Preparation method and application of high-temperature-resistant and high-pressure-resistant water environment composite coating

Abstract

The invention discloses a preparation method and application of a high-temperature-resistant and high-pressure-resistant water environment composite coating. According to the method, SiO2 serves as a pretreatment layer (providing binding force between a coating and a substrate), silicon resin serves as a main resin framework, a high-temperature-resistant organic resin material serves as nano particles (serving as a secondary resin framework after sintering), zirconium and cerium composite oxide nano particles serve as a high-temperature corrosion inhibitor, and the high-temperature corrosion inhibitor is prepared. And an isocyanate polymer is used as a cross-linking curing agent of the components to prepare the high-temperature-resistant and high-pressure-resistant water environment coating after high-temperature sintering. The coating disclosed by the invention can be coated on metal substrates such as low-carbon steel, stainless steel, aluminum alloy and copper alloy, so that the metal substrates can resist corrosion in a high-temperature and high-pressure water environment. And after the coating is cured and sintered, the surface is smooth and has certain hydrophobicity.

Description

Technical Field

[0001] The invention relates to the fields of high temperature and high pressure water environment resistant coating and high temperature and high pressure corrosion. Technical Background

[0002] In clean green energy such as geothermal water and nuclear power plants, the service environment of structural metals has severe temperatures and pressures. So far, the method of hydrothermal resistant coating developed by researchers is mainly prepared by high-temperature spraying or sintering heat-resistant materials above 500°C. This method not only has harsh conditions, but also has poor adhesion between the coating and the metal substrate, and has low protective performance in high-temperature and high-pressure water environments. Therefore, it is very important to develop a simple coating that can last for a long time in high-temperature and high-pressure water environments.

[0003] Heat-resistant polymer resins are widely used in daily life, and are widely used in various aspects such as metal coating protection, home decoration, and object decoration. At present, the hydrothermal resistant coatings on the market are mainly silicone resins and special plastics. Although the common silicone resin coating can withstand temperatures of 200-300°C, it is easy to degrade or swell in hot water environments, resulting in a decrease in bonding strength. Special plastics are difficult to adhere to the surface of the metal substrate, and the substrate is very susceptible to corrosion after being damaged in a hydrothermal environment. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method and application of a composite high temperature and high pressure water environment resistant coating.

[0005] The present invention has developed a composite coating that can be coated on a metal substrate commonly used in a hydrothermal environment through medium and high temperature curing and sintering to construct a high temperature and high pressure water environment resistant coating. Commonly used silicone resins, such as methylphenyl silicone resin (providing the main coating skeleton), high temperature resistant organic resins such as polyphenylene sulfide (providing the secondary organic skeleton), inorganic composite metal oxide nanoparticles (providing a sustained release function for the base metal), etc. are pre-grafted, and then the isocyanate group can react with amino, hydroxyl, carboxyl and other active groups at room temperature and high temperature to quickly cure the above composite components. After being coated on the metal surface loaded with SiO2 nanofilm and sintered, the integrity of the coating can be maintained for a long time in a high temperature and high pressure water environment, effectively slowing down the corrosion process of the base metal.

[0006] A method for preparing a high temperature and high pressure water environment resistant composite coating, 1) Prepare component A: weigh 0.1-5 g silicone resin, 0.1-5 g high temperature resistant organic resin powder, 0.1-5 g zirconium and cerium composite oxide powder, and 5-50 mL organic solvent, and disperse them into a uniform suspension under magnetic stirring; Prepare component B: 0.5~5 mL of isocyanate polymer; The silicone resin in component A is one or more silicone resins such as methyl silicone resin, epoxy silicone resin, phenyl silicone resin, etc.; The high temperature resistant organic resin powder in component A is one or more of polyphenylene sulfide (PPS) powder, polytetrafluoroethylene (PTFE) powder and ethylene tetrafluoroethylene copolymer (PFA) powder; The composite oxide powder of zirconium and cerium in component A is Ce x Zr 1-x O, one of x=0.5~0.8; 2) Mix components A and B and load them onto the metal with SiO2 intermediate layer deposited by dipping, brushing, dripping or spin coating. The loading times are 1 to 5 times and then placed in a constant temperature drying oven at 180°C for drying. 3) The prepared metal material loaded with the composite component coating with SiO2 as the intermediate layer is placed in a muffle furnace, and calcined according to the procedure of heating from 100°C to 340°C for 2 to 4 hours, then maintaining a constant temperature of 340°C for 1 to 3 hours, and finally automatically cooling to room temperature. After cooling, a high temperature and high pressure water environment resistant composite coating with SiO2 as the intermediate layer is obtained.

