Method for simulating anodic polarization curve

Abstract

The invention discloses a method for simulating an anodic polarization curve. The method comprises a preparation step, a first calculation step, a corrosion voltage simulation step, a second calculation step, a corrosion current simulation step and a coupling step. The method comprises the following steps: a first calculation step: substituting crystal face arrangement and a plurality of background charges into a density functional theory for calculation; the method comprises a first calculation step of obtaining a contact potential difference corresponding to each background charge, a second calculation step of obtaining a simulated corrosion voltage by adding the contact potential difference corresponding to each background charge to a work function corresponding to crystal face arrangement, and a third calculation step of obtaining a surface vacancy energy corresponding to each background charge through a density functional theory. And a corrosion current simulation step: substituting the surface vacancy energy of the plurality of background charges into an Arrhenius formula to calculate a simulation current density so as to simulate an anode polarization curve and reduce the time of a complex experiment.

Description

Technical Field

[0001] The present invention relates to a simulation method, and more particularly to a simulation method for anodic polarization curves. Background Art

[0002] Existing metal polarization curves represent the relationship curves between electrode potential and polarization current or polarization current density. For example, when the electrodes are the anode or the cathode respectively, the obtained curves are called anodic polarization curve and cathodic polarization curve respectively. Existing polarization curves can be measured by experimental methods. Analyzing and studying polarization curves is one of the basic methods to explain the basic laws of metal corrosion, reveal the mechanism of metal corrosion, and explore the ways to control corrosion.

[0003] However, the existing method for fabricating metal anodic polarization curves is generally obtained directly through experiments. The experimental steps for obtaining metal anodic polarization curves through experiments are complex and time-consuming, and it is quite cost-ineffective.

[0004] Therefore, the inventor believes that the above defects can be improved. After painstaking research and in combination with the application of scientific principles, the inventor finally proposed the present invention with a reasonable design and effective improvement of the above defects. Summary of the Invention

[0005] An embodiment of the present invention provides a simulation method for anodic polarization curves, which can effectively improve the defects that may occur in the existing method for fabricating anodic polarization curves.

[0006] One embodiment of the present invention discloses a simulation method for anodic polarization curves, and the steps thereof include: a preparation step: obtaining a work function corresponding to at least one crystal plane arrangement according to at least one crystal plane arrangement of a metal object to be simulated; a first calculation step: inputting at least one crystal plane arrangement and a plurality of background charges into a density functional theory for calculation to obtain a contact potential difference corresponding to each background charge for at least one crystal plane arrangement; a simulated corrosion voltage step: adding the contact potential difference corresponding to each background charge for at least one crystal plane arrangement to the work function corresponding to at least one crystal plane arrangement to obtain a simulated corrosion voltage; a second calculation step: calculating through the density functional theory to obtain a surface vacancy energy corresponding to each background charge; a simulated corrosion current step: inputting the surface vacancy energies of a plurality of background charges into an Arrhenius formula for calculation to obtain a simulated current density; and a coupling step: coupling the simulated corrosion voltage and the simulated current density to generate a simulated anodic polarization curve.

[0007] Optionally, the steps of the method for simulating the anodic polarization curve further include: a step of establishing a simulated corrosion voltage curve: establishing a corrosion voltage curve under multiple background charges based on multiple background charges and their corresponding simulated corrosion voltages.

[0008] Optionally, the steps of the method for simulating the anodic polarization curve further include: a step of establishing a simulated corrosion current curve: establishing a corrosion current curve under multiple background charges based on multiple background charges and their corresponding simulated current densities.

[0009] Optionally, the density functional theory includes a surface vacancy energy formula, and the surface vacancy energy formula is:

[0010]

[0011] where n represents the number of vacancies; E (slab+n(vac)) represents a layered model with n vacancies; E (slab) represents a perfect structure model; and E (bulk) represents the bulk phase.

[0012] Optionally, the Arrhenius formula is:

[0013]

[0014] where n represents the amount of charge transfer; F represents the Faraday constant; R represents the gas constant; T represents the temperature; and Io represents 10-10 amperes per square centimeter.

