Method for processing surface of corrosion resistant nickel group alloy, and structure thereof

Abstract

To provide a method for processing the surface of nickel group alloy, capable of stably forming a homogeneous dulling layer on the surface of the nickel group alloy and saving energy to hold alloy peculiar performance.SOLUTION: A method for processing the surface of nickel group alloy having corrosion resistance comprises steps of: immersing the nickel group alloy in a first neutral or alkaline solution to remove the contaminant of the surface; immersing the cleaned nickel group alloy in a second neutral or alkaline solution to form a functional group on the surface of nickel group alloy; and processing the nickel group alloy in a low-temperature heating process to form a dulling layer on at least one surface of the nickel group alloy. The low-temperature heating process is performed in environment including oxygen and protective gas, and the dulling layer has a surface roughness of 0.04 μm or less and a thickness of 5 nm or more and 200 nm or less.

Description

[Technical field]

[0001] The present invention relates to a method for surface treatment of a corrosion-resistant alloy and the corrosion-resistant alloy, and more particularly to a method for surface treatment of a corrosion-resistant nickel-based alloy and the corrosion-resistant nickel-based alloy. [Background technology]

[0002] Nickel-based alloys are widely used in many industrial sectors due to their excellent mechanical performance and high corrosion resistance. These alloys are particularly suited to harsh environments with high temperatures, pressures and corrosive materials, such as chemical processing, aerospace and energy. Although nickel-based alloys have some corrosion resistance, they can be vulnerable to certain types of corrosion, especially under extreme conditions or over long periods of use.

[0003] One of the major challenges in using nickel-base alloys is the formation of a stable, protective dulling layer on the alloy surface. This layer is typically composed of metal oxides and acts as a barrier to prevent further corrosion of the base metal. However, forming a uniform, dense, stable dulling layer on nickel-base alloys can be challenging. Conventional methods typically involve high-temperature heat treatment processes, which are energy intensive and can cause adverse changes to the alloy's microstructure and mechanical properties. Furthermore, the presence of surface contaminants (e.g., organic residues) hinders the formation of an effective dulling layer. These contaminants cause inhomogeneities within the layer, increasing localized corrosion susceptibility. Therefore, a method is needed to effectively remove these contaminants prior to the formation of the dulling layer. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above problems, there is a great need to improve the processing method of nickel-based alloys and improve their corrosion resistance. Specifically, a method is needed to effectively form a stable and uniform blunt layer on the alloy surface, while simultaneously saving energy and preserving the inherent performance of the alloy. How to solve these problems is an important issue that should be considered by those with general knowledge in this field. [Means for solving the problem]

[0005] In order to solve the above problems, an object of the present invention is to provide a surface treatment method for a corrosion-resistant nickel-based alloy and a corrosion-resistant nickel-based alloy.

[0006] In accordance with the above and other objects, the present invention provides a method for surface treatment of a corrosion-resistant nickel-base alloy and the resulting alloy, the method comprising the steps of: first, immersing the nickel-base alloy in a first neutral or alkaline solution to remove surface contaminants, the pH value of which is between 7 and 12; then immersing the cleaned nickel-base alloy in a second neutral or alkaline solution to form functional groups on the alloy surface, the pH value of which is also between 7 and 12; and then subjecting the nickel-base alloy to a low-temperature heat treatment process to form a dulling layer on at least one surface of the alloy, the low-temperature heat treatment process being carried out in an environment containing oxygen and a protective gas, wherein the dulling layer has a surface roughness of 0.04 μm or less and a thickness of 5 nm or more and 200 nm or less.

[0007] In one embodiment, the functional groups formed on the nickel-based alloy surface are selected from the group consisting of hydroxyl groups, carbonyl groups, and carboxyl groups. Furthermore, the first neutral or alkaline solution and the second neutral or alkaline solution can be selected from various compounds such as sodium hydroxide, acetic acid, potassium hydroxide, sodium chloride, etc.

[0008] In another embodiment, the nickel-base alloy can be immersed in the first solution for a period of 1 to 3 hours at a temperature of 25° C. to 50° C. Ultrasonic vibration treatment can be performed during the immersion period. The alloy can be immersed in the second neutral or alkaline solution for a period of 1 to 12 hours at a temperature of 25° C. to 60° C.

[0009] In another embodiment, the temperature of the low temperature heat treatment process is 250° C. to 600° C., the gas flow rate is 5 sccm to 200 sccm, and the treatment time is 1 hour to 6 hours. The protective gas used may be nitrogen or argon.

