Test method for simulating tropical marine atmospheric corrosion

Abstract

The application relates to a test method for simulating tropical marine climate corrosion, comprising the following steps: mixing sand, ionic compounds and water solution for the first time, controlling the pH value of the obtained sand ionic mixture to be 7.5-8.5; the cations in the ionic compounds include Na + and Ca 2+ , and the anions in the ionic compounds include Cl ‑ and SO4 2‑ ; drying the sand ionic mixture to obtain a sand medium; mixing the sand medium with calcium carbonate for the second time to obtain a corrosion medium; irradiating a sample to be tested with ultraviolet light, and then placing the corrosion medium on the surface of the sample to be tested for medium corrosion. The test method for simulating the tropical marine climate corrosion can simulate the corrosion condition of a material in a tropical marine climate in a short time, and the difference between the simulated corrosion and the natural corrosion in the tropical marine climate is small.

Description

Technical Field

[0001] This application relates to the field of simulation testing, and in particular to test methods for simulating corrosion in tropical marine climates. Background Technology

[0002] In tropical maritime climates, aging and corrosion are more severe, and the unique climatic environment places high demands on the weather resistance of materials. Natural exposure testing is the most realistic and reliable method for verifying material weather resistance, but it is time-consuming and costly. Therefore, it is of great significance to develop a testing method that is shorter in time and more closely approximates the degree of natural corrosion, simulating the corrosion of tropical maritime climates. Summary of the Invention

[0003] Based on this, this application provides a test method for simulating tropical marine climate corrosion that is less time-consuming and has a smaller difference from the degree of natural corrosion.

[0004] The technical solution to the above-mentioned technical problems in this application is as follows.

[0005] A test method for simulating corrosion in a tropical marine climate includes the following steps:

[0006] The sand, ionic compound, and water are first mixed, and the pH of the resulting sand-ionic mixture is controlled to be 7.5–8.5; the cations in the ionic compound include Na+. + and Ca 2+ The anions in the ionic compound include Cl. - and SO4 2- ;

[0007] The sand-soil ion mixture is dried to obtain a sand-soil medium;

[0008] The sandy medium is mixed with calcium carbonate in a second step to obtain a corrosive medium;

[0009] After the sample to be tested is irradiated with ultraviolet light, the corrosive medium is placed on the surface of the sample to be tested for medium corrosion test.

[0010] In some embodiments, in the test method simulating tropical marine climate corrosion, the mass ratio of the ionic compound to the sand is (0.2–0.8):1.

[0011] In some embodiments, in the test method simulating tropical marine climate corrosion, the cations in the ionic compound also include Mg. 2+ .

[0012] In some embodiments, in the test method simulating tropical marine climate corrosion, Na + Mg2+ With Ca 2+ The molar ratio is (15–50):(0.5–3.0):1, Cl - With SO4 2- The molar ratio is (15-25):1.

[0013] In some embodiments, in the test method simulating tropical marine climate corrosion, the ionic compound is selected from at least one of sodium chloride, calcium chloride, sodium sulfate, calcium sulfate, magnesium sulfate, and magnesium chloride.

[0014] In some embodiments, in the test method simulating tropical marine climate corrosion, the sand has a particle size of 0.25 mm to 0.35 mm.

[0015] In some embodiments, in the test method simulating tropical marine climate corrosion, the pH value of the sand-soil ion mixture is controlled using hydrochloric acid solution or sodium hydroxide solution.

[0016] In some embodiments, in the test method simulating tropical marine climate corrosion, the mass ratio of calcium carbonate to the sandy medium is (0.005 to 0.015):1.

[0017] In some embodiments, the test method for simulating tropical marine climate corrosion is wherein the conditions for corrosion of the medium are: temperature 40°C to 55°C and humidity 35% to 55%RH.

[0018] In some embodiments, in the test method simulating tropical marine climate corrosion, the corrosion time of the medium is 240h to 360h.