[0015] Optionally, the method for simulating the anodic polarization curve further includes in the first calculation step: calculating through the density functional theory based on at least one crystal plane arrangement, the volume of the metal object to be simulated, and multiple background charges to obtain the contact potential difference corresponding to each background charge for at least one crystal plane arrangement.

[0016] Optionally, the metal object to be simulated is a magnesium metal.

[0017] Optionally, at least one crystal plane arrangement of the magnesium metal includes (0001), (11-20), (1-100) A , and (1-100) B .

[0018] In summary, the method for simulating the anodic polarization curve disclosed in the embodiments of the present invention includes "the first calculation step: substituting the at least one crystal plane arrangement and multiple background charges into a density functional theory for calculation to obtain a contact potential difference corresponding to each background charge for the at least one crystal plane arrangement", "the step of simulating the corrosion voltage: adding the contact potential difference corresponding to each background charge for the at least one crystal plane arrangement to the work function corresponding to the at least one crystal plane arrangement to obtain a simulated corrosion voltage", "the second calculation step: calculating through the density functional theory to obtain a surface vacancy energy corresponding to each background charge", and "the step of simulating the corrosion current: substituting the surface vacancy energies of the multiple background charges into an Arrhenius formula for calculation to obtain a simulated current density", so as to simulate the anodic polarization curve and reduce the time of complex experiments.

[0019] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, these descriptions and drawings are only used to illustrate the present invention and do not impose any limitation on the protection scope of the present invention. Description of the Drawings

[0020] Figure 1 It is a flowchart of the method for simulating the anodic polarization curve in Embodiment 1 of the present invention.

[0021] Figure 2 It is Figure 1 an anodic polarization curve graph showing the relationship between the simulated corrosion voltage and the simulated current density.

[0022] Figure 3 It is a flowchart of the method for simulating the anodic polarization curve in Embodiment 2 of the present invention.

[0023] Figure 4 It is Figure 3 a corrosion voltage curve graph under multiple background charges of

[0024] Figure 5 It is a flowchart of the method for simulating the anodic polarization curve in Embodiment 3 of the present invention.

[0025] Figure 6 It is Figure 5 a corrosion current curve graph under multiple background charges of Detailed Embodiments

[0026] The following is an illustration of the implementation manner of the "simulation method of anodic polarization curve" disclosed in the present invention through specific specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Additionally, the drawings of the present invention are only for simple schematic illustration and are not drawn according to actual dimensions, hereby stating in advance. The following implementation manners will further detail the related technical content of the present invention, but the disclosed content is not intended to limit the protection scope of the present invention.

[0027] It should be understood that although terms such as "first", "second", "third", etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another, or one signal from another. Additionally, the term "or" used herein should, depending on the actual situation, possibly include any one or a combination of more of the associated listed items.

[0028] [Embodiment 1]

[0029] Please refer to Figures 1 to 2 as shown, which is Embodiment 1 of the present invention. The embodiment of the present invention provides a simulation method S100 of an anodic polarization curve, which calculates a simulated corrosion voltage and a simulated current density through a density functional theory (DFT) and an Arrhenius equation to respectively simulate a corrosion voltage and a corrosion current, and then establish a simulated anodic polarization curve. In this way, the simulation method S100 of the anodic polarization curve in the embodiment of the present invention simulates the anodic polarization curve to reduce the time of complex experiments.

[0030] As Figure 1 shown, the simulation method S100 of the anodic polarization curve in this embodiment includes (or is implemented in sequence) a preparation step S101, a first calculation step S103, a simulated corrosion voltage step S105, a second calculation step S107, a simulated corrosion current step S109, and a coupling step S111.

[0031] For the convenience of understanding this embodiment, the respective contents of the preparation step S101, the first calculation step S103, the simulated corrosion voltage step S105, the second calculation step S107, the simulated corrosion current step S109, and the coupling step S111 will be described separately below, but the present invention is not limited thereto. For example, in other embodiments not shown in the present invention, any step included in the simulation method S100 of the anodic polarization curve can be adjusted, changed, or omitted according to design requirements.

