Effectiveness evaluation method for tulip contact surface anti-corrosion treatment and tulip contact surface partition anti-corrosion treatment method

Abstract

The invention belongs to the technical field of metal corrosion resistance, and particularly relates to a tulip contact surface anti-corrosion treatment effectiveness evaluation method and a tulip contact surface partition anti-corrosion treatment method.According to the anti-corrosion treatment method, partition anti-corrosion treatment is implemented on the basis of different performance requirements of a tulip contact for a flow guide contact surface and a non-flow guide contact surface; according to the effectiveness evaluation method, corrosion potentials, corrosion currents and corrosion inhibition rates of different partitions in the three corrosion stages before corrosion, in the corrosion process and after corrosion serve as evaluation parameters of the effectiveness evaluation method, and the evaluation parameters of the different stages are subjected to normalization processing; and setting weight coefficients according to corrosion mechanisms of different stages to construct an evaluation function. Compared with the prior art, the method solves the problem that in the prior art, the corrosion resistance effectiveness of the tulip contact is not evaluated; according to the scheme, a method for carrying out partition anti-corrosion treatment on the tulip contact is provided, a method for evaluating the whole corrosion stage is provided, and effective evaluation on the anti-corrosion effect of the tulip contact is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal anti-corrosion, and particularly relates to a method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact and a method for anti-corrosion treatment of surface zoning of a plum blossom contact. Background Art

[0002] With the rapid development of China's power industry, more and more large-scale distribution networks have emerged, and high-voltage switchgear is one of the important core devices for power transmission in substations. During its operation, it is usually affected by a high-humidity environment and fails, especially the plum blossom contacts located in the circuit breaker room. When the surface of the plum blossom contact is damp for a long time, various types of corrosion will inevitably occur under the influence of a complex electromagnetic environment of high electric field and large current, as well as oxygen and carbon dioxide in the air. After running for a certain period of time, faults such as overheating of the contact will occur, which will seriously affect the normal operation of the power system, greatly reduce the safety and reliability of power supply, and cause economic losses and negative impacts.

[0003] Surface treatment technologies, such as surface metal coating, passivation treatment, and hydrophobic treatment, are one of the commonly used methods in the field of metal surface anti-corrosion. The basic principle of surface metal coating is to deposit a metal coating on the substrate to change the surface properties or dimensions of the substrate and enhance the corrosion resistance of the metal (the coating metal is mostly made of corrosion-resistant metal), increase hardness, prevent wear, improve electrical conductivity, lubricity, heat resistance, and surface aesthetics. Passivation treatment forms a very thin, dense, well-covered, and firmly adsorbed passivation film on the metal surface to completely separate the metal from the corrosive medium, prevent the metal from contacting the corrosive medium, and thus basically stop the metal from dissolving to form a passive state to achieve the anti-corrosion effect. Hydrophobic treatment technology uses hydrophobic coatings to treat the metal surface. By changing the surface energy and nano-scale surface roughness, the contact angle of static water is made greater than 90°C to achieve functions such as waterproofing, antioxidant, and anti-corrosion. However, in actual applications, corrosion still occurs in the surface treatment of the metal of the plum blossom contact, which is due to the lack of evaluation of the effectiveness of the surface treatment anti-corrosion. Therefore, studying a method for evaluating the effectiveness of anti-corrosion of the surface of the plum blossom contact of high-voltage switchgear and improving the safety and reliability of the operation of high-voltage switchgear are major problems that need to be solved urgently in the power industry.

[0004] Through the retrieval of the effectiveness evaluation of existing metal surface treatments, it was found that Chinese Patent Document No. CN202211190927.7, with a publication date of September 28, 2022, discloses a corrosion monitoring probe and its preparation method; Chinese Patent Document No. CN202210724650.5, with a publication date of June 24, 2022, discloses a method and system for evaluating the corrosion resistance of complex electronic equipment samples in reef environments; both achieve the effectiveness evaluation of the corrosion resistance of metal surface treatments through electrochemical corrosion parameter measurement and evaluation function construction. The above patents prove the application feasibility of the electrochemical corrosion method and the evaluation function in the effectiveness evaluation of the surface treatment corrosion resistance of the plum blossom contacts in high-voltage switchgear from theoretical derivation and method application.

