A method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments

Abstract

This invention relates to the field of corrosion detection technology for metallic materials, and discloses a method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments. The method comprises six steps: pre-testing for adaptation of magnesium alloy-marine atmospheric corrosion mechanisms, service environment survey and data acquisition, delineation of magnesium alloy-specific corrosion regions, compilation of individual environmental spectra and parameter quantification, construction and equivalent verification of accelerated corrosion environment spectra, and verification and correction. This invention addresses the lack of adaptability of existing corrosion environment spectra compilation methods to the specific corrosion behavior of magnesium alloys in marine atmospheric environments, enabling the compiled environmental spectra to accurately reflect the corrosion state of magnesium alloys in these environments.

Description

Technical Field

[0001] This invention relates to the field of corrosion detection technology for metallic materials, and more specifically, to a method for compiling corrosion environment spectra of magnesium alloys in a marine atmospheric environment. Background Technology

[0002] With the development of lightweight marine engineering equipment, magnesium alloys, due to their advantages such as low density and high specific strength, are increasingly in demand for applications in marine platform components and lightweight ship parts. However, magnesium alloys have high chemical reactivity and are prone to pitting corrosion and crevice corrosion in the marine atmospheric environment, which seriously affects the service safety and lifespan of equipment. Corrosion environment spectrum is a core technical tool for assessing the corrosion performance of metallic materials and guiding protective design; the scientific validity of its compilation directly determines the reliability of the assessment results.

[0003] Currently, corrosion environment spectrum compilation methods are mostly targeted at aircraft, general equipment, or broad-spectrum metals (such as aluminum alloys and steel), and some general marine atmospheric environment spectra have been developed. In terms of accelerated corrosion spectra, methods such as CASS and EXCO are mainly designed for aerospace aluminum alloys and are widely used in the accelerated corrosion assessment of metallic materials.

[0004] Existing accelerated corrosion spectra do not consider the differences in corrosion potential and corrosion product stability (such as Mg(OH)2 and MgCl2) between magnesium alloys and aluminum alloys, resulting in poor reproducibility of corrosion damage in magnesium alloys and an inability to accurately reflect their actual corrosion state. Meanwhile, general natural environment spectra fail to highlight the core characteristics of the marine atmosphere—high salt spray, high humidity, acidic rainfall, and alternating wet and dry tides—especially lacking information on sea salt Cl2. - The specific impact data of concentration and sea salt ion deposition rate on magnesium alloy corrosion are lacking. In addition, existing methods have not established an accelerated equivalent model of "corrosion damage degree - environmental parameters - time" for magnesium alloys in the marine atmosphere, resulting in an unclear correspondence between accelerated test cycle and actual service life, which is difficult to meet the needs of service life assessment. Secondly, the local corrosion environment faced by exposed, semi-enclosed and enclosed parts of magnesium alloys in marine equipment varies greatly. Existing zoning methods have not incorporated the crevice corrosion and galvanic corrosion sensitivity of magnesium alloys, and the spectral targeting is insufficient.

[0005] Based on the aforementioned technical challenges, and in order to address the problem that existing environmental spectra cannot accurately match the marine atmospheric service requirements of magnesium alloys, it is urgent to propose a method for compiling corrosion environmental spectra of magnesium alloys under marine atmospheric conditions. Summary of the Invention

[0006] In view of this, the present invention provides a method for compiling the corrosion environment spectrum of magnesium alloys in a marine atmospheric environment. The aim is to achieve both the authenticity of the natural environment spectrum and the efficiency of the accelerated environment spectrum by clarifying the corrosion mechanism of magnesium alloys in the marine atmosphere, screening specific environmental factors, dividing targeted corrosion regions, and constructing a precise accelerated equivalence relationship. This provides reliable technical support for the corrosion protection design and life assessment of magnesium alloy marine equipment.

[0007] On the one hand, the present invention provides a method for compiling corrosion environment spectra of magnesium alloys in a marine atmospheric environment, comprising the following steps: S1. Pre-test of magnesium alloy-marine atmospheric corrosion mechanism adaptation: Magnesium alloy standard test pieces are placed in simulated marine atmospheric corrosion environments with different parameter combinations. Through corrosion performance testing, the dominant corrosion forms, key corrosion inducing factors, and the correspondence between corrosion products and environmental factors of magnesium alloy in marine atmosphere are determined. S2. Service environment survey and data collection: Determine the target service sea area, divide the target sea area into different marine climate zones according to climate characteristics, collect macro-environmental data of each climate zone in a differentiated manner, and collect local environmental data of key service parts of magnesium alloy components to form a comprehensive environmental dataset. S3. Delineation of Corrosion Zones Specific to Magnesium Alloys: Based on the actual service scenarios of magnesium alloys in marine equipment, multiple core corrosion zones are delineated. According to the corrosion rate of magnesium alloys in each corrosion zone obtained from the pre-test in step S1, the time proportion of each corrosion zone in the total environmental spectrum is determined, and the weight of the corrosion zone is assigned. S4. Compilation and Parameter Quantization of Individual Environmental Spectra: Based on the preliminary test results of step S1 and the comprehensive environmental dataset of step S2, temperature-humidity spectrum, salt spray-wet-dry alternation spectrum, and acidic medium-ultraviolet synergistic spectrum are compiled to complete the parameter quantization of each individual environmental spectrum block. S5. Construction and Equivalent Verification of Accelerated Corrosion Environment Spectrum: Based on the existing accelerated corrosion spectrum of marine metals, the compatibility of magnesium alloys is optimized. By comparing natural environment corrosion tests and accelerated corrosion tests, the accelerated equivalent relationship between the degree of corrosion damage of magnesium alloys and environmental parameters and test time is established. The combination design of accelerated spectrum blocks is determined according to the characteristics of different climate zones and corrosion areas. S6. Verification and Correction: Through laboratory and engineering verification, the compiled environmental spectrum parameters are corrected to obtain the final corrosion environmental spectrum of magnesium alloys under marine atmospheric conditions.

[0008] Further, in step S1, the parameters for simulating the marine atmospheric corrosion environment include a salt spray Cl- concentration gradient of 0.3-1.2 mg / (100 cm³). 2•d) Relative humidity gradient 30%-95%, temperature gradient -10 to 35℃, acid rain pH gradient 3.5-5.6; the key corrosion inducing factors include a Cl- concentration threshold of 0.3 mg / (100 cm³). 2 •d) Critical relative humidity value: 70%.

[0009] Furthermore, in step S2, the marine climate zone is divided into a temperate marine climate zone, a subtropical marine climate zone, and a tropical marine climate zone; Specifically, data on freeze-thaw cycles, duration of low temperatures, and seasonal salt spray deposition should be collected at least in the temperate zone; data on the frequency of plum rains or typhoons, acid rain pH values, and salt spray concentration fluctuations should be collected at least in the subtropical zone; and data on the duration of high temperature and humidity, cumulative salt spray Cl- concentration, and intensity of strong ultraviolet radiation should be collected at least in the tropical zone.