[0032] The preparation step S101: According to the arrangement of at least one crystal plane of a metal object to be simulated, obtain a work function corresponding to the at least one crystal plane arrangement. In this embodiment, the metal object to be simulated is a magnesium metal, but the present invention is not limited thereto. For example, the metal object to be simulated can also be a lithium metal.

[0033] It should be noted that each metal has multiple crystal plane arrangements, and each crystal plane arrangement has a corresponding work function. Furthermore, in order to accurately analyze the anodic polarization curve, generally, several crystal plane arrangements among the multiple crystal plane arrangements are simulated. For example, as shown in Table 1 below, taking the multiple crystal plane arrangements of the magnesium metal as the (0001) crystal plane arrangement, the (11-20) crystal plane arrangement, the (1-100)A crystal plane arrangement, and the (1-100)B crystal plane arrangement as examples, and the work functions corresponding to the (0001) crystal plane arrangement, the (11-20) crystal plane arrangement, the (1-100)A crystal plane arrangement, and the (1-100)B crystal plane arrangement are 3.66, 3.47, 3.66, and 3.67 respectively.

[0034] The first calculation step S103: Substitute the at least one crystal plane arrangement and multiple background charges into the density functional theory for calculation to obtain a contact potential difference corresponding to each of the at least one crystal plane arrangement under each of the background charges. In this embodiment, select a crystal plane arrangement of the magnesium metal (for example: 0001), and introduce multiple background charges to simulate the anodic polarization process, determine the electrode potential and electrolyte potential under different background charges, and calculate the contact potential difference according to formula (1):

[0035] -------(1)

[0036] Where, ∆U is the contact potential difference; U M is the electrode potential; U S is the electrolyte potential.

[0037] It should be noted that by analyzing the electric potential at the interface between water and the magnesium metal, according to the definition of corrosion, the electrode potential can be expressed as: Charge passes from the surface at infinity through the surface charge layer into the metal interior. Therefore, the equilibrium potential can be the magnesium metal plane (i.e., expressed as UM ), and the electrolyte potential (denoted as U S ). The total potential difference between them (i.e., the contact potential difference ∆U). This contact potential difference ∆U represents the potential that electrons need to overcome to escape from the metal layer into the solution. A high contact potential difference ∆U indicates that it is difficult for electrons to escape from the metal layer.

[0038] Furthermore, the electrode potential and the electrolyte potential are obtained through the calculation of the electrostatic potential (ESP). When the background charge changes, the electrostatic potential changes correspondingly, so that the electrode potential and the electrolyte potential change simultaneously. Thus, under different background charges, the contact potential difference is also different.

[0039] In this embodiment, as shown in Table 1 below, this embodiment calculates the contact potential differences corresponding to the (0001) crystal plane arrangement, (11-20) crystal plane arrangement, (1-100) A crystal plane arrangement, and (1-100) B crystal plane arrangement under different background charges.

[0040] Table 1:

[0041]

[0042] The step S105 of simulating the corrosion voltage: adding the contact potential difference corresponding to each background charge of the at least one crystal plane arrangement to the work function corresponding to the at least one crystal plane arrangement to obtain a simulated corrosion voltage.

[0043] It should be noted that when multiple background charges are introduced, since the Fermi energy level and the vacuum energy level change synchronously, the work function will remain unchanged. Different from the stable work function, the contact potential difference changes continuously with the applied background charge, and this change is linear. It is worth noting that after the background charge is introduced, the vacuum energy level shows an inclination. This is because after the background charge is introduced, due to the complete destruction of the symmetry of the system, dipoles cannot be introduced, resulting in the non-convergence of the vacuum energy level. The inclination of the vacuum energy level does not affect the calculation result of the contact potential difference because the calculation of the contact potential difference only needs to determine the potential difference from the water molecule to the metal layer surface.

[0044] The second calculation step S107: obtaining a surface vacancy energy corresponding to each background charge through the density functional theory calculation. In this embodiment, the density functional theory includes a surface vacancy energy formula, and the surface vacancy energy formula is:

[0045] ----------------- (2)

[0046] where n represents the number of vacancies; E (slab+n(vac)) represents a layered model with n vacancies. In other words, E (slab+n(vac)) is the total energy of the surface model containing n vacancies; E (slab) represents a perfect structure model. In other words, E (slab) is the total energy of the complete surface (i.e., without vacancies); and E (bulk) represents the bulk phase. In other words, E(bulk) is the energy of a single atom in the bulk material. It should be noted that when the background charge changes, E (slab+n(vac)) changes correspondingly, so as to obtain the surface vacancy energy E vac .

