KR102453371B1 - Ni-based amorphous alloy for prevent corrosion of plant, and preparing method thereof - Google Patents

Abstract

The present invention, in atomic%, tantalum (Ta) 7 to 18%, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8% and the remaining Ni and inevitable impurities, characterized in that consisting of, the inside of a thermal power plant It relates to a Ni-based amorphous alloy for corrosion coating.

Description

Ni-based amorphous alloy for corrosion-resistant coating of thermal power plant and manufacturing method thereof {Ni-based amorphous alloy for prevent corrosion of plant, and preparing method thereof}

The present invention relates to a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant and a manufacturing method.

Fossil fuels contain various impure elements such as S and Cl. In thermal power plants using such fossil fuels, there is always a problem of deterioration due to corrosion in piping facilities, which are passages through which exhaust gases generated in combustion and combustion processes pass. In particular, S and Cl contained in exhaust gas meet with water vapor in the air and are transformed into sulfuric acid and hydrochloric acid, thereby accelerating corrosion.

As a method for preventing the corrosion, there is a method of forming a corrosion-resistant coating layer on the surface of a structure, various materials, hulls and various parts by using a thermal spraying method, a method of using a corrosion-resistant and anti-rust paint, and the like.

For example, Korean Patent Laid-Open No. 10-2006-0037202 discloses a method of forming a skin by spraying a Fe-Cr-B-Si-Mn-based alloy, and Korean Patent Laid-Open Patent Publication No. 2000-0039464 discloses aluminum (Al ), a zirconium (Zr) alloy powder containing copper (Cu) and nickel (Ni) is disclosed, but the above methods are concerned with whether it is possible to stably maintain corrosion resistance even at 650° C. or higher, where high-temperature corrosion is actively generated. has not been verified for

Republic of Korea Patent Publication No. 10-2006-0037202 (2006.05.03.) Republic of Korea Patent Publication No. 2000-0039464 (2000.07.05.)

An object of the present invention is to provide a Ni-based amorphous alloy for corrosion resistance coating for thermal power plants with improved corrosion resistance at a high temperature of 650° C. or more and a manufacturing method in order to solve the above problems.

One aspect of the present invention for achieving the above object is in atomic%, tantalum (Ta) 7 to 18%, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8% and the remaining Ni and inevitable impurities It is a Ni-based amorphous alloy for corrosion-resistant coating of thermal power plants, characterized in that made.

In the one embodiment, the content of tantalum (Ta) and niobium (Nb) may satisfy the following relational expression (1).

[Relational Expression 1]

32 ≤ [Ta] + [Nb] ≤ 38

(In Relation 1, [Ta] is the atomic % of Ta, and [Nb] is the atomic % of Nb)

In the one embodiment, the content of tantalum (Ta), niobium (Nb), and molybdenum (Mo) may satisfy the following relational expression (2).

In the one aspect, the molybdenum (Mo) may be 2.4 to 3.6 atomic%.

In the one aspect, the molybdenum (Mo) may be 5.6 to 8.4 atomic%.

In the one aspect, the amorphous alloy may satisfy the system-free change rate of the following relation 5.

[Relational Expression 5]

-1 ≤ (W ₀ -W _t )/W ₀ × 100 ≤ 1

(In Relational Expression 5, W ₀ is the initial weight (g) of the amorphous alloy, and W _t is the weight (g) of the amorphous alloy measured after being supported in a hydrochloric acid solution of 5 to 20% by volume for 60 days.)

In another aspect of the present invention, a) tantalum (Ta) 7 to 18%, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8% and the remaining Ni and unavoidable impurities to prepare a material consisting of Step, b) dissolving the material to prepare a molten master alloy; and c) solidifying the molten master alloy to prepare a Ni-based amorphous alloy for corrosion resistance coating for thermal power plants. It relates to a method for manufacturing a Ni-based amorphous alloy.

In the above aspect, d) may further include the step of heat-treating the Ni-based amorphous alloy for corrosion-resistant coating in a thermal power plant in a temperature range of 730 to 800K.

In atomic% of thermal power plant according to the present invention, tantalum (Ta) 7 to 18%, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8% and the remaining Ni and unavoidable impurities Ni for corrosion-resistant coating By providing an amorphous alloy based on the corrosion resistance at a high temperature of 650 ℃ or higher, there is an advantage that can improve the thermal efficiency of the power plant of the thermal power plant.