[0019] In some embodiments, in the test method simulating tropical marine climate corrosion, the ultraviolet irradiation time is 18h to 30h.

[0020] In some embodiments, in the test method simulating tropical marine climate corrosion, the sample to be tested includes an alloy material.

[0021] In some embodiments, in the test method simulating tropical marine climate corrosion, the ratio of the mass of the corrosive medium to the surface area of ​​the sample to be tested is (3g~8g) / cm². 2 .

[0022] Compared with existing technologies, the test method for simulating tropical marine climate corrosion in this application has the following advantages:

[0023] The above-mentioned experimental method for simulating tropical marine climate corrosion involves mixing sand with an ionic compound containing specific cations and anions and water, controlling the pH value of the resulting sand-ion mixture, and then mixing the dried sand-ion mixture with calcium carbonate to prepare a corrosive medium. This corrosive medium is used to corrode the sample after it has been exposed to ultraviolet light. After ultraviolet irradiation, the surface coating and passivation film of the sample are destroyed, further synergizing with the corrosive medium containing specific components. By controlling the pH value of the sand-ion mixture in the preparation step of the corrosive medium, the sample is placed in a neutral to slightly alkaline environment for rapid corrosion, effectively simulating the marine environment to achieve accelerated corrosion damage. Thus, the corrosion of materials in a tropical marine climate can be simulated in a short time, and the degree of corrosion is very close to that of natural corrosion in a tropical marine climate. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a diagram showing the corrosion of carbon steel substrate under natural conditions.

[0026] Figure 2 The corrosion pattern of the carbon steel substrate using the corrosion method of Example 3 is shown in the figure.

[0027] Figure 3 Corrosion diagram of carbon steel substrate using the corrosion method of Comparative Example 3;

[0028] Figure 4 The corrosion pattern of carbon steel substrate using the corrosion method of Comparative Example 9 is shown in the figure. Detailed Implementation

[0029] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0030] Therefore, this invention is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the invention are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0032] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element preceded by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The indefinite articles “a” and “an” preceding an element or component of the invention are not restrictive in terms of the number of elements or components (i.e., the number of times they appear). Therefore, “an” or “an” should be interpreted as including one or at least one, and singular elements or components also include plural forms, unless the quantity clearly refers only to the singular. “A plurality” means at least two, such as two, three, etc., unless otherwise expressly specified.

[0033] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0034] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0035] One embodiment of this application provides a test method for simulating corrosion in tropical marine climates, including:

[0036] Step S10: The sand, ionic compound, and water are mixed for the first time, and the pH of the resulting sand-ionic mixture is controlled to be 7.5–8.5; wherein the cations in the ionic compound include Na+. + and Ca 2+ Anions in ionic compounds include Cl- - and SO4 2- .

[0037] It is understood that the pH value of the sand-soil ion mixture is including, but is not limited to, 7.5, 7.8, 8, 8.2, and 8.5. In some examples, any two of these values ​​can be used as endpoints within a range, and the same applies below.

[0038] By mixing sand with ionic compounds containing specific cations and anions and water, and controlling the pH value of the resulting sand-ion mixture, the sample to be tested can be rapidly corroded in a neutral to slightly alkaline environment.

[0039] In some of these examples, in step S10, the mass ratio of the ionic compound to the sand is (0.2–0.8):1.

[0040] It is understood that the mass ratio of ionic compounds to sand includes, but is not limited to, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, and 0.8:1.

[0041] Optionally, the mass ratio of the ionic compound to the sand is (0.2–0.8):1.

[0042] In some of these examples, in step S10, the cation in the ionic compound also includes Mg. 2+ .

[0043] In some of these examples, in step S10, Na + Mg2+ With Ca 2+ The molar ratio is (15–50):(0.5–3.0):1, Cl - With SO4 2- The molar ratio is (15-25):1.

