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The corrosion protection of ultra-high temperature flue and chimney systems must take into account factors such as corrosion resistance, tolerance to ultra-high temperatures, impermeability, flexibility, resistance to sudden temperature changes, resistance to sudden stress changes, and bonding properties at high temperatures. Currently, some units in China still use the older type of vinyl glass flake putty to prevent corrosion in flues and chimneys. Vinyl glass flake mortar presents certain issues when used in boiler flue gas systems under special operating conditions, where the flue gas temperature is high (>200°C). Such high-temperature conditions occur not only under special operating conditions; in power plants, boiler factories, and sintering plants, the temperature of flue gases in the original flues and chimneys can instantly reach over 200°C, with some cases reaching as high as 700°C, while the temperature during prolonged operation is also close to 180°C. Furthermore, since chimneys and flues are generally made of steel or concrete, they deform differently under sudden temperature changes depending on their material. As a result, the basic properties of vinyl glass flake mortar prove to be insufficient when faced with such complex temperature and deformation conditions. The only reason people still choose this coating for protection under such conditions is their lack of knowledge and familiarity with nano-ceramic flue gas anti-corrosion coatings. Currently, the ZS-1041 flue gas anti-corrosion coating is quietly gaining a foothold in the market for anti-corrosion solutions for ultra-high temperature flues and chimneys. Thanks to its excellent properties in terms of resistance to temperature changes, penetration, corrosion, and ease of application, this coating successfully addresses the anti-corrosion challenges associated with ultra-high temperature flues and chimneys. Even when the flue gas temperature is kept below 180°C, which is within the range that vinyl glass flake can tolerate over a long period of time, the anti-corrosion solution using vinyl glass flakes still faces the following challenges: The coating applied with vinyl glass flake slurry consists of three layers – bottom, middle, and top – or two layers – bottom only. The primer used in this system must also be able to withstand temperatures of 180°C, and it must possess a certain degree of flexibility. Unfortunately, it is difficult to achieve such properties in primers due to the characteristics of vinyl resin, and products available on the market have technical shortcomings in meeting these requirements ； Glass flake mortar itself has poor toughness and tends to become brittle. Especially under sudden temperature changes, the adhesion between the clay primer layer and the substrate is insufficient, making it prone to peeling off. If the substrate treatment has defects such as incomplete degreasing or insufficient roughness, the adhesion will be worse ； When the temperature changes suddenly, the deformation resulting from these temperature fluctuations induces local stresses in the coating, leading to the concentrated release of stress at weak points, which in turn causes peeling and cracking. This lack of resistance to stress-strain is an inherent flaw of the film-forming substance (resin) in glass flake putty, and it is difficult to address it at its root ； The main reasons for the poor resistance to stress and strain, as well as to sudden temperature changes, lie in the fact that after curing, the linear expansion coefficient of the coating formed by the glass flake mortar method differs significantly from that of the substrate. The greater the temperature difference, the larger the difference in thermal expansion and contraction between the substrate and the coating, resulting in higher deformation stresses ； The polar group in vinyl resin is the hydroxyl group, which results in a low bonding strength to the substrate; this bonding strength is even more difficult to maintain in the presence of deformation stress at high temperatures ； Glass flake mortar has a low tolerance for substrates; therefore, the pretreatment of the substrate must be carried out very thoroughly. In practical applications, substrate treatment cannot always achieve such perfection due to various factors such as equipment and labor, and poor-quality substrates can lead to the peeling and cracking of the glass flake mortar. To address the aforementioned drawbacks, many methods were considered, and the final solution was to adopt a composite approach using ethylene, namely resin glass flake mortar and fiberglass reinforced plastic. The core of this solution lies in lining the mortar with fiber-reinforced composite materials (FRP) during construction, which is based on the principle commonly referred to as “three oils and two fabrics”. Due to the presence of fiber-reinforced composite materials, when there are sudden temperature changes, the fiber layers serve to effectively release stress (through their network structure, stress is distributed from a single point across the entire surface), thereby endowing the composite coating with a certain ability to withstand sudden temperature changes and stress fluctuations. But even with such improvements, this solution still has the drawbacks listed above. Moreover, this improvement solution brings about further negative consequences: the construction process is complex, and such complexity increases the workload