1 is a flowchart for explaining a method of manufacturing a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an embodiment of the present invention.
2 is a scanning electron microscope (SEM) photograph of a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an embodiment of the present invention.
3 is an X-ray diffraction (XRD) analysis result of a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an embodiment of the present invention.
4 is a differential thermal analysis (DTA) result of a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an embodiment of the present invention.
5 is a graph showing the weight reduction rate (%) of the Ni-based amorphous alloy prepared through the Examples and Comparative Examples of the present invention with the lapse of corrosion time.

Hereinafter, a Ni-based amorphous alloy for corrosion-resistant coating and a manufacturing method for a thermal power plant according to the present invention will be described in detail. The drawings introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, if there is no other definition in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of known functions and configurations that may be unnecessarily obscure will be omitted.

Fossil fuels contain various impure elements such as S and Cl. In thermal power plants using such fossil fuels, there is always a problem of deterioration due to corrosion in piping facilities, which are passages through which exhaust gases generated in combustion and combustion processes pass.

In order to improve this, a method of enhancing corrosion resistance by coating nickel (Ni) or a nickel (Ni)-based alloy in which a predetermined element is mixed with nickel (Ni) on a structural steel such as iron (Fe) is being studied.

For this reason, in one embodiment of the present invention, tantalum (Ta), niobium (Nb) and molybdenum (Mo) are added to the nickel (Ni) to provide a Ni-based amorphous alloy having excellent corrosion resistance in a high temperature environment of 650° C. or higher. can do.

In the present specification, the Ni-based amorphous alloy exhibits a homogeneous isotropic property without anisotropy, grain boundary, segregation of surface defects, etc., which is seen in a general crystalline structure alloy, and has excellent mechanical strength because there is no crystallographic anisotropy. In addition, since the structure and composition are uniform, it shows excellent corrosion resistance, so it is suitable for use in extreme environments.

Hereinafter, the composition range of the Ni-based amorphous alloy for thermal power plant corrosion-resistant coating according to an embodiment of the present invention will be described in detail. Hereinafter, unless otherwise specified, the unit is atomic %.

Tantalum (Ta) is included in 7 to 18 atomic%.

The tantalum (Ta) may serve to improve corrosion resistance of the Ni-based amorphous alloy. However, when the tantalum (Ta) is included in the Ni-based amorphous alloy in an amount of less than 7 atomic%, it is difficult to expect an effect of improving corrosion resistance. In order to make this action useful, the tantalum (Ta) may be included in an amount of 7 atomic% or more, more preferably 8 atomic% or more. On the other hand, when the tantalum (Ta) is included in an amount exceeding 18 atomic%, it is difficult to form an amorphous phase of the Ni-based amorphous alloy, and amorphousness may be lost. For this reason, the tantalum (Ta) is preferably contained in an amount of 7 to 18 atomic %, more preferably 8 to 16 atomic %.

Niobium (Nb) is included in 13 to 33 atomic%.

The niobium (Nb) is an element that secures the formation of an amorphous phase of the Ni-based amorphous alloy and improves corrosion resistance. In addition, the niobium (Nb) has the advantage of improving the wettability of the Ni-based amorphous alloy to improve adhesion to the target metal during coating. Furthermore, niobium (Nb) can easily combine with oxygen in the Ni-based amorphous alloy to form niobium oxide such as niobium (Nb)O ₂ and niobium (Nb) ₂ O ₅ . This has an advantage in that corrosion resistance is very excellent compared to chromium oxide in which chromium (Cr) and oxygen commonly contained in a conventional Ni-based alloy composition are combined. In order to make this action useful, the niobium (Nb) may be included in an amount of 13 atomic% or more, and more preferably 17 atomic% or more. However, when the content of niobium (Nb) exceeds 33 atomic %, it is difficult to form an amorphous phase of the Ni-based amorphous alloy, and thus the amorphous property may be lost. For this reason, the niobium (Nb) may be included in 13 to 33 atomic%, more preferably 17 to 22 atomic%.

Molybdenum (Mo) is included in 2 to 8 atomic%.

