TWI769559B - Method for evaluating corrosion resistance of coating - Google Patents

Abstract

A method for evaluating corrosion resistance of coating is provided. The method is applicable to a to-be-tested object which includes a coating layer and a first metal material covered by the coating layer. The method includes the following steps: placing the to-be-tested object and a conductor into an electrolyte and then applying a voltage by a multimeter to perform electrolysis, wherein the to-be-tested object and the conductor are an anode and a cathode respectively; measuring a resistance value of the to-be-tested object by the multimeter during electrolysis; comparing the measured resistance value with a preset resistance value, and a measured resistance-time curve with a preset resistance-time curve, and determining accordingly the corrosion resistance ability of the coating layer.

Description

Methods for evaluating the corrosion resistance of coatings

The present invention relates to a method for evaluating the corrosion resistance of a coating layer, in particular to a method for evaluating the corrosion resistance of the coating layer measured by a three-meter electric meter.

The use of common metals in life, such as aluminum doors and windows, metal shelves, etc., in order to prolong the service life, the surface of these metals will be coated with a coating layer, that is, an anti-oxidation film, to prevent the metal surface from rusting due to oxidation.

In general, the method of testing the corrosion resistance of the coating layer requires the use of a specific instrument, a test piece of standard size, and a specific electrolyte to conduct electrolysis experiments. However, the instrument is expensive and has been plated with the The metal size of the coating layer has been fixed. When conducting the electrolysis experiment, it is necessary to make a special test piece of standard size for testing. In addition, the type and pH of the electrolyte are also fixed, which cannot be reconfigured according to the actual inspection needs. Therefore, , the conventional method of testing the corrosion resistance of the coating layer is limited.

Therefore, the present inventor proposes a method for evaluating the corrosion resistance of the coating layer in order to make the method for testing the corrosion resistance of the coating layer simpler, easier and cheaper.

The method for evaluating the corrosion resistance of the coating layer is suitable for an object to be tested, the object to be tested includes a coating layer and a first metal substrate, the coating layer covers the first metal substrate, and the method for evaluating the corrosion resistance of the coating layer includes the following step.

Put the object to be tested and a conductor into an electrolyte, and perform electrolysis with a three-use electricity meter as an applied voltage required for electrolysis, wherein the applied voltage is a multiple of 9 volts, and the three-use electricity meter A positive electrode contact and a negative electrode contact are respectively electrically connected to the first metal base material of the object to be tested and the conductor, the object to be tested and the conductor are respectively an anode and a cathode; The electric meter measures a resistance value of the object to be tested during the electrolysis process; and compares the resistance value with a preset resistance value, and compares the variation curves of the resistance values with the electrolysis time with the predetermined resistance values. A curve of resistance value versus electrolysis time is set to determine the corrosion resistance of the coating layer, wherein the preset resistance value is positively correlated with the resistance value of a standard object, the standard object includes a second metal substrate, the second The material of the metal base material is the same as the material of the first metal base material.

Further, measure a plurality of the resistance values corresponding to a plurality of electrolysis times of the object to be tested in the electrolysis process by the three-use electric meter, and obtain a resistance value according to the electrolysis times and the corresponding resistance values function, the resistance value function is the change curve of these resistance values with the electrolysis time, the slope change of the resistance value function is less than 5% after a moderate electrolysis time, and the moderate electrolysis time is determined to be a corrosion resistance time of the coating layer , and compare a slowing resistance value corresponding to the slowing electrolysis time with the preset resistance value to judge the corrosion resistance of the coating layer.

Further, before the object to be tested is electrolyzed, both the standard object and the conductor are put into the electrolyte, the standard object and the conductor are respectively used as the anode and the cathode, and the three-purpose meter is used as the The applied voltage is electrolyzed, and a standard resistance value is obtained by measuring the resistance value of the standard object by the three-purpose electric meter, and the preset resistance value is positively correlated with the standard resistance value.

Further, when the moderate resistance value is greater than the preset resistance value, the coating layer is not damaged, and when the moderate resistance value is smaller than the preset resistance value, the coating layer is damaged.