[0044] It is understandable that Na + With Ca 2+ The molar ratio is (15–50):1, including but not limited to 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 28:1, 30:1, 35:1, 40:1, 45:1, and 50:1; Mg 2+ With Ca 2+ The molar ratio is (0.5–3.0):1, including but not limited to 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, and 3:1; Cl - With SO4 2- The molar ratios include, but are not limited to, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, and 25:1.

[0045] By controlling Na + Ca 2+ With Mg 2+ molar ratio and Cl - With SO4 2- The molar ratio simulates the molar ratio of cations and anions in a marine environment, effectively reducing the degree of corrosion compared to natural environments.

[0046] This is understandable, including cation Na. + Ca 2+ Mg 2+ and anion Cl - SO4 2- Ionic compounds include, but are not limited to, sodium chloride (NaCl), sodium sulfate (Na2SO4), calcium chloride (CaCl2), calcium sulfate (CaSO4), magnesium chloride (MgCl2), and magnesium sulfate (MgSO4).

[0047] In some of these examples, in step S10, the ionic compound is selected from at least one of sodium chloride, calcium chloride, magnesium sulfate, and magnesium chloride.

[0048] Optionally, the ionic compounds include sodium chloride, calcium chloride, and magnesium sulfate.

[0049] In some specific examples, in step S10, the ionic compound comprises the following components by mass fraction:

[0050] Sodium chloride 20g~50g, calcium chloride 0.5g~3g, magnesium sulfate 0g~6g.

[0051] It is understood that the mass fractions of sodium chloride include, but are not limited to, 20g, 22g, 25g, 28g, 30g, 35g, 40g, 45g, 50g; calcium chloride includes, 0.5g, 0.8g, 1g, 1.2g, 1.5g, 2g, 2.2g, 2.5g, 3g; and magnesium sulfate includes, 0g, 0.5g, 1g, 1.25g, 1.8g, 2g, 3g, 4g, 5g, 5.5g, 6g.

[0052] In some of these examples, in step S10, the ionic compound comprises the following components by mass fraction:

[0053] Sodium chloride 25g, calcium chloride 1g, magnesium sulfate 3g.

[0054] In some of these examples, in step S10, the particle size of the sand is 0.25 mm to 0.35 mm.

[0055] It is understood that the particle size of sand includes, but is not limited to, 0.25mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm, and 0.35mm.

[0056] By simulating the particle size of sand in a marine climate, the difference between the degree of corrosion of the material under the simulated test in this application and the degree of natural corrosion under a tropical marine climate can be further reduced, and the repeatability of the simulated test can be further improved.

[0057] In some of these examples, step S10 includes:

[0058] Step S11: Mix sand and ionic compounds to obtain a sand-ionic mixture.

[0059] Furthermore, after mixing the sand and the ionic compound, the process also includes a step of grinding the mixture obtained by mixing the sand and the ionic compound.

[0060] It's understandable that grinding can make the mixture more homogeneous.

[0061] This can be further understood as using a grinding machine for grinding.

[0062] In some of these examples, the grinding time in step S11 is 1 to 3 hours.

[0063] It is understood that the grinding time includes, but is not limited to, 1h, 1.2h, 1.5h, 2h, 2.5h, 2.8h, and 3h.

[0064] Optionally, the grinding time is 1.5h to 2.5h.

[0065] Furthermore, the grinding time is 2 hours.

[0066] Step S12: Mix the sand ion mixture with water, and control the pH value of the resulting sand ion mixture to be 7.5-8.5.

[0067] It is understandable that acid or alkali can be dissolved in water to form an acid solution or alkali solution, which is then mixed with sand and ionic compounds. The pH value of the resulting sand-ionic mixture can be controlled by adjusting the amount of acid or alkali solution.

[0068] It is understood that acid or alkali solutions primarily dissolve substances in the sand that are soluble in water, acid, or alkali solutions, as well as any additional ionic compounds, and adjust the pH of the sand-soil ion mixture to a specific value. In some examples, in step S12, hydrochloric acid or sodium hydroxide solution is used to control the pH of the sand-soil ion mixture.

