm or less exist, and some bonds exist at the particle boundary, In Example 9, very few defects or pores were observed, and in Examples 10, 11 and Comparative Example 5, oxides were observed at the grain boundary or pores having a relatively large size were observed.

Experimental Example 6: Measurement of porosity and oxidation resistance of alloy coating layer

Electron probe X-ray microanalyzer (EPMA, Electron Probe X-ray Microanalyzer, Joel JXA-8500F) analysis of the alloy coating layers of Examples 8 to 16 and Comparative Examples 4 to 9, and then FE_TEM (FEI, TALOS F200X) for the coating layer The porosity and the oxide scal area were measured. The experimental results are shown in Table 3 below, and the results of Examples 8 to 11 and Comparative Examples 4 to 5 are graphically illustrated in FIG. 8 .

division Porosity (%) Oxidation area ratio (%) Example 8 0.18 0.51 Example 9 0.03 0.03 Example 10 1.35 4.79 Example 11 3.84 1.50 Example 12 0.71 0.15 Example 13 0.54 0.55 Example 14 1.84 2.50 Example 15 2.8 2.00 Example 16 0.25 0.21 Comparative Example 4 0.25 0.31 Comparative Example 5 1.56 2.48 Comparative Example 6 0.92 0.65 Comparative Example 7 3.9 2.55 Comparative Example 8 2.24 0.49 Comparative Example 9 3.17 2.5

The porosity and the oxidation region ratio were overall lower in the example using the HVOF method than in the example coated by the plasma method, and in particular, in Example 9, the porosity and the oxidation region ratio were low.

In addition, the low ratio of the oxidation region in Examples 9 and 11 using the alloy powder of Example 2 according to the alloy powder composition is expected to be due to the excellent heat resistance and oxidation resistance of the alloy powder of Example 2, especially in Examples In the case of using the alloy powder of No. 2, compared to Comparative Examples 4 and 5 using the same coating method, plasma coating was 1.65 times and HVOF coating was 10.33 times lower.

Experimental Example 7: Hardness evaluation of alloy coating layer

The Vickers hardness of the alloy coating layers of Examples 8 to 16 and Comparative Examples 4 to 9 was measured under the condition that a load of 300 g was maintained for 10 seconds, which is shown in Table 4 below.

In Examples 8 to 11 and Comparative Examples 4 to 5, it was measured to be 616.5, 760.4, 530.5, 726.0, 725.7, and 662.7, respectively, and the measurement results are shown in FIG. 9 as a graph.

The hardness of the alloy coating layer was obtained higher than Examples 10 to 11 using plasma in Examples 8 to 9 using the HVOF method in common, and in particular, high hardness was obtained in Example 9, and Example 11 also using the plasma coating method The hardness was excellent compared to Examples 14 and 15 and Comparative Examples 5, 7, and 9 used.

Experimental Example 8: Evaluation of wear resistance of alloy coating layer

Examples 8 to 16 and Comparative Examples 4 to 9 using a wear measuring device (Pin on disc wear test machine, RB-102PD) at room temperature conditions with respect to Si ₃ N ₄ A load of 5 kgf, 0.05 m / s The degree of wear by friction at speed and the average of the coefficient of friction were measured and calculated and shown in Table 4 below.

division Hardness (Hv) Wear (mm ³ ) average coefficient of friction Example 8 616.5 0.15 0.19 Example 9 760.4 0.016 0.22 Example 10 530.5 0.74 0.17 Example 11 726.0 0.31 0.26 Example 12 680.2 0.20 0.20 Example 13 654.5 0.24 0.23 Example 14 617.3 0.64 0.24 Example 15 608.7 0.72 0.26 Example 16 600.4 0.020 0.19 Comparative Example 4 725.7 0.033 0.25 Comparative Example 5 662.7 0.46 0.23 Comparative Example 6 590.3 0.10 0.30 Comparative Example 7 585.4 0.49 0.28 Comparative Example 8 597.1 0.12 0.24 Comparative Example 9 550.6 0.48 0.26

The wear resistance of the alloy coating layer was generally found to be better than that of the example using the plasma in the example using the HVOF method, and in particular, it was found to be excellent in Example 9.

In addition, Example 11 showed that the amount of wear was small compared to Examples 14 and 15 and Comparative Examples 5, 7 and 9 using the plasma coating method, and thus excellent wear resistance.

Additionally, the alloy coating layers according to Examples 8, 9 and Comparative Example 4 showed mostly abrasive surfaces after abrasion, and had a characteristic that the roughness of the surface of the crater region in which the particles were removed was not high, and the inside of the coating layer in the cross section There are no cracks or defects, little deformation of grain boundaries, and wavy marks on the wear surface are developed at 0.5, 0.18, and 0.26 μm intervals, respectively.

In addition, it was observed that wear on the surface of the alloy coating layer was peeled off along the grain boundary, and it was generated by a high heat source and was due to the low bonding force and crack generation by the Fe-Cr-based oxide (type 1) present at the interface. It is expected.

On the other hand, Fe-Cr-based oxide (type 2), which is a black phase with a high fraction of O, Fe, and Cr, formed by flash temperature in sliding wear of metals in the atmosphere, was observed on the wear surface due to wear. The ratio was 8.46% in Example 8, 46.29% in Example 9, and 28.10% in Comparative Example 4.

It is understood that the oxide (type 2) generated during wear reduces frictional force as it performs a solid lubrication role, and plays a role in reducing the friction coefficient in the alloy coating layer in which there is little micro-peel of the coating layer.

