CN114778432A - Method for testing corrosion resistance of low-tin-content tin plate - Google Patents

Abstract

The application relates to the field of corrosion resistance testing, in particular to a method for testing corrosion resistance of a tin plate, which comprises the following steps: taking a tin plate to be tested as a test electrode to obtain a three-electrode system; carrying out electrochemical corrosion on the test electrode through the three-electrode system, and detecting to obtain a potentiodynamic polarization curve of the tin plate to be tested; obtaining two groups of point values according to the corrosion potential in the potentiodynamic polarization curve, and respectively obtaining two straight lines; obtaining the corrosion current density of the tin plate to be tested according to the ordinate of the intersection point of the two straight lines; evaluating the corrosion resistance of the tin plate to be tested according to the corrosion current density; the two groups of point values are respectively located in the near-polarization area of the potentiodynamic polarization curve, and the corrosion resistance of the tin plate to be tested can be evaluated more accurately and conveniently by testing the corrosion current density at fixed points, so that an accurate test value can be obtained, and the corrosion resistance of the tin plate to be tested can be evaluated quickly.

Description

A kind of test method of corrosion resistance of tinplate with low tin content

technical field

The present application relates to the field of corrosion resistance testing, and in particular, to a method for testing the corrosion resistance of tin-plated plates.

Background technique

ASTM Standard A623-2010 "Standard Specifications for Tin Rolled Products for General Requirements", discloses tin alloy galvanometry (ATC) and iron stripping value (ISV), ATC test by testing pure tin and tin-iron alloys To evaluate the corrosion resistance of the tinplate, the ISV test evaluates the corrosion resistance of the tinplate by measuring the amount of iron leached out of a certain area of the tinplate in an acid solution at a certain temperature for a certain period of time. Although the two are quantitative tests, the detection time exceeds 24 hours and the operation is difficult, so they are only used for experimental research.

The second edition of "Electroplating Solution and Coating Performance Test" discloses the method of testing the corrosion resistance of the coating with the Tafel curve. If the measured corrosion potential is more positive, the corrosion resistance of the coating system in the corrosive medium is better; if The measured corrosion current density is small, or the corrosion resistance is large, indicating that the corrosion resistance of the coating is good. However, this method is affected by the surface morphology and coating thickness of the tin-plated plate, and a straight line segment cannot be generated in the Tafel interval to solve the corrosion current density, so it is not suitable for the test of the corrosion resistance of the tin-plated plate with low tin content.

Patent CN1677083A, "Rapid Test Method for Corrosion Resistance of Tin-Plated Sheets", introduces a method to test the whiteness value of the alloy layer of tin-plated sheets with a whiteness meter after detinning treatment to evaluate its corrosion resistance grade. However, for the tin plate with low tin content, the alloy layer cannot completely cover the surface of the substrate, and the corrosion resistance mainly depends on the coverage of the alloy layer, tin layer and passivation layer on the substrate. Since the whiteness value only indicates the degree of coverage of the substrate by the alloy layer, the corrosion resistance of the low tin content tin plate cannot be tested.

Patent CN108020500A, "A test solution for rapid detection of corrosion resistance of tin-plated steel sheet and its detection method", introduces a method of using color developer and accelerator as the detection solution, soaked in filter paper and applied to the surface of tin-plated steel plate and calculated. Blue Dot Porosity as a method for evaluating the corrosion resistance of tinplate. However, for tin-plated plates with different coating thicknesses, different application times are required, and the pore sizes are different, so it is difficult to count the number of blue dots. In practical application, it can only qualitatively analyze the corrosion resistance of tinplate, but it can not be applied to quantitative test of tinplate factory inspection.

Patent CN105241806A, "A Test Method for Rapid Evaluation of Corrosion Resistance of Tinplate", introduces a method of using 2% NaCl and a certain concentration of NaHSO ₃ solution as the corrosive medium to achieve corrosion resistance of tinplate through a salt spray test chamber A method for quantitative rating of sexuality indicators. However, the corrosion rate is too fast for the low tin content tin plate, and the experimental results tend to be consistent, and it is difficult to distinguish the corrosion resistance of the tin plate.

