Ceramic-based coating for enhancing corrosion resistance of boiler water wall and preparation method thereof

Abstract

The application discloses a kind of ceramic-based paint for enhancing the anticorrosion performance of boiler water-cooled wall, including by weight parts: amino silane coupling agent 10~15 parts, composite ceramic base material 15~30 parts, defoaming agent 2.5~5 parts, dispersion aid 2.5~4 parts, epoxy coal tar pitch 3~7 parts, chlorosulfonated polyethylene rubber 3~7 parts;The preparation method includes the following steps: S1, the preparation of mixture M, S2, the preparation of mixture N, S3, solidification cooling;The composite ceramic coating prepared by the application has excellent chemical medium corrosion resistance, good adhesion, high mechanical strength, good toughness and other comprehensive properties, and also has good acid resistance, alkali resistance and salt fog resistance at high temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anticorrosive ceramic base paint, in particular to a ceramic base paint for enhancing the anticorrosive performance of boiler water cooling wall and a preparation method thereof. BACKGROUND

[0002] High temperature corrosion is caused by alkali metal and sulfur. The compound of alkali metal volatilizes in high temperature, and condenses on the surface of the heated surface of water cooling wall when meeting water cooling wall. At the same time, most of the sulfur in the fuel is oxidized into SO2, and a small part is oxidized into SO3. SO3 combines with the compound of alkali metal into K2SO4 and Na2SO4 in gaseous state or on the wall of water cooling wall. Because of the low melting point, when they are attached to the wall, other fly ash particles are bonded into a thick layer of accumulated ash, which also contains iron oxide. The iron oxide oxidizes sulfur dioxide in flue gas into sulfur trioxide. Under this condition, the sulfate of alkali metal and iron oxide form a complex salt with SO3. The melting point of this salt is very low, and under the condition of high concentration of SO3, it can melt and flow away at 580-590℃, which destroys the original protective film of water cooling wall and causes corrosion of the inner wall of the boiler.

[0003] Water cooling wall is the main evaporation heating surface of the boiler to produce steam. After the water cooling wall is bonded with ash, the thermal resistance increases due to the small thermal conductivity of ash, which weakens the heat transfer effect of the heated surface of the water cooling wall and reduces the heat absorption, resulting in a decrease in the evaporation capacity of the boiler. When the ash accumulation is serious, it will affect and damage the water circulation, and even cause water circulation failure, affecting the safe operation of the boiler. Using high temperature resistant ceramic surface coating to protect the boiler water cooling wall pipe from high temperature abrasion and prevent ash accumulation is an effective protection method. It can reduce ash accumulation, prevent corrosion and wear, and prolong the operation cycle of the boiler. The ceramic base paint for enhancing the anticorrosive performance of boiler water cooling wall is a special ceramic wave-absorbing paint, which is used to improve the heat exchange efficiency and anticorrosive performance of the boiler water cooling wall, so as to achieve the purpose of energy saving.

[0004] The existing ceramic paint has limited anticorrosive effect, and cannot simultaneously achieve excellent anticorrosive performance in high temperature conditions under acidic, alkaline and salt fog environments, and has limited permeability resistance, thereby shortening the service life of the boiler. SUMMARY

[0005] To solve the above technical problems, the present application provides a ceramic base paint for enhancing the anticorrosive performance of boiler water cooling wall and a preparation method thereof.

[0006] The technical scheme of the present application is: a ceramic base paint for enhancing the anticorrosive performance of boiler water cooling wall, characterized by comprising, by weight: 10-15 parts of amino silane coupling agent, 15-30 parts of composite ceramic base material, 2.5-5 parts of defoaming agent, 2.5-4 parts of dispersion aid, 3-7 parts of epoxy coal tar pitch, and 3-7 parts of chlorosulfonated polyethylene rubber.

[0007] The composite ceramic base is composed of A component, B component accounting for 3.5-5 wt.% of the A component, and mixed solvent accounting for 25-35 wt.% of the total amount of the A component and B component; the A component is composed of titanium boride, nickel powder and mica according to the mass ratio of 5-7:5-7:2-3; the B component is composed of silicon carbide ceramic powder, carbon fiber and curing agent according to the mass ratio of 3-3.8:3.2-4:2.2-2.8; the mixed solvent is obtained by uniformly mixing isocyanate and n-butanol according to the mass ratio of 2-3:1-1.2;

[0008] The dispersing aid is composed of polyacrylamide, cashew nut shell oil and glass flake according to the mass ratio of 0.5-1:0.5-0.7:3-5;

[0009] Description: The composite ceramic coating prepared by the above components can effectively improve the brittleness of the ceramic base, thereby improving the toughness of the ceramic coating and further improving the performance of the coating; the amino silane coupling agent can effectively enhance the adhesion of the coating, further improve the adhesion of the ceramic base coating on the surface of the boiler water wall, and the amino group contained in the amino silane coupling agent can undergo ring-opening reaction with the epoxy group in the epoxy resin to form a coating with greater cross-linking density, making the coating more uniform; the epoxy coal tar pitch has excellent chemical medium corrosion resistance, good adhesion, high mechanical strength, good toughness and other comprehensive properties, and also has good acid resistance, alkali resistance and salt fog resistance, which can enhance the performance of the ceramic base coating; the interpenetrating network corrosion-resistant coating formed by mixing and curing the epoxy coal tar pitch and chlorosulfonated polyethylene rubber between the epoxy resin chain and the rubber chain has the characteristics of low water absorption, good water resistance, strong resistance to microbial erosion and high anti-permeation ability.