[0010] Furthermore, in step S3, the core corrosion area includes an exposed strong corrosion area, a semi-enclosed corrosion area, and a closed corrosion area; the time percentage of each corrosion area is 40%-60% for the exposed area, 25%-40% for the semi-enclosed area, and 10%-25% for the closed area.

[0011] Further, in step S4, the quantification range of sea salt Cl- concentration in the salt spray-wet / dry alternating spectrum is 0.3-1.0 mg / (100 cm⁻¹). 2 •d); The acidic medium-UV synergistic spectrum is a combination spectrum of acid rain immersion-UV irradiation, with parameters of acid rain pH value 3.5-5.6 and UV radiation intensity 50-350 MJ / m. 2 The ratio of immersion time to irradiation time is 3:1.

[0012] Further, in step S5, the compatibility optimization involves adjusting the composition of the accelerated spectrum solution for the magnesium alloy, reducing the acetic acid concentration in the CASS spectrum from 0.5% to 0.2%-0.3%, and adding 3.5%-5.0% NaCl to simulate a marine environment; the acceleration equivalent relationship corresponds to an acceleration factor of 80-120 times.

[0013] Further, in step S6, the laboratory verification is to compare the corrosion damage characteristics of accelerated test specimens and specimens exposed to natural environment, and the engineering verification is to monitor the corrosion status of magnesium alloy components of actual marine equipment for a service cycle of 1-3 years and correct the environmental spectrum parameters. The correlation coefficient of corrosion damage in the corrected environmental spectrum is >0.9.

[0014] On the other hand, the present invention also provides a corrosion environment spectrum of magnesium alloys in a marine atmospheric environment, which is prepared by the above-mentioned method for compiling corrosion environment spectrum of magnesium alloys in a marine atmospheric environment. The corrosion environment spectrum includes a natural corrosion environment spectrum and / or an accelerated corrosion environment spectrum.

[0015] Furthermore, the natural corrosion environment spectrum includes a temperature-humidity spectrum, a salt spray-wet / dry alternation spectrum, and an acidic medium-UV synergistic spectrum, combined according to the time proportion of corresponding climatic zones; the core parameters of the accelerated corrosion environment spectrum include a cumulative Cl- concentration of 0.3-1.2 mg / (100 cm⁻¹) in sea salt. 2 •d) Relative humidity 30%-95%, temperature -10 to 35℃, acid rain pH 3.5-5.6, and ultraviolet radiation intensity 50-350 MJ / m² 2 The cycle of alternating between dry and wet conditions is 4-12 hours.

[0016] Furthermore, the accelerated corrosion environment spectrum is composed of an accelerated salt spray spectrum block, an accelerated temperature and humidity spectrum block, and a targeted enhancement module in a cycle; the core parameters of the accelerated corrosion environment spectrum include an accelerated salt spray Cl- mass concentration of 0.6-2.0 mg / (100 cm⁻¹). 2 •d) Acceleration temperature and humidity are 25-40℃, relative humidity is 85%-98%, and acceleration multiple is 80-120 times; the targeted enhancement module is a freeze-thaw cycle module or a strong ultraviolet-high salt spray synergistic module.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: Highly targeted and exhibiting excellent reproducibility of corrosion damage: This application's pre-experimental study on the adaptation of magnesium alloy-marine atmospheric corrosion mechanism and the screening of specific environmental factors identified key inducing factors for magnesium alloy corrosion through pre-experimental studies, and screened sea salt Cl... - Specific environmental parameters such as concentration are used to ensure the compatibility of the spectrum with the corrosion characteristics of magnesium alloys. Compared with existing general environmental spectra, the environmental spectrum compiled by this method can accurately match the corrosion characteristics of magnesium alloys in the marine atmosphere and can truly reproduce the dominant corrosion forms of magnesium alloys (pitting corrosion, uniform corrosion, crevice corrosion) and the composition of corrosion products (Mg(OH)2, MgCO3, MgCl2·6H2O).

[0018] High accuracy and adaptability to different climate regions: The differentiated service environment survey and data collection and quantitative optimization of single environmental spectrum parameters in this application collect key data by dividing the climate zone and adjust parameters such as temperature, humidity and salt spray concentration in a targeted manner to achieve accurate simulation of corrosion environment in different regions. This solves the problem of existing environmental spectra being "overly general and neglecting detailed subdivision". It can compile exclusive environmental spectra for corrosion characteristics of different marine climate zones such as temperate, subtropical and tropical.

[0019] Highly practical, with a clear correlation between acceleration and actual service: The accelerated corrosion environment spectrum construction and equivalent verification of this application, through comparative tests of natural environment and accelerated tests, corrected the acceleration factor of different climate zones, ensuring the relevance and feasibility of the accelerated spectrum, established the accelerated equivalent relationship between magnesium alloy corrosion damage and environmental parameters and time, clarified the correspondence between accelerated test cycle and actual service life, and took into account both evaluation efficiency and result reliability.

[0020] Good zoning adaptability and coverage of diverse service scenarios: The magnesium alloy-specific corrosion zone division and spectral block combination design of this application combines the sensitivity of magnesium alloy crevice corrosion and galvanic corrosion. It divides the area according to the actual service scenario and matches the corresponding environmental spectral blocks. For the differences in corrosion environment of different service parts of magnesium alloy in marine equipment, it divides the specific corrosion area and designs the corresponding spectral block combination, which can meet the corrosion assessment needs of different parts such as exposed, semi-enclosed and enclosed. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart illustrating a method for compiling corrosion environment spectra of magnesium alloys in a marine atmospheric environment, as provided in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] See Figure 1 As shown, the present invention provides a method for compiling corrosion environment spectra of magnesium alloys in a marine atmospheric environment, comprising the following steps: S1. Pre-test of magnesium alloy-marine atmospheric corrosion mechanism adaptation: Magnesium alloy standard test pieces are placed in simulated marine atmospheric corrosion environments with different parameter combinations. Through corrosion performance testing, the dominant corrosion forms, key corrosion inducing factors, and the correspondence between corrosion products and environmental factors of magnesium alloy in marine atmosphere are determined. S2. Service environment survey and data collection: Determine the target service sea area, divide the target sea area into different marine climate zones according to climate characteristics, collect macro-environmental data of each climate zone in a differentiated manner, and collect local environmental data of key service parts of magnesium alloy components to form a comprehensive environmental dataset. S3. Delineation of Corrosion Zones Specific to Magnesium Alloys: Based on the actual service scenarios of magnesium alloys in marine equipment, multiple core corrosion zones are delineated. According to the corrosion rate of magnesium alloys in each corrosion zone obtained from the pre-test in step S1, the time proportion of each corrosion zone in the total environmental spectrum is determined, and the weight of the corrosion zone is assigned. S4. Compilation and Parameter Quantization of Individual Environmental Spectra: Based on the preliminary test results of step S1 and the comprehensive environmental dataset of step S2, temperature-humidity spectrum, salt spray-wet-dry alternation spectrum, and acidic medium-ultraviolet synergistic spectrum are compiled to complete the parameter quantization of each individual environmental spectrum block. S5. Construction and Equivalent Verification of Accelerated Corrosion Environment Spectrum: Based on the existing accelerated corrosion spectrum of marine metals, the compatibility of magnesium alloys is optimized. By comparing natural environment corrosion tests and accelerated corrosion tests, the accelerated equivalent relationship between the degree of corrosion damage of magnesium alloys and environmental parameters and test time is established. The combination design of accelerated spectrum blocks is determined according to the characteristics of different climate zones and corrosion areas. S6. Verification and Correction: Through laboratory and engineering verification, the compiled environmental spectrum parameters are corrected to obtain the final corrosion environmental spectrum of magnesium alloys under marine atmospheric conditions.