The molybdenum (Mo) is an element that improves the amorphous forming ability of the Ni-based amorphous alloy. In particular, when molybdenum (Mo) is co-added with tantalum (Ta) and niobium (Nb), corrosion resistance of the Ni-based amorphous alloy due to sulfuric acid or hydrochloric acid can be greatly improved. In order to make this action useful, the molybdenum (Mo) may be included in an amount of 2 atomic% or more, and more preferably 3 atomic%. However, when the content of molybdenum (Mo) exceeds 8 atomic %, there is no significant improvement in corrosion resistance, and manufacturing cost may be unnecessarily increased, thereby lowering economic efficiency. In addition, when molybdenum (Mo) exceeds 8 atomic %, wettability may be lowered, and thus adhesion may be reduced during coating. For this reason, the molybdenum (Mo) may be included in 2 to 8 atomic %, more preferably 3 to 7 atomic %.

Lastly, Ni is an element constituting a matrix of a Ni-based amorphous alloy according to an embodiment of the present invention, and by forming an alloy with the above-mentioned elements, it may have high corrosion resistance and excellent amorphous forming ability to be achieved in the present invention. . In addition, since unintended impurities from raw materials or the surrounding environment may be unavoidably mixed in a typical manufacturing process, this cannot be excluded. Since these impurities are known to anyone skilled in the art of manufacturing processes, all details thereof are not specifically mentioned in the present specification.

In other words, the Ni-based amorphous alloy according to an embodiment of the present invention is tantalum (Ta) 7 to 11 atomic%, niobium (Nb) 6 to 23 atomic%, molybdenum (Mo) 1 to 5 atomic% and the remaining Ni and inevitable It may consist of impurities. Through this, excellent abrasion resistance and corrosion resistance are improved at a high temperature of 650° C. or higher, so that the inside of the boiler of a thermal power plant can be replaced with a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant.

The Ni-based amorphous alloy for corrosion resistance coating for thermal power plants according to the present invention is not easily corroded even in severe abrasive environments and corrosive environments by appropriately controlling the relative atomic percent of tantalum (Ta), niobium (Nb) and molybdenum (Mo). It can be prevented, and through this, it is possible to effectively protect the base material coated with the Ni-based amorphous alloy for corrosion-resistant coating of thermal power plants. In addition, since the content of a non-metal capable of forming a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant has a limit, it is preferable to design the alloy so that the semi-metal and the non-metal have an appropriate content.

For example, the Ni-based amorphous alloy for corrosion resistance coating of the thermal power plant has the content of the tantalum (Ta) and the niobium (Nb) fixed in a certain range, and the content of molybdenum (Mo) is adjusted at a high temperature. can improve the corrosion resistance of

According to an embodiment, the content of the tantalum (Ta) and niobium (Nb) in the Ni-based amorphous alloy for corrosion resistance coating of the thermal power plant may satisfy the following relational expression (1).

[Relational Expression 1]

32 ≤ [Ta] + [Nb] ≤ 38

(In Relation 1, [Ta] is the atomic % of Ta, and [Nb] is the atomic % of Nb)

With respect to the tantalum (Ta) and niobium (Nb), when the sum of each component is less than 32 atomic%, relatively molybdenum (Mo) is excessively contained in the Ni-based amorphous alloy, and when coated on a predetermined target metal The adhesion between the Ni-based amorphous alloy and the target gold may be reduced. Conversely, when the sum of tantalum (Ta) and niobium (Nb) exceeds 38 atomic %, molybdenum (Mo) is relatively decreased, thereby reducing corrosion resistance of the Ni-based amorphous alloy. For this reason, the sum of tantalum (Ta) and niobium (Nb) ([Ta] + [Nb]) is preferably 30 to 38, more preferably 36.5 to 37.5 atomic %. Alternatively, it may be 32 to 34 atomic %.

According to an embodiment, when the sum ([Ta] + [Nb]) of the tantalum (Ta) and niobium (Nb) satisfies the above relation 1, the tantalum (Ta), niobium (Nb) and molybdenum ( The content of Mo) may satisfy the following relational expression (2).