[0069] Using the specific types of acid or alkali solutions mentioned above will not introduce other impurity ions.

[0070] In some of these examples, in step S10, the concentration of the acid solution or the alkaline solution is 0.05 mol / L to 0.15 mol / L, respectively.

[0071] It is understood that the concentrations of the acid or alkaline solutions are, but are not limited to, 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L, respectively.

[0072] Optionally, the concentration of the acid or alkaline solution is 0.1 mol / L.

[0073] Furthermore, the concentrations of the hydrochloric acid solution or the sodium hydroxide solution are 0.05 mol / L to 0.15 mol / L, respectively.

[0074] Furthermore, an acid solution or an alkaline solution is added to the sand-soil ion mixture.

[0075] Furthermore, the sand-soil ion mixture is stirred simultaneously while adding acid or alkali solutions.

[0076] Step S20: Dry the sand-soil ion mixture to obtain the sand-soil medium.

[0077] In some of these examples, in step S20, the drying temperature is 30°C to 50°C and the time is 24h to 48h.

[0078] Optionally, the drying temperature is 30°C and the time is 24 hours.

[0079] Step S30: Mix the sandy medium with calcium carbonate for the second time to obtain a corrosive medium.

[0080] It is understandable that after adjusting the pH of the sand-soil ion mixture and drying it, it is then mixed with calcium carbonate. Calcium carbonate can provide carbonate ions, which can promote corrosion, and has little impact on the pH of the final corrosive medium in a humid environment. If calcium carbonate is added directly to the sand-soil ion mixture, carbonate ions will react with hydrogen ions, affecting the pH adjustment.

[0081] In some of these examples, in step S30, the mass ratio of calcium carbonate to sandy medium is (0.005–0.015):1.

[0082] It is understood that this includes, but is not limited to, 0.0051:1, 0.008:1, 0.01:1, 0.012:1, and 0.015:1.

[0083] In some examples, step S30, after the second mixing, also includes a step of grinding the mixture obtained from the second mixing.

[0084] It is understandable that grinding in step S30 can make the mixture more uniform; furthermore, a grinding machine is used for grinding.

[0085] In some of these examples, the grinding time in step S30 is 1 to 3 hours.

[0086] It is understood that the grinding time includes, but is not limited to, 1h, 1.2h, 1.5h, 2h, 2.5h, 2.8h, and 3h.

[0087] Optionally, the grinding time is 1.5h to 2.5h.

[0088] Furthermore, the grinding time is 2 hours.

[0089] Step S40: After irradiating the sample with ultraviolet light, place the corrosive medium on the surface of the sample for medium corrosion.

[0090] The above-mentioned experimental method for simulating tropical marine climate corrosion involves mixing sand with an ionic compound containing specific cations and anions and water, controlling the pH value of the resulting sand-ion mixture, and then mixing the dried sand-ion mixture with calcium carbonate to prepare a corrosive medium. This corrosive medium is used to corrode the sample after it has been exposed to ultraviolet light. After ultraviolet irradiation, the surface coating and passivation film of the sample are destroyed, further synergizing with the corrosive medium containing specific components. By controlling the pH value of the sand-ion mixture in the preparation step of the corrosive medium, the sample is placed in a neutral to slightly alkaline environment for rapid corrosion, effectively simulating the marine environment to achieve accelerated corrosion damage. Thus, the corrosion of materials in a tropical marine climate can be simulated in a short time, and the degree of corrosion is very close to that of natural corrosion in a tropical marine climate.

[0091] In some of these examples, in step S40, the conditions for media corrosion are: temperature 40℃~55℃, humidity 35RH~55RH.

[0092] It is understood that the conditions for media corrosion include, but are not limited to, temperatures of 40℃, 42℃, 45℃, 48℃, 50℃, 52℃, 53℃, and 55℃, and humidity of 35RH, 40RH, 45RH, 50RH, and 55RH.