[0005] Currently, in the application of the above methods for evaluating the corrosion resistance of metal surfaces, the evaluation is generally directly carried out through electrochemical corrosion parameters. Due to the differences in each experimental specimen and the surface treatment effect, although the parameters obtained directly through measurement have certain reference value, they will fluctuate with different experimental conditions, and the electrochemical corrosion parameters mostly characterize the performance of the metal in the middle and early stages of corrosion. Therefore, in order to ensure the rationality and accuracy of the evaluation method for the effectiveness of the anti-corrosion treatment of the plum blossom contacts, it is necessary to extract the corrosion characteristic parameters in the entire corrosion stage and perform data processing and optimization of the evaluation function. Summary of the Invention

[0006] The purpose of the present invention is to provide an effectiveness evaluation method for the anti-corrosion treatment of the plum blossom contact surface and a method for the anti-corrosion treatment of the plum blossom contact surface with partitioned areas to solve at least one of the above problems, so as to solve the lack of evaluation of the anti-corrosion effectiveness of the plum blossom contacts in the prior art; this solution proposes a method for the anti-corrosion treatment of the plum blossom contact surface with partitioned areas and gives a method for evaluating the entire corrosion stage, realizing an effective evaluation of the anti-corrosion effect of the plum blossom contacts.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] In the first aspect of the present invention, an effectiveness evaluation method for the anti-corrosion treatment of the plum blossom contact surface is disclosed. The surface of the plum blossom contact is partitioned according to functions, and the corrosion potential, corrosion current, and corrosion inhibition rate of different partitions in the three corrosion stages before corrosion, during corrosion, and after corrosion are used as evaluation parameters for the effectiveness evaluation method. The evaluation parameters of different stages are normalized, and weight coefficients are set according to the corrosion mechanisms of different stages to construct an evaluation function.

[0009] Preferably, the effectiveness evaluation method includes electrochemical corrosion testing and simulated corrosion testing.

[0010] Preferably, the evaluation function is shown in formula (I):

[0011]

[0012] In the formula, θ i is the weight coefficient at different corrosion stages, and η i is the evaluation parameter at different corrosion stages. i = 1 represents before corrosion, i = 2 represents during corrosion, and i = 3 represents after corrosion.

[0013] Preferably, the weight coefficient is related to the role played by the evaluation parameter during corrosion, and θ 1 > θ 2 > θ 3 .

[0014] Preferably, the evaluation parameter is selected according to different corrosion stages as follows: η 1 is the normalized corrosion potential, η 2 is the normalized corrosion current, and η 3 is the corrosion inhibition rate.

[0015] Preferably, the η 1 is calculated by Equation (II):

[0016]

[0017] In the formula, E corr is the corrosion potential of the sample after the partition anti-corrosion treatment, and E 0 is the corrosion potential of the sample without the anti-corrosion treatment.

[0018] Preferably, the η 2 is calculated by Equation (III):

[0019]

[0020] In the formula, I corr is the corrosion current of the sample after the partition anti-corrosion treatment, and I 0 is the corrosion current of the sample without the anti-corrosion treatment.

[0021] Preferably, the η 3 is calculated by Equation (IV):

[0022]

[0023] In the formula, Δm inh is the mass increment of the sample after the partition anti-corrosion treatment, and Δm cor is the mass increment of the sample without the anti-corrosion treatment.

[0024] The second aspect of the present invention discloses a method for surface partition anti-corrosion treatment of a plum blossom contact, which is obtained by any one of the above effectiveness evaluation methods, and based on the different performance requirements of the plum blossom contact for the current-carrying contact surface and the non-current-carrying contact surface, the partition anti-corrosion treatment is implemented.

[0025] Preferably, a surface metal coating is applied to the current-carrying contact surface of the petal-shaped contact, and one or more of surface metal coating, passivation treatment, and hydrophobic treatment are applied to the non-current-carrying contact surface of the petal-shaped contact.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention evaluates the effectiveness of the corrosion resistance treatment of the petal-shaped contact after surface treatment, and proposes an effective corrosion resistance treatment method for surface zoning of the petal-shaped contact in combination with the actual functional zoning of the petal-shaped contact, thereby improving the surface corrosion resistance of the petal-shaped contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the meshing structure of the petal-shaped contact and the supporting static contact;

[0029] Figure 2 It is a schematic flow diagram of the method for evaluating the effectiveness of the surface corrosion resistance treatment of the petal-shaped contact. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Embodiment

[0032] This solution is a method for surface zoning corrosion resistance treatment and effectiveness evaluation of petal-shaped contacts in high-voltage switchgear. The effectiveness evaluation method is to achieve quantitative determination and evaluation of the corrosion resistance of petal-shaped contacts after different surface treatments, and further optimize the surface treatment method of petal-shaped contacts. The selection basis of this surface zoning corrosion resistance treatment technology is the conductive performance requirements of petal-shaped contacts.

