Corrosion-resistant nickel-based alloy

Abstract

The utility model discloses a corrosion-resistant nickel-based alloy. The alloy comprises: a substrate made of a nickel-based alloy; and a passivation layer on at least one surface of the substrate. The passivation layer has a surface roughness of less than 0.04 [mu] m and a thickness of between 5 and 200 nm. The corrosion-resistant nickel-based alloy structure provides a passivation layer with extremely low surface roughness, so that the corrosion resistance of the substrate can be effectively enhanced, and the service life of the alloy is further prolonged.

Description

Technical Field

[0001] The utility model relates to a corrosion-resistant alloy, in particular to a corrosion-resistant nickel-based alloy. Background Art

[0002] Nickel-based alloys are widely used in various industries due to their excellent mechanical properties and high corrosion resistance. These alloys are particularly suitable for harsh environments where high temperatures, high pressures and corrosive materials are present, such as in chemical processing, aerospace and energy. Although nickel-based alloys have some corrosion resistance, they are still susceptible to certain types of corrosion, especially under extreme conditions or when used for a long time.

[0003] One of the main challenges of using nickel-based alloys is the formation of a stable, protective passivation layer on the alloy surface. This layer, which is usually composed of metal oxides, acts as a barrier to prevent further corrosion of the underlying metal. However, it can be challenging to form a uniform, dense and stable passivation layer on nickel-based alloys. Conventional methods often involve high-temperature heat treatment procedures, which can be energy intensive and can cause undesirable changes in the microstructure and mechanical properties of the alloy. In addition, the presence of surface contaminants (such as organic residues) can hinder the formation of an effective passivation layer. These contaminants can create inhomogeneities in the layer, leading to increased corrosion susceptibility in localized areas. Therefore, there is a need for an effective method to remove these contaminants before the formation of the passivation layer.

[0004] In view of the above challenges, there is a great need for improved methods of treating nickel-based alloys to enhance their corrosion resistance. Specifically, there is a great need for methods that can effectively form a stable and uniform passivation layer on the alloy surface while saving energy and retaining the inherent properties of the alloy. How to solve the above problems is something that people with ordinary knowledge in the field should consider. Utility Model Content

[0005] In order to solve the above problems, the purpose of the utility model is to provide a surface treatment method of a corrosion-resistant nickel-based alloy and a corrosion-resistant nickel-based alloy.

[0006] Based on the above and other purposes, the utility model provides a surface treatment method for corrosion-resistant nickel-based alloys and the resulting alloys. The method comprises the following steps. First, the nickel-based alloy is immersed in a first neutral or alkaline solution to remove surface contaminants. The pH value of the solution is between 7 and 12. Next, the cleaned nickel-based alloy is immersed in a second neutral or alkaline solution to form functional groups on the surface of the alloy. The pH value of the second neutral or alkaline solution is also between 7 and 12. Afterwards, the nickel-based alloy is subjected to a low-temperature heat treatment procedure to form a passivation layer on at least one surface of the alloy, and the low-temperature heat treatment procedure is carried out in an environment containing oxygen and a protective gas. The surface roughness of the passivation layer is less than 0.04 microns and the thickness is between 5 and 200 nanometers.

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

[0008] In one embodiment, the nickel-based alloy can be immersed in the first solution at a temperature between 25 and 50 degrees Celsius for a time between 1 and 3 hours. During the immersion, ultrasonic vibration can be performed. The alloy can be immersed in the second neutral or alkaline solution at a temperature between 25 and 60 degrees Celsius for a time between 1 and 12 hours.

[0009] In one embodiment, the temperature of the low temperature heat treatment process may be between 250 and 600 degrees Celsius, the gas flow rate may be between 5 and 200 sccm, and the treatment time may be between 1 and 6 hours. The protective gas used may be selected from the group consisting of nitrogen and argon.

[0010] The corrosion-resistant nickel-based alloy obtained by the above method includes a substrate composed of a nickel-based alloy and a passivation layer disposed on at least one surface of the substrate. The nickel content of the nickel-based alloy can be greater than 50%, and the alloy can also contain Cr and Mn metals. The passivation layer can be a nickel-containing oxide layer, a manganese-containing oxide layer (MnOx), and a chromium-containing oxide layer (CrOx) or a combination thereof.