[0093] Optionally, the conditions for media corrosion are: temperature 45℃~55℃, humidity 40RH~50RH.

[0094] In some of these examples, in step S40, the temperature of the medium corrosion is 50°C and the humidity is 45% RH.

[0095] In some of these examples, the corrosion time of the medium in step S40 is 200h to 300h.

[0096] It is understood that the time for media corrosion includes, but is not limited to, 200h, 210h, 220h, 230h, 240-25h, 260h, 270h, 280h, 290h, and 300h.

[0097] Optionally, the corrosion time of the medium is 220h to 260h.

[0098] Optionally, the corrosion time is 240 hours.

[0099] In some of these examples, in step S40, ultraviolet irradiation is performed according to the test method of GB / T 14522.

[0100] In some of these examples, the ultraviolet irradiation time in step S40 is 18h to 30h.

[0101] It is understood that the duration of ultraviolet irradiation includes, but is not limited to, 18h, 20h, 22h, 24h, 25h, 28h, and 30h.

[0102] Optionally, the duration of ultraviolet irradiation is 20h to 28h.

[0103] Optionally, the ultraviolet irradiation time is 24 hours.

[0104] It is understandable that after the media corrosion step is completed, the material is removed, cleaned, dried, and then the corrosion status of the material is observed and evaluated.

[0105] In some of these examples, the test samples used in simulated tropical marine climate corrosion methods include, but are not limited to, alloy materials.

[0106] Furthermore, the samples to be tested include, but are not limited to, carbon steel, alloy steel, and aluminum alloy.

[0107] Optionally, the samples to be tested include carbon steel and aluminum alloys.

[0108] It is understood that the thickness of the sample to be tested is not limited in this application.

[0109] In some specific examples, in the test method simulating tropical marine climate corrosion, the thickness of the sample to be tested is 0.3 cm to 1.5 cm.

[0110] In some of these examples, in test methods simulating tropical marine climate corrosion, the ratio of the mass of the corrosive medium to the surface area of ​​the sample being tested is (3g–8g) / cm². 2 .

[0111] It is understood that the ratio of the mass of the corrosive medium to the surface area of ​​the sample to be tested includes, but is not limited to, 3 g / cm³. 2 5g / cm 2 8g / cm 2 .

[0112] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0113] Example 1

[0114] (1) Preparation of corrosive media

[0115] 1.1) Mix 25g sodium chloride, 1g calcium chloride, 3g magnesium sulfate, and 70g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Ca 2+The molar ratio is 47.48:2.78:1, Cl - With SO4 2- The molar ratio was 17.82:1, and the mass ratio of the ionic compound to the sand was approximately 0.41:1.

[0116] 1.2) In a fume hood, slowly add a 0.1 mol / L sodium hydroxide solution to the sand ion mixture while stirring until the pH of the resulting sand ion mixture is 8.

[0117] 1.3) The sand-soil ion mixture was dried in a drying oven at 30°C for 24 hours to obtain 99g of sand-soil medium;

[0118] 1.4) Place the sandy medium and 1g of calcium carbonate into a grinder and grind and stir for 2 hours to obtain the corrosive medium; the mass ratio of calcium carbonate to sandy medium is 0.01:1.

[0119] (2) The surface area is 25cm² 2 A carbon steel substrate with a thickness of 0.3 cm was placed in an ultraviolet aging chamber for ultraviolet irradiation (according to the test method of GB / T 14522) for 24 hours. After that, it was taken out and 5g of corrosive medium was evenly placed on the surface of the carbon steel substrate. The substrate was then placed in a temperature and humidity control chamber, with the temperature controlled at 50℃ and the humidity at 45RH, for medium corrosion for 240 hours. After that, the substrate was taken out, the corrosive medium was washed off, and the substrate was dried.