[0026] In this invention, a six-step closed-loop process of "mechanism-driven—data-supported—partition modeling—parameter quantification—equivalent calibration—empirical iteration" is constructed to enable S1 to identify Cl - Concentration threshold: 0.3 mg / (100 cm³) 2 ·d) and the critical relative humidity of 70% serve as the physical benchmark for setting all subsequent spectral block parameters. S2 and S3 jointly establish a three-dimensional mapping relationship between macro-climate zones, local micro-environments, and structural service locations. S4 transforms abstract environmental factors into executable spectral block parameters (such as Cl in the salt spray-wet / dry alternation spectrum). - Concentration 0.3–1.0 mg / (100 cm³) 2 •d) Coupling settings with a cycle of 4–12h), S5 uses CASS spectrum to reduce the acetic acid concentration (0.5%→0.2%–0.3%) and add NaCl (3.5%–5.0%) to avoid excessive dissolution of Mg(OH)2 by strong acid, thereby ensuring that the corrosion morphology (mainly pitting corrosion) is consistent with the natural state while maintaining acceleration efficiency. S6 uses the corrosion damage correlation coefficient >0.9 as the quantitative criterion to achieve full-chain reliable verification from laboratory to engineering site.

[0027] As a specific implementation method, this invention provides a method for compiling a corrosion environment spectrum of magnesium alloys under marine atmospheric conditions. In step S1, the parameters simulating the marine atmospheric corrosion environment include salt spray Cl... - Concentration gradient 0.3–1.2 mg / (100 cm⁻¹) 2 •d) Relative humidity gradient 30%–95%, temperature gradient -10 to 35°C, acid rain pH gradient 3.5–5.6; key corrosion inducing factors include Cl - Concentration threshold: 0.3 mg / (100 cm³) 2 •d) Critical relative humidity value of 70%. In this invention, a four-dimensional parameter gradient is set to cover extreme working conditions in all sea areas of my country (temperate zone -10℃ freeze-thaw, tropical zone 35℃ high humidity, subtropical zone pH 3.5 acid rain), and the Cl... - The dual-threshold synergistic mechanism with RH, when Cl - ≥0.3mg / (100cm 2 ·d) When RH≥70%, the stability of the liquid film on the magnesium alloy surface is significantly enhanced, and the electrochemical corrosion current density jumps by 2.3 times (see electrochemical test data in Example 1), thereby triggering the conversion of Mg(OH)2 to MgCl2·6H2O, which solves the problem of misjudgment of corrosion initiation point caused by the broad general spectral parameters or the fuzzy threshold.

[0028] As a specific implementation method, this invention provides a method for compiling the corrosion environment spectrum of magnesium alloys under marine atmospheric conditions. In step S2, the marine climate zone is divided into a temperate marine climate zone, a subtropical marine climate zone, and a tropical marine climate zone. Specifically, for the temperate zone, at least the number of freeze-thaw cycles, duration of low temperatures, and seasonal salt spray deposition data are collected; for the subtropical zone, at least the frequency of plum rains or typhoons, acid rain pH values, and salt spray concentration fluctuation data are collected; and for the tropical zone, at least the duration of high temperature and humidity, and salt spray Cl- content data are collected. - Cumulative concentration and strong ultraviolet radiation intensity data. In this invention, by dividing climate zones into three categories—temperate, subtropical, and tropical—and differentiating the data collection focus, microcracks in the coating caused by freeze-thaw cycles (5–20 times / year) in the temperate zone can be accurately captured. This allows for the assignment of higher weight to exposed areas in S3 and triggers the embedding of the freeze-thaw cycle module in S5. Peak salt spray concentration during the typhoon season in the subtropical zone (1.0–1.2 mg / (100 cm³)) 2 •d) and acid rain pH fluctuations (3.5–4.2) work together in the crevice, accelerating galvanic corrosion. This characteristic directly supports the 25%–40% weighting of the semi-enclosed region in weight 4 and the increase of the upper limit of the salt spray spectrum to 1.0 mg / (100cm²). 2 •d); Tropical regions with high temperature and humidity (30–35℃, RH ≥ 85%, cumulative 180–250 days / year) and strong ultraviolet radiation (≥300MJ / m²). 2The synergistic promotion of Mg(OH)2 photolysis to generate active MgO intermediates, thereby exacerbating matrix exposure, provides a structured basis for the necessity of the "strong ultraviolet-high salt spray synergistic module". The data acquisition strategies of the three climate zones jointly ensure that the parameters of the S4 single spectral block have regional specificity, avoiding the evaluation distortion caused by a one-size-fits-all approach to the spectrum.

[0029] As a specific implementation method, the present invention provides a method for compiling the corrosion environment spectrum of magnesium alloys in a marine atmospheric environment. In step S3, the core corrosion region includes an exposed strong corrosion region, a semi-enclosed corrosion region, and a closed corrosion region; the time percentage of each corrosion region is 40%–60% for the exposed region, 25%–40% for the semi-enclosed region, and 10%–25% for the closed region. In this invention, three types of corrosion zones are divided based on the actual spatial location of magnesium alloys in marine equipment. Time weights are assigned based on the regional corrosion rates measured in the S1 pre-test (exposed zone 1.0–2.5 mm / a, semi-enclosed zone 0.5–1.2 mm / a, enclosed zone 0.2–0.6 mm / a). This ensures that the high proportion (≥40%) of the exposed zone guarantees the full interaction of the salt spray-wet / dry alternation spectrum and the ultraviolet irradiation spectrum in the overall spectrum, thus realistically reproducing the pitting corrosion deepening process on the deck. The moderate proportion (25%–40%) of the semi-enclosed zone matches the characteristics of moisture accumulation and intermittent salt spray deposition at the hatches, supporting the "salt spray-wet / dry alternation-mild ultraviolet irradiation" cyclic design in S5. The low proportion (≤25%) of the enclosed zone, with the ultraviolet module excluded (see method scheme 5), accurately responds to the lack of light and high Cl- concentration in bolt gaps. - In a microenvironment dominated by accumulation and galvanic corrosion, the partitioning weighting system directly determines the combination ratio of each spectral block in S4 in the total environmental spectrum, solving the problem of missed evaluation of crevice corrosion caused by neglecting spatial heterogeneity in traditional spectra.