[Relational Expression 2]

35 ≤ [Ta] + [Nb] + [Mo] ≤ 44

(In Relation 2, [Ta] is atomic % of Ta, [Nb] is atomic % of Nb, and [Mo] is atomic % of Mo)

Through Equation 2, the content of nickel (Ni) may be determined when the sum of tantalum (Ta) and niobium (Nb) ([Ta] + [Nb]) satisfies Equation 1 above.

Specifically, with respect to the tantalum (Ta), niobium (Nb) and molybdenum (Mo), if the sum of each component is less than 35 atomic%, relatively nickel (Ni) is excessively saturated and the effect of each component is effective may not be implemented properly. Conversely, when the sum of tantalum (Ta), niobium (Nb), and molybdenum (Mo) exceeds 44 atomic %, the component of nickel (Ni) in the amorphous alloy is relatively decreased, so that amorphousness may not be realized. For this reason, the sum of tantalum (Ta), niobium (Nb), and molybdenum (Mo) ([Ta] + [Nb] + [Mo]) is preferably 35 to 44 atomic%, more preferably 39 to 41 atomic %.

Alternatively, when the sum ([Ta] + [Nb]) of the tantalum (Ta) and niobium (Nb) satisfies the above relation 1, the tantalum (Ta), niobium (Nb) and molybdenum (Mo) The content may satisfy Relational Equation 3 below.

[Relational Expression 3]

0.06 ≤ [Mo] / ([Ta] + [Nb]) ≤ 0.26

(In Relation 3, [Ta] is atomic % of Ta, [Nb] is atomic % of Nb, and [Mo] is atomic % of Mo)

Through Equation 3, the content of molybdenum (Mo) may be determined when the sum of tantalum (Ta) and niobium (Nb) ([Ta] + [Nb]) satisfies Equation 1 above.

When the ratio of molybdenum (Mo) to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) is less than 0.06 atomic %, the predetermined When coating the target metal, the adhesion between the Ni-based amorphous alloy and the target gold may decrease. Conversely, when the ratio of molybdenum (Mo) to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) exceeds 0.26, relatively molybdenum (Mo) decreases, The corrosion resistance of the Ni-based amorphous alloy may be reduced. For this reason, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) may be 0.06 to 0.26.

According to an embodiment, when the molybdenum (Mo) is included in 2.4 to 3.6 atomic %, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb]) ) may be 0.06 to 0.1.

According to another embodiment, when the molybdenum (Mo) is included in 5.6 to 8.4 atomic %, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb) ])) may be 0.2 to 0.26. A detailed description of the above-described two embodiments will be provided later.

On the other hand, the crystallization temperature (Tx) of the Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an example of the present invention may be 600 ℃ or more, specifically 600 to 800 ℃, more preferably 650 to 710 ℃ can be Accordingly, even when used in a high temperature environment of 650° C. or higher, a stable state can be maintained without physical and chemical transformation.

1 is a flowchart for explaining a method of manufacturing a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant according to an embodiment of the present invention.

Referring to Figure 1, another aspect of the present invention relates to a method for producing a Ni-based amorphous alloy for corrosion resistance coating of the thermal power plant, in detail a) atomic%, tantalum (Ta) 7 to 18%, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8%, and preparing a material consisting of the remaining Ni and unavoidable impurities; b) preparing a master alloy molten metal by dissolving the material; and c) solidifying the molten mother alloy to prepare a Ni-based amorphous alloy for corrosion-resistant coating in a thermal power plant.

First, step a) is a step for preparing the above-mentioned Ni-based amorphous alloy material for corrosion resistance coating of thermal power plant, Ni-based amorphous alloy material for corrosion resistance coating of thermal power plant is atomic%, tantalum (Ta) 7 to 18 %, niobium (Nb) 14 to 33%, molybdenum (Mo) 2 to 8%, and the remaining Ni and unavoidable impurities may be formed.

As described above, the tantalum (Ta), niobium (Nb), and molybdenum (Mo) may be included within a range satisfying the above Relations 1 to 3, and more preferably, the molybdenum (Mo) has 2.4 to 3.6 atoms. %, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) may be 0.06 to 0.1. Or when the molybdenum (Mo) is included in 5.6 to 8.4 atomic%, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) is 0.2 to 0.26 can be

As described above, when the Ni-based amorphous alloy material for corrosion-resistant coating of a thermal power plant is prepared, it can be melted to prepare a molten mother alloy.