[0010] The corrosion-resistant nickel-base alloy obtained by the above method includes a substrate made of a nickel-base alloy and a retarding layer disposed on at least one surface of the substrate. The nickel content of the nickel-base alloy is greater than or equal to 50%, and the alloy may also contain chromium (Cr) and manganese (Mn) metals. The retarding layer may be an oxide layer containing nickel, manganese (MnO x ), an oxide layer containing chromium (CrO x ), or a combination thereof. Effect of the Invention

[0011] The present invention provides an efficient surface treatment method for corrosion-resistant nickel-based alloys, which uses a specific neutral or alkaline solution and a low-temperature heat treatment process to form a dulling layer on the surface of the nickel-based alloy to improve its corrosion resistance. In this method, specific functional groups can be formed on the alloy surface to form a dulling layer with specific surface roughness and thickness. This provides the nickel-based alloy with excellent corrosion resistance, which can be applied to various applications requiring this property. The surface treatment method of the present invention provides a corrosion-resistant nickel-based alloy, which has a nickel content of 50% or more and may contain chromium (Cr) and manganese (Mn) metals. That is, the dulling layer is a nickel oxide layer (NiO x ), manganese oxide layer (MnO x ), chromium oxide layer (CrO x) and can be flexibly adapted to the needs of specific applications. [Brief description of the drawings]

[0012] [Figure 1] 1 is a flow chart of a surface treatment method for a corrosion-resistant nickel-based alloy of the present invention. [Figure 2A] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2B] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2C] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2D] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2E] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2F] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. [Figure 2G] 1 is a schematic diagram of steps constituting a surface treatment method for a corrosion-resistant nickel-based alloy according to the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Referring to FIG. 1 and FIG. 2A to FIG. 2G, FIG. 1 shows a flow chart of the method for surface treatment of a corrosion-resistant nickel-based alloy of the present invention, and FIG. 2A to FIG. 2G are conceptual diagrams of each step of the method for surface treatment of a corrosion-resistant nickel-based alloy of the present invention.

[0014] First, in step S110, the required nickel-based alloy is selected. Nickel-based alloys have excellent mechanical performance and high corrosion resistance, making them ideal choices in various industries such as chemical processing, aerospace, and energy fields. In this embodiment, it is recommended that the nickel content of the selected nickel-based alloy is 50% or more, which ensures a certain corrosion resistance of the nickel-based alloy. In the present invention, the nickel-based alloy may also contain other metals such as chromium (Cr) and manganese (Mn). These metals can further enhance the corrosion resistance and mechanical performance of the alloy. The specific components of the nickel-based alloy in the actual application depend on the intended application and the specific performance required. In this embodiment, the selected nickel-based alloy is prepared in the form of a substrate. Furthermore, before proceeding to the next step, the substrate can be cleaned in an initial cleaning operation to remove any surface contaminants, such as organic residues, that may prevent the formation of an effective dulling layer. This initial cleaning is effective in preventing contaminants that cause inhomogeneities in the layer and increase localized corrosion susceptibility.

[0015] In step S110, the cleaning process may include standard techniques commonly used in the industry. For example, ultrasonic cleaning in a suitable solvent, followed by rinsing and drying. Furthermore, it is important to be careful not to introduce new contaminants during the cleaning process. This initial cleaning is the basis for the subsequent steps of the surface treatment method of the present invention. Once the nickel-based alloy has been initially treated, the process proceeds to the next step S120, in which the nickel-based alloy 110 shown in FIG. 2A is immersed in a first neutral or alkaline solution 10. It should be noted that even after the initial treatment, the nickel-based alloy 110 still has surface contaminants 120 that cannot be removed by the initial treatment, and therefore the next step S120 is necessary. Although FIG. 2A shows the surface contaminants on only one surface of the nickel-based alloy 110, one having ordinary skill in the art will understand that the surface contaminants may be present on the entire surface of the nickel-based alloy 110.

[0016] 2B, after the nickel-based alloy 110 has completed the initial treatment, in step S120, the nickel-based alloy 110 is immersed in a first neutral or alkaline solution 10. In this embodiment, the pH value of the first neutral or alkaline solution 10 is 7 or more and 12 or less. This range is suitable for removing the surface contaminants 120 of the nickel-based alloy 110, and is not likely to cause adverse reactions that may damage the surface of the nickel-based alloy 110. Specifically, the neutral to weakly alkaline solution removes and dissolves most surface contaminants, including organic and inorganic residues, while not causing excessive corrosion or dissolution of the nickel-based alloy 110.