SUMMARY OF THE INVENTION

The present application provides a method for testing the corrosion resistance of a tin-plated plate, so as to solve the technical problem that the corrosion resistance of a tin-plated plate with low tin content cannot be accurately detected.

In a first aspect, the application provides a method for testing the corrosion resistance of a tinplate, the method comprising the following steps:

The tin-plated plate to be tested is used as the test electrode to obtain a three-electrode system;

The test electrode is electrochemically corroded by the three-electrode system, and the Tafel curve of the tin-plated plate to be tested is obtained by detection;

Two sets of point values are obtained according to the corrosion potential in the potentiodynamic polarization curve, and two straight lines are obtained respectively;

According to the ordinate of the intersection of the two straight lines, the corrosion current density of the tin-plated plate to be measured is obtained;

Evaluate the corrosion resistance of the tinplate to be tested by the corrosion current density;

Wherein, at least one surface of the tin-plated plate to be tested includes a coating layer, the two groups of point values are respectively located in the near-polarization region of the potentiodynamic polarization curve, and the horizontal value of each group of point values in the two groups of point values The coordinate values are respectively located in a near-polarization region.

Optionally, evaluating the corrosion resistance of the tin-plated plate to be tested by the corrosion current density specifically includes:

obtaining a plurality of the corrosion current densities;

Through a plurality of the corrosion current densities, the average value of the corrosion current densities is obtained;

If the average value is less than the preset current density density, the corrosion resistance of the tin-plated plate to be tested meets the standard.

Optionally, if the electrolyte is a 1-5% mass fraction NaCl solution, the detection area is 0.5-1 cm ² , the preset current density is 0.8×10 ^-7 A/cm ² , and the average value is less than 0.8×10 ^{- 7} A/cm ² , the corrosion resistance of the tin-plated plate to be tested meets the standard.

Optionally, the amount of tin plating is less than or equal to 2.8 g/m ² .

Optionally, the detection conditions include: a scanning rate of 0.5-5 mV/s, and a scanning range of -1-+1V.

Optionally, the three-electrode system is obtained by using the tin-plated plate to be tested as a test electrode, which includes: removing grease and impurities on the surface of the tin-plated plate to be tested.

Optionally, using the tin-plated plate to be tested as a test electrode to obtain a three-electrode system, specifically including: using the tin-plated plate to be tested as a test electrode, using a saturated calomel electrode as a reference electrode, and using a platinum electrode as an auxiliary electrode , a three-electrode system is obtained.

Optionally, the near-polarization interval of the potentiodynamic polarization curve is located between (εcorr-0.11V)～(εcorr-0.01V) or (εcorr+0.01V)～(εcorr+0.11V), where εcorr represents corrosion potential.

Optionally, one of the two sets of point values is a fixed point of (εcorr-0.01V) and any point within the range of (εcorr-0.02V)～(εcorr-0.03V), and the other group is (εcorr+ A fixed point of 0.01V) and any point within the range of (εcorr+0.02V)～(εcorr+0.03V), and the distances on the abscissa of the two sets of point values are equal.

In the second aspect, the present application provides an application of a method for testing the corrosion resistance of a tin-plated sheet, and the method described in the first aspect is used in the inspection of the tin-plated sheet to be tested or in evaluating the risk of rusting of the tin-plated sheet to be tested. .

Compared with the prior art, the above technical solutions provided by the embodiments of the present application have the following advantages: the method provided by the embodiments of the present application uses the tin-plated plate to be tested as the test electrode to obtain a three-electrode system; The test electrode is electrochemically corroded, and the potentiodynamic polarization curve of the tin-plated plate to be tested is obtained by detection; two sets of point values are obtained according to the corrosion potential in the potentiodynamic polarization curve, and two straight lines are obtained respectively; According to the ordinate of the intersection of the two straight lines, the corrosion current density of the tin-plated plate to be tested is obtained; the corrosion resistance of the tin-plated plate to be tested is evaluated by the corrosion current density; the two groups of The point values are respectively located in the near-polarization region of the potentiodynamic polarization curve, the abscissa value of a group of point values in the two groups of point values is located in the near-polarization region of the cathodic polarization curve, and the remaining group of point values are in the near-polarization region of the cathodic polarization curve. The abscissa value is located in the near-polarization area of the anodic polarization curve; this method can more accurately and conveniently evaluate the corrosion resistance of the tinplate to be tested. Accurate test values are obtained, and the corrosion current density value to identify the corrosion resistance of low-tin tin-plated plates is given, and the corrosion resistance of the tin-plated plates to be tested can be quickly evaluated, and the possibility of spot rust can also be judged. sex.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. In other words, on the premise of no creative labor, other drawings can also be obtained from these drawings.