Further, under the condition that the parameters of the electrolyte are fixed, according to the trend of the resistance value function, the slower the resistance value of the object to be tested tends to the preset resistance value, the stronger the corrosion resistance of the coating layer, the stronger the corrosion resistance of the coating layer. The faster the resistance value of the object to be tested approaches the preset resistance value, the weaker the corrosion resistance of the coating layer is.

Further, the parameters of the electrolyte can be adjusted, and the parameters of the electrolyte are the pH, concentration and temperature of the electrolyte.

Further, the electrolytic solution is accommodated in an electrolytic cell, the object to be tested and the conductor are put into the electrolytic solution, and the electrolytic cell is sealed and pumped in the process of electrolyzing the object to be side.

Further, a plurality of positive taps are connected to the positive contact of the three-use electricity meter, and the positive taps are electrically connected to the object to be measured at multiple points at intervals.

Further, the object to be tested is disposed obliquely with respect to the conductor in parallel to an oblique direction in the electrolyte, and the positive tap points are respectively electrically connected to the object to be tested at intervals along the oblique direction.

Further, measure a plurality of the resistance values corresponding to a plurality of electrolysis times of the object to be tested in the electrolysis process by the three-use electric meter, and obtain a resistance value according to the electrolysis times and the corresponding resistance values The resistance value function is the change curve of the resistance values with the electrolysis time. In the resistance value function, when the change of the resistance value with time is less than 5% of the preset resistance value, the resistance value corresponds to The electrolysis time is a corrosion resistance time.

According to the above technical features, the following effects can be achieved:

1. By electrically connecting the three-use meter to the object to be measured and the conductor, the object to be measured does not need to be limited to a specific shape and size, and the object to be measured can be directly measured physically, such as the product type. The shape of the object can be complex and diverse. Compared with the second metal substrate of the same material as the first metal substrate, the corrosion resistance effect of the first metal substrate covered with the coating layer is compared. No special It is more convenient and easier to implement when making test pieces.

2. By using the three-use meter to replace the original expensive instrument, the cost is reduced during implementation.

3. The parameters such as the electrolyte concentration, temperature and pH value can be adjusted according to the simulated corrosion environment. Since the corrosion resistance relative to the second metal substrate is adopted, the corrosion resistance of the coating layer can be visually compared, and the data is more accurate. Easy to interpret, easier to understand when reading and communicating, and easy for production line quality control.

4. The power source used for electrolysis is only the battery of the three-purpose electricity meter, no AC power supply is required, and the convenience is higher. The three-purpose electricity meter handles both power supply and resistance measurement, making wiring and operation easier, and the whole set of measurement system Can be moved at any time without power failure.

5. The three-use electric meter provides a stable fixed voltage output, no signal and surge interference, which can stabilize the electrolytic reaction of the system. The measured resistance value changes less than 1%, compared to the AC-to-DC power supply method. , the resistance value changes by more than 2%, the data keeps beating up and down, and the data measured by the three-use meter is more stable.

S01: Steps of establishing a preset resistance value

S02: Electrolysis step

S03: Real-time measurement steps

S04: Continuous measurement steps

S05: Judgment step

S06: Analysis step

1: Three-use meter

2: Conductor

3: Electrolyzer

4: Electrolyte

5: Processor

10: Object to be tested

10a: The first object to be tested

10b: The second object to be tested

10c: The third object to be tested

[FIG. 1] is a flow chart illustrating the flow of a first embodiment of the method for estimating the corrosion resistance of a coating layer of the present invention.

[Second Figure] is a schematic diagram illustrating the operation of the first embodiment.

[Figure 3] is a measurement diagram, illustrating that a standard resistance value function is obtained by measuring a plurality of resistance values of a standard object, measuring a first object to be measured, a second object to be measured, and a third object to be measured A plurality of resistance values of the object are measured to obtain a respective resistance value function.

[FIG. 4] is a schematic diagram illustrating the operation of a second embodiment of the method for estimating the corrosion resistance of a coating layer of the present invention.

In view of the above technical features, the main effect of the method for evaluating the corrosion resistance of the coating layer of the present invention will be clearly presented in the following examples.