[0010] The glass flake in the dispersing aid can be laid flat and oriented during the mixing and dispersion of the coating and the formation of the film, and can be overlapped and covered between the flakes; the active groups such as phenolic hydroxyl groups in the cashew nut shell oil can form hydrogen bonds with the hydroxyl groups on the surface of the glass flake, thereby enhancing the compatibility between the cashew nut shell oil and the glass flake, which helps to reduce the agglomeration of the glass flake in the coating and make it better dispersed in the coating; in addition, the phenolic hydroxyl groups in the cashew nut shell oil can also undergo addition reaction with isocyanate, thereby further enhancing the bonding force between the glass flake and the coating, which can form a more stable dispersion system of the glass flake in the coating and prevent it from settling or floating during the drying or use of the coating.

[0011] Further, the preparation method of the composite ceramic base is as follows:

[0012] Take titanium boride, nickel powder and mica in turn and add them into the blender, stir for 10-15 min at a stirring speed of 500-700 r / min, then add 1 / 3-1 / 2 of the mixed solvent and the curing agent and increase the stirring speed to 1000-1200 r / min, and stir until uniform to obtain the first base material;

[0013] Mix the silicon carbide ceramic powder and the remaining mixed solvent at a first temperature and stir at a speed of 300-500 r / min for 5-10 min, then add the carbon fiber, adjust the temperature to a second temperature, continue to stir at a speed of 600-800 r / min for 10-15 min, finally adjust the temperature to a third temperature and continue to stir for 2-4 min and filter with silk gauze to obtain the second base material; wherein the first temperature is 85-100℃, the second temperature is 15-30% of the first temperature, and the third temperature is 55-65℃;

[0014] Mix the first base material and the second base material and stir until uniform, then grind by the alcohol wet ball method for 8-10 h, and finally dry at 55-65℃ to obtain the composite ceramic base material for standby use; wherein the relative humidity during the alcohol wet ball method grinding process is maintained at 40-45 RH%;

[0015] Description: The carbon fiber has the characteristics of high strength, high modulus, high temperature resistance, oxidation resistance, corrosion resistance, radiation resistance, electrical conductivity, thermal conductivity and stable performance, and the use of carbon fiber can effectively improve the toughness of the brittle silicon carbide ceramic powder. The second base material can effectively improve the mixing efficiency by mixing the silicon carbide ceramic powder and the remaining mixed solvent at a high temperature first, then adjusting the temperature to the second temperature after adding the carbon fiber to avoid the decline of the thermal stability of the carbon fiber at too high a temperature, which affects the effectiveness of the carbon fiber, and finally increasing the temperature to the third temperature for further mixing of the second base material. By limiting the relative humidity of the alcohol wet ball method, the problem of wet oxidation or fire of the carbon fiber and the silicon carbide ceramic powder can be avoided, thereby improving the stability of the ceramic base coating.

[0016] Further, the curing agent is composed of phenolic amine, nano-Al2O3 particles and polyphenylene diamine in a ratio of 0.5-0.7:1-1.5:0.3-0.5;

[0017] Description: The curing agent obtained by the above ratio can fully utilize the nano-aluminum oxide to enhance the hardness, wear resistance and heat resistance of the curing agent, and the phenolic amine and polyphenylene diamine can be compounded to improve the adhesion, flexibility and chemical corrosion resistance of the curing agent.

[0018] Further, the preparation method of the dispersing aid comprises the following steps:

[0019] Take polyacrylamide and 1 / 4~1 / 3 cashew nut shell oil into the reaction kettle, adjust the temperature of the reaction kettle to 85~95 DEG C, the pressure is 0.25~0.45 Mpa, ultrasonic dispersion treatment 15~20 min pour out to obtain dispersion liquid;The temperature of the reaction kettle is reduced to 55~65 DEG C, the pressure is unchanged, then the glass scale is added to the reaction kettle, the remaining amount of cashew nut shell oil is added to the reaction kettle and mixed at a speed of 100~110 r / min for 25~30 min, to obtain dispersion carrier;The temperature of the reaction kettle is raised to 80~90 DEG C, then the dispersion liquid is added to the dispersion carrier at an addition rate of 60~80 mL / min, and mixed to obtain a dispersing aid.

[0020] Description: cashew nut shell oil is a kind of natural plant oil, has certain viscosity and lubricity, glass scale is mixed with cashew nut shell oil first, can make scale better infiltration and dispersion in oil, form a uniform mixture. This helps the subsequent mixing with polyacrylamide, reduces the phase separation or precipitation phenomenon due to incompatibility. At the same time, mixing glass scale with cashew nut shell oil first can obtain a relatively stable intermediate product, so that the mixing process can be more simple and fast when mixing with polyacrylamide, reduce the operation difficulty and time. Adding a large amount of cashew nut shell oil after reducing the temperature can increase the viscosity of cashew nut shell oil, which is beneficial to better mixing and infiltration with glass scale. At the same time, mixing at low temperature can reduce the volatilization and bubble generation caused by high temperature, make the coating more uniform and stable;Avoid the oxidation reaction of cashew nut shell oil at high temperature, which can cause the deterioration of oil quality and affect the performance of coating. Mixing at low temperature can slow down the oxidation rate of cashew nut shell oil and maintain its excellent performance.

[0021] Further, the parameters of ultrasonic dispersion treatment are as follows: ultrasonic frequency is 25~35 kHz, ultrasonic intensity is 200~300 W;

[0022] Description: under the above parameters, ultrasonic treatment can make polyacrylamide and a small amount of cashew nut shell oil mix well, thereby achieving better dispersion effect.

[0023] Further, the shape of the nickel powder is flaky or spherical, and the particle size of the nickel powder is 500~5000 mesh;

[0024] Description: the above setting of nickel powder effectively increases the surface area of the powder, which helps better contact and mixing with other components, thereby improving the mixing uniformity;Large nickel powder particle size may cause the mixture to settle or stratify during storage, thereby reducing the stability of the mixture.