Specifically, in order to form a molten mother alloy, the prepared Ni-based amorphous alloy material for corrosion-resistant coating of a thermal power plant is charged into a molten crucible, and the temperature inside the molten crucible is raised to 1500° C. or higher to manufacture a molten master alloy. .

Next, by solidifying the molten mother alloy, it is possible to manufacture a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant. In detail, the amorphous alloy may be produced by rapidly cooling the molten master alloy, and the rapid cooling of millions of degrees Celsius per second is too fast for crystals to form and may be solidified into a glass state.

Step c) is a step of preparing a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant by solidifying the molten mother alloy. At this time, as a solidification method, the melt spinning method, gas atomizing method, etc. can be used to rapidly solidify the mother alloy molten metal. Hereinafter, the application of melt spinning as a method of rapid coagulation will be described as an example, but the present disclosure is not limited thereto, and any known rapid coagulation method may be applied.

According to an embodiment, when the melt spinning method is applied, the master alloy molten metal may be put into a quartz nozzle and spun over a wheel rotating at 2000 to 4000 rpm. Through this, it is possible to prepare a Ni-based amorphous alloy for corrosion-resistant coating of a thermal power plant in a ribbon shape having a width of 0.1 to 1 mm and a thickness of 5 to 50 μm.

In addition, another aspect of the present invention relates to a thermal power plant boiler in which the entire region or a partial region is coated with the Ni-based amorphous alloy for corrosion resistance coating of the thermal power plant described above. In this way, when the inside of the boiler used at a high temperature is treated with the Ni-based amorphous alloy for corrosion-resistant coating of the thermal power plant, excellent high-temperature corrosion resistance and abrasion resistance can be secured.

In particular, conduits or protective tubes such as super heaters for biomass power plants are used under severe conditions and have severe corrosion and abrasion at high temperatures. It can have excellent corrosion resistance even under conditions.

Hereinafter, a Ni-based amorphous alloy for corrosion-resistant coating according to the present invention and a manufacturing method according to the present invention will be described in more detail through examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention. In addition, the unit of additives not specifically described in the specification may be atomic%.

[Examples 1 to 3, and Comparative Example 1]

The alloy having the atomic% composition of Table 1 is melted through a vacuum arc melting furnace to prepare a molten mother alloy, and the master alloy is used in a ribbon-type thermal power plant through melt spinning at a rotation speed of 3000 rpm. A Ni-based amorphous alloy for corrosion-resistant coating was prepared.

Tantalum (Ta) Niobium (Nb) Molybdenum (Mo) Ni Example 1 8.8 28.2 3.0 remaining amount Example 2 12.0 23.0 5.0 remaining amount Example 3 15.2 17.0 7.0 remaining amount Comparative Example 1 4.0 36.0 - remaining amount Comparative Example 2 20.0 10.0 10.0 remaining amount

[Analysis and Performance Evaluation]

1) SEM analysis:

The shapes of the Ni-based amorphous alloys prepared in Examples 1 to 3 and Comparative Example 1 were confirmed using a scanning electron microscope (SEM), and the results are shown in FIG. 2 . Specifically, Figure 2 (a) is a photograph taken of the alloy prepared in Example 1, Figure 2 (b) is a photograph taken of the alloy prepared in Example 2, Figure 2 (c) is the implementation It is a photograph taken of the alloy prepared in Example 3.

As shown in (a) to (c) of Figure 2, the alloy prepared in Examples 1 to 3 has a wide width in the longitudinal direction, it was confirmed that the ribbon shape having a thin thickness.

2) XRD analysis:

As a result of analyzing the alloys prepared in Examples 1 to 3 using X-ray diffraction analysis (XRD, X-ray diffraction), as shown in FIG. 3 , a typical amorphous halo pattern was found in all alloys. As shown, it was confirmed that all alloys prepared in Examples 1 to 3 were Ni-based amorphous alloys for corrosion-resistant coating of thermal power plants.

3) DTA analysis:

Differential thermal analysis (DTA, difNirential thermal analysis) was performed on the alloys prepared in Examples 1 to 3, and the results are shown in FIG. 4 .