[0017] In this embodiment, the specific solution used in the immersion process (i.e., the first neutral or alkaline solution 10) may include sodium hydroxide, acetic acid, potassium hydroxide, sodium chloride, etc., with concentrations ranging from 1 mmol to 1 molar. The choice of which components and concentrations depends on the required functional groups and the requirements of the dulling layer to be formed, and these solutions can effectively clean the metal surface.

[0018] In this embodiment, the specific solution used in the immersion process (i.e., the first neutral or alkaline solution 10) includes sodium hydroxide, acetic acid, potassium hydroxide, sodium chloride, etc., and the concentration may be 1 mmol or more and 1 molar or less. The choice of which components and concentrations depends on the required functional groups and the requirements of the dull layer to be formed. These solutions can effectively clean the metal surface.

[0019] Also, the immersion time and temperature have a certain effect on the cleaning process. Immersing the nickel-based alloy in the solution at 25°C to 50°C for 1 hour to 3 hours can strike a balance between effective removal of contaminants and prevention of unwanted reactions and excessive metal dissolution. In addition, ultrasonic vibration is performed during immersion. The use of ultrasonic energy enhances the cleaning process by causing implosion of microscopic bubbles on the surface of the nickel-based alloy 110, a process called airing. This operation is effective in removing contaminants on the surface of the nickel-based alloy 110 and achieving a more thorough cleaning process. After the step S120 is completed, the nickel-based alloy 110 is more thoroughly cleaned, the surface contaminants of the nickel-based alloy 110 are significantly reduced (see FIG. 2C), and it is ready for the next step S130.

[0020] Referring to step S130 and FIG. 2D, in step S130, the nickel-based alloy 110 is immersed in a second neutral or alkaline solution 20. The purpose of this step is to form functional group bonds on the surface of the nickel-based alloy 110, which will later act as a catalyst during the formation of the dulling layer and accelerate the formation of the dulling layer. The specific components of the second neutral or alkaline solution 20 are selected from a combination of one or more selected from the group consisting of sodium hydroxide, acetic acid, ammonium hydroxide, potassium hydroxide, hydrogen peroxide, and sodium chloride, and the concentration is 1 mmol or more and 1 mol or less. The selection of which components and concentrations depends on the requirements of the required functional groups and the dulling layer to be formed. The pH range of the second neutral or alkaline solution 20 is 7 to 12, which ensures the formation of the required functional groups while not causing bad surface reaction or dissolution of the nickel-based alloy 110. In step S130, the functional groups formed may include one or more selected from the group consisting of hydroxyl groups, carbonyl groups, and carboxyl groups. These functional groups are chemically active, and in particular the hydroxyl groups, act as catalysts in the formation of the oxide layer, reducing the temperature required for the formation of the retardation layer.

[0021] In addition, the immersion time and temperature in the second neutral or alkaline solution 20 are also important. For example, an immersion time of 1 hour or more and 12 hours or less ensures sufficient time for the formation of functional groups on the surface of the nickel-based alloy 110. In addition, the selection of a temperature range of 25°C to 60°C is to optimize the formation of functional groups and prevent undesirable side reactions and excessive dissolution of the nickel-based alloy 110. A low temperature may slow down the reaction rate, while a high temperature may cause undesirable side reactions and changes in the microstructure of the nickel-based alloy 110. After the completion of step S130, a functional layer 130 is formed on the surface of the nickel-based alloy 110 (see FIG. 2E), which lays the foundation for the subsequent low-temperature heat treatment process.

[0022] Referring to step S140 and FIG. 2F, after completing step S130, the nickel-based alloy 110 is subjected to a low-temperature heat treatment process. In step S140, the nickel-based alloy 110 undergoes a low-temperature heat treatment process in the internal space of the heat treatment chamber 40. In the low-temperature heat treatment process, the internal conditions of the heat treatment chamber 40 play an important role in forming a dulled layer 140 on the nickel-based alloy 110. By carefully controlling the temperature, air flow, pressure and treatment time in the heat treatment chamber 40, a dense, uniform and stable dulled layer 140 can be formed, and the corrosion resistance of the nickel-based alloy 110 can be significantly improved. Due to the catalytic action of the functional groups on the surface of the nickel-based alloy, the dulled layer can be formed when the temperature in the heat treatment chamber 40 is between 250°C and 600°C. This temperature range is much lower than the temperature used in the traditional dulled layer formation method, and the traditional method usually performs high-temperature heat treatment, but by performing such a low-temperature heat treatment, energy consumption can be reduced and the dulled layer can be made denser.