[0025] The application also provides a preparation method of a ceramic-based coating for enhancing the corrosion resistance of boiler water wall, based on the above-mentioned ceramic-based coating for enhancing the corrosion resistance of boiler water wall, comprising the following steps:

[0026] S1, Preparation of the mixture M

[0027] The composite ceramic base material and 1 / 3-1 / 2 of the amino silane coupling agent are added to a high-speed disperser, ultrasonic dispersion is carried out at a temperature of 35-45℃ for 8-12 min, then a dispersion aid is added, and ultrasonic dispersion is continued at 55-65℃ for 50-70 min until the mixture is uniform, and finally centrifugal treatment is carried out at a rotation speed of 1500-2000 r / min for 25-65 min / time for 2-3 times, and the mixture is left to stand for 2-3 h to obtain the mixture M;

[0028] S2, Preparation of the mixture N

[0029] The epoxy coal tar pitch, chlorosulfonated polyethylene rubber, and the remaining amino silane coupling agent are added to a container, and stirring and mixing are carried out at a rotation speed of 300-500 r / min for 30-50 min to obtain the mixture N;

[0030] S3, Curing and cooling

[0031] The mixture M is dispersed and ground to a particle size of 30-40 μm, then the mixture N is sprayed on the surface of the mixture M for curing, and the mixture is naturally cooled to room temperature to obtain the ceramic-based coating for enhancing the corrosion resistance of the water-cooled wall of a boiler; wherein the spraying rate of the spraying curing is 45-75 mL / min, the curing temperature is 70-150℃, and the curing time is 2-2.5 h.

[0032] Further, in step S3, the dispersion and grinding are carried out in the following manner: first, the high-speed stirring disperser is used for dispersion treatment at a speed of 1000-1500 r / min for 25-40 min, and then the ball mill is used for grinding for 2.5-3.5 h;

[0033] Note: The dispersion and grinding under the above parameters are more conducive to the mixing of the mixture M and the mixture N, thereby improving the performance of the ceramic-based coating.

[0034] Further, in step S3, the spraying curing is carried out by layer-by-layer spraying, and the method of the layer-by-layer spraying curing is divided into the following three stages:

[0035] Stage one: the initial spraying rate of the mixture N is 45 mL / min, then the spraying rate is increased to 65-75 mL / min at a rate of 3 mL / min, and the curing temperature is maintained at 75℃ during the spraying process;

[0036] Stage two: when the spraying rate of the mixture N reaches 65-75 mL / min, the spraying rate is adjusted to decrease to 50-55 mL / min at a rate of 5 mL / min, and the curing temperature is increased to 110℃ at a rate of 5℃ / min;

[0037] Stage three: when the spraying rate of the mixture N reaches 50-55 mL / min, the spraying rate is adjusted to decrease to 0 mL / min at 8 mL / min, the curing temperature is increased to 130-150 DEG C at the temperature increasing rate of 10 DEG C / min, and the temperature is kept until the curing is completed;

[0038] Description: the layer-by-layer curing method is used to spray the mixture N on the surface of the mixture M and perform the curing treatment, compared with the method that the mixture M and the mixture N are mixed and then co-cured, the method has lower porosity, stronger shielding effect and better comprehensive performance.

[0039] The present application has the following advantages:

[0040] (1) The composite ceramic coating prepared by the present application has excellent chemical medium corrosion resistance and good adhesion, high mechanical strength, good toughness and other comprehensive properties, and also has good acid resistance, alkali resistance and salt fog resistance at high temperature.

[0041] (2) The dispersion aid and the composite ceramic base material prepared by the present application are used together, compared with the dispersion aid in the prior art, can effectively improve the settlement or floating phenomenon of the coating during drying or use, the glass flake can be laid and oriented during the mixing and dispersion of the coating, and the flake and the flake are overlapped, which realizes the shielding effect of overlapping coverage and prevents the corrosion of water vapor and chemical solvent to the base material during the dispersion process, and further improves the chemical resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Fig. 1 is a mechanical property fold line statistical diagram of ceramic base coatings of embodiment 1 to embodiment 9 and comparative examples 1 to 3 of the present application;

[0043] Figure 2 Fig. 2 is a chemical resistance fold line statistical diagram of ceramic base coatings of embodiment 1 to embodiment 9 and comparative examples 1 to 3 of the present application;

[0044] Figure 3 Fig. 3 is a mechanical property fold line statistical diagram of ceramic base coatings of embodiment 1, embodiment 10 to embodiment 17 and comparative examples 4 to 5 of the present application;

[0045] Figure 4 Fig. 4 is a chemical resistance fold line statistical diagram of ceramic base coatings of embodiment 1, embodiment 10 to embodiment 17 and comparative examples 4 to 5 of the present application;

[0046] Figure 5 Fig. 5 is a mechanical property fold line statistical diagram of ceramic base coatings of embodiment 1, embodiment 18 to embodiment 23 and comparative examples 6 to 7 of the present application;

[0047] Figure 6 Fig. 6 is a chemical resistance fold line statistical diagram of ceramic base coatings of embodiment 1, embodiment 18 to embodiment 23 and comparative examples 6 to 7 of the present application;

[0048] Figure 7 is a mechanical property fold line statistical graph of the ceramic-based coating of the embodiment 1 and the embodiments 24-31 of the present application;

[0049] Figure 8 is a chemical resistance fold line statistical graph of the ceramic-based coating of the embodiment 1 and the embodiments 24-31 of the present application. DETAILED DESCRIPTION

[0050] The present application will be further described in more detail with the specific embodiments. The advantages of the present application can be better embodied.