1 is a schematic flowchart of a method for testing the corrosion resistance of a tin-plated plate provided by an embodiment of the application;

Fig. 2 is the potentiodynamic polarization curve test result of the tinplate to be tested of the application;

Figure 3 is a diagram of the evaluation method of corrosion current density;

Fig. 4 is the corrosion current density test result of the tinplate A to be tested of the application;

Fig. 5 is the corrosion current density test result of the tinplate B to be tested of the application;

Fig. 6 is the corrosion current density test result of the tinplate C to be tested of the application;

FIG. 7 is a graph of potentiodynamic polarization curves of three types of tin-plated plates to be tested in the application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of this application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present application.

In the first aspect, the present application provides a method for testing the corrosion resistance of a tinplate, as shown in FIG. 1 , the method includes the following steps:

S1. Use the tin-plated plate to be tested as the test electrode to obtain a three-electrode system;

S2. carry out electrochemical corrosion to the test electrode by the three-electrode system, and detect the potentiodynamic polarization curve of the tin-plated plate to be tested;

In the examples of this application, an electrolyte solution can be prepared, the three-electrode system can be placed in the electrolyte solution, an electrochemical test system can be used, and the detection can be performed according to the set scanning rate and scanning range, and an alkaline washing solution or an organic solvent can be used to remove the plating to be tested. Grease and impurities on the surface of the tin plate.

S3. According to the corrosion potential in the potentiodynamic polarization curve, two groups of point values are obtained, and two straight lines are obtained respectively;

In the embodiment of the present application, each group of point values consists of two points, the abscissa value of a group of point values is located in the near-polarization region of the cathodic polarization curve, and the abscissa values of the remaining group of point values are located in the anode polarization In the near-polarized region of the curve, a straight line is obtained from each group of point values.

S4. according to the ordinate of the intersection of the two straight lines, obtain the corrosion current density of the tinplate to be measured;

In the embodiment of the present application, it specifically includes: the point selection method is as follows: one of the two groups of point values is a fixed point of (εcorr-0.01V) and any point within the range of (εcorr-0.02V)～(εcorr-0.03V) , the other group is a fixed point of (εcorr+0.01V) and any point within the range of (εcorr+0.02V)～(εcorr+0.03V), and the distances of the two groups of point values on the abscissa are equal. Make a straight line for each of the two sets of point values, so that the two straight lines intersect, and the ordinate corresponding to the intersection point is the corrosion current density icorr. S5. Evaluate the corrosion resistance of the tin-plated plate to be tested through the corrosion current.

Wherein, the two groups of point values are respectively located in the near-polarization region of the potentiodynamic polarization curve, and the abscissa value of each group of point values in the two groups of point values is respectively located in a near-polarization region. Specifically, the abscissa values of a group of point values in the two groups of point values are located in the near-polarization region of the cathodic polarization curve, and the abscissa values of the remaining group of point values are located in the near-polarization region of the anodic polarization curve.

In the embodiments of the present application, the range of the near-polarization region is between (εcorr-0.11V)～(εcorr-0.01V) or (εcorr+0.01V)～(εcorr+0.11V), where εcorr represents the corrosion potential.