Experimental Example 9: Measurement of amorphous ratio of alloy coating layer

Analyze crystals of the alloy coating layers of Examples 8 to 11 and Comparative Examples 4 to 5 by electron backscatter diffraction (EBSD) method using a back scattering electron diffraction pattern analyzer (nordlys CMOS detector, step size: 0.05 μm) and the results are shown in FIGS. 10 and 11 .

As a result of the EBSD analysis, (Cr,Fe) ₂ B and Fe(BCC) phases were commonly observed, and in Examples 8 and 10, the Fe phase showed a relatively high ratio, and was particularly observed in the first tissue region. In Examples 8 to 11, the volume ratio of the amorphous region was calculated to be 13.5, 10.3%, 39.1, and 48.2, and the results for the amorphous ratio of the first and second tissue regions are summarized and shown in Table 5.

division Total coating layer amorphous ratio (vol%) 1st tissue area amorphous ratio (vol%) Amorphous ratio of the second tissue area (vol%) Example 8 13.5 10.7 16.2 Example 9 10.3 9.8 10.6 Example 10 39.1 33.2 46.5 Example 11 48.2 42.0 53.7 Comparative Example 4 9.9 10.9 9.5 Comparative Example 5 45.3 18.6 58.6

Experimental Example 10: Observation of the microstructure of the alloy coating layer

The alloy coating layers of Examples 8 to 11 and Comparative Examples 4 to 5 were subjected to microstructure analysis using an electron probe micro analyzer (EPMA), and the results are shown in FIGS. 12 to 13 .

As a result of the analysis, it can be confirmed that molybdenum and niobium are evenly distributed throughout and are included as a solid solution in the iron-based alloy. In the first texture region, iron-based alloys containing iron and chromium were mainly present, and some Fe and Cr-based borides were observed. In the second texture region, most alloying elements were uniformly dispersed and individual fine boride phases were present.

In Examples 8 and 9 of FIGS. 12 and 13 , the size of the boride particle phase included in the second tissue region was 293.20 nm and 218.93 nm, respectively, and the size of the boride particle phase included in the first tissue region was 322.5 nm and 580.1, respectively. appeared in nm.

Features, structures, effects, etc. exemplified in each of the above-described embodiments may be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

1: 1st organization area 2: 2nd organization area

Claims (16)

base material; and
Including; an alloy coating layer provided in at least one section on the base material;
The alloy coating layer,
A first tissue region in which the proportion of the amorphous phase is 5 to 49% by volume, and
A coating body comprising a second tissue region separated by a boundary from the first tissue region and having an amorphous phase ratio higher than the amorphous phase ratio of the first tissue region.
According to claim 1,
The alloy coating layer includes a boride,
The size of the individual particle phase of the boride included in the first tissue region is larger than the size of the individual particle phase of the boride included in the second tissue region.
According to claim 1,
The volume of the second tissue region is 1.4 to 10 times the volume of the first tissue region.
The method of claim 1,
The first texture region is a powder laminate, and the second texture region is a melt spray body.
3. The method of claim 2,
The alloy coating layer is
with respect to 100 parts by weight of iron,
17.22 to 58.23 parts by weight of chromium;
1.2 to 26.1 parts by weight of molybdenum,
0.12 to 6.22 parts by weight of niobium, and
A coating comprising 0.12 to 6.63 parts by weight of boron.
6. The method of claim 5,
At least a portion of the niobium or molybdenum is dissolved in the iron coating body.
6. The method of claim 5,
The boride is a boride comprising at least one of iron and chromium or a boride of niobium.
6. The method of claim 5,
The thickness of the alloy coating layer is 0.05 to 0.3 mm coating body.
6. The method of claim 5,
The alloy coating layer is a coating body comprising a semi-amorphous (Metamorphic) alloy.
6. The method of claim 5,
A coating body having a Vickers hardness of 600 to 900 Hv of the alloy coating layer.
6. The method of claim 5,
The coating body having an oxidation region ratio of 2.50% or less of the alloy coating layer.
6. The method of claim 5,
A coating body having a porosity of 0.001 to 5% of the alloy coating layer.
8. The method of claim 7,
The size of the individual particle phase of the boride included in the first tissue region is 1.1 to 30 times the size of the individual particle phase of the boride included in the second tissue region.
A method for manufacturing a coating body by forming an alloy coating layer on a base material, the method comprising:
The alloy powder is thermally sprayed at a speed of 600 to 2,200 m/s at a temperature of 3,000 to 18,000 ℃,
a first tissue region formed by stacking the alloy powder and having an amorphous phase ratio of 5 to 49% by volume; and
a second structure region formed by melt-spraying the alloy powder and having a higher ratio of amorphous phase than the ratio of the amorphous phase of the first tissue region; Coating body manufacturing method for forming the alloy coating layer comprising a.
15. The method of claim 14,
The alloy powder
with respect to 100 parts by weight of iron,
17.22 to 58.23 parts by weight of chromium;
1.2 to 26.1 parts by weight of molybdenum,
0.12 to 6.22 parts by weight of niobium, and
A method for preparing a powder coating body comprising 0.12 to 6.63 parts by weight of boron.
15. The method of claim 14,
The alloy coating layer includes a boride,
The method of manufacturing a coating body, wherein the size of the individual particle phase of the boride included in the second tissue region is larger than the size of the individual particle phase of the boride included in the first tissue region.

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