[0051] Embodiment 1: A ceramic-based coating for enhancing the corrosion resistance of a boiler water wall, comprising by weight parts: 13 parts of amino silane coupling agent, 22 parts of composite ceramic base material, 3.5 parts of defoaming agent, 3.2 parts of dispersion aid, 5 parts of epoxy coal tar pitch, and 5 parts of chlorosulfonated polyethylene rubber;

[0052] The composite ceramic base material is composed of A component, B component accounting for 4.2wt.% of A component, and mixed solvent accounting for 30wt.% of the total amount of A component and B component; A component is composed of titanium boride, nickel powder, and mica in a mass ratio of 6:6:2.5; B component is composed of silicon carbide ceramic powder, carbon fiber, and curing agent in a mass ratio of 3.4:3.3:2.6; the mixed solvent is obtained by uniformly mixing isocyanate and n-butanol in a mass ratio of 2.5:1.1; the dispersion aid is composed of polyacrylamide, cashew nut shell oil, and glass flake in a mass ratio of 0.7:0.6:4;

[0053] The preparation method of the composite ceramic base material is as follows:

[0054] Titanium boride, nickel powder, and mica are weighed in sequence and added to a blender, stirred at a stirring speed of 600r / min for 13min, then 5 / 14 amount of mixed solvent and curing agent are added and the stirring speed is increased to 1100r / min, and the first base material is obtained after uniform stirring; wherein the curing agent is composed of phenolic amine, nano-Al2O3 particles, and polyphenylene diamine in a ratio of 0.6:1.3:0.4;

[0055] Silicon carbide ceramic powder and the remaining mixed solvent are mixed under a first temperature condition and stirred at a speed of 400r / min for 8min, then carbon fiber is added, the temperature is adjusted to a second temperature, and stirring is continued at a speed of 700r / min for 13min, finally the temperature is adjusted to a third temperature for continuous stirring for 3min and filtered with silk gauze to obtain the second base material; wherein the first temperature is 92℃, the second temperature is 22% of the first temperature, and the third temperature is 60℃;

[0056] The first base material and the second base material are mixed and stirred uniformly, and are ground by an alcohol wet ball method for 9 hours, and finally are dried at 60 DEG C to obtain a composite ceramic base material, which is used for standby; wherein the relative humidity of the alcohol wet ball method is kept at 43 RH %;

[0057] A method for preparing a dispersing aid includes the following steps:

[0058] The polyacrylamide and 7 / 24 of cashew nut shell oil are taken into a reaction kettle, the temperature of the reaction kettle is adjusted to 90 DEG C, the pressure is 0.35 Mpa, ultrasonic dispersion treatment is performed for 18 min, and then the dispersion liquid is poured out; the temperature of the reaction kettle is reduced to 60 DEG C, the pressure is kept unchanged, then the glass flake is added into the reaction kettle, the remaining amount of cashew nut shell oil is added into the reaction kettle and mixed at a speed of 105 r / min for 28 min to obtain a dispersion carrier; the temperature of the reaction kettle is increased to 85 DEG C, then the dispersion liquid is added into the dispersion carrier at an adding speed of 70 mL / min, and mixing is performed to obtain a dispersing aid;

[0059] The parameters of ultrasonic dispersion treatment are as follows: the ultrasonic frequency is 30 kHz, and the ultrasonic intensity is 250 W;

[0060] The shape of the nickel powder is flaky;

[0061] The embodiment also provides a preparation method of the ceramic base paint for enhancing the corrosion resistance of a boiler water cooling wall, including the following steps:

[0062] S1, preparation of the mixed material M

[0063] The composite ceramic base material and 5 / 14 of the amino silane coupling agent are added into a high-speed disperser, ultrasonic dispersion is performed at a temperature of 40 DEG C for 10 min, then the dispersing aid is added, and ultrasonic dispersion is continuously performed at 60 DEG C for 60 min until the mixture is uniformly mixed, finally centrifugal treatment is performed twice at a rotating speed of 1750 r / min for 45 min per time, and the mixture is left to stand for 2.5 h to obtain the mixed material M;

[0064] S2, preparation of the mixed material N

[0065] The epoxy coal tar pitch, the chlorosulfonated polyethylene rubber and the remaining amount of the amino silane coupling agent are added into a container, and stirring and mixing are performed at a rotating speed of 400 r / min for 40 min to obtain the mixed material N;

[0066] S3, curing and cooling

[0067] The mixed material M is dispersed and ground to a particle size of 30-40 mu m, then the mixed material N is sprayed on the surface of the mixed material M for curing, and the ceramic base paint for enhancing the corrosion resistance of the boiler water cooling wall is obtained after natural cooling to room temperature; wherein the spraying speed of the spraying curing is 60 mL / min, the curing temperature is 105 DEG C, and the curing time is 2.2 h;

[0068] In step S3, the dispersion and grinding mode is: first dispersed by high-speed stirring dispersion machine at a speed of 1250 r / min for 33 min, and then ground in a ball mill for 3 h.

[0069] Example 2: Different from example 1, a ceramic-based coating for enhancing the corrosion resistance of boiler water wall, comprising by weight parts: amino silane coupling agent 10 parts, composite ceramic base 15 parts, defoaming agent 2.5 parts, dispersion aid 2.5 parts, epoxy coal tar pitch 3 parts, chlorosulfonated polyethylene rubber 3 parts.

[0070] Example 3: Different from example 1, a ceramic-based coating for enhancing the corrosion resistance of boiler water wall, comprising by weight parts: amino silane coupling agent 15 parts, composite ceramic base 30 parts, defoaming agent 5 parts, dispersion aid 4 parts, epoxy coal tar pitch 7 parts, chlorosulfonated polyethylene rubber 7 parts.

[0071] Example 4: Different from example 1, the composite ceramic base is composed of A component, B component accounting for 3.5 wt.% of A component, and mixed solvent accounting for 25 wt.% of the total amount of A component and B component.

[0072] Example 5: Different from example 1, the composite ceramic base is composed of A component, B component accounting for 5 wt.% of A component, and mixed solvent accounting for 35 wt.% of the total amount of A component and B component.

[0073] Example 6: Different from example 1, the A component is composed of titanium boride, nickel powder, mica according to the mass ratio of 5:5:2; the B component is composed of silicon carbide ceramic powder, carbon fiber, curing agent according to the mass ratio of 3:

[0074] 2:2.2; the mixed solvent is obtained by uniformly mixing isocyanate and n-butanol according to the mass ratio of 2:1.