[0030] As a specific implementation method, this invention provides a method for compiling corrosion environment spectra of magnesium alloys under marine atmospheric conditions. In step S4, the sea salt Cl... - The concentration range is 0.3–1.0 mg / (100 cm³). 2 •d); The acidic medium-UV synergistic spectrum is a combined spectrum of acid rain immersion and UV irradiation, with parameters of acid rain pH 3.5–5.6 and UV radiation intensity 50–350 MJ / m². 2 The ratio of immersion to irradiation time is 3:1. In this invention, the salt spray-wet / dry alternating spectrum Cl - The upper limit of concentration is set at 1.0 mg / (100 cm³). 2 ·d), reflecting the physical law of the decrease in effective sediment concentration during the tidal wet-dry cycle, and related to Cl in S1 - Threshold 0.3 mg / (100 cm) 2•d) Jointly define the corrosion activation range; the acidic medium-UV synergistic spectrum uses a 3:1 immersion / irradiation ratio, derived from the dissolution kinetics of Mg(OH)2 in an acidic environment (dissolution half-life of approximately 2.1 h at pH 4.0) and the UV-induced matrix oxidation kinetics (300 MJ / m²). 2 Mg under irradiation 0 →Mg 2+ The matching relationship (conversion rate up to 85%) ensures that the matrix can be exposed to the ultraviolet field in time after the corrosion products dissolve, thereby driving the expansion of pitting corrosion pits rather than simple surface discoloration; the synergistic effect of the two allows the single-item spectral blocks compiled by S4 to characterize both tidal periodicity (wet-dry alternation period 4–12h) and Mg(OH)2 photosensitivity (ultraviolet intensity 50–350MJ / m²). 2 This provides a parameter basis for the "strong ultraviolet-high salt spray synergistic module" in the tropical region of S5 and the natural spectrum acidic-ultraviolet block in S9.

[0031] As a specific implementation method, this invention provides a method for compiling corrosion environment spectra of magnesium alloys under marine atmospheric conditions. In step S5, the adaptability optimization involves adjusting the composition of the accelerated spectrum solution for magnesium alloys, reducing the acetic acid concentration in the CASS spectrum from 0.5% to 0.2%–0.3%, and adding 3.5%–5.0% NaCl to simulate the marine environment; the acceleration factor corresponding to the acceleration equivalent relationship is 80–120 times. In this invention, the drastic dissolution of magnesium alloys by a strongly acidic environment is avoided by reducing the concentration of acetic acid, while NaCl is added to reduce the ionic composition of the marine environment, so that the corrosion products return to the Mg(OH)2 / MgCO3 coexistence system. The acceleration factor of 80–120 times is derived from the fitting of natural-accelerated control test data in tropical, temperate and subtropical regions (100 times error ≤4% in tropical region, 80 times error ≤5.2% in temperate region, and 90 times error ≤4.7% in subtropical region). This range reflects the differences in corrosion kinetics in different climatic zones. The high temperature and humidity in tropical region accelerate the electrochemical reaction rate, so the factor is higher. This optimization scheme ensures that the accelerated test improves efficiency without sacrificing the authenticity of corrosion morphology.

[0032] As a specific implementation method, this invention provides a method for compiling corrosion environment spectra of magnesium alloys under marine atmospheric conditions. In step S6, laboratory verification involves comparing the corrosion damage characteristics of accelerated testing specimens with those exposed to natural environments, while engineering verification involves monitoring the corrosion status of magnesium alloy components in actual marine equipment over a 1–3 year service cycle and correcting the environmental spectrum parameters. The correlation coefficient of the corrected environmental spectrum corrosion damage is >0.9. In this invention, laboratory verification focuses on the consistency of microscopic mechanisms (XRD confirms the coexistence of Mg(OH)2 and MgCO3, and SEM shows similar pitting size distribution), while engineering verification focuses on macroscopic service realism (bolt crevice corrosion propagation rate, coating damage area growth curve). The two form a micro-macro cross-verification; a correlation coefficient >0.9 is used as a quantitative criterion (Pearson linear correlation coefficient), indicating that the corrosion depth, area, and morphological evolution trends predicted by the accelerated spectrum are highly consistent with the measured data (R0). 2 =0.92–0.96), this standard directly constrains the acceleration factor setting in S5 and the boundary of the spectral block parameters in S4, ensuring the reliability of the entire chain from environmental spectrum compilation to application.

[0033] Another aspect of this invention provides a corrosion environment spectrum for magnesium alloys in a marine atmospheric environment. This corrosion environment spectrum includes a natural corrosion environment spectrum and / or an accelerated corrosion environment spectrum. The combined structure of the temperature-humidity block, salt spray-wet / dry alternation block, and acidic medium-UV synergistic block in the natural spectrum (i.e., the natural corrosion environment spectrum) directly maps the results of the S4 single-item spectrum compilation to the regional time proportion in S3. Meanwhile, the cyclical architecture of the accelerated salt spray block, accelerated temperature and humidity block, and targeted enhancement module in the accelerated spectrum corresponds to the climate zone adaptation design of the "freeze-thaw cycle module" (temperate zone) and the "strong UV-high salt spray synergistic module" (tropical zone) in S5. This physical and chemical output allows users to conduct protective design or life assessment without repeated compilation. For example, users in the South China Sea can directly call the tropical parameter group (high temperature and high humidity proportion ≥60%, Cl...). - 0.6–1.0 mg / (100 cm²) 2 ·d) Ultraviolet ≥300MJ / m 2 This significantly improves the efficiency of engineering applications.

[0034] As a specific implementation method, this invention provides a corrosion environment spectrum for magnesium alloys under marine atmospheric conditions. The natural corrosion environment spectrum includes a temperature-humidity block, a salt spray-wet / dry alternation block, and an acidic medium-UV synergistic block, combined according to the time proportion of corresponding climatic zones; the core parameters of the accelerated corrosion environment spectrum include sea salt Cl. - The cumulative mass concentration is 0.3–1.2 mg / (100 cm³). 2 •d) Relative humidity 30%–95%, temperature -10 to 35℃, acid rain pH 3.5–5.6, and ultraviolet radiation intensity 50–350 MJ / m²2 The wet-dry cycle is 4–12 hours. In this invention, the natural spectrum is structured into three major spectral blocks and combined according to the time proportion of climate zones. The temperate zone spectral block is embedded in the freeze-thaw cycle submodule (freezing temperature -10–-5℃, thawing temperature 10–20℃, cycle 8–12 hours), the subtropical zone spectral block strengthens the high humidity period of the plum rain season (RH ≥ 90%, proportion ≥ 30%), and the tropical zone spectral block highlights the high temperature and high humidity range (30–35℃, RH ≥ 85%, proportion ≥ 60%). This structure directly inherits the S2 climate zone division and the S3 regional weights; the parameter range integrates the Cl in S1. - Cl derived from the RH / temperature / pH gradient and the corrosion rate in zone S3 - The cumulative concentration and UV intensity settings in S5 form a complete parameter matrix; for example, Cl - Range 0.3–1.2 mg / (100cm²) 2 ·d) Coverage of S1 threshold (0.3), S5 tropical upper limit (1.0), and S3 tropical Cl - Accumulated redundancy space (+0.2) ensures the applicability and robustness of the spectrum across the entire ocean area.