and prolongs the construction time, thereby raising the risk level associated with the anti-corrosion work on chimneys, which are already involved in high-risk high-altitude operations; both safety costs and construction costs increase as a result ； When cracks or peeling occur at a certain point in the coating, the presence of the fiber fabric prevents it from coming off immediately; as a result, a large amount of gas remains between the peeled-off coating and the substrate. Under high temperatures, this gas seeps in from the bottom of the coating, further expanding the area of peeling. If this happens, the damage to the coating will be catastrophic ； Due to the high hardness of the vinyl glass flake coating and the presence of a backing fabric, it is difficult to grind it when the coating is damaged. If renovation is required, removing this coating will be the most challenging part of the work. As a result, vinyl glass flake mortar anti-corrosion coatings have very poor reworkability, repairability, and refurbishability, **which increases maintenance costs. Owners and designers often overlook these costs during the initial design and application stages, only to realize the substantial additional expenses when such problems arise. The ZS-1041 flue gas anti-corrosion coating mentioned earlier overcomes the disadvantages of the vinyl glass flake putty mentioned above. The advantages of this material are as follows: 1. Surface drying time: This is a parameter related to the ease of application; since conventional flue gas anti-corrosion coatings require multiple thick coats, the surface drying time has a direct impact on the construction timeline. Therefore, a shorter surface drying time allows for reduced construction time, as well as lower costs associated with equipment, labor, safety measures, and other aspects of construction. The thickest film thickness of conventional flue anti-corrosion coatings can reach 3 mm; there are more than 5 application steps, with a long curing time between each step, and the total construction period is approximately 30 days. The ZS-1041 flue gas anti-corrosion coating requires only a thickness of 300–500 μm to achieve the same protective effects and service life as conventional anti-corrosion coatings. The interval between application coats should not exceed 2 hours; applying around 4 coats using airless spraying is sufficient to reach the desired coating thickness, which saves time and effort. 2. Water absorption rate after 24 hours of immersion: Due to the moisture present in flue gas, and if a wet flue gas desulfurization system is installed, the moisture content in the flue gas will be even higher. Although this test measures the water absorption rate, what it actually assesses is the density and impermeability of the coating; density, impermeability, and resistance to swelling are essential properties for corrosion-resistant coatings. Ordinary anti-corrosion coatings such as glass flake putty use flaky glass flakes with a diameter of around 0.2 mm; during the formation of the coating film, these glass flakes overlap in a fish-scale pattern, thereby providing excellent impermeability. However, glass flake sheets with a diameter of 0.2 mm are relatively large in size; coupled with their high density, their dispersion in the working fluid is uneven, resulting in uneven overlapping of the flakes. Moreover, during application, factors such as viscosity and the method of application can lead to gaps and voids formed as a result of overlapping, which reduces the waterproofing performance. In the ZS-1041 flue gas anti-corrosion coating, the functional anti-corrosive pigments are nanoscale flake-shaped powders that have been remanufactured at high temperatures. Their extremely fine particle size enables individual flakes to disperse more stably within the coating system, preventing any overlapping or voids from forming; as a result, their resistance to penetration is superior. This is one of the main reasons why the ZS-1041 flue gas anti-corrosion coating can achieve the same anti-corrosion effects as conventional coatings with several millimeters of thickness, using only 300μm of thickness. 3. Heat resistance: The temperature of flue gas is generally between 70–500°C; in chimneys equipped with desulfurization systems, the flue gas temperature is usually below 100°C. The temperature tolerance limit of 250°C specified in the standards is sufficient for most operating conditions, but it is not adequate for certain special situations, including emergency conditions. The ZS-1041 flue gas anti-corrosion coating can withstand temperatures up to 750°C, and can function properly at 600°C for extended periods of time. This property enhances the reliability of flue pipe corrosion protection and reduces damage to the anti-corrosion coating caused by extreme operating conditions. 4. Corrosion resistance: For this performance test, sulfuric acid is used as the standard acidic solution; however, the corrosive agents present in flue gas are not limited to sulfides. In particular, after desulfurization in flues equipped with desulfurization devices, only trace amounts of sulfides remain in the flue gas, and the main corrosive agent is CL-. In the case of wet desulfurization, alkaline substances may also be present in the flue gas. Therefore, in addition to considering acid corrosion (caused by sulfides), corrosion caused by CL- and alkalis must also be taken into account. The ZS-1041 flue gas anti-corrosion coating can withstand prolonged exposure to acid, alkali, and NaCl solutions, offering comprehensive resistance to leakage and corrosion to address various types of corrosion that may occur in flues. 