[0075] Example 7: Different from example 1, the A component is composed of titanium boride, nickel powder, mica according to the mass ratio of 7:7:3; the B component is composed of silicon carbide ceramic powder, carbon fiber, curing agent according to the mass ratio of 3.8:4:2.8; the mixed solvent is obtained by uniformly mixing isocyanate and n-butanol according to the mass ratio of 3:1.2.

[0076] Example 8: Different from example 1, the dispersion aid is composed of polyacrylamide, cashew nut shell oil and glass flake according to the mass ratio of 0.5:0.5:3.

[0077] Example 9: Different from example 1, the dispersion aid is composed of polyacrylamide, cashew nut shell oil and glass flake according to the mass ratio of 1:0.7:5.

[0078] Example 10: Different from example 1, in the preparation method of the composite ceramic base, titanium boride, nickel powder, and mica are weighed in sequence and added to a blender, stirred at a stirring speed of 500 r / min for 15 min, then 1 / 3 amount of mixed solvent and curing agent are added and the stirring speed is increased to 1000 r / min, and the first base is obtained after uniform stirring.

[0079] Example 11: Different from example 1, in the preparation method of the composite ceramic base, titanium boride, nickel powder, and mica are weighed in sequence and added to a blender, stirred at a stirring speed of 700 r / min for 10 min, then 1 / 2 amount of mixed solvent and curing agent are added and the stirring speed is increased to 1200 r / min, and the first base is obtained after uniform stirring.

[0080] Example 12: Different from example 1, in the preparation method of the composite ceramic base, silicon carbide ceramic powder and the remaining mixed solvent are mixed at a first temperature and stirred at a speed of 300 r / min for 10 min, then carbon fibers are added, the temperature is adjusted to a second temperature, and stirring is continued at a speed of 600 r / min for 15 min, finally the temperature is adjusted to a third temperature and stirring is continued for 2 min and filtered with silk gauze to obtain the second base; wherein the first temperature is 85°C, the second temperature is 15% of the first temperature, and the third temperature is 55°C.

[0081] Example 13: Different from example 1, in the preparation method of the composite ceramic base, silicon carbide ceramic powder and the remaining mixed solvent are mixed at a first temperature and stirred at a speed of 500 r / min for 5 min, then carbon fibers are added, the temperature is adjusted to a second temperature, and stirring is continued at a speed of 800 r / min for 10 min, finally the temperature is adjusted to a third temperature and stirring is continued for 4 min and filtered with silk gauze to obtain the second base; wherein the first temperature is 100°C, the second temperature is 30% of the first temperature, and the third temperature is 65°C.

[0082] Example 14: Different from example 1, in the preparation method of the composite ceramic base, the first base and the second base are mixed and stirred uniformly, and are ground by alcohol wet ball method for 8 h, and finally dried at 55°C to obtain the composite ceramic base, which is ready for use; wherein the relative humidity during the alcohol wet ball grinding process is maintained at 45 RH%.

[0083] Example 15: Different from example 1, in the preparation method of the composite ceramic base, the first base and the second base are mixed and stirred uniformly, and are ground by alcohol wet ball method for 10 h, and finally dried at 65°C to obtain the composite ceramic base, which is ready for use; wherein the relative humidity during the alcohol wet ball grinding process is maintained at 40 RH%.

[0084] Example 16: Unlike Example 1, in the preparation method of the composite ceramic matrix, the curing agent is composed of phenolic amine, nano Al2O3 particles and polyphenylene diamine in a ratio of 0.5:1:0.3.

[0085] Example 17: Unlike Example 1, in the preparation method of the composite ceramic matrix, the curing agent is composed of phenolic amine, nano Al2O3 particles and polyphenylene diamine in a ratio of 0.7:1.5:0.5.

[0086] Example 18: Unlike Example 1, the preparation method of the dispersing agent...

[0087] Add polyacrylamide and 1 / 4 of cashew nut shell oil to a reaction vessel, adjust the temperature of the reaction vessel to 85℃ and the pressure to 0.25Mpa, and ultrasonically disperse for 15min to obtain a dispersion.

[0088] Example 19: Unlike Example 1, the preparation method of the dispersing agent...

[0089] Add polyacrylamide and 1 / 3 of cashew nut shell oil to a reaction vessel, adjust the temperature of the reaction vessel to 95℃ and the pressure to 0.45Mpa, and ultrasonically disperse for 20min to obtain a dispersion.

[0090] Example 20: Unlike Example 1, in the preparation method of the dispersing agent, the temperature of the reactor was reduced to 55°C while the pressure remained unchanged. Then, glass flakes were added to the reactor, and the remaining amount of cashew shell oil was added to the reactor and mixed at a rate of 100 r / min for 30 min to obtain the dispersing carrier. The temperature of the reactor was increased to 80°C, and then the dispersion was added to the dispersing carrier at an addition rate of 60 mL / min and mixed to obtain the dispersing agent.

[0091] Example 21: Unlike Example 1, in the preparation method of the dispersing agent, the temperature of the reactor was reduced to 65°C while the pressure remained unchanged. Then, glass flakes were added to the reactor, and the remaining amount of cashew shell oil was added to the reactor and mixed at a rate of 110 r / min for 25 min to obtain the dispersing carrier. The temperature of the reactor was increased to 90°C, and then the dispersion was added to the dispersing carrier at an addition rate of 80 mL / min and mixed to obtain the dispersing agent.

[0092] Example 22: Unlike Example 1, the parameters for ultrasonic dispersion treatment are: ultrasonic frequency of 25kHz and ultrasonic intensity of 200W.

[0093] Example 23: Unlike Example 1, the parameters for ultrasonic dispersion treatment are: ultrasonic frequency of 35kHz and ultrasonic intensity of 300W.

[0094] Example 24: Different from example 1, the shape of the nickel powder is spherical, and the particle size of the nickel powder is 500-5000 mesh.