Specifically, a NaCl solution with a mass fraction of 1-5% was prepared, the treated tin-plated plate was used as the test electrode, the test area was 0.5-1 cm ² , the saturated calomel electrode was used as the reference electrode, and the platinum electrode was used as the auxiliary electrode. Three-electrode system; use the electrochemical test system to test the potentiodynamic polarization curve, set the scanning rate to 0.5～5mV/s and the scanning range to -1～+1V or less. The test result of the potentiodynamic polarization curve is shown in Figure 2, where , the abscissa is the electrode potential/V, and the ordinate is the log current density (i)/mA·cm ² ; the curve on the left is the cathodic polarization curve, and the curve on the right is the anodic polarization curve; the intersection of the cathodic and anodic polarization curves corresponds to The electrode potential is the corrosion potential ε _corr ;

Area A is a polarized area, and its interval is (ε _corr -0.01V)～(ε _corr +0.01V); B area is a near-polarized area, and its interval is (ε _corr -0.11V)～(ε _corr -0.01V) or (ε _corr +0.01V)～(ε _corr +0.11V); the C area is the passivation area.

The corrosion current density i _corr is obtained by selecting points in the B region (near polarization region). The point selection method is: on the cathode polarization curve, take the abscissa (ε _corr -0.01V) corresponding to the curve point as point 1, and in the B region of the cathode polarization curve (ε _corr -0.02V)～(ε _corr -0.03 V) Take any point as point 2, and connect point 1 and point 2 to make a straight line. On the anodic polarization curve, take the abscissa (ε _corr +0.01V) corresponding to the curve point as point 3, and in the B region of the anodic polarization curve (ε _corr +0.02V)～(ε _corr +0.03V) take point 4 Make the horizontal axis distance of points 3 and 4 equal to the horizontal axis distance of points 1 and 2, and connect point 3 and point 4 to make a straight line. Make two straight lines intersect, and the ordinate corresponding to the intersection point is the corrosion current density i _corr . Figure 3.

As an optional embodiment, evaluating the corrosion resistance of the tin-plated plate to be tested by the corrosion current density specifically includes:

obtaining a plurality of the corrosion current densities;

Through a plurality of the corrosion current densities, the average value of the corrosion current densities is obtained;

If the average value is less than the preset corrosion current density, the corrosion resistance of the tin-plated plate to be tested meets the standard.

As an optional embodiment, if the electrolyte is a 0.5-10% mass fraction NaCl solution, the test area is 0.5-1 cm ² , the preset current density is 0.8×10 ^-7 A/cm ² , and the average value is <0.8×10 ⁻⁷ A/cm ² , the corrosion resistance of the tin-plated plate to be tested meets the standard.

As an optional embodiment, the amount of tin plating is less than or equal to 2.8 g/m ² . Preferably, the amount of tin plating≤1.1g/m ^2, the amount of tin plating≤1.0g/m ²

In the embodiment of the present application, the tin-plated plate with the amount of tin plating less than or equal to 2.8 g/m ² can be detected; and the reason for the accurate corrosion resistance detection result is to overcome the difficulty of covering the surface morphology of the substrate due to the thin tin layer. The effect of corrosion resistance test, and if the amount of tin plating is 5.6g/m ² or 11.2g/m ² , it belongs to high tin iron, and can be tested by using the conventional tin plate corrosion resistance testing method.

In the embodiment of the present application, it only takes 15 minutes for each test to obtain accurate experimental data, so as to achieve the purpose of quantitative testing. Since the thickness of the tin-plated plate with a tin plating amount of 1.1g/m ² is about 0.15μm, and the roughness of the substrate is already 0.4μm, the coating layer covers the substrate unevenly, and there will be tiny point rust defects. The tinplate to be tested with a weight of 1.1g/m ² has a very effective control function, which can prevent and control the spot rust of the tinplate to be tested during transportation and use.

As an optional implementation manner, the detection conditions include: a scan rate of 1 mV/s, and a scan range of -0.25 to +0.25V.

In the embodiment of the present application, the reason why the detection condition is 1 mV/s is that the lower the scanning rate, the more accurate the curve, and the reason why the scanning range is -0.25 to +0.25 V is that the scanning range is convenient for the observation of the near-polarized area and the polarized area. analyze.

As an optional embodiment, the tin-plated plate to be tested is used as a test electrode to obtain a three-electrode system, which includes: removing grease and impurities on the surface of the tin-plated plate to be tested.