[0047] As described above, in this embodiment, through the above surface vacancy energy formula, the surface vacancy energy formula of each crystal plane arrangement of the magnesium metal at different background charges is calculated. As shown in Table 2 below, in this embodiment, through the surface vacancy energy formula, the (0001) crystal plane arrangement, (11-20) crystal plane arrangement, (1-100) A crystal plane arrangement, and (1-100) B crystal plane arrangement of the magnesium metal at different background charges are calculated for the surface vacancy energy.

[0048] Table 2:

[0049]

[0050] In the step S109 of simulating the corrosion current: Substitute the surface vacancy energies of multiple background charges into the Arrhenius formula for calculation to obtain a simulated current density as a simulated corrosion current. In this embodiment, the Arrhenius formula is:

[0051] ----------------------(3)

[0052] where n represents the amount of charge transfer; F represents the Faraday constant; R represents the gas constant; T represents the temperature; and Io represents 10-10 amperes per square centimeter.

[0053] It should be noted that since vacancies are necessarily left during the dissolution reaction of the anode during the corrosion process of the magnesium metal, the simulated current density can be deduced from the surface vacancy energy of the anode. The Arrhenius formula can relate the surface vacancy energy and the simulated current density.

[0054] As described above, as shown in Table 3 below, in this embodiment, through the Arrhenius formula, the (0001) crystal plane arrangement, (11-20) crystal plane arrangement, (1-100) A crystal plane arrangement, and (1-100)B The simulated current density with the crystal plane arrangement under different background charges.

[0055] Table III

[0056]

[0057] The coupling step S111: coupling the simulated corrosion voltage and the simulated current density to generate a simulated anodic polarization curve. It should be noted that through the above calculations of the relationships between multiple background charges and the simulated corrosion voltage, and between multiple background charges and the simulated corrosion current, the relationship between the simulated corrosion voltage and the simulated corrosion current (i.e., the simulated current density) is coupled through multiple background charges.

[0058] As shown in Table IV below, in this embodiment, the (0001) crystal plane arrangement, (11-20) crystal plane arrangement, (1-100) A crystal plane arrangement, and (1-100) B The relationship between the simulated corrosion voltage and the simulated corrosion current of the crystal plane arrangement under different background charges, and through the relationship between the simulated corrosion voltage and the simulated corrosion current of different background charges, the simulated anodic polarization curve is coupled (as Figure 2 shown).

[0059] Table IV

[0060]

[0061] [Embodiment 2]

[0062] As Figure 3 and Figure 4 shown, it is Embodiment 2 of the present invention. Since this embodiment is similar to the above Embodiment 1, the same parts of the two embodiments will not be elaborated again, and the differences between this embodiment and the above Embodiment 1 are generally described as follows:

[0063] In this embodiment, the steps of the simulation method S100 of the anodic polarization curve further include: a step S106 of establishing a simulated corrosion voltage curve: establishing corrosion voltage curves under multiple background charges according to multiple background charges and their corresponding simulated corrosion voltages (as Figure 4 shown). This embodiment can judge the degree of corrosion of different materials in cooperation with the corrosion voltage curve. When the corrosion voltage is higher, it is not easy to corrode.

[0064] [Embodiment 3]

[0065] Figure 5 and Figure 6As shown, this is the third embodiment of the present invention. Since this embodiment is similar to the above-mentioned Embodiment 1, the same parts of the two embodiments will not be elaborated, and the differences between this embodiment and the above-mentioned Embodiment 1 are roughly described as follows:

[0066] In this embodiment, the steps of the simulation method S100 of the anodic polarization curve further include: a step S110 of establishing a simulated corrosion current curve: establishing a corrosion current curve under multiple background charges according to the multiple background charges and their corresponding simulated current densities (as Figure 6 shown). This embodiment can judge the degree of corrosion occurring in combination with different materials through this corrosion current curve.