[0023] Furthermore, the heat treatment chamber 40 has an inlet 41 and an outlet 42 for air flow. Oxygen and protective gas (e.g., nitrogen or argon) are introduced into the inner space of the heat treatment chamber 40 through the inlet 41, and the outlet 42 removes excess gas and by-products during the heat treatment process. In this embodiment, the gas flow rate is controlled to be between 5 sccm and 200 sccm, and the pressure is between 0.1 atm and 1 atm. The protective gas is nitrogen or argon, and the oxidation process can be controlled to prevent undesired reactions.

[0024] In step S140, the nickel-based alloy 110 is held in the heat treatment chamber 40 for 1 to 6 hours. This heat treatment time allows enough time for the blunted layer 140 to be fully formed while preventing surface roughness and unevenness due to excessive growth of the blunted layer 140. Of course, the specific duration depends on various factors, such as the specific components of the nickel-based alloy 110, the required performance of the blunted layer 140, and the temperature of the heat treatment. In addition, pressure control during the low-temperature heat treatment process is also important. By controlling the pressure and reaction gas concentration in the heat treatment chamber 40, uniform treatment can be ensured and undesirable reactions can be prevented. Furthermore, after the end of the low-temperature heat treatment process, the heat treatment chamber 40 is cooled in a controlled manner to room temperature. The cooling process is usually performed slowly in this embodiment, because rapid cooling can cause thermal stress and damage to the newly formed blunted layer 140.

[0025] After undergoing the low-temperature heat treatment process of step S140, the nickel-based alloy 110 forms a dulling layer 140 on at least one surface, resulting in the corrosion-resistant nickel-based alloy 100 shown in Figure 2G. In this embodiment, the surface roughness of the dulling layer 140 is less than 0.04 μm, and the thickness is 5 nm to 200 nm. Thus, the dulling layer 140 has a smooth surface and a dense and uniform interior, and can effectively protect the nickel-based alloy 110 under the dulling layer 140 from corrosion.

[0026] The corrosion-resistant nickel-based alloy 100 formed after undergoing the surface treatment method shown in FIG. 1 will be described in more detail. The substrate of the corrosion-resistant nickel-based alloy 100 is composed of a nickel-based alloy 110. The selection of the nickel-based alloy 110 is based on its inherent mechanical strength and corrosion resistance. In this embodiment, the nickel content of the nickel-based alloy 110 is 50% or more, which ensures a certain corrosion resistance performance of the nickel-based alloy 110. This high nickel content allows the nickel-based alloy 110 to maintain its strength and corrosion resistance even under harsh conditions such as high temperature and corrosive environment. Besides nickel, the nickel-based alloy 110 may contain other metals such as chromium (Cr) and manganese (Mn), and the presence of these additional metals can further enhance the corrosion resistance and other performance of the alloy.

[0027] Furthermore, the dulling layer 140 is a protective layer formed on at least one surface of the nickel-based alloy 110, which effectively protects the underlying nickel-based alloy 110 from environmental attack and significantly improves its corrosion resistance. The dulling layer 140 is a metal oxide layer formed by the low temperature heat treatment process described in step S140 of FIG.

[0028] In one embodiment, the nickel-based alloy 110 may contain additional metals, such as chromium (Cr) and manganese (Mn), such that the dulling layer 140 may be composed of a mixture of different metal oxides. These mixtures include nickel oxide, chromium oxide (CrO x ), manganese oxide (MnO x ), and these oxide layers can improve the corrosion resistance of the alloy.

[0029] In addition, the dulling layer 140 has a surface roughness of 0.04 μm or less and a thickness of 5 nm to 200 nm or less. These characteristics result in a dense and uniform dulling layer 140 that can effectively protect the underlying nickel-based alloy 110. The appropriate thickness of the dulling layer 140 maintains the corrosion resistance of the alloy, and the low surface roughness prevents the accumulation of contaminants and reduces the risk of localized corrosion.

[0030] The above examples show the surface treatment method of the corrosion-resistant nickel-base alloy of the present invention and the resulting corrosion-resistant nickel-base alloy. The method includes immersing the nickel-base alloy in a neutral or alkaline solution, followed by a low-temperature heat treatment process to form a stable and uniform blunting layer on the nickel-base alloy. The formation of this blunting layer significantly improves the corrosion resistance of the nickel-base alloy, allowing it to be applied to harsh environmental conditions with high temperature, high pressure, and corrosive properties. In addition, the blunting layer has a controlled surface roughness and thickness, and acts as a robust anti-corrosion barrier to effectively protect the underlying nickel-base alloy. The blunting layer can form various metal oxides based on the components of the nickel-base alloy, and each metal oxide contributes to the corrosion resistance.