As an optional embodiment, the tin-plated plate to be tested is used as the test electrode to obtain a three-electrode system, which specifically includes: using the tin-plated plate to be tested as the test electrode, the saturated calomel electrode as the reference electrode and the A platinum electrode was used as the auxiliary electrode to obtain a three-electrode system.

In the second aspect, the present application provides an application of a method for testing the corrosion resistance of a tin-plated sheet, and the method described in the first aspect is used in the inspection of the tin-plated sheet to be tested or in evaluating the risk of rusting of the tin-plated sheet to be tested. .

The method of the present invention will be described in detail below in conjunction with examples, comparative examples and experimental data.

Use the method of this application to test the tinplate to be tested produced by a company. The amount of tin plating of the tinplate to be tested is 1.1g/m ² , and the selected tinplate has good corrosion resistance (tinplate A to be tested) and slight rust. (The tinplate to be tested B) and the three tinplates to be tested with severe corrosion (the tinplate to be tested C) were tested for potentiodynamic polarization curves. The test method includes the following steps:

S1. The sampling area is 0.785cm ² respectively, after removing the grease on the surface of the tin-plated plate to be tested with an alkaline washing solution, the tin-plated plate to be tested is used as a test electrode to obtain a three-electrode system;

S2. carry out electrochemical corrosion to the test electrode by the three-electrode system, and detect the potentiodynamic polarization curve of the tin-plated plate to be tested; specifically include: preparing a 3.5% NaCl solution as an electrolyte, using the treated The tin-plated plate to be tested is the test electrode (measured area is 0.785 cm ² ), the saturated calomel electrode is used as the reference electrode, and the platinum electrode is used as the auxiliary electrode to build a three-electrode system. Use the electrochemical test system to set the parameters, the scan rate is 1mV/s, and the scan range is -0.25 to +0.25V.

S3. According to the corrosion potential in the potentiodynamic polarization curve, two groups of point values are obtained, and two straight lines are obtained respectively;

S4. according to the ordinate of the intersection of the two straight lines, obtain the corrosion current density of the tinplate to be measured;

Wherein, the two groups of point values are respectively located in the near-polarization region of the potentiodynamic polarization curve, and the abscissa value of each group of point values in the two groups of point values is respectively located in a near-polarization region. The test uses a tin plate produced by a company, the amount of tin plating is 1.1g/m ² , selects good corrosion resistance (tin plate A), slight rust (tin plate B) and severe rust (tin plate C) Three tinplates were tested. The test method is as follows:

After the curve is drawn, take the abscissa (ε _corr -0.01V) corresponding curve point as point 1 and the abscissa (ε _corr -0.02V) corresponding curve point as point 2 on the cathode polarization curve, so that point 1, point A straight line is generated between 2. On the anode polarization curve, the abscissa (ε _corr +0.01V) corresponds to the curve point as point 3, and the abscissa (ε _corr +0.02V) corresponds to the curve point as point 4, so that a line is generated between points 3 and 4. straight line. The two straight lines intersect at a point, and the corresponding ordinate is the desired corrosion current density i _corr .

The test potentiodynamic polarization curves of the tinplate to be tested A), the slight spot rust (the tinplate to be tested B) and the severe rust (the tinplate to be tested C) are shown in Figure 4, Figure 5 and Figure 6, where the horizontal The coordinates are electrode potential/V, and the ordinate is log[current density/(A/cm ² )], reflecting the respective corrosion resistance characteristics of the tinplate A, B and C to be tested, which can be predicted. Set the current density to be 0.8×10-7A/cm ² to judge the corrosion resistance of the tinplate to be tested; Figure 7 shows the potentiodynamic polarization curves of the three tinplates to be tested, abscissa: electrode potential, ordinate: The logarithm of the current density, and in Figure 2-6, the abscissa is the electrode potential, and the ordinate is the logarithm of the current density. Figure 7 reflects the corrosion resistance of the tinplates to be tested. From the potentiodynamic polarization curves, it can be seen that the corrosion resistance of the three tinplates to be tested decreases with the increase of the corrosion current density; The corrosion current of the tinplate to be tested is shown in Table 1.