Referring to FIG. 4 , it can be confirmed that all alloys prepared in Examples 1 to 3 have amorphous properties. For example, the alloy prepared in Example 1 had a crystallization initiation temperature (Tx) of 670.63°C and a glass transition temperature (Tg) of 630.96°C, which was confirmed to have an amorphous formation ability (ΔT) of 39.67°C, It can be seen that the alloy prepared in Example 2 has a crystallization initiation temperature (Tx) of 680.16°C, a glass transition temperature (Tg) of 650.79°C, and an amorphous formation ability (ΔT) of 29.37°C. Finally, it can be seen that the alloy prepared in Example 3 has a crystallization initiation temperature (Tx) of 706.98°C, a glass transition temperature (Tg) of 668.86°C, and an amorphous formation ability (ΔT) of 38.12°C.

Through this, the alloys prepared in Examples 1 to 3 can have a homogeneous isotropic property without anisotropy, grain boundaries, surface defect segregation, etc. It can be confirmed that there is

The glass transition temperature (Tg), crystallization initiation temperature (Tx), amorphous formation ability (ΔT) and crystallization enthalpy (ΔH) of the amorphous alloy prepared in Examples 1 to 3 are summarized in Table 2 below.

Tg(℃) Tx(℃) △T (℃) ΔH (J/g) Example 1 630.96 670.63 39.67 22.22 Example 2 650.79 680.16 29.37 18.65 Example 3 668.86 706.98 38.12 14.91

4) Corrosion resistance evaluation:

In order to evaluate the corrosion resistance of the Ni-based amorphous alloys prepared in Examples 1 to 3 and Comparative Examples 1 to 2, the weight reduction rate over time was measured.

The weight reduction rate measurement was performed by immersing a sample cut into a width of 5 mm and a length of 30 mm of the alloy prepared in Examples 1 to 3 and Comparative Example 1 in 10% by volume hydrochloric acid solution, and at room temperature for 1 day, 4 days, 7 days, After leaving for 10 days, 30 days, and 60 days, each sample was recovered and its weight was measured, and the weight reduction rate was calculated as shown in the following Relational Equation 4.

[Relational Expression 4]

Weight reduction rate (%) = (W ₀ -W ₁ )/W ₀ × 100

(In Relation 4, W ₀ is the weight (g) of the initial sample, and W ₁ is the weight (g) of the sample after a certain time has elapsed.)

The calculated non-based reduction rate is shown in Table 3 and FIG. 5 below.

Weight Reduction Rate (%) 1 day 4 days 7 days 10 days 20 days 30 days 60 days Example 1 0 0 0 0 0 0 -0.8 Example 2 0 0 1.06 1.06 1.06 1.06 3.19 Example 3 0 0 0 -0.75 -0.75 -0.75 -0.75 Comparative Example 1 0 -1.28 -2.47 -3.92 -10.2 -12.31 -13.62 Comparative Example 2 0 0 1.23 2.35 5.38 5.38 5.38

Referring to Tables 3 and 5, it can be seen that the Ni-based amorphous alloy for thermal power plant corrosion resistance coating prepared in Examples 1 to 3 has very excellent corrosion resistance compared to the amorphous alloy prepared in Comparative Examples 1 and 2 can

Specifically, in Examples 1 to 3 in which the contents of tantalum (Ta), niobium (Nb) and molybdenum (Mo) satisfy all of the above Relations 1 to 3, a weight loss of less than 1% occurs even when left for 60 days or (Example 1, Example 32) Alternatively, it can be seen that the weight increased due to corrosion that reacted with oxygen in the air (Example 2), but the increase rate of the weight was up to 4%.

More specifically, when the molybdenum (Mo) corresponding to Example 1 is included in 2.4 to 3.6 atomic %, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + In the range where [Nb])) satisfies 0.06 to 0.1, it can be seen that the non-based reduction rate is between -1 and 0%.

In addition, when the molybdenum (Mo) corresponding to Example 3 is included in 5.6 to 8.4 atomic %, the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb) ]))) satisfies 0.2 to 0.26, it can also be confirmed that the non-based reduction rate is between -1 and 0%.

In other words, the Ni-based amorphous alloy satisfying the ratio of molybdenum to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) of 0.06 to 0.1 or 0.2 to 0.26 is non-based It can be seen that the reduction rate satisfies the following Relational Expression 5.