[0095] Example 25: Different from example 1, in a preparation method of a ceramic-based coating for enhancing the corrosion resistance of a boiler water wall, S1, preparation of the mixture M

[0096] The composite ceramic base material and 1 / 3 of the amino silane coupling agent are added to a high-speed disperser, ultrasonic dispersion is carried out at a temperature of 35°C for 12 min, then a dispersion aid is added, and ultrasonic dispersion is continued at 55°C for 70 min until the mixture is uniform, and finally centrifugal treatment is carried out twice at a speed of 1500 r / min for 65 min / time, and the mixture is left to stand for 2 h to obtain the mixture M;

[0097] S2, preparation of the mixture N

[0098] The epoxy coal tar pitch, chlorosulfonated polyethylene rubber, and the remaining amount of amino silane coupling agent are added to a container and stirred and mixed at a speed of 300 r / min for 50 min to obtain the mixture N;

[0099] S3, curing and cooling

[0100] The mixture M is dispersed and ground to a particle size of 30-40 μm, then the mixture N is sprayed on the surface of the mixture M for solidification, and naturally cooled to room temperature to obtain the ceramic-based coating for enhancing the corrosion resistance of a boiler water wall; wherein the spraying rate of the spraying solidification is 45 mL / min, the solidification temperature is 70°C, and the solidification time is 2.5 h.

[0101] Example 26: Different from example 1, in a preparation method of a ceramic-based coating for enhancing the corrosion resistance of a boiler water wall, S1, preparation of the mixture M

[0102] The composite ceramic base material and 1 / 2 of the amino silane coupling agent are added to a high-speed disperser, ultrasonic dispersion is carried out at a temperature of 45°C for 8 min, then a dispersion aid is added, and ultrasonic dispersion is continued at 65°C for 50 min until the mixture is uniform, and finally centrifugal treatment is carried out three times at a speed of 2000 r / min for 25 min / time, and the mixture is left to stand for 3 h to obtain the mixture M;

[0103] S2, preparation of the mixture N

[0104] The epoxy coal tar pitch, chlorosulfonated polyethylene rubber, and the remaining amount of amino silane coupling agent are added to a container and stirred and mixed at a speed of 500 r / min for 30 min to obtain the mixture N;

[0105] S3, curing and cooling

[0106] The mixture M is dispersed and ground to a particle size of 30-40 μm, and then the mixture N is sprayed on the surface of the mixture M for solidification, and naturally cooled to room temperature to obtain a ceramic-based coating for enhancing the corrosion resistance of the boiler water wall; wherein the spraying rate of the spraying solidification is 75 mL / min, the solidification temperature is 150°C, and the solidification time is 2 h.

[0107] Example 27: Different from Example 1, in step S3, the dispersion and grinding method is: first dispersed by a high-speed stirring disperser at a speed of 1000 r / min for 40 min, and then ground in a ball mill for 2.5 h.

[0108] Example 28: Different from Example 1, in step S3, the dispersion and grinding method is: first dispersed by a high-speed stirring disperser at a speed of 1500 r / min for 25 min, and then ground in a ball mill for 3.5 h.

[0109] Example 29: Different from Example 1, in step S3, the spraying solidification adopts layer-by-layer spraying solidification, and the layer-by-layer spraying solidification method is divided into the following three stages:

[0110] Stage one: the initial spraying rate of the mixture N is 45 mL / min, and then the spraying rate is increased to 65 mL / min at a rate of 3 mL / min, and the solidification temperature is maintained at 75°C during the spraying process;

[0111] Stage two: when the spraying rate of the mixture N reaches 65 mL / min, the spraying rate is adjusted to decrease to 50 mL / min at a rate of 5 mL / min, and the solidification temperature is increased to 110°C at a rate of 5°C / min;

[0112] Stage three: when the spraying rate of the mixture N reaches 50 mL / min, the spraying rate is adjusted to decrease to 0 mL / min at a rate of 8 mL / min, and the solidification temperature is increased to 130°C at a rate of 10°C / min, and the temperature is maintained until the solidification is completed.

[0113] Example 30: Different from Example 1, in step S3, the spraying solidification adopts layer-by-layer spraying solidification, and the layer-by-layer spraying solidification method is divided into the following three stages:

[0114] Stage one: the initial spraying rate of the mixture N is 45 mL / min, and then the spraying rate is increased to 70 mL / min at a rate of 3 mL / min, and the solidification temperature is maintained at 75°C during the spraying process;

[0115] Stage two: when the spraying rate of the mixture N reaches 70 mL / min, the spraying rate is adjusted to decrease to 53 mL / min at a rate of 5 mL / min, and the solidification temperature is increased to 110°C at a rate of 5°C / min;

[0116] Stage three: when the spraying rate of mixture N reaches 53 mL / min, the spraying rate is adjusted to decrease to 0 mL / min at a rate of 8 mL / min, the curing temperature is increased to 140 °C at a rate of 10 °C / min, and the temperature is maintained until the curing is completed.

[0117] Example 31: different from example 1, in step S3, the spray curing is layer-by-layer spray curing, and the method of layer-by-layer spray curing is divided into the following three stages:

[0118] Stage one: the initial spraying rate of mixture N is 45 mL / min, and then the spraying rate is increased to 75 mL / min at a rate of 3 mL / min, and the curing temperature is maintained at 75 °C during the spraying process;

[0119] Stage two: when the spraying rate of mixture N reaches 75 mL / min, the spraying rate is adjusted to decrease to 55 mL / min at a rate of 5 mL / min, and the curing temperature is increased to 110 °C at a rate of 5 °C / min;

[0120] Stage three: when the spraying rate of mixture N reaches 55 mL / min, the spraying rate is adjusted to decrease to 0 mL / min at a rate of 8 mL / min, the curing temperature is increased to 150 °C at a rate of 10 °C / min, and the temperature is maintained until the curing is completed.