[0033] Figure 1 It is the meshing structure of the petal-shaped contact and the supporting static contact. Among them, the electrical performance on the current-carrying contact surface is the key to determining the stable operation of the contact. Once the contact resistance between the petal-shaped contact and the static contact increases, under the action of a rated current of several hundred to thousands of amperes, the contact is extremely prone to heat generation, forming local high temperature, accelerating the insulation aging of the insulating sleeve of the breaker contact arm, and under the combined action of surface moisture and high operating electric field, it is extremely prone to surface flashover along the surface, resulting in a rapid increase in indicators such as partial discharge and the formation of electric ablation on the insulation surface. Therefore, when performing surface treatment, the conductive performance of the current-carrying contact surface needs to be considered first. Generally speaking, since surface passivation technology and surface hydrophobic coating technology will form a protective film with a relatively high contact resistance on the contact surface, reducing the conductive performance, for the current-carrying contact surface, it is speculated that it is preferably to use a surface treatment technology mainly based on metal coating, and for the non-current-carrying contact surface, it is speculated that it is preferably to use a surface treatment technology mainly based on surface passivation and hydrophobic coating.

[0034] Figure 2 The flowchart of the evaluation method for the effectiveness of anti-corrosion treatment on the surface of the plum blossom contacts in the high-voltage switchgear is shown. First, surface metal coating, passivation, and hydrophobic treatment are respectively carried out on the plum blossom contacts, and then the electrochemical corrosion characteristics and simulated corrosion environment characteristics of each specimen are studied. Among them, the electrochemical corrosion test obtains the corrosion potential E corr and the corrosion current I corr according to the Tafel polarization curve. The simulated corrosion environment test uses a thermostatic and humidistatic test chamber, and the mass difference Δm of the specimen before and after corrosion in the high-humidity environment is obtained through a precision electronic balance. The corrosion potential is an index to measure the tendency of a metal to corrode in a given environment. By measuring the corrosion potential, the relative corrosion tendency and corrosion resistance of the copper contact in different environments can be evaluated. The lower the corrosion potential, the easier it is to corrode. The corrosion current refers to the current generated during the corrosion process of the copper contact and is an important index to describe the corrosion rate of the copper contact. By measuring the magnitude of the corrosion current, the corrosion rate and degree of the copper contact can be evaluated. The larger the corrosion current, the faster the corrosion rate. After corrosion, the corrosion inhibition rate can be calculated according to the change in sample mass, and then its effectiveness in improving the anti-corrosion of the plum blossom contacts can be analyzed. Therefore, the corrosion potential, corrosion current, and corrosion inhibition rate, which respectively characterize three different corrosion stages before, during, and after corrosion, are selected as the evaluation parameters for the evaluation method of the effectiveness of anti-corrosion treatment on the surface of the plum blossom contacts.

[0035] To ensure the rationality and accuracy of the evaluation method, relative indexes of the corrosion potential and corrosion current of the specimens after each surface treatment are obtained, and the above data are normalized with copper as the reference (copper contact, purple copper material is used in this scheme). The normalization calculation formulas for the corrosion potential and corrosion current are as shown in the following formula:

[0036]

[0037]

[0038] Among them, η 1 and η 2 are the normalized corrosion potential and normalized corrosion current respectively, E corr and I corr are the corrosion potential and corrosion current of the specimens after different surface treatments respectively, and E 0 and I 0 are the corrosion potential and corrosion current of the purple copper without any surface treatment respectively. The corrosion inhibition rate is obtained according to the change in mass before and after corrosion. The calculation formula for the corrosion inhibition rate is as follows:

[0039]

[0040] Among them, Δm inh and Δmcor are the mass gain amounts of the specimens after surface treatment and the specimens without any surface treatment, respectively, η 3 represents the corrosion inhibition rate of the surface treatment technology.

[0041] Finally, to better evaluate the effectiveness of different surface treatment technologies, by synthesizing the corrosion change laws in the three stages before, during, and after the corrosion of the copper contact, a normalized evaluation function F based on the weighted average of the normalized corrosion potential η 1 , the normalized corrosion current η 2 and the corrosion inhibition rate η 3 is proposed. The expression of this function is:

[0042]

[0043] where θ i is the weight coefficient set according to the corrosion mechanism and is determined according to the engineering experience of actual applications.