[0011] In summary, the utility model provides an efficient surface treatment method for corrosion-resistant nickel-based alloys. A passivation layer is formed on the surface of the nickel-based alloy using a specific neutral or alkaline solution and a low-temperature heat treatment procedure to enhance its corrosion resistance. The method allows the formation of specific functional groups on the surface of the alloy and forms a passivation layer with a specific surface roughness and thickness. This makes the nickel-based alloy have excellent corrosion resistance and is suitable for various applications requiring such properties. The utility model also provides the resulting corrosion-resistant nickel-based alloy, which has a nickel content greater than 50% and may also contain Cr and Mn metals. That is, the passivation layer can be a nickel oxide layer (NiOx), a manganese oxide layer (MnOx) or a chromium oxide layer (CrOx), providing flexibility according to specific application requirements.

[0012] In order to achieve the above and other purposes, the technical means, components and their effects adopted by the present invention are described as follows with reference to a preferred embodiment with accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The flowchart shown is a surface treatment method of the corrosion-resistant nickel-based alloy of the present invention.

[0014] Figures 2A to 2GShown are schematic diagrams of various steps of the surface treatment method for corrosion-resistant nickel-based alloy of the present invention. DETAILED DESCRIPTION

[0015] Please refer to Figure 1 and Figures 2A to 2G , Figure 1 The figure shows a flow chart of the surface treatment method of the corrosion-resistant nickel-based alloy of the utility model. Figures 2A to 2G Shown are schematic diagrams of various steps of the surface treatment method for corrosion-resistant nickel-based alloy of the present invention.

[0016] First, please refer to step S110 to select the required nickel-based alloy. Nickel-based alloys have excellent mechanical properties and high corrosion resistance, making them ideal for various industries such as chemical processing, aerospace and energy fields. In this embodiment, the nickel content of the selected nickel-based alloy should be greater than 50% to ensure a certain corrosion resistance of the nickel-based alloy. 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 properties of the alloy. In practical applications, the specific composition of the nickel-based alloy depends 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. Moreover, before proceeding to the next step, an initial cleaning of the substrate can remove any surface contaminants, such as organic residues, that may hinder the formation of an effective passivation layer. Initial cleaning can prevent contaminants from causing inhomogeneities in the layer, resulting in increased corrosion sensitivity in local areas.

[0017] In this step S110, the cleaning process may involve standard techniques commonly used in the industry, such as ultrasonic cleaning in an appropriate solvent, followed by rinsing and drying. In addition, care should be taken to avoid introducing new contaminants during the cleaning process. This initial cleaning work lays the foundation for the subsequent steps in the surface treatment method of the utility model. Once the nickel-based alloy has been initially treated, the next step S120 can be carried out to Figure 2A The nickel-based alloy 110 is shown immersed in a first neutral or alkaline solution 10. It should be noted that although the nickel-based alloy 110 has undergone the preliminary treatment, there are still surface contaminants 120 that cannot be removed by the preliminary treatment, so the next step S120 is required. Figure 2A In the figure, the surface contaminants are only shown on one surface of the nickel-based alloy 110 , but a person skilled in the art should understand that the surface contaminants may exist on the entire surface of the nickel-based alloy 110 .

[0018] Please refer to step S120 and Figure 2BAfter the initial treatment of the nickel-based alloy 110 is completed, step S120 is performed to immerse the nickel-based alloy 110 in a first neutral or alkaline solution 10. In the present embodiment, the pH value of the first neutral or alkaline solution 10 ranges from 7 to 12. This range is more suitable for removing surface contaminants 120 of the nickel-based alloy 110, and is less likely to cause adverse reactions that may damage the surface of the nickel-based alloy 110. In detail, neutral to weakly alkaline solutions help remove and dissolve most surface contaminants, including organic and inorganic residues, without causing excessive corrosion or dissolution of the nickel-based alloy 110.

[0019] In this embodiment, the specific solution that can be used for the immersion process (i.e., the first neutral or alkaline solution 10) can include sodium hydroxide, acetic acid, potassium hydroxide and sodium chloride, with a concentration between 1 millimolar and 1 molar, and the specific selection of which components and concentrations depend on the desired functional groups and the need to form a passivation layer. These solutions are effective cleaning agents for metal surfaces.