Referring to Figures 1 to 3, a first embodiment of the method for evaluating the corrosion resistance of a coating layer of the present invention is applicable to an object to be tested 10 . The object to be tested 10 includes a coating layer and a first metal substrate. The coating film layer covering the first metal substrate, the method for evaluating the corrosion resistance of the coating layer is suitable for evaluating the corrosion resistance of the coating layer, especially the first metal substrate is formed on the first metal substrate through a reactive coating For the coating layer, evaluate the corrosion resistance of the coating layer, for example, the coating layer has disappeared or may be general corrosion, pitting corrosion, intergranular corrosion, etc., wherein the reactive coating is the fluid that forms the substrate of the coating layer A chemical change occurs on the surface of the first metal substrate, and the solid coating layer is formed on the surface of the first metal substrate. The method for evaluating the corrosion resistance of the coating layer can also evaluate the corrosion resistance strength of the coating layer. In an example, the first metal substrate is a copper sheet, the coating layer is a benzotriazole copper film, and the object to be tested 10 is a copper sheet plated with the benzotriazole copper film. It should be noted that The size and shape of the object to be tested 10 are not limited. The method for evaluating the corrosion resistance of the coating layer can be implemented by a three-use electricity meter 1, a conductor 2, an electrolytic cell 3, an electrolyte 4 and a processor 5. The processor 5 is electrically connected to the three-use electricity meter 1 to receive a resistance value measured by the three-use electricity meter 1. In this example, the conductor 2 is a copper sheet, and the electrolytic cell 3 is a rectangular parallelepiped and defines an accommodation Space, this accommodation space is equipped with this electrolyte 4, and this electrolyte 4 is PH3.2 Copper sulfate solution, the processor 5 is a computer. The method for evaluating the corrosion resistance of the coating layer includes a step S01 of establishing a predetermined resistance value, an electrolysis step S02, a real-time measurement step S03, a continuous measurement step S04, a determination step S05, and an analysis step S06.

Step S01 of establishing a preset resistance value: put a standard object and the conductor 2 into the electrolyte 4, and a positive contact and a negative contact of the three-use electricity meter 1 are respectively electrically connected to the standard object and the The conductor 2, the standard object and the conductor 2 are used as an anode and a cathode respectively, and the three-use electricity meter 1 is used as an applied voltage required for electrolysis to perform electrolysis. Measure the resistance value of the standard object during the electrolysis process to obtain a standard resistance value, wherein the standard object is similar to the state of the object to be tested 10 without the coating layer, the standard object includes a second metal substrate, The material of the second metal substrate is the same as that of the first metal substrate, that is, the standard object is the copper sheet, and the processor 5 is used to preset a predetermined resistance value, and the predetermined resistance value is the same as the standard The resistance value is positively correlated. As shown in the third figure, the standard resistance value is about 20 ohms, and the preset resistance value is preset by the processor 5 to be, for example, 1.5 times the standard resistance value to be 30 ohms, and the resistance value of the object to be tested 10 will vary with Destruction of the coating layer decreases. For example, when the resistance value of the object to be tested 10 drops to 30 ohms, the coating layer of the object to be tested 10 may have been damaged. Further, measure a plurality of the standard resistance values corresponding to a plurality of electrolysis times of the standard object in the electrolysis process by the three-use electricity meter 1, use the processor 5 to receive the standard resistance values, and according to the A standard resistance value function is obtained by equalizing the electrolysis time and the corresponding standard resistance values, and the standard resistance value function is a change curve of the preset resistance values with the electrolysis time. The third graph shows that the slope of the standard resistance value function approaches zero, and the standard resistance values all approach 20 ohms.

Electrolysis step S02: both the object to be tested 10 and the conductor 2 are put into the electrolyte 4, and the three-use electricity meter 1 is used as the applied voltage required for electrolysis to perform electrolysis. The positive contact and the negative contact of 1 are respectively electrically connected to the first metal substrate and the The conductor 2 , the object to be tested 10 and the conductor 2 are the anode and the cathode, respectively. During the electrolysis process of the object to be tested 10 , the coating layer of the object to be tested 10 is gradually eroded by the electrolyte 4 and damaged. It should be added that the voltage that the three-use electricity meter 1 can provide is a multiple of 9 volts, which is enough to be the voltage required for electrolysis of most metals.