[Relational Expression 5]

-1 ≤ (W ₀ -W _t )/W ₀ × 100 ≤ 1

(In Relational Expression 5, W ₀ is the initial weight (g) of the amorphous alloy, and W _t is the weight (g) of the amorphous alloy measured after being supported in a hydrochloric acid solution of 5 to 20% by volume for 60 days.)

These results were obtained because, as described above, the ratio of molybdenum (Mo) to tantalum (Ta) and niobium (Nb) ([Mo] / ([Ta] + [Nb])) was optimized in the Ni alloy. It is interpreted that the corrosion resistance is significantly improved.

On the other hand, in the amorphous alloy prepared in Comparative Example 1, after 60 days, the reduction rate of the system free of -13.62%. This means that corrosion in the oxidized form occurred and the weight increased by 13.62%. In addition, the amorphous alloy prepared in Comparative Example 2 lost 5.38% of the weight due to corrosion. It can be seen that the Ni-based amorphous alloy prepared in Comparative Examples 1 to 2 exhibited more active corrosion than the alloy prepared in Examples 1 to 3. As a result, it can be proved that the Ni-based amorphous alloy prepared in Examples 1 to 3 has excellent corrosion resistance compared to the Ni-based amorphous alloy prepared in Comparative Example 1.

Although the present invention has been described through specific matters and limited examples as described above, these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and the present invention pertains to Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims described below, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (7)

In atomic%, 7 to 18% of tantalum (Ta), 14 to 33% of niobium (Nb), 2 to 8% of molybdenum (Mo), and the remaining Ni and inevitable impurities,
Ni-based amorphous alloy for thermal power plant corrosion-resistant coating, characterized in that it satisfies the following Relations 1 to 3.
[Relational Expression 1]
32 ≤ [Ta] + [Nb] ≤ 38
[Relational Expression 2]
35 ≤ [Ta] + [Nb] + [Mo] ≤ 44
[Relational Expression 3]
0.06 ≤ [Mo] / ([Ta] + [Nb]) ≤ 0.26
(In Relations 1 to 3, [Ta] is atomic % of Ta, [Nb] is atomic % of Nb, and [Mo] is atomic % of Mo.) delete The method of claim 1,
The molybdenum (Mo) is a Ni-based amorphous alloy for thermal power plant corrosion-resistant coating, characterized in that 2.4 to 3.6 atomic%. The method of claim 1,
The molybdenum (Mo) is characterized in that 5.6 to 8.4 atomic %, Ni-based amorphous alloy for corrosion-resistant coating of thermal power plants. 5. The method according to claim 3 or 4,
The amorphous alloy is a Ni-based amorphous alloy for thermal power plant corrosion-resistant coating, characterized in that it satisfies the system-free change rate of the following relation 5.
[Relational Expression 5]
-1 ≤ (W ₀ -W _t )/W ₀ × 100 ≤ 1
(In Relation 5, W ₀ is the initial weight (g) of the amorphous alloy, and W _t is the weight (g) of the amorphous alloy measured after being supported in a hydrochloric acid solution of 5 to 20% by volume for 60 days.) a) In atomic%, 7 to 18% of tantalum (Ta), 14 to 33% of niobium (Nb), 2 to 8% of molybdenum (Mo), and the remaining Ni and unavoidable impurities, satisfy the following relations 1 to 3 preparing the material;
b) preparing a master alloy molten metal by dissolving the material; and
c) solidifying the molten mother alloy to prepare a Ni-based amorphous alloy for corrosion-resistant coating in a thermal power plant;
[Relational Expression 1]
32 ≤ [Ta] + [Nb] ≤ 38
[Relational Expression 2]
35 ≤ [Ta] + [Nb] + [Mo] ≤ 44
[Relational Expression 3]
0.06 ≤ [Mo] / ([Ta] + [Nb]) ≤ 0.26
(In Relations 1 to 3, [Ta] is atomic % of Ta, [Nb] is atomic % of Nb, and [Mo] is atomic % of Mo.) 7. The method of claim 6,
d) Heat-treating the Ni-based amorphous alloy for corrosion-resistant coating of thermal power plant in a temperature range of 730 to 800K, characterized in that it further comprises the step of, a method of manufacturing a Ni-based amorphous alloy for corrosion-resistant coating of thermal power plant.

Images