5. Temperature variation resistance: In this standard, temperature variation resistance is divided into resistance to freeze-thaw cycles, and resistance to rapid cooling and heating. This mainly takes into account whether the linear expansion coefficient of the coating (the degree of expansion and contraction due to heat) is roughly consistent with that of the inner wall of the flue, as well as whether the coating possesses a certain degree of flexibility. The linear expansion coefficient of bricks and cement is 10–14×10-6/°C, while that of steel is 12–18×10-6/°C. The linear expansion coefficient of glass flake materials is approximately 1.15×10-6/°C, which is an order of magnitude different from that of the substrate; as a result, temperature differences can lead to stress, causing cracks in the coating (applying layers of oil and fabric is mainly done to prevent such cracking). Due to the thickness of this coating material, heat transfer is affected to some extent, resulting in a relatively large difference between the temperature inside the flue and the temperature on the surface of the coating, thereby increasing the risk of stress-induced cracking. Although glass flake coatings can prevent stress cracking during short-term use through the use of multiple layers of oil and fabric, when special operating conditions occur frequently, the coating and crack-resistant fabric will suffer from fatigue due to repeated deformation, eventually leading to cracks. The linear expansion coefficient of the ZS-1041 flue gas anti-corrosion coating is 16–23×10-6/°C, which is in the same order of magnitude as that of the substrates used in flues; the difference between the two is not significant. Since this coating only needs to be applied in a thin layer, it has a fast heat conduction rate, allowing it to reach thermal equilibrium with the substrate quickly. In situations of sudden temperature changes, its deformation remains almost consistent with that of the substrate, reducing the risk of temperature-induced stress that could damage the coating. 6. Wear resistance: The flow velocity of flue gas is generally above 5 m/s, and since the flue gas contains dust, this dust causes significant abrasion and erosion of the anti-corrosion coating at high speeds. It is therefore very necessary and scientific to conduct tests using the methods specified in the standards (GB/T9266-88). However, abrasion can occur not only through parallel friction but also through impact friction. Taking this into account, the ZS-1041 flue gas anti-corrosion coating undergoes an even more stringent sand-splash wear resistance test (SY/T0315-97) in addition to meeting the standard requirements. The test results show that this product exhibits excellent wear and impact resistance. 7. Aging resistance: Acid-resistant and anti-corrosive coatings for flues can also experience aging, hardening, and embrittlement during normal use. Testing the aging resistance of organic coatings is particularly important; it is also a necessary test to ensure long-term effective corrosion protection for flues. The ZS-1041 flue gas anti-corrosion coating uses an inorganic-organic high-temperature chelating resin, with an extremely low content of organic components; as a result, the coating becomes inert after forming a film and exhibits excellent aging resistance, with the tested performance values exceeding the 500 hours specified in the standards. When selecting acid-resistant coatings for flue ducts, in addition to performance criteria, factors such as application ease and maintenance costs should also be taken into consideration. Taking glass flake coatings as another example, in order to prevent cracking during use and to ensure that a sufficient thickness is achieved, these coatings are typically applied using a backing fabric. Usually, three layers of coating are applied – a base layer, an intermediate layer, and a top layer – following a \"three-coats-two-backings\" method. This process is complex and time-consuming; when the coating is damaged in certain areas, it is necessary to remove all adjacent layers of coating (due to the effect of the backing fabric), which makes repairs difficult and costly. The ZS-1041 flue gas anti-corrosion coating is suitable for anti-corrosion protection of flues at various temperature ranges. When carrying out chimney anti-corrosion projects, there is no need to purchase multiple types of products based on operating conditions or locations, which would otherwise increase costs and complicate material management and construction oversight. Meanwhile, this coating can be applied by brushing, rolling, or airless spraying; it has a high solid content and excellent thick-coating properties, does not require auxiliary materials such as backing fabrics or special application processes, and is simple to apply with a short construction time. When defects appear in the coating or problems arise during subsequent use, only local repainting is required, **which reduces repair costs and shortens the repair time. Conclusion: The properties of the ZS-1041 flue gas anti-corrosion coating make it more suitable for protecting flues, chimneys, and desulfurization towers. It is believed that in the near future, ZS-1041 will become another term used to refer to anti-corrosion materials for flues and chimneys, alongside glass flake mortar.