[0020] In addition, the immersion time and temperature will also have a certain impact on the cleaning process. The nickel-based alloy is immersed in the solution at a temperature of 25 to 50 degrees Celsius for 1 to 3 hours to ensure a balance between effectively removing contaminants and preventing unnecessary reactions or excessive metal dissolution. In addition, ultrasonic oscillation is performed during the immersion process. The use of ultrasonic energy enhances the cleaning process by generating tiny bubbles that implode on the surface of the nickel-based alloy 110, a process called cavitation. This operation helps to remove contaminants from the surface of the nickel-based alloy 110, thereby achieving a more thorough cleaning process. After completing step S120, the nickel-based alloy 110 can be cleaned more thoroughly, so that the surface contaminants of the nickel-based alloy 110 are reduced to extremely low levels (such as cavitation). Figure 2C As shown), and prepare for the next step S130.

[0021] Please refer to step S130 and Figure 2DIn 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 are used to produce catalytic effects when the passivation layer is formed later, accelerating the formation of the passivation layer. The specific components of the second neutral or alkaline solution 20 can be selected from a combination of sodium hydroxide, acetic acid, ammonium hydroxide, potassium hydroxide, hydrogen peroxide and sodium chloride, with a concentration between 1 millimolar and 1 molar. The specific selection of which components and concentrations depends on the required functional groups and the requirements for forming the passivation layer. The pH range of the second neutral or alkaline solution 20 is between 7 and 12. This pH range can ensure the formation of the required functional groups without causing adverse surface reactions of the nickel-based alloy 110 or dissolution of the nickel-based alloy 110. In this step S130, the functional groups formed may include hydroxyl, carbonyl and carboxyl functional groups. These functional groups are chemically active, especially hydroxyl groups, which can act as catalysts in the formation of the metal oxide layer, thereby reducing the temperature required to form the passivation layer.

[0022] In addition, the duration and temperature of the immersion in the second neutral or alkaline solution 20 are also important. For example, a duration between 1 and 12 hours ensures that there is enough time for the functional groups to form on the surface of the nickel-based alloy 110. In addition, the temperature range of 25 to 60 degrees Celsius is selected to optimize the formation of functional groups while preventing undesirable side reactions or excessive dissolution of the nickel-based alloy 110. Lower temperatures may slow down the reaction rate, while higher temperatures may cause undesirable side reactions or changes in the microstructure of the nickel-based alloy 110. When step S130 is completed, the surface of the nickel-based alloy 110 has a functional base layer 130 (such as Figure 2E This lays the foundation for the subsequent low temperature heat treatment procedure.

[0023] Please refer to step S140 and Figure 2F After step S130 is completed, the nickel-based alloy 110 undergoes a low-temperature heat treatment procedure. In step S140, the nickel-based alloy 110 is placed in the inner space of a heat treatment chamber 40 for a low-temperature heat treatment procedure. In the low-temperature heat treatment procedure, the internal conditions of the heat treatment chamber 40 play an important role in the successful formation of the passivation layer 140 on the nickel-based alloy 110. By carefully controlling the temperature, airflow, pressure and treatment time in the heat treatment chamber 40, a dense, uniform and stable passivation layer 140 can be formed, thereby significantly enhancing the corrosion resistance of the nickel-based alloy 110. Under the catalysis of the functional groups on the surface of the nickel-based alloy, the temperature in the heat treatment chamber 40 can form a passivation layer between 250 and 600 degrees Celsius. This temperature range is much lower than the temperature used in the traditional method of forming a passivation layer, which usually involves high-temperature heat treatment. Low-temperature heat treatment can reduce energy consumption and make the passivation layer denser.

[0024] In addition, the heat treatment chamber 40 also has an inlet 41 and an outlet 42 for gas flow. Oxygen and protective gas (such as nitrogen or argon) are introduced into the interior space of the heat treatment chamber 40 through the inlet 41, and the outlet 42 can remove excess gas and any by-products of the heat treatment process. In this embodiment, the gas flow rate is controlled between 5 and 200 sccm, and the pressure is between 0.1 and 1 atmosphere. The protective gas can be nitrogen or argon, which is used to control the oxidation process and prevent unwanted reactions.

[0025] In step S140, the nickel-based alloy 110 is left in the heat treatment chamber 40 for 1 to 6 hours. The heat treatment process lasts for a suitable time to allow the passivation layer 140 to be fully formed while preventing the passivation layer 140 from overgrowing and causing a rough or uneven surface. Of course, the exact duration may depend on various factors, including the specific composition of the nickel-based alloy 110, the desired properties of the passivation layer 140, and the temperature of the heat treatment. In addition, pressure control is also important in the low-temperature heat treatment process. By controlling the pressure and reaction gas concentration inside the heat treatment chamber 40, uniform treatment can be ensured and unnecessary reactions can be prevented. In addition, after the low-temperature heat treatment process is completed, the heat treatment chamber 40 can also be cooled to room temperature in a controlled manner. Since rapid cooling may cause thermal stress and damage the newly formed passivation layer 140, the cooling process is usually carried out slowly in this embodiment.