Real-time measurement step S03 : measuring the resistance value of the object to be measured 10 during the electrolysis process by using the three-use electricity meter 1 . If it is only to immediately judge whether the coating layer of the object to be tested 10 is damaged, the process can be skipped to the judgment step S05.

Continuous measurement step S04 : measure a plurality of the resistance values corresponding to a plurality of electrolysis times of the object to be measured 10 during the electrolysis process by using the three-use electricity meter 1 , and use the processor 5 to receive the resistance values And according to the electrolysis times and the corresponding resistance values, a resistance value function is obtained, and the resistance value function is a change curve of the resistance values with the electrolysis time. The third figure shows that the difference between the three objects to be tested 10 is that the object to be tested 10 forms the coating layers with different thicknesses at three different coating times respectively. For the sake of clarity, the object to be tested 10 is represented as a A first object to be tested 10a, a second object to be tested 10b, a third object to be tested 10c, the coating layer of the first object to be tested 10a is formed by a coating time of 5 minutes, the second object to be tested 10b The coating layer is formed by a coating time of 10 minutes, the coating layer of the third test object 10c is formed by a coating time of 15 minutes, the first test object 10a, the second test object 10b and the third test object 10b. The resistance values of the test object 10c are relatively large at the beginning, and the resistance values gradually decrease with the increase of the electrolysis time, and the resistance value functions of the second test object 10b and the third test object 10c The trend of the resistance value function is similar. Therefore, the coating layer of the object to be tested 10 can be optimized by forming a coating time of 10 minutes.

Judgment step S05 : using the processor 5 to compare the resistance value with the preset resistance value to determine whether the coating layer has been damaged. Further, the processor 5 determines that the resistance value function is in a moderate The slope change of the resistance value function after the electrolysis time is less than 5%, wherein, it is determined that the moderate electrolysis time is a corrosion resistance time of the coating layer, and a moderate resistance value corresponding to the moderate electrolysis time is compared with the preset resistance value, To judge the corrosion resistance of the coating layer. For example, from the third figure, during the electrolysis process of the object to be tested 10, any resistance value at each moment is greater than the preset resistance value, so it can be determined that the coating layer of the object to be tested 10 is not damaged. Or the moderate resistance values in the resistance value functions of the object to be measured 10 are all greater than the preset resistance value, so it can be more accurately determined that the coating layer of the object to be measured 10 is not damaged. Another judgment method is that, in the resistance value function, when the variation of the resistance value with time is less than 5% of the preset resistance value, the electrolysis time corresponding to the resistance value is also the corrosion resistance time, and the corrosion resistance time The corresponding resistance value is compared with the preset resistance value, which is also used to judge the corrosion resistance of the coating layer.

Analysis step S06: Under the condition that the parameters of the electrolyte 4 are fixed, according to the trend of the resistance value function, the slower the resistance value of the object to be tested 10 tends to the preset resistance value, the stronger the corrosion resistance of the coating layer is. The stronger it is, the faster the resistance value of the object to be tested 10 tends to the predetermined resistance value, and the weaker the corrosion resistance of the coating layer is. For example, from the third graph, according to the trend of the resistance value function of the second object to be tested 10b, the function trend of the resistance value of the third object to be tested 10c and the trend of the function of resistance value of the first object to be tested 10a, the second object to be tested 10a The resistance value of the object to be tested 10b and the resistance value of the third object to be tested 10c tend to be slower than the resistance value of the first object to be tested 10a and tend to the predetermined resistance value, the second object to be tested 10b and the resistance value of the The corrosion resistance of the coating layer of the third object to be tested 10c is stronger. Therefore, from the trend of the resistance value function, the strength of the corrosion resistance of the coating layer of the object to be tested 10 can be analyzed.