[0031] The surface treatment method for corrosion-resistant nickel-base alloys of the present invention improves upon conventional methods in terms of efficiency and energy consumption, while preserving the original performance of nickel-base alloys, making it an ideal solution for areas where the life and reliability of nickel-base alloys are crucial. [Explanation of symbols]

[0032] 10 First neutral or alkaline solution 20 Second neutral or alkaline solution 40 Heat Treatment Room 41 Entrance 42 Exit 100 Corrosion-resistant nickel-based alloy 110 Nickel-based alloy 120 Surface Contaminants 130 Functional base layer 140 Slowing Layer S110~S140 Flowchart symbols

Claims

1. A method for surface treatment of a nickel-based alloy having corrosion resistance, comprising the steps of: removing surface contaminants by immersing the nickel-base alloy in a first neutral or alkaline solution; forming functional groups on the surface of the nickel-based alloy by immersing the cleaned nickel-based alloy in a second neutral or alkaline solution; forming a blunting layer on at least one surface of the nickel-base alloy by treating the nickel-base alloy with a low temperature heat treatment process; The pH value of the first neutral or alkaline solution is 7 or more and 12 or less; The pH value of the second neutral or alkaline solution is 7 or more and 12 or less; The low-temperature heat treatment process is carried out in an environment containing oxygen and a protective gas; The surface roughness of the blunted layer is 0.04 μm or less, and the thickness is 5 nm to 200 nm.

2. 2. The method for surface treatment of a corrosion-resistant nickel-based alloy according to claim 1, wherein the functional group is at least one selected from the group consisting of a hydroxyl group, a carbonyl group, and a carboxyl group.

3. 2. The method of claim 1, wherein the first neutral or alkaline solution comprises one or more selected from the group consisting of sodium hydroxide, acetic acid, potassium hydroxide, and sodium chloride.

4. 2. The method of claim 1, wherein the second neutral or alkaline solution comprises one or more selected from the group consisting of sodium hydroxide, acetic acid, ammonium hydroxide, potassium hydroxide, hydrogen peroxide, and sodium chloride.

5. 2. The method for surface treatment of corrosion-resistant nickel-based alloy according to claim 1, characterized in that the nickel-based alloy is immersed in the first neutral or alkaline solution for 1 hour to 3 hours, and the temperature is 25° C. to 50° C.

6. The method for surface treatment of a corrosion-resistant nickel-based alloy according to claim 1, characterized in that an ultrasonic vibration treatment is performed when the nickel-based alloy is immersed in the first neutral or alkaline solution.

7. 2. The method for surface treatment of corrosion-resistant nickel-based alloy according to claim 1, characterized in that the nickel-based alloy is immersed in the second neutral or alkaline solution for 1 hour to 12 hours, and the temperature is 25°C to 60°C.

8. 2. The method for surface treatment of anti-corrosive nickel-based alloy according to claim 1, characterized in that the temperature of the low temperature heat treatment process is 250°C to 600°C, the gas flow rate is 5 sccm to 200 sccm, the pressure is 0.1 atm to 1 atm, and the dross treatment time is 1 hour to 6 hours.

9. 2. The method for surface treatment of corrosion-resistant nickel-based alloys according to claim 1, characterized in that the protective gas comprises nitrogen or argon.

10. A nickel-based alloy having corrosion resistance, A substrate made of a nickel-based alloy; a damping layer disposed on at least one surface of the substrate; The surface roughness of the dull layer is 0.04 μm or less, and the thickness is 5 nm to 200 nm.

11. 11. The corrosion resistant nickel-base alloy of claim 10, wherein the nickel content of the nickel-base alloy is greater than or equal to 50%.

12. 12. The corrosion resistant nickel-base alloy of claim 11, wherein the nickel-base alloy includes chromium (Cr) and manganese (Mn) metals.

13. The slow-tempering layer may be an oxide layer containing nickel, manganese (MnO x ) and an oxide layer containing chromium (CrO x 11. The corrosion resistant nickel-base alloy of claim 10, further comprising at least one oxide layer selected from the group consisting of:

14. The blunting layer is made of nickel (NiO x 12. The corrosion resistant nickel-base alloy of claim 11, wherein the oxide layer comprises

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