[0120] Example 2

[0121] The process is basically the same as in Example 1, except that step 1.1) of Example 2 is as follows:

[0122] Mix 50g sodium chloride, 2g calcium chloride, 6g magnesium sulfate, and 70g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Ca 2+ The molar ratio is 47.48:2.78:1, Cl - With SO4 2- The molar ratio is 17.82:1, and the mass ratio of ionic compound to sand is approximately 0.83:1; in step 1.4), the mass ratio of calcium carbonate to sand medium is 0.01:1.

[0123] Example 3

[0124] The example is basically the same as Example 1, except that step 1.1) of Example 3 is as follows:

[0125] Mix 30g sodium chloride, 3g calcium chloride, 3g magnesium sulfate, and 60g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Ca 2+ The molar ratio is 18.99:0.93:1, Cl - With SO4 2- The molar ratio is 22.57:1, and the mass ratio of ionic compound to sand is approximately 0.6:1.

[0126] Example 4

[0127] The process is basically the same as in Example 1, except that in step 1.2) of Example 4, the addition of sodium hydroxide solution is stopped when the pH value of the sand-soil ion mixture is adjusted to 7.5.

[0128] Example 5

[0129] The process is basically the same as in Example 1, except that step (2) in Example 5 is as follows:

[0130] (2) The surface area is 25cm² 2 A carbon steel substrate with a thickness of 0.3 cm was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation. After that, it was taken out and 5g of corrosive medium was evenly placed on the surface of the carbon steel substrate. The substrate was then placed in a temperature and humidity control chamber, with the temperature controlled at 40℃ and the humidity at 55RH, for 300 hours of medium corrosion. After that, the substrate was taken out, the corrosive medium was washed off, and the substrate was dried.

[0131] Example 6

[0132] The process is basically the same as in Example 1, except that step (2) in Example 6 is as follows:

[0133] (2) The surface area is 25cm² 2 A carbon steel substrate with a thickness of 0.3 cm was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation. After that, it was taken out and 5g of corrosive medium was evenly placed on the surface of the carbon steel substrate. The substrate was then placed in a temperature and humidity control chamber, with the temperature controlled at 60℃ and the humidity at 45RH, for 240 hours of medium corrosion. After that, the substrate was taken out, the corrosive medium was washed off, and the substrate was dried.

[0134] Example 7

[0135] The process is basically the same as in Example 1, except that step (2) in Example 7 is as follows:

[0136] (2) The surface area is 25cm² 2A carbon steel substrate with a thickness of 0.3 cm was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation. After that, it was taken out and 5g of corrosive medium was evenly placed on the surface of the carbon steel substrate. The substrate was then placed in a temperature and humidity control chamber, with the temperature controlled at 30℃ and the humidity at 45RH, for 240 hours of medium corrosion. After that, the substrate was taken out, the corrosive medium was washed off, and the substrate was dried.

[0137] Comparative Example 1

[0138] (1) Preparation of corrosive media

[0139] Mix 25g sodium chloride, 1g calcium chloride, 3g magnesium sulfate, and 70g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Ca 2+ The molar ratio is 47.48:2.78:1, Cl - With SO4 2- The molar ratio is 17.82:1;

[0140] (2) The surface area is 25cm² 2 A carbon steel substrate with a thickness of 0.3 cm was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation. After that, 5g of sand ion mixture was evenly placed on the surface of the carbon steel substrate and placed in a temperature and humidity control chamber. The temperature was controlled at 50℃ and the humidity at 45RH for 240 hours of medium corrosion. Then, it was taken out, the corrosive medium was washed off and dried.

[0141] Comparative Example 2

[0142] (1) Preparation of corrosive media

[0143] 1.1) Mix 25g sodium chloride, 1g calcium chloride, 3g magnesium sulfate, and 70g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Ca 2+ The molar ratio is 47.48:2.78:1, Cl - With SO4 2- The molar ratio was 17.82:1, and the mass ratio of the ionic compound to the sand was approximately 0.41:1.