[0035] As a specific implementation method, this invention provides a corrosion environment spectrum for magnesium alloys under marine atmospheric conditions. The accelerated corrosion environment spectrum consists of an accelerated salt spray spectrum block, an accelerated temperature and humidity spectrum block, and a targeted strengthening module, which are cycled together. The core parameters of the accelerated corrosion environment spectrum include the accelerated salt spray Cl... - The mass concentration is 0.6–2.0 mg / (100 cm³). 2 •d) Acceleration temperature and humidity are 25–40℃, relative humidity is 85%–98%, and acceleration factor is 80–120 times; the targeted enhancement module is either a freeze-thaw cycle module or a strong ultraviolet-high salt spray synergistic module. In this invention, through modular architecture design, the acceleration spectrum has the ability to be used for multiple purposes: the freeze-thaw cycle module (applicable to temperate regions) includes an 8–12h freeze-thaw cycle, and its freezing temperature of -10–-5℃ and melting temperature of 10–20℃ accurately simulate the winter conditions in the Bohai Sea; the strong ultraviolet-high salt spray synergistic module (applicable to tropical regions) uses Cl - Concentration 1.2–2.0 mg / (100 cm³) 2 ·d) with UV intensity 300–350 MJ / m 2 Combining and matching the characteristics of strong ultraviolet radiation and high salt spray deposition in the South China Sea; accelerating the deposition of Cl in salt spray - Upper limit 2.0 mg / (100cm) 2 ·d) represents the concentration of NaCl added in S5 (3.5%–5.0%) and the upper limit of the salt spray spectrum in S4 (1.0 mg / (100 cm⁻¹)). 2The 2x acceleration of d) reflects the reasonable enhancement of the corrosion driving force; the modular structure relies on S3 region division (UV module is enabled in the exposed area and eliminated in the closed area) and S6 verification standard (correlation coefficient > 0.9) to improve the targeting efficiency and engineering adaptability of accelerated testing.

[0036] Unless otherwise specified, all materials, reagents and instruments used in the embodiments of this invention can be obtained through commercial channels.

[0037] Materials and reagents: AZ31 magnesium alloy standard test piece (100mm × 50mm × 5mm, surface roughness Ra 1.2μm, Baosteel Group Corporation); NaCl (analytical grade, Sinopharm Chemical Reagent Co., Ltd.); dilute sulfuric acid solution (purity ≥99.5%, Shanghai Aladdin Biochemical Technology Co., Ltd.); artificial seawater (prepared according to ISO 16701, containing Na+). + K + Ca 2+ Mg 2+ (Natural ions, Shanghai Maclean Biochemical Technology Co., Ltd.)

[0038] Instruments and equipment: WX-WQX6 six-element micro-meteorological instrument (Zhejiang Top Cloud-Agri Technology Co., Ltd.); Cl - Concentration sensor (model CL-100, accuracy ±0.01mg / (100cm³)) 2 •d), Jiangsu Shengda Instrument Co., Ltd.); Salt spray test chamber (model YWX / Q-150, Shanghai Yiheng Scientific Instrument Co., Ltd.); Ultraviolet aging test chamber (model UV-3, Q-Lab, USA); X-ray diffractometer (model D8 ADVANCE, Bruker, Germany); Scanning electron microscope (model SU8010, Hitachi, Japan); Electrochemical workstation (model CHI660E, Shanghai Chenhua Instrument Co., Ltd.).

[0039] Characterization and testing methods: Corrosion morphology was observed using a scanning electron microscope (accelerating voltage 15 kV, working distance 10 mm); phase analysis of corrosion products was performed using an X-ray diffractometer (Cu Kα radiation, scan rate 4° / min, 2θ range 10°–80°); corrosion rate was determined according to GB / T 16545–2015 "Corrosion of Metals and Alloys - Removal of Corrosion Products from Corrosion Specimens" using the weight loss method; electrochemical impedance spectroscopy (EIS) was performed in 3.5% NaCl solution, with a frequency range of 10... 5 -10 - 2 Hz, disturbance signal amplitude 10mV; corrosion depth measurement was performed using a super depth-of-field three-dimensional microscopy system (model VHX-7000, Keyence Corporation, Japan), and the average value of 10 random points was taken.

[0040] Example 1: This embodiment aims to verify the feasibility of compiling an accelerated corrosion environment spectrum for magnesium alloys in exposed highly corrosive areas of the tropical marine climate zone in the South China Sea and the reproducibility of corrosion damage.

[0041] AZ31 magnesium alloy standard test pieces (100mm×50mm×5mm, surface roughness Ra1.2μm) were used. After ultrasonic cleaning with acetone, rinsing with deionized water, and drying with cold air, they were ready for use. Preliminary test conditions: salt spray Cl... - Concentration 0.8 mg / (100 cm³) 2 •d), temperature 32℃, relative humidity 90%, acid rain pH=4.0, test period 60 days; service environment data collection: WX-WQX6 type six-element micro meteorological instrument and Cl were deployed continuously for 3 years in the waters of a certain island reef in the South China Sea. - Concentration sensor, sampling interval 2 hours, acquiring the duration of high temperature and high humidity (30–35℃, RH≥85%, cumulative 218 days / year), salt spray Cl - Cumulative concentration (0.85 mg / (100 cm³)) 2 ·d)), ultraviolet radiation intensity (320MJ / m 2 Corrosion zone classification: Based on the service characteristics of the ship's deck area, it was determined to be an exposed area of ​​strong corrosion, accounting for 55% of the time; Single-item spectrum compilation: Salt spray-wet / dry alternating spectrum (Cl - Concentration 0.8 mg / (100 cm³) 2 ·d), dry-wet alternation cycle 6h: 3h dry – 3h wet), ultraviolet irradiation spectrum (300MJ / m 2 Acid rain immersion spectrum (pH=4.0); Accelerated spectrum construction: Based on the CASS spectrum, the acetic acid concentration was reduced to 0.25%, the NaCl concentration was set to 4.2%, the acceleration factor was set to 100 times, and the single acceleration cycle was 2.5 days; Validation experiment: The test piece was placed under the accelerated spectrum for 2.5 days, and test pieces naturally exposed to the South China Sea for 1 year were collected simultaneously as a control.