[0067] [Technical effects of the embodiments of the present invention]

[0068] In summary, the simulation method of the anodic polarization curve disclosed in the embodiments of the present invention obtains, through "the first calculation step: calculating according to the at least one crystal plane arrangement and multiple background charges through a density functional theory to obtain a contact potential difference corresponding to each background charge of the at least one crystal plane arrangement", "the step of simulating the corrosion voltage: adding the work function corresponding to the at least one crystal plane arrangement to the contact potential difference corresponding to each background charge of the at least one crystal plane arrangement to obtain a simulated corrosion voltage", "the second calculation step: calculating through the density functional theory to obtain a surface vacancy energy corresponding to each background charge" and "the step of simulating the corrosion current: calculating a simulated current density according to the surface vacancy energies of the multiple background charges through an Arrhenius formula", to simulate the anodic polarization curve and reduce the time of complex experiments.

[0069] The content disclosed above is only the preferred feasible embodiments of the present invention, and does not limit the patent scope of the present invention. Therefore, all equivalent technical changes made by using the content of the specification and drawings of the present invention are included in the patent scope of the present invention.

Claims

1. A method for simulating an anodic polarization curve, characterized in that, The simulation method steps of the anodic polarization curve include: A preparation step: Obtain a work function corresponding to at least one crystal plane arrangement according to the at least one crystal plane arrangement of a metal object to be simulated. A first calculation step: Substitute the at least one crystal plane arrangement and a plurality of background charges into a density functional theory for calculation to obtain a contact potential difference corresponding to the at least one crystal plane arrangement for each of the background charges. A simulated corrosion voltage step: Add the contact potential difference corresponding to the at least one crystal plane arrangement for each of the background charges to the work function corresponding to the at least one crystal plane arrangement to obtain a simulated corrosion voltage. A second calculation step: Calculate through the density functional theory to obtain a surface vacancy energy corresponding to each of the background charges. A simulated corrosion current step: Substitute the surface vacancy energies of the plurality of background charges into an Arrhenius formula for calculation to obtain a simulated current density; and A coupling step: Couple the simulated corrosion voltage and the simulated current density to generate a simulated anodic polarization curve.

2. The simulation method of the anodic polarization curve according to claim 1, wherein The steps of the simulation method of the anodic polarization curve further include: A step of establishing a simulated corrosion voltage curve: Establish a corrosion voltage curve under a plurality of background charges according to the plurality of background charges and the simulated corrosion voltages corresponding to the plurality of background charges.

3. The simulation method of the anodic polarization curve according to claim 1, characterized in that The steps of the simulation method of the anodic polarization curve further include: A step of establishing a simulated corrosion current curve: Establish a corrosion current curve under a plurality of background charges according to the plurality of background charges and the simulated current densities corresponding to the plurality of background charges.

4. The simulation method of the anodic polarization curve according to claim 1, wherein The density functional theory includes a surface vacancy energy formula, and the surface vacancy energy formula is: where n represents the number of vacancies; E (slab+n(vac)) represents a layered model with n vacancies; E (slab) represents a perfect structure model; and E (bulk) represents the bulk phase.

5. The simulation method of the anodic polarization curve according to claim 1, characterized in that, The Arrhenius formula is: Wherein, n represents the amount of charge transfer; F represents the Faraday constant; R represents the gas constant; T represents the temperature; and I o represents 10 -10 amperes per square centimeter.

6. The simulation method of the anodic polarization curve according to claim 1, characterized in that In the first calculation step of the simulation method of the anodic polarization curve, it further includes: Calculate through the density functional theory according to the at least one crystal plane arrangement, the volume of the metal object to be simulated, and a plurality of background charges to obtain the contact potential difference corresponding to the at least one crystal plane arrangement for each of the background charges.

7. The simulation method of the anodic polarization curve according to claim 1, wherein The metal object to be simulated is a magnesium metal.

8. The simulation method of the anodic polarization curve according to claim 7, characterized in that The at least one crystal plane arrangement of the magnesium metal includes (0001), (11-20), (1-100) A , and (1-100) B .

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