[0144] 1.2) In a fume hood, slowly add a 0.1 mol / L sodium hydroxide solution to the sand ion mixture while stirring until the pH of the resulting sand ion mixture is 8.

[0145] 1.3) The sand-soil ion mixture was dried in a drying oven at 30°C for 24 hours to obtain the sand-soil medium;

[0146] (2) Place 5g of sandy medium evenly on a surface area of ​​25cm². 2 A carbon steel substrate with a thickness of 0.3 cm was placed in a temperature and humidity control chamber at a temperature of 50℃ and a humidity of 45RH for 240 hours to undergo medium corrosion. Then it was removed, cleaned of the corrosive medium, and dried.

[0147] Comparative Example 3

[0148] Similar to Example 1, except that in Comparative Example 3, calcium chloride in step 1.1) of Example 1 is replaced with an equal mass of aluminum chloride. Step 1.1) of Comparative Example 3 is as follows:

[0149] Mix 25g sodium chloride, 1g aluminum chloride, 3g magnesium sulfate, and 70g sand with a particle size of 0.25mm-0.35mm. Grind and stir evenly in a grinder for 2 hours to obtain a sand-soil ion mixture; Na + Mg 2+ With Al 3+ The molar ratio is 56.99:3.33:1, Cl - With SO4 2- The molar ratio is 17.99:1, and the mass ratio of ionic compound to sand is approximately 0.41:1.

[0150] Comparative Example 4

[0151] The results are basically the same as in Example 1, except that in step 1.1) of Comparative Example 4, calcium chloride is not added, while the amount of sodium chloride added is 26g.

[0152] Comparative Example 5

[0153] The comparison is basically the same as Example 1, except that Comparative Example 5 omits step 1.4) of mixing with calcium carbonate in Example 1 and step 1.3) of preparing the sand medium. Step (2) of Comparative Example 5 is as follows:

[0154] (2) The surface area is 25cm² 2 A carbon steel substrate with a thickness of 0.3cm was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation. After that, 5g of sand medium was evenly placed on the surface of the carbon steel substrate and placed in a temperature and humidity control chamber. The temperature was controlled at 50℃ and the humidity at 45RH for 240 hours of medium corrosion. Then, it was taken out, the corrosive medium was washed off and dried.

[0155] Comparative Example 6

[0156] The process is basically the same as in Example 1, except that the ultraviolet irradiation step is omitted. Step (2) of Comparative Example 6 is as follows:

[0157] (2) Place 5g of corrosive medium evenly on a surface area of ​​25cm². 2 A carbon steel surface with a thickness of 0.3 cm was placed in a temperature and humidity control chamber, with the temperature controlled at 50℃ and the humidity at 45RH, and subjected to medium corrosion for 240 hours; then it was taken out, cleaned of the corrosive medium, and dried.

[0158] Comparative Example 7

[0159] The process is basically the same as in Example 1, except that the medium corrosion is performed first, followed by ultraviolet irradiation. Step (2) of Comparative Example 7 is as follows:

[0160] (2) Place 5g of corrosive medium evenly on a surface area of ​​25cm². 2 A carbon steel surface with a thickness of 0.3cm was placed in a temperature and humidity control chamber at a temperature of 50℃ and a humidity of 45RH for 240 hours of medium corrosion. After that, it was taken out, cleaned of the corrosive medium, and dried. Then it was placed in an ultraviolet aging chamber for 24 hours of ultraviolet irradiation.

[0161] Comparative Example 8

[0162] The process is basically the same as in Example 1, except that in step 1.2 of Comparative Example 8, the addition of sodium hydroxide solution was stopped when the pH of the sand-soil ion mixture was adjusted to 6.5.

[0163] Comparative Example 9

[0164] The process is basically the same as in Example 1, except that in Comparative Example 9, step 1.2), the addition of sodium hydroxide solution was stopped when the pH of the sand-soil ion mixture was adjusted to 9.5.