[0121] Experimental example: the ceramic-based coating prepared by example 1~example 31 and control example 1~control example 7 is respectively detected for its adhesion, impact resistance and chemical medium resistance, and the results are as follows:

[0122] Among them, the chemical medium resistance test refers to "water-based anticorrosive coating for steel structure" (HG / T 5176-2017), and the corrosion medium is 50g / L sulfuric acid solution, 50g / L sodium hydroxide solution and 3.5% sodium chloride solution. The prepared ceramic-based coating steel plate is placed in the test box containing sulfuric acid solution, sodium hydroxide solution and sodium chloride solution, respectively, taken out every certain period of time and cleaned in distilled water, placed in air at 50 °C±2 °C, then the time when the sample surface starts to bubble or rust spot appears is observed and recorded, unit: d (day). The damage phenomenon caused by external factors within 5mm around the edge of the test plate and the hole is not investigated;

[0123] 1, according to Figures 1-2 Data observation of the influence of the proportion of each component of the ceramic-based coating on the performance of the ceramic-based coating

[0124] According to Figures 1-2The data shows that the performance differences of the ceramic-based coatings prepared with different component proportions in Examples 1-9 are small. Specifically, in Comparative Example 1, unlike Example 1, component B does not contain carbon fiber. In Comparative Example 2, unlike Example 1, isocyanate in the mixed solvent is replaced with polyurethane. In Comparative Example 3, unlike Example 1, cashew nut shell oil is not added to the dispersing agent.

[0125] A comparison of the data from Examples 1, 6, 7, and Comparative Example 1 shows that the lack of carbon fiber significantly weakens the impact resistance of the prepared ceramic-based coating, thus affecting its adhesion performance. A comparison of the data from Examples 1, 6, 7, and Comparative Example 2 shows that replacing isocyanate with polyurethane significantly weakens the binding effect of the cashew nutshell oil dispersant, thus reducing the dispersing effect of the dispersant on the coating and further reducing the various properties of the ceramic-based coating. A comparison of the data from Examples 1, 8-9, and Comparative Example 3 shows that the lack of cashew nutshell oil in Comparative Example 3, although the glass flakes can form a tortuous labyrinthine impermeable layer structure by overlapping the flakes, delaying the diffusion of corrosive media to the metal substrate surface, this corrosion-delaying effect is weakened by coating agglomeration.

[0126] 2. According to Figures 3-4 Data observation on the impact of composite ceramic matrix preparation methods on the performance of ceramic matrix coatings

[0127] Depend on Figures 3-4 The data shows that the performance differences of the ceramic-based coatings prepared in Examples 1 and 10-17 under different parameters are small. Specifically, in Comparative Example 4, unlike Example 1, the addition temperature of silicon carbide ceramic powder and carbon fiber is not limited in the preparation method of the composite ceramic matrix. In Comparative Example 5, unlike Example 1, the relative humidity of the alcohol wet-bulb grinding method is not limited.

[0128] Comparison of data from Examples 1, 12-13, and Comparative Examples 4 and 5 shows that neither limiting the mixing temperature of silicon carbide ceramic powder and carbon fiber nor limiting the relative humidity of the alcohol wet-bulb grinding process will reduce the final performance of the prepared ceramic-based coating. This is because carbon fiber is sensitive to temperature and relative humidity. The above-mentioned limitations can avoid the problem of wet oxidation or ignition of carbon fiber and silicon carbide ceramic powder during the mixing process, thereby improving the stability of the ceramic matrix and further enhancing the performance of the ceramic-based coating.

[0129] 3. According to Figures 5-6 Data observation on the effect of dispersant preparation method on the performance of ceramic matrix coatings

[0130] Depend on Figures 5-6The data shows that the performance differences of the dispersants prepared in Examples 1 and 18-23 under different parameters are small. Specifically, in Comparative Example 6, unlike Example 1, the cashew nut shell oil was added all at once, without batch addition. In Comparative Example 7, unlike Example 1, no temperature limit was imposed on the addition of the cashew nut shell oil.

[0131] A comparison of the data from Examples 1, 20, 21, and the comparative examples reveals that in Comparative Example 6, directly adding cashew nut shell oil to the prepared dispersant resulted in poor wetting of the scales, thus reducing the mixing effect and weakening the dispersant's effect on the ceramic-based coating. In Comparative Example 7, due to the properties of cashew nut shell oil, it was prone to oxidation at high temperatures, thereby weakening the oil quality and affecting the coating performance. In contrast, the dispersant obtained by adding cashew nut shell oil at low temperatures in this application is more uniform and stable.

[0132] 4. According to Figures 7-8 Data observation on the impact of spray curing method on the performance of ceramic matrix coatings

[0133] Depend on Figures 7-8 The data shows that the ceramic-based coatings prepared in Examples 1 and 24-28 under different parameters have little difference in performance; the ceramic-based coatings prepared in Examples 29-31 have slightly better performance than those prepared in Examples 1-28.

[0134] A comparison of the data from Examples 1, 29-31, and the control example shows that the ceramic-based coatings prepared by a single curing and cooling process in Examples 1 and 25-26 have inferior performance compared to Examples 29-31. Figure 7 , 8 It can be seen that using the layer-by-layer curing method to spray mixture N onto the surface of mixture M and then curing it sequentially results in better overall performance than directly mixing mixture M and mixture N and then co-curing them.

Claims

1. A ceramic-based coating for enhancing the corrosion resistance of boiler water-cooled walls, characterized in that, By weight, it includes: 10-15 parts of aminosilane coupling agent, 15-30 parts of composite ceramic matrix, 2.5-5 parts of defoamer, 2.5-4 parts of dispersant, 3-7 parts of epoxy coal tar pitch, and 3-7 parts of chlorosulfonated polyethylene rubber. The composite ceramic matrix is ​​composed of component A, component B accounting for 3.5-5 wt.% of component A, and a mixed solvent accounting for 25-35 wt.% of the total amount of components A and B; component A is composed of titanium boride, nickel powder, and mica in a mass ratio of 5-7:5-7:2-3; component B is composed of silicon carbide ceramic powder, carbon fiber, and curing agent in a mass ratio of 3-3.8:3.2-4:2.2-2.8; the mixed solvent is obtained by mixing isocyanate and n-butanol in a mass ratio of 2-3:1-1.