[0044] The larger the value of the normalized evaluation function, the better the corrosion resistance of the copper contact and the more effective the corresponding surface treatment technology. Generally speaking, for the plum blossom contacts of high-voltage switchgear, the sensitivity to the environment before corrosion is the key factor determining whether the high-voltage switchgear will fail, that is, the corrosion potential determining the corrosion tendency before corrosion is a key indicator, which directly affects the performance of the copper contact in the corrosive environment. By assigning a higher weight, the importance of this parameter is highlighted; secondly, the corrosion current reflects the actual performance of the copper contact during the corrosion process. However, compared with the corrosion potential, the corrosion current evaluates the mechanism during the corrosion process that has already occurred, and its importance is secondary, so the assigned weight is lower; finally, the corrosion inhibition rate after corrosion is an index parameter for evaluating the performance of the copper contact after corrosion. Although the corrosion inhibition rate can reflect the corrosion resistance ability after different surface treatment technologies, since the corrosion potential determining the corrosion tendency before corrosion and the corrosion current determining the corrosion rate during the corrosion process have a more direct impact on the corrosion resistance of the copper contact, the weight of the corrosion inhibition rate after corrosion is set to the lowest value.

[0045] In other embodiments, for the metal coating technology of the current-carrying contact surface, there are changes in the coating materials and conditions. The specimens of different coating materials are blank copper, silver-plated copper, gold-plated copper, and gold-plated after silver-plated copper (low-oxidation enhanced coating), and the specimens of different coating conditions are silver-plated layers and / or gold-plated layers with different coating thicknesses.

[0046] For the setting of specific weight coefficients, they can be selected according to the actual operating conditions and different requirements of the plum blossom contacts.

[0047] Compared with traditional metal corrosion resistance surface treatment and evaluation methods, the present invention formulates a corrosion resistance performance treatment plan for plum blossom contacts in on-site actual engineering applications through surface zoning, effectively solving the problem of corrosion still occurring after single surface treatment. At the same time, characteristic quantities at different corrosion stages: corrosion potential, corrosion current, and corrosion inhibition rate are used as evaluation parameters, and an evaluation function F is constructed through normalization processing and weight coefficient selection, realizing the effectiveness evaluation of the surface corrosion resistance treatment of plum blossom contacts in high-voltage switchgear.

[0048] Table 1 gives the polarization curve fitting data of copper contact specimens after seven different surface treatment technologies (treated according to the optimal methods of each treatment method, and each optimal treatment method is common knowledge in the art). The normalized data is shown in Table 2.

[0049] Table 1 Polarization Curve Fitting Data of Specimens after Different Surface Treatments

[0050] Material <![CDATA[Corrosion potential E corr (V)]]> <![CDATA[Corrosion current I corr (A)]]> Copper plated with silver -0.266 <![CDATA[7.39×10 -5 > Copper plated with gold -0.242 <![CDATA[1.82×10 -5 > Copper plated with silver and then with gold -0.185 <![CDATA[1.35×10 -5 > Copper passivation -0.233 <![CDATA[1.20×10 -5 > Copper hydrophobic coating -0.237 <![CDATA[1.35×10 -5 > Copper passivated and then plated with silver -0.203 <![CDATA[4.90×10 -6 > Copper plated with silver and then with hydrophobic coating -0.226 <![CDATA[1.31×10 -5 >

[0051] Table 2 Polarization Curve Fitting Data of Specimens after Normalization Processing

[0052]

[0053]

[0054] In actual engineering, different weight coefficients can be selected according to specific requirements. In this example, three selection schemes for the weight coefficients of the normalized evaluation function are initially proposed, as shown in Table 3.

[0055] Table 3 Selection Schemes for Weight Coefficients of Normalized Evaluation Function

[0056]

[0057] Based on the above normalized evaluation parameter values, the normalized evaluation function F corresponding to different schemes is calculated, and the results are shown in Table 4.

[0058] Table 4 Calculation Results of Normalized Evaluation Function

[0059]

[0060] As can be seen from the table, the best scheme of the surface treatment technology is closely related to whether it is a composite treatment, that is, the corrosion resistance performance of copper contact pieces after single surface treatment is poor, which also coincides with the corrosion situation of only silver plating on the surface of plum blossom contacts in actual engineering.