[0042] XRD analysis showed that the corrosion products of both accelerated and naturally exposed specimens were mainly Mg(OH)2 (characteristic peaks 2θ=18.6°, 34.3°) and MgCO3 (characteristic peaks 2θ=23.1°, 29.4°), with no MgO detected. SEM observation showed that both exhibited a typical pitting and uniform corrosion morphology, with average pit diameters of 12.3 μm and 11.8 μm, respectively. The corrosion depth of the accelerated specimen was measured to be 0.025 mm using a super depth-of-field three-dimensional microscopy system, while that of the naturally exposed specimen was 0.024–0.026 mm, with an error ≤4%. Electrochemical impedance spectroscopy fitting results showed that the charge transfer resistance R of both specimens was 1.82 kΩ·cm. 2 With 1.76–1.88 kΩ·cm2 This indicates that the interfacial electrochemical behavior is highly consistent.

[0043] The results show that the accelerated corrosion environment spectrum of tropical exposed areas compiled in this embodiment can accurately reproduce the composition, morphological characteristics and damage degree of corrosion products of magnesium alloys in the natural environment of the South China Sea.

[0044] Example 2 The purpose of this embodiment is to verify the Cl in the salt spray-wet / dry alternation spectrum. - Lower limit of concentration: 0.3 mg / (100 cm³) 2 •d) Feasibility under tropical climate conditions.

[0045] Under the same preparation conditions as in Example 1, only the Cl-strained salt spray-wet / dry alternating spectrum was analyzed. - The concentration was 0.8 mg / (100 cm³). 2 ·d) Adjusted to 0.3 mg / (100cm) 2 ·d), other parameters (temperature 32℃, RH 90%, acid rain pH=4.0, UV intensity 300MJ / m) 2 The accelerated corrosion test piece was prepared by keeping the wet-dry alternation cycle (6h) and acceleration factor (100x) constant.

[0046] XRD analysis showed that the corrosion products were still mainly Mg(OH)2, but the intensity of the characteristic peak of MgCO3 decreased by about 40%; SEM observation showed that the number of pitting corrosion pits decreased, with an average diameter of 8.2 μm; the corrosion depth was 0.012 mm, a decrease of 52% compared to Example 1; electrochemical impedance spectroscopy showed an R value of 3.45 kΩ·cm. 2 The increase was 89% compared to Example 1.

[0047] The results showed that in Cl - Lower limit of concentration: 0.3 mg / (100 cm³) 2 Under condition d), the specimen still showed obvious corrosion, and the corrosion products and morphology were consistent with the basic characteristics of tropical corrosion of magnesium alloys.

[0048] Example 3 The purpose of this embodiment is to verify the lower limit of ultraviolet radiation intensity of 50 MJ / m in the acidic medium-UV synergistic spectrum. 2 Feasibility under tropical climate conditions.

[0049] With all other preparation conditions the same as in Example 1, only the ultraviolet radiation intensity was changed from 300 MJ / m 2 Adjusted to 50 MJ / m 2 The remaining parameters (Cl) - Concentration 0.8 mg / (100 cm³) 2•d) Keeping the temperature 32℃, RH 90%, acid rain pH=4.0, dry-wet alternation cycle 6h, and acceleration factor 100 times constant, accelerated corrosion test pieces were prepared.

[0050] XRD analysis showed a significant increase in the intensity of the characteristic peak of Mg(OH)2, while the characteristic peak of MgCO3 almost disappeared; SEM observation showed that the corrosion morphology changed from pitting corrosion + uniform corrosion to predominantly uniform corrosion, with the number of pits decreasing by 65%; the corrosion depth was 0.018 mm, a decrease of 28% compared to Example 1; and R was 2.51 kΩ·cm. 2 The increase was 38% compared to Example 1.

[0051] The results show that at the lower limit of ultraviolet radiation intensity of 50 MJ / m 2 Under these conditions, observable corrosion still occurred on the test piece, and the corrosion products and morphological changes conformed to the photolysis kinetics of Mg(OH)2.

[0052] Example 4 The purpose of this embodiment is to verify the feasibility of an acceleration factor of 80 times in the accelerated corrosion environment spectrum under the conditions of a semi-enclosed corrosion zone in a temperate marine climate zone.

[0053] Referring to the method in Example 1, the difference lies in adjusting the target climate zone to the temperate zone of the northern Yellow Sea, the corrosion area to a semi-enclosed corrosion zone (35% of the time), the acceleration factor to 80 times, and the single acceleration cycle to 3.5 days; the salt spray-wet / dry alternation spectrum Cl - The concentration was adjusted to 0.4 mg / (100 cm³). 2 •d) The dry-wet alternation cycle is adjusted to 8h (6h dry – 2h wet) and a freeze-thaw cycle module is embedded (freezing temperature -8℃, thawing temperature 15℃, cycle 10h); the other parameters (temperature 20℃, RH 85%, acid rain pH=4.5) remain unchanged.

[0054] XRD analysis showed that the corrosion products were Mg(OH)₂ and a small amount of MgCl₂·6H₂O; SEM observation showed that the corrosion morphology was mainly crevice corrosion, with a corrosion depth of up to 15.6 μm; the corrosion depth was 0.014 mm; and the resistance (R) was 2.13 kΩ·cm. 2 ; and specimens naturally exposed in the northern Yellow Sea for 1 year (corrosion depth 0.013–0.015 mm, R = 2.05–2.21 kΩ·cm). 2 Compared to [previous method], the error is ≤5.2%.

[0055] The results show that, under an acceleration factor of 80, the corrosion damage characteristics of the specimen in the temperate semi-enclosed zone are highly consistent with those under natural exposure, proving that the lower limit of this parameter has engineering applicability.

[0056] Example 5 The purpose of this embodiment is to verify the accelerated salt spray Cl in the accelerated corrosion environment spectrum. - The upper limit of mass concentration is 2.0 mg / (100 cm³). 2 •d) Feasibility under conditions of exposed corrosion zones in tropical marine climate zones.

[0057] Based on the process in Example 1, Cl was used in a salt spray-wet / dry alternating spectrum. - The concentration was 0.8 mg / (100 cm³). 2 ·d) Increase to 2.0 mg / (100cm) 2 ·d), other parameters (temperature 32℃, RH 90%, acid rain pH = 4.0, UV intensity 300MJ / m 2 The accelerated corrosion test piece was obtained by keeping the wet-dry alternation cycle (6h) and acceleration factor (100x) constant.

[0058] XRD analysis showed a decrease in the intensity of the characteristic peak of Mg(OH)2 and an increase in the intensity of the characteristic peak of MgCl2·6H2O; SEM observation showed an increase in the density of pitting corrosion, with the average diameter expanding to 18.7 μm, and localized flaking in some areas; the corrosion depth was 0.038 mm, an increase of 52% compared to Example 1; R was 1.24 kΩ·cm. 2 The decrease was 32% compared to Example 1.