2. The preparation method of the composite ceramic matrix is ​​as follows: Weigh out titanium boride, nickel powder, and mica in sequence and add them to a mixer. Stir for 10 to 15 minutes at a stirring speed of 500 to 700 r / min. Then add 1 / 3 to 1 / 2 of the mixed solvent and curing agent and increase the speed to 1000 to 1200 r / min. Stir until uniform to obtain the first base material. Prepare silicon carbide ceramic powder and the remaining mixed solvent, mix them at a first temperature and stir at a rate of 300~500 r / min for 5~10 min, then add carbon fiber and adjust the temperature to a second temperature, continue stirring at a rate of 600~800 r / min for 10~15 min, finally adjust the temperature to a third temperature and continue stirring for 2~4 min, and filter with silk to obtain the second base material; wherein, the first temperature is 85~100℃, the second temperature is 15~30% of the first temperature, and the third temperature is 55~65℃; The first and second base materials are mixed and stirred evenly, and then ground using the alcohol wet-bulb method for 8-10 hours. Finally, they are dried at 55-65℃ to obtain the composite ceramic base material for later use. The relative humidity during the alcohol wet-bulb grinding process is maintained at 40-45% RH. The dispersing agent is composed of polyacrylamide, cashew nut shell oil, and glass flakes in a mass ratio of 0.5~1:0.5~0.7:3~5; The method for preparing the dispersing agent includes the following steps: Add polyacrylamide and 1 / 4 to 1 / 3 of cashew nut shell oil to a reaction vessel. Adjust the reaction vessel temperature to 85 to 95°C and the pressure to 0.25 to 0.45 MPa. Perform ultrasonic dispersion treatment for 15 to 20 minutes and pour out to obtain a dispersion. Lower the reaction vessel temperature to 55 to 65°C while keeping the pressure constant. Then add the glass flakes to the reaction vessel. Add the remaining cashew nut shell oil to the reaction vessel and mix at a rate of 100 to 110 r / min for 25 to 30 minutes to obtain a dispersion carrier. Raise the reaction vessel temperature to 80 to 90°C and add the dispersion to the dispersion carrier at an addition rate of 60 to 80 mL / min. Mix well to obtain a dispersing aid.

2. The ceramic-based coating for enhancing the corrosion resistance of boiler water-cooled walls as described in claim 1, characterized in that, The curing agent is composed of phenolic amine, nano-Al2O3 particles and polyphenylene diamine in a mass ratio of 0.5~0.7:1~1.5:0.3~0.

5.

3. The ceramic-based coating for enhancing the corrosion resistance of boiler water-cooled walls as described in claim 1, characterized in that, The parameters for the ultrasonic dispersion treatment are: ultrasonic frequency of 25~35kHz and ultrasonic intensity of 200~300W.

4. A ceramic-based coating for enhancing the corrosion resistance of boiler water-cooled walls as described in claim 1, characterized in that, The nickel powder is in the shape of flakes or spheres, and the particle size of the nickel powder is 500~5000 mesh.

5. A method for preparing a ceramic-based coating that enhances the corrosion resistance of boiler water-cooled walls, used to prepare the ceramic-based coating for enhancing the corrosion resistance of boiler water-cooled walls as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Preparation of S1 and Mixture M The composite ceramic matrix and 1 / 3 to 1 / 2 of the aminosilane coupling agent are added to a high-speed disperser and ultrasonically dispersed at 35 to 45°C for 8 to 12 minutes. Then, the dispersing agent is added and ultrasonically dispersed at 55 to 65°C for 50 to 70 minutes until the mixture is uniform. Finally, the mixture is centrifuged 2 to 3 times at a speed of 1500 to 2000 r / min for 25 to 65 minutes each time, and then allowed to stand for 2 to 3 hours to obtain the mixture M. Preparation of S2 and Mixture N Epoxy coal tar pitch, chlorosulfonated polyethylene rubber, and the remaining aminosilane coupling agent are added to a container and stirred at a speed of 300~500 r / min for 30~50 min to obtain mixture N; S3, solidification and cooling Mixture M is dispersed and ground to a particle size of 30-40 μm, and then mixture N is sprayed onto the surface of mixture M for curing. After natural cooling to room temperature, a ceramic-based coating that enhances the corrosion resistance of boiler water-cooled walls is obtained. The spraying rate for curing is 45-75 mL / min, the curing temperature is 70-150℃, and the curing time is 2-2.5 h.

6. The method for preparing a ceramic-based coating as described in claim 5, characterized in that, In step S3, the dispersion and grinding methods are as follows: first, disperse the material using a high-speed stirring disperser at a rate of 1000~1500r / min for 25~40min, and then grind it in a ball mill for 2.5~3.5h.

7. The method for preparing a ceramic-based coating as described in claim 5, characterized in that, In step S3, the spray curing is carried out layer by layer spray curing, which is divided into the following three stages: Stage 1: The initial spraying rate of the mixture N is 45 mL / min, and then the spraying rate is increased by 3 mL / min to 65~75 mL / min. The curing temperature is maintained at 75℃ during the spraying process. Phase 2: When the spraying rate of the mixed material N reaches 65~75mL / min, adjust the spraying rate to 50~55mL / min at 5mL / min. During this phase, the curing temperature is increased to 110℃ at a heating rate of 5℃ / min. Stage 3: When the spraying rate of the mixed material N reaches 50~55mL / min, adjust the spraying rate to 8mL / min and reduce it to 0mL / min. During this stage, the curing temperature is increased to 130~150℃ at a heating rate of 10℃ / min and maintained at this temperature until curing is complete.

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