[0061] From the perspective of comprehensively considering the three solutions, the normalized evaluation function value is the largest after strengthening the metal coating technology (copper plating with silver and then gold plating), which indicates that its corrosion resistance is the best. However, considering the cost issue of preparing the plum blossom contact, it is obviously not appropriate to adopt the solution of silver plating and then gold plating for the entire contact. Combining the actual contact structure analysis, the area of the current-carrying contact surface is relatively small. Therefore, for the current-carrying contact surface of the plum blossom contact in the high-voltage switchgear, the method of silver plating and then gold plating can not only protect the key corrosion areas where the plum blossom contact is prone to damage and improve the corrosion resistance of the current-carrying contact surface of the plum blossom contact, but also control the cost of surface treatment. Moreover, as can be seen from Table 4, the normalized evaluation function value of the sample after passivation and then silver plating is only second to that of the strengthened coating technology. Therefore, for the selection of the surface treatment technology for the non-current-carrying contact surface, adopting the method of passivation and then silver plating can significantly improve the corrosion resistance of the non-current-carrying contact surface.

[0062] In addition, further considering the mechanical stress wear caused by plugging and unplugging during the maintenance process of the current-carrying contact surface and the thermal stress borne by the non-current-carrying contact surface, it is also found in the research that using a nano-hydrophobic coating with a solid content of 1%. For the hydrophobic coating technology, it is an existing technology, and a fluorine-based nano-hydrophobic agent with a solid content of 1% prepared from nano-fluoride is used. The film thickness of this nano-hydrophobic coating does not exceed 1μm and belongs to an ultra-thin layer, which has a very small impact on the surface contact resistance and conductivity of the copper contact piece. Therefore, the brushing method can be used as one of the means to repair the surface defects of the plum blossom contact on-site.

[0063] The above description of the embodiments is to enable those of ordinary skill in the art in this technical field to understand and use the invention. Obviously, those who are familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact, characterized in that: The surface of the plum blossom contact is divided into zones according to its function. The corrosion potential, corrosion current and corrosion inhibition rate of different zones in the three corrosion stages before corrosion, during corrosion and after corrosion are used as evaluation parameters of the effectiveness evaluation method. The evaluation parameters of different stages are normalized, and the weight coefficients are set according to the corrosion mechanisms of different stages to construct the evaluation function.

2. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 1, characterized in that: The effectiveness evaluation method includes an electrochemical corrosion test and a simulated corrosion test.

3. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 1, characterized in that: The evaluation function is shown in formula (I): In the formula, θ i is the weight coefficient of different corrosion stages, η i are evaluation parameters for different corrosion stages, i=1 is before corrosion, i=2 is during corrosion, and i=3 is after corrosion.

4. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 3, characterized in that: The weight coefficient is related to the role of the evaluation parameter in corrosion, and θ1>θ2>θ3.

5. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 3, characterized in that: The evaluation parameters are selected according to different corrosion stages: η1 is the normalized corrosion potential, η2 is the normalized corrosion current, and η3 is the corrosion inhibition rate.

6. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 5, characterized in that: The η1 is calculated by formula (II): In the formula, E corr E0 is the corrosion potential of the sample after the anti-corrosion treatment, and E0 is the corrosion potential of the sample without anti-corrosion treatment.

7. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 5, characterized in that: The η2 is calculated by formula (III): In the formula, I corr I0 is the corrosion current of the sample after the partition anti-corrosion treatment, and I1 is the corrosion current of the sample without anti-corrosion treatment.

8. The method for evaluating the effectiveness of anti-corrosion treatment on the surface of a plum blossom contact according to claim 5, characterized in that: The η3 is calculated by formula (IV): In the formula, Δm inh is the mass increment of the sample after the partition anti-corrosion treatment, Δm cor This is the mass increase of the sample without anti-corrosion treatment.

9. A method for treating the surface of a plum blossom contact by partitioning and anti-corrosion, characterized in that: According to the effectiveness evaluation method as described in any one of claims 1 to 8, based on the different performance requirements of the plum blossom contact for the flow-guiding contact surface and the non-flow-guiding contact surface, a zoned anti-corrosion treatment is implemented.

10. A method for treating the surface of a plum blossom contact by partitioning and anti-corrosion according to claim 9, characterized in that: The flow-guiding contact surface of the plum blossom contact is subjected to surface metal coating, and the non-flow-guiding contact surface of the plum blossom contact is subjected to surface metal coating, passivation treatment and hydrophobic treatment or one or more thereof.

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