It should be added that the electrolysis process is not disturbed by gas, which affects the determination result. The object to be tested 10 and the conductor 2 are all put into the electrolyte 4, and the object 10 to be tested is subjected to In the process of electrolysis, the electrolytic cell 3 is sealed and the gas is continuously pumped, so that the gas generated during the electrolysis process can be extracted without affecting the electrolysis process.

It should be added that the parameters of the electrolyte 4 can be adjusted, and the parameters of the electrolyte 4 are parameters such as pH, concentration and temperature of the electrolyte 4, and the pH of the electrolyte 4 can be obtained as desired. The degree of detail of the resistance value function and the total electrolysis time can be adjusted, and the pH value of the electrolyte solution can be preset. For example, the thickness of the coating layer of the object to be tested 10 is thick, or the electrolysis needs to be accelerated, a high acid-base value can be selected. On the contrary, if the thickness of the coating layer of the object to be tested 10 is relatively thin, or the resistance value function needs to be more detailed, the electrolyte 4 that tends to be neutral is selected, but the electrolysis time also varies accordingly. lengthened. Therefore, the parameters such as pH value, concentration and temperature of the electrolyte can be adjusted according to the simulated corrosive environment.

Therefore, when the method for evaluating the corrosion resistance of the coating layer is carried out, the object to be tested 10 and the electrolytic cell 3 do not need to be limited to a specific shape and size, and the object to be tested 10 can be directly measured physically without the need to make a special test piece. The experiment can be carried out by using the combination of the three-use electricity meter 1 and the processor 5, without the need to use expensive instruments, and the electrolyte 4 acid can be adjusted by itself according to factors such as the experiment time, the thickness of the coating layer, and the degree of detail of the analysis. Parameters such as alkali value, concentration and temperature make the method of evaluating the corrosion resistance of the coating layer simple, easy to implement, low cost and convenient.

Referring to the first and fourth figures, a second embodiment of the method for evaluating the corrosion resistance of a coating layer of the present invention is similar to the first embodiment, except that in the electrolysis step S02, the electrolytic cell 3 used is a Hastelloy slot, the horizontal section of the Hastelloy slot is a trapezoid, the object to be tested 10 is placed on a hypotenuse of the trapezoid, the conductor 2 is placed on a long side of the trapezoid opposite to the hypotenuse, so , the object to be measured 10 is arranged obliquely relative to the conductor 2 in a parallel oblique direction in the electrolyte 4, the positive contact of the three-use meter 1 is connected to a plurality of positive taps, the The positive tap points are respectively electrically connected to the object to be measured 10 at multiple points along the oblique direction, and then a plurality of measurement points of the object to be measured 10 are formed respectively. a function of the resistance value. Then, the corrosion resistance strength of the coating layer of the object to be tested 10 can be more comprehensively analyzed from the resistance value functions. Therefore, in this example, by measuring a plurality of the measurement points of the object to be tested 10, and the lengths of the current loop paths of the measurement points are different, the corrosion resistance of the coating layer of the object to be tested 10 can be fully understood. sex.

To sum up, by electrically connecting the three-use meter 1 to the object to be measured 10 and the conductor 2, the object to be measured 10 does not need to be limited to a specific shape and size, and the object to be measured 10 can be directly For measurement, there is no need to make a special test piece, and by using the three-use electricity meter 1 to replace the original expensive instrument, and the parameters of the electrolyte 4 can be adjusted according to the needs, making the case more convenient and easier to implement, and the cost is lower. Low.

Based on the descriptions of the above embodiments, one can fully understand the operation, use and effects of the present invention, but the above-mentioned embodiments are only preferred embodiments of the present invention, which should not limit the implementation of the present invention. Scope, that is, simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the invention, all fall within the scope of the present invention.