[0165] Carbon steel substrates of the same size and type as in Example 1 were subjected to natural corrosion for one year in the tropical corrosive climate of Qionghai City, Hainan Province (natural corrosion group A). ​​The corrosion depth of natural corrosion and the corrosion depth of the carbon steel substrates in each example and comparative example were tested using metallographic methods. The maximum corrosion depth was taken. Three parallel test groups were set up for each group, and the average value of the three groups was taken. The results are shown in Table 1. The corrosion conditions of natural corrosion, Example 3, Comparative Example 3, and Comparative Example 9 are as follows: Figures 1-4 As shown.

[0166] Table 1

[0167]

[0168] The difference refers to the difference between the corrosion depth of group A under natural corrosion and the corrosion depth of each embodiment or comparative example.

[0169] 12 pieces, each 25cm in size 2A380 aluminum alloy with a thickness of 0.3 cm was divided into 4 groups. One group was placed in the tropical corrosive climate environment of Qionghai, Hainan for natural corrosion for 1 year (natural corrosion group B). The other 3 groups were subjected to corrosion by simulation methods of Example 1 and Comparative Examples 1-2, respectively. The average value of each group was taken, and the results are shown in Table 2.

[0170] Table 2

[0171]

[0172]

[0173] As can be seen from Tables 1 and 2, compared with the comparative example, the accelerated corrosion test results of the examples are similar to the natural corrosion results, within ±10%, while the accelerated corrosion test results of the comparative example differ significantly from the natural corrosion results.

[0174] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A test method for simulating corrosion in tropical marine climates, characterized in that, Includes the following steps: The sand, ionic compound, and water are first mixed, and the pH of the resulting sand-ionic mixture is controlled to be 8-8.5; the cations in the ionic compound include Na+. + Mg 2+ and Ca 2+ The anions in the ionic compound include Cl. - and SO4 2- The mass ratio of the ionic compound to the sand is (0.4~0.83):1, and the ionic compound contains Na... + Mg 2+ With Ca 2+ The molar ratio is (45~50):(2.5~3.0):1, Cl - With SO4 2- The molar ratio is (15~18):1; the particle size of the sand is 0.25mm~0.35mm; The sand-soil ion mixture is dried to obtain a sand-soil medium; The sandy medium is mixed with calcium carbonate in a second process to obtain a corrosive medium; the mass ratio of calcium carbonate to the sandy medium is (0.005~0.015):

1. After the sample to be tested is irradiated with ultraviolet light, the corrosive medium is placed on the surface of the sample to be tested for medium corrosion. The ultraviolet irradiation time is 18 h to 30 h. The medium corrosion conditions are: temperature 40℃ to 55℃, humidity 35 RH to 55 RH, and time 240 h to 360 h.

2. The test method as described in claim 1, characterized in that, The mass ratio of the ionic compound to the sand is (0.6~0.83):

1.

3. The test method as described in claim 1, characterized in that, In the ionic compound, Cl - With SO4 2- The molar ratio is (16~18):

1.

4. The test method as described in claim 1, characterized in that, The ionic compound is selected from sodium chloride, calcium chloride, and magnesium sulfate.

5. The test method as described in claim 1, characterized in that, The pH value of the sand-soil ion mixture is controlled using hydrochloric acid solution or sodium hydroxide solution.

6. The test method as described in claim 1, characterized in that, The mass ratio of calcium carbonate to the sandy medium is (0.01~0.015):

1.

7. The test method according to any one of claims 1 to 6, characterized in that, Ionic compounds include the following components: Sodium chloride 25 g, calcium chloride 1 g, magnesium sulfate 3 g.

8. The test method according to any one of claims 1 to 6, characterized in that, The sample to be tested includes alloy materials.

9. The test method according to any one of claims 1 to 6, characterized in that, The ratio of the mass of the corrosive medium to the surface area of ​​the sample to be tested is (3 g~8 g) / cm². 2 .

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