[0026] After the low temperature heat treatment process of step S140, the nickel-based alloy 110 may form a passivation layer 140 on at least one surface, thereby forming a Figure 2G The corrosion-resistant nickel-based alloy 100 is shown. In this embodiment, the surface roughness of the passivation layer 140 is less than 0.04 microns and the thickness is between 5 and 200 nanometers, which ensures that the passivation layer 140 has a smooth surface and a dense and uniform interior, thereby effectively protecting the nickel-based alloy 110 under the passivation layer 140 from corrosion.

[0027] via Figure 1 After the surface treatment method, a nickel-based alloy 110 protected by a passivation layer 140 is formed. The corrosion-resistant nickel-based alloy 100 will be described in more detail below. The substrate of the corrosion-resistant nickel-based alloy 100 is made of a nickel-based alloy 110. The selection of the nickel-based alloy 110 depends on its inherent mechanical strength and corrosion resistance. In the present embodiment, the nickel content in the nickel-based alloy 110 is greater than 50%, which ensures a certain corrosion resistance of the nickel-based alloy 110. This high nickel content enables the nickel-based alloy 110 to maintain its strength and corrosion resistance even in harsh environments such as high temperatures or corrosive conditions. In addition to nickel, the nickel-based alloy 110 may also 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 properties of the alloy.

[0028] In addition, the passivation layer 140 is a protective barrier formed on at least one surface of the nickel-based alloy 110, which can effectively protect the nickel-based alloy 110 underneath from environmental damage and significantly enhance its corrosion resistance. Figure 1 The metal oxide formed by the low temperature heat treatment process described in step S140

[0029] In one example, the nickel-based alloy 110 contains additional metals, such as chromium (Cr) and manganese (Mn), so that the passivation layer 140 can be composed of a mixture of different metal oxides. These mixtures may include nickel oxide, chromium oxide (CrOx) and manganese oxide (MnOx), and these oxide layers can improve the corrosion resistance of the alloy in different ways.

[0030] In addition, the surface roughness of the passivation layer 140 is less than 0.04 microns, and the thickness is between 5 and 200 nanometers. These characteristics ensure the formation of a smooth, dense and uniform passivation layer 140, which effectively protects the nickel-based alloy 110 underneath. The appropriate thickness of the passivation layer 140 helps maintain the corrosion resistance of the alloy, while the low surface roughness helps prevent the accumulation of contaminants to avoid situations that may cause localized corrosion.

[0031] The above example shows a surface treatment method for a corrosion-resistant nickel-based alloy and the resulting corrosion-resistant nickel-based alloy. The method includes immersing the nickel-based alloy in a neutral or alkaline solution and then performing a low-temperature heat treatment process to form a stable and uniform passivation layer on the nickel-based alloy. The formation of this passivation layer significantly enhances the corrosion resistance of the nickel-based alloy, making it suitable for severe environmental conditions such as high temperature, pressure and corrosion. In addition, the passivation layer has a controlled surface roughness and thickness, which can act as a strong anti-corrosion barrier and effectively protect the nickel-based alloy below. The passivation layer may form various metal oxides depending on the composition of the nickel-based alloy, each of which contributes to the overall corrosion resistance.

[0032] This corrosion-resistant nickel-based alloy surface treatment method not only improves existing methods in terms of efficiency and energy consumption, but also retains the original properties of the nickel-based alloy, making this method an ideal solution for industries where the life and reliability of nickel-based alloys are very important.

[0033] The above is the description of the utility model, but it is not intended to limit the scope of the patent rights claimed by the utility model. Any changes or modifications made by technicians in this field without departing from the spirit or scope of this patent shall be equivalent changes or designs completed under the spirit disclosed by the utility model and shall be included in the claims of the utility model.

Claims

1. A corrosion-resistant nickel-based alloy, characterized in that: include: a substrate composed of a nickel-based alloy; as well as A passivation layer is disposed on at least one surface of the substrate.

2. The corrosion-resistant nickel-based alloy according to claim 1, characterized in that: The surface roughness of the passivation layer is less than 0.04 microns.

3. The corrosion-resistant nickel-based alloy according to claim 1, characterized in that: The thickness of the passivation layer is between 5 and 200 nanometers.

Images