Table 1 The corrosion current density of the tinplate A to be tested, the tinplate B to be tested, and the tinplate C to be tested.

S5. Evaluate the corrosion resistance of the tinplate to be tested by the corrosion current density;

It can be seen from Table 1 that according to the test standard that the corrosion current density is lower than 0.8×10 ^-7 A/cm ² , the corrosion resistance of the tinplate A to be tested is up to the standard, and the corrosion resistance of the tinplate B to be tested and the tinplate C to be tested are corrosion resistant. The performance is not up to standard, which is in line with the actual production of the tinplate to be tested.

It should be noted that, in this document, relational terms such as "first" and "second" etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these There is no such actual relationship or sequence between entities or operations. Furthermore, the terms "comprising", "comprising" or any other variation are intended to encompass non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also not expressly listed Other elements, or also include elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above descriptions are only specific embodiments of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims (10)

1. a test method of tinplate corrosion resistance, is characterized in that, described method may further comprise the steps: The tin-plated plate to be tested is used as the test electrode to obtain a three-electrode system; The test electrode is electrochemically corroded by the three-electrode system, and the potentiodynamic polarization curve of the tin-plated plate to be tested is obtained by detection; Two sets of point values are obtained according to the corrosion potential in the potentiodynamic polarization curve, and two straight lines are obtained respectively; According to the ordinate of the intersection of the two straight lines, the corrosion current density of the tin-plated plate to be measured is obtained; Evaluate the corrosion resistance of the tinplate to be tested by the corrosion current density; Wherein, at least one surface of the tin-plated plate to be tested includes a coating layer, the two groups of point values are respectively located in the near-polarization region of the potentiodynamic polarization curve, and the horizontal value of each group of point values in the two groups of point values The coordinate values are respectively located in a near-polarization region. 2. The method according to claim 1, characterized in that, evaluating the corrosion resistance of the tin-plated plate to be tested by the corrosion current density, specifically comprising: obtaining a plurality of the corrosion current densities; Through a plurality of the corrosion current densities, the average value of the corrosion current densities is obtained; If the average value is less than the preset corrosion current density, the corrosion resistance of the tin-plated plate to be tested meets the standard. 3 . The method according to claim 2 , wherein if the electrolyte is a 1-5% mass fraction NaCl solution, and the detection area is 0.5-1 cm ² , the preset corrosion current density is 0.8×10 ^-7 A/ cm ² , and the average value is less than 0.8×10 ^-7 A/cm ² , then the corrosion resistance of the tin-plated plate to be tested meets the standard. 4 . The method according to claim 1 , wherein the amount of tin plating is less than or equal to 2.8 g/m ² . 5 . The method according to claim 1 , wherein the detection conditions include: a scanning rate of 0.5 to 5 mV/s, and a scanning range of -1 to +1V. 6 . 6 . The method according to claim 1 , wherein the method of using the tin-plated plate to be tested as a test electrode to obtain a three-electrode system comprises: removing grease and impurities on the surface of the tin-plated plate to be measured. 7 . 7. The method according to claim 1, wherein the described tin-plated plate to be measured is used as a test electrode to obtain a three-electrode system, specifically comprising: the tin-plated plate to be measured is used as a test electrode, the saturated calomel electrode is used As the reference electrode and the platinum electrode as the auxiliary electrode, a three-electrode system was obtained. 8 . The method according to claim 1 , wherein the near-polarization interval of the potentiodynamic polarization curve is located between (ε _corr -0.11V)～(ε _corr -0.01V) and (ε _corr +0.01 8 . V)～(ε _corr +0.11V), where ε _corr represents the corrosion potential. 9 . The method according to claim 1 , wherein one of the two sets of point values is located in ε _corr -0.01V and (ε _corr -0.02V)～(ε _corr -0.03V) respectively, and the other One group is located in ε _corr +0.01V) and (ε _corr +0.02V)～(ε _corr +0.03V) respectively, and the distances of the two groups of point values on the abscissa are equal. 10. The application of the test method of tinplate corrosion resistance, it is characterized in that, the method as described in any one in claim 1-9 is used for the inspection of tinplate or the point of evaluating tinplate at risk of rust.

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