1: Three-use meter

2: Conductor

3: Electrolyzer

4: Electrolyte

5: Processor

10: Object to be tested

Claims (9)

A method for evaluating the corrosion resistance of a coating layer, which is suitable for an object to be tested, the object to be tested includes a coating layer and a first metal substrate, the coating layer covers the first metal substrate, and the method for evaluating the corrosion resistance of the coating layer comprises: : Put the object to be tested and a conductor into an electrolyte, and perform electrolysis with a three-use electricity meter as an applied voltage required for electrolysis, wherein the applied voltage is a multiple of 9 volts, and the three-use electricity A positive contact and a negative contact of the watch are respectively electrically connected to the first metal substrate of the object to be tested and the conductor, and the object to be tested and the conductor are an anode and a cathode respectively; Measure a resistance value of the object to be tested during the electrolysis process with an electric meter; and compare the resistance value with a preset resistance value, and compare the change curves of the resistance values with the electrolysis time with the plurality of the resistance values. The change curve of the preset resistance value with the electrolysis time is used to judge the corrosion resistance of the coating layer, wherein the preset resistance value is positively correlated with the resistance value of a standard object, and the standard object includes a second metal substrate, the first The material of the second metal substrate is the same as that of the first metal substrate; wherein, before the object to be tested is electrolyzed, both the standard object and the conductor are put into the electrolyte, the standard object and the conductor are As the anode and the cathode respectively, electrolysis is carried out with the three-purpose electricity meter as the applied voltage, and a standard resistance value is obtained by measuring the resistance value of the standard object by the three-purpose electricity meter, and the preset resistance value is the same as the This standard resistance value is positively correlated. The method for evaluating the corrosion resistance of a coating layer as claimed in claim 1, wherein the resistance values corresponding to the electrolysis times of the object to be tested during the electrolysis process are measured by the three-meter electric meter, and according to the Equivalent electrolysis time and the corresponding resistance values to obtain a resistance value function, the resistance value function is the change curve of the resistance values with the electrolysis time, and the slope of the resistance value function changes during a gentle electrolysis After the time is less than 5%, it is determined that the moderate electrolysis time is a corrosion resistance time of the coating layer, and a moderate resistance value corresponding to the moderate electrolysis time is compared with the preset resistance value to judge the corrosion resistance of the coating layer. The method for evaluating the corrosion resistance of a coating layer according to claim 2, wherein when the moderate resistance value is greater than the preset resistance value, the coating layer is not damaged, and when the moderate resistance value is less than the preset resistance value, the coating layer Layer is destroyed. The method for evaluating the corrosion resistance of a coating layer as described in claim 2, wherein, when the parameters of the electrolyte are fixed, according to the trend of the resistance value function, the slower the resistance value of the object to be tested tends to the preset value The resistance value, the stronger the corrosion resistance of the coating layer, the faster the resistance value of the object to be tested tends to the preset resistance value, and the weaker the corrosion resistance of the coating layer. The method for evaluating the corrosion resistance of a coating layer according to claim 1, wherein the parameters of the electrolyte can be adjusted, and the parameters of the electrolyte are the pH, concentration and temperature of the electrolyte. The method for evaluating the corrosion resistance of a coating layer as claimed in claim 1, wherein the electrolyte is contained in an electrolytic cell, the object to be tested and the conductor are both placed in the electrolyte, and the object to be tested is subjected to During the electrolysis process, the electrolytic cell is sealed and pumped. The method for evaluating the corrosion resistance of a coating layer as set forth in claim 1, wherein the positive terminal of the three-use meter is connected to a plurality of positive taps, and the positive taps are electrically connected at multiple points at intervals. the object to be tested. The method for evaluating the corrosion resistance of a coating layer as claimed in claim 7, wherein the object to be tested is arranged obliquely with respect to the conductor in parallel to an oblique direction in the electrolyte, and the positive tap points are respectively along the oblique direction. The object to be tested is electrically connected at intervals in the direction. The method for evaluating the corrosion resistance of a coating layer according to claim 1, wherein a plurality of the resistance values corresponding to a plurality of electrolysis times of the object to be tested during the electrolysis process are measured by the three-meter electric meter, A resistance value function is obtained according to the electrolysis times and the corresponding resistance values, and the resistance value function is the change curve of the resistance values with the electrolysis time. In the resistance value function, when the resistance value changes with time The amount is less than 5% of the preset resistance value, and the electrolysis time corresponding to the resistance value is a corrosion resistance time.

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