[0007] The preparation method, preparation of SiO2 pretreatment layer: 1) The metal substrate is ultrasonically degreased with anhydrous acetone for 10 to 30 minutes, rinsed with deionized water, rinsed with anhydrous ethanol, and then dried at a constant temperature of 60 to 100°C for use; 2) Preparation of the exogenous solution: add 50-100 mL of anhydrous ethanol, 50-100 mL of 0.2 M sodium nitrate solution, 1-10 mL of tetramethyl silicate or tetraethyl silicate, and 1 M acetic acid solution to adjust the pH to 2.0-5.0, stir at room temperature for 6-24 hours, and set aside; 3) Add the prepared precursor solution into the three-electrode tank, use the metal substrate as the working electrode, Ag / AgCl as the reference electrode, and the platinum sheet as the counter electrode. Control the potential at -1.0 to -3.0 V, the deposition time is 100s to 500s, and the deposition temperature is 30 to 60°C. After deposition, rinse with deionized water and ethanol in turn, and then dry at 40 to 100°C. After cooling, the metal loaded with SiO2 nanofilm is obtained.

[0008] The metal matrix includes low carbon steel, stainless steel, aluminum alloy and copper alloy.

[0009] In the preparation method, the organic solvent in component A is one or more of toluene, xylene, methanol and ethanol.

[0010] In the preparation method, the dispersion time of component A under magnetic stirring is 12 to 24 hours.

[0011] In the preparation method, the isocyanate polymer substance of component B is one or more isocyanate trimer substances, and the isocyanate trimer cyanate substances include hexamethylene diisocyanate dimer, toluene diisocyanate dimer, and isophorone diisocyanate dimer; the trimer substances include hexamethylene diisocyanate trimer, toluene diisocyanate trimer, and isophorone diisocyanate trimer.

[0012] In the preparation method, the temperature for mixing components A and B is between room temperature and 50°C.

[0013] A high temperature and high pressure water environment resistant composite coating comprises the SiO2 layer, component A and component B of the composite coating.

[0014] The application of the high temperature and high pressure water environment resistant composite coating is that the composite coating after sintering and curing is used to protect metals in a water environment of 120-250°C and 0.15-10 MPa.

[0015] Beneficial effects of the present invention: (1) The preparation conditions of the composite coating are simple and can be applied by common brushing and spraying methods. The composite coating can be sintered and solidified at medium or high temperatures and is easy to use in practice.

[0016] (2) The composite coating has excellent bonding strength with the metal substrate and is suitable for long-term use in hydrothermal environments.

[0017] (3) The composite coating is loaded with metal oxide corrosion inhibitors, which can effectively slow down metal corrosion in the long term while reducing the environmental pollution caused by organic corrosion inhibitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the principles of related curing and sintering reactions, taking the resin as methylphenyl silicone resin, the high-temperature organic resin as polyphenylene sulfide, and the isocyanate as hexamethylene diisocyanate trimer as an example.

[0019] Figure 2 This is a SEM image of the high temperature and high pressure water environment resistant composite coating prepared in Example 1. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below with specific embodiments, but the protection scope of the present invention is not limited thereto. The composite coating is composed of a pretreatment layer and two-component coatings A and B: 1) The metal substrate is ultrasonically degreased with anhydrous acetone for 10 to 30 minutes, rinsed with deionized water, rinsed with anhydrous ethanol, and placed in a 60 to 100 ° C constant temperature drying oven for drying; 2) Preparation of precursor solution: add 50-100 mL of anhydrous ethanol, 50-100 mL of 0.2 M sodium nitrate solution, 5-10 mL of tetramethyl silicate or tetraethyl silicate, and 1 M acetic acid solution to adjust the pH to 2.0-5.0, stir at room temperature for 6-24 hours, and set aside; 3) Add the prepared precursor solution into the three-electrode tank, use the metal substrate as the working electrode, Ag / AgCl as the reference electrode, and the platinum sheet as the counter electrode, control the potential at -1.0 to -1.5 V, the deposition time is 250s to 500s, the deposition temperature is 30 to 60°C, and after deposition, rinse with deionized water and ethanol in turn, and then dry at 40 to 100°C. After cooling, the metal loaded with SiO2 nanofilm is obtained; 4) Prepare component A: weigh 0.1-5 g silicone resin, 0.1-5 g high-temperature organic resin powder, 0.1-5 g zirconium and cerium composite oxide powder, and 5-50 mL organic solvent, and disperse them into a uniform suspension under magnetic stirring; Prepare component B: 0.5~5 mL of isocyanate polymer; 5) Mix components