[0059] The results showed that in Cl - Concentration 2.0 mg / (100 cm³) 2 Under condition d), the specimen remained within the controllable corrosion range and no non-natural corrosion morphology (such as complete pulverization or melting) appeared. The corrosion depth was still within the reasonable extrapolation range (±50%) of the actual corrosion depth (0.024–0.026 mm) after 1 year of service in tropical exposed areas.

[0060] Example 6 The purpose of this embodiment is to verify the applicability of the corrosion environment spectrum of magnesium alloys in marine atmospheric environments to different magnesium alloy grades.

[0061] The method is the same as in Example 1, except that the test piece is replaced with an AZ91 magnesium alloy standard test piece (100mm × 50mm × 5mm, surface roughness Ra 1.2μm), and the other parameters (tropical exposure conditions, Cl) are the same. - Concentration 0.8 mg / (100 cm³) 2 ·d) Temperature 32℃, RH 90%, acid rain pH = 4.0, UV intensity 300MJ / m 2 The dry-wet alternation cycle (6 hours) and acceleration factor (100 times) remain unchanged.

[0062] XRD analysis showed that the corrosion products were still Mg(OH)₂ and MgCO₃, but the relative content of MgCO₃ was about 15% higher than that of AZ31. SEM observation showed that the pitting density was slightly lower than that of AZ31, with an average diameter of 10.5 μm. The corrosion depth was 0.021 mm, a decrease of 16% compared to AZ31, and was 2.03 kΩ·cm. 2 It is 11% higher than AZ31.

[0063] The results show that the corrosion environment spectrum prepared in this invention has good adaptability to both AZ31 and AZ91, two mainstream magnesium alloys, and the corrosion damage trends are consistent. The only difference is the corrosion rate due to the difference in alloy composition (AZ91 contains 8.3–9.7 wt% Al), which proves that the spectrum has universality for magnesium alloys.

[0064] Using existing technology as a comparative example, this illustrates how the solution of the present invention solves the problems of the prior art. Comparative Example 1: Using the existing general marine atmospheric environment spectrum (not for magnesium alloys) test method: AZ31 magnesium alloy specimens, the same as in Example 1, were selected and tested using the general marine atmospheric environment spectrum (salt spray Cl) test method. - Concentration 0.5 mg / (100cm³) 2 •d) Accelerated testing was conducted under fixed temperature and humidity (25℃, RH 80%, without UV irradiation module) for 2.5 days. Test results: The corrosion depth of the specimen was 0.0175 mm, 30% lower than the 0.025 mm in Example 1; only Mg(OH)2 was detected as corrosion product, with no MgCO3 detected. This significantly differed from the composition of corrosion products from naturally exposed specimens in the South China Sea, failing to accurately reflect the actual corrosion state of the magnesium alloy. This demonstrates that the present invention solves the problem of poor adaptability of existing general environmental spectra to magnesium alloys.

[0065] Comparative Example 2: Using the CASS spectrum test method for aluminum alloys: AZ31 magnesium alloy specimens, identical to those in Example 1, were selected and accelerated under standard CASS spectrum (acetic acid concentration 0.5%, NaCl concentration 5%, CuCl2·2H2O concentration 0.26 g / L, temperature 50℃, RH 100%) for 2.5 days. Test results: The specimens showed excessive corrosion, with a corrosion depth of 0.08 mm, 3.2 times that of Example 1; the corrosion products were non-natural MgO (characteristic peaks 2θ = 42.9°, 62.3°), completely different from the corrosion products of naturally exposed specimens, and therefore unsuitable for magnesium alloy corrosion assessment. This demonstrates that the present invention solves the problems of poor reproducibility of existing accelerated spectrum methods for excessive corrosion and damage to magnesium alloys.

[0066] 2. Using a control experiment as a comparative example, the rationality of the technical parameter range of the present invention is illustrated. Comparative Example 3: Salt Spray Cl -The concentration is below the range of this invention (0.2 mg / (100 cm³)). 2 ·d)) Test method: Refer to the method in Example 1, only apply salt spray Cl - The concentration was adjusted to 0.2 mg / (100 cm³). 2 •d), with other parameters unchanged, an accelerated test was conducted. Test results: The corrosion depth of the specimen was only 0.008 mm, far lower than the actual corrosion depth after one year of service (0.024~0.026 mm), failing to simulate the true degree of corrosion, proving that salt spray Cl... - Concentration below 0.3 mg / (100 cm³) 2 ·d) cannot meet the evaluation requirements.

[0067] Comparative Example 4: Salt Spray Cl - The concentration is higher than the range of this invention (1.3 mg / (100 cm³)). 2 ·d)) Test method: Refer to the method in Example 1, only apply salt spray Cl - The concentration was adjusted to 1.3 mg / (100 cm³). 2 •d), with other parameters unchanged, an accelerated test was conducted. Test results: The corrosion depth of the specimen reached 0.042 mm, far exceeding the corrosion depth after one year of actual service, indicating excessive corrosion and distorting the evaluation results. This proves that salt spray Cl - Concentration higher than 1.2 mg / (100 cm³) 2 The parameters in step d) are unreasonable.

[0068] Table 1 shows the test results of the examples and comparative examples, and Table 2 shows the statistical results of the characterization of the examples and comparative examples.

[0069] Table 1 Results of the effect test ; Table 2 Characterization Results ; The results are shown in Table 1. Table 2 shows that the corrosion environment spectrum prepared in this invention is significantly superior to Comparative Examples 1–4 in all four dimensions: corrosion depth, product composition, morphological characteristics, and electrochemical behavior. Compared to Comparative Example 1 (general marine spectrum), Example 1 showed a 43% increase in corrosion depth and successfully reproduced MgCO3 products, demonstrating that this invention, through differentiated data acquisition and spectral block quantification in S2–S4, solved the problem of insufficient corrosion driving force caused by the generality of general spectral parameters. Compared to Comparative Example 2 (CASS spectrum), Example 1 showed a 68.8% decrease in corrosion depth, and the products reverted from non-natural MgO to the Mg(OH)2 / MgCO3 coexistence system, proving that the reduction in acetic acid concentration and the addition of NaCl in S5 effectively avoided excessive dissolution of magnesium alloys in a strongly acidic environment. Comparative Examples 3 and 4 confirmed that Cl... -Concentrations below 0.3 or above 1.2 mg / (100cm³) 2 ·d) Both lead to corrosion damage deviating from the natural state, verifying the presence of Cl in S1. - The scientific validity of the threshold setting; the corrosion depth error between Example 1 and the naturally exposed specimens in the South China Sea is ≤4%, and the R-bias is <5%, indicating that the 80–120 times acceleration equivalent relationship established in this invention has high precision, solving the problem of ambiguity in the correlation between accelerated testing and service life in the prior art. In summary, this invention achieves four major technical effects: corrosion damage reproducibility, regional adaptability, accelerated-service correlation, and comprehensive coverage of service locations. Each effect can be reasonably derived from the corresponding technical characteristics, demonstrating outstanding substantive features and significant progress.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the present invention.

Claims

1. A method for preparing a corrosion environmental spectrum of magnesium alloys in a marine atmospheric environment, characterized in that, Includes the following steps: S1. Pre-test of magnesium alloy-marine atmospheric corrosion mechanism adaptation: Magnesium alloy standard test pieces are placed in simulated marine atmospheric corrosion environments with different parameter combinations. Through corrosion performance testing, the dominant corrosion forms, key corrosion inducing factors, and the correspondence between corrosion products and environmental factors of magnesium alloy in marine atmosphere are determined. S2. Service environment survey and data collection: Determine the target service sea area, divide the target sea area into different marine climate zones according to climate characteristics, collect macro-environmental data of each climate zone in a differentiated manner, and collect local environmental data of key service parts of magnesium alloy components to form a comprehensive environmental dataset. S3. Delineation of Corrosion Zones Specific to Magnesium Alloys: Based on the actual service scenarios of magnesium alloys in marine equipment, multiple core corrosion zones are delineated. According to the corrosion rate of magnesium alloys in each corrosion zone obtained from the pre-test in step S1, the time proportion of each corrosion zone in the total environmental spectrum is determined, and the weight of the corrosion zone is assigned. S4. Compilation and Parameter Quantization of Individual Environmental Spectra: Based on the preliminary test results of step S1 and the comprehensive environmental dataset of step S2, temperature-humidity spectrum, salt spray-wet-dry alternation spectrum, and acidic medium-ultraviolet synergistic spectrum are compiled to complete the parameter quantization of each individual environmental spectrum block. S5. Construction and Equivalent Verification of Accelerated Corrosion Environment Spectrum: Based on the existing accelerated corrosion spectrum of marine metals, the compatibility of magnesium alloys is optimized. By comparing natural environment corrosion tests and accelerated corrosion tests, the accelerated equivalent relationship between the degree of corrosion damage of magnesium alloys and environmental parameters and test time is established. The combination design of accelerated spectrum blocks is determined according to the characteristics of different climate zones and corrosion areas. S6. Verification and Correction: Through laboratory and engineering verification, the compiled environmental spectrum parameters are corrected to obtain the final corrosion environmental spectrum of magnesium alloys under marine atmospheric conditions.

2. The method of preparing a corrosion environment profile of magnesium alloys in a marine atmospheric environment according to claim 1, characterized in that, In step S1, the parameter combination of the simulated marine atmospheric corrosion environment includes salt spray Cl - concentration gradient 0.3-1.2 mg / (100 cm 2 d), relative humidity gradient 30%-95%, temperature gradient -10 to 35℃, acid rain pH value gradient 3.5-5.6; the key corrosion inducing factor includes Cl - concentration threshold 0.3 mg / (100 cm 2 d), relative humidity threshold 70%.

3. The method of preparing a corrosion environment profile of magnesium alloys in a marine atmospheric environment according to claim 1, characterized in that, In step S2, the marine climate zone is divided into a temperate marine climate zone, a subtropical marine climate zone, and a tropical marine climate zone; Among them, the temperate zone at least collects freeze-thaw cycle times, low temperature duration and seasonal salt deposition data, the subtropical zone at least collects plum rain or typhoon rain frequency, acid rain pH value and salt concentration fluctuation data, the tropical zone at least collects high temperature and high humidity duration, salt spray Cl - cumulative concentration and strong ultraviolet radiation intensity data.

4. The method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments according to claim 1, characterized in that, In step S3, the core corrosion area includes an exposed strong corrosion area, a semi-enclosed corrosion area, and a closed corrosion area; the time percentage of each corrosion area is 40%-60% for the exposed area, 25%-40% for the semi-enclosed area, and 10%-25% for the closed area.

5. The method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments according to claim 1, characterized in that, In step S4, the sea salt Cl - The concentration quantification range is 0.3-1.0 mg / (100 cm 2 d); the acid medium-ultraviolet synergistic spectrum is an acid rain immersion-ultraviolet irradiation combined spectrum, the parameters are acid rain pH value 3.5-5.6, ultraviolet radiation intensity 50-350 MJ / m 2 , and the immersion and irradiation action time ratio is 3:

1.

6. The method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments according to claim 1, characterized in that, In step S5, the compatibility optimization involves adjusting the composition of the accelerated spectrum solution for magnesium alloys, reducing the acetic acid concentration in the CASS spectrum from 0.5% to 0.2%-0.3%, and adding 3.5%-5.0% NaCl to simulate a marine environment; the acceleration equivalent relationship corresponds to an acceleration factor of 80-120 times.

7. The method for compiling corrosion environment spectra of magnesium alloys in marine atmospheric environments according to claim 1, characterized in that, In step S6, the laboratory verification is to compare the corrosion damage characteristics of accelerated test specimens and specimens exposed to natural environment, and the engineering verification is to monitor the corrosion status of magnesium alloy components of actual marine equipment for a service cycle of 1-3 years and correct the environmental spectrum parameters. The correlation coefficient of corrosion damage in the corrected environmental spectrum is >0.

9.

8. A corrosion environment spectrum of magnesium alloys under marine atmospheric conditions, characterized in that, The corrosion environment spectrum of magnesium alloys under marine atmospheric environment is prepared by the method described in any one of claims 1-7, wherein the corrosion environment spectrum includes natural corrosion environment spectrum and / or accelerated corrosion environment spectrum.

9. The corrosion environment spectrum of magnesium alloys in a marine atmospheric environment according to claim 8, characterized in that, The natural corrosion environment spectrum includes a temperature-humidity spectrum block, a salt spray-dry-wet alternating spectrum block, an acidic medium-ultraviolet synergistic spectrum block, and is combined according to the corresponding climate area time proportion; the core parameters of the accelerated corrosion environment spectrum include sea salt Cl - The cumulative mass concentration is 0.3-1.2mg / (100cm 2 The relative humidity is 30%-95%, the temperature is-10 to 35℃, the acid rain pH value is 3.5-5.6, the ultraviolet radiation intensity is 50-350MJ / m 2 , and the dry-wet alternating period is 4-12h.

10. The corrosion environment spectrum of magnesium alloys under marine atmospheric conditions according to claim 8, characterized in that, The accelerated corrosion environment spectrum is composed of an accelerated salt spray spectrum block, an accelerated temperature and humidity spectrum block, and a targeted strengthening module cycle. - The mass concentration is 0.6-2.0 mg / (100 cm 2 The accelerated temperature and humidity is 25-40 DEG C, the relative humidity is 85%-98%, and the acceleration multiple is 80-120 times; the targeted strengthening module is a freeze-thaw cycle module or a strong ultraviolet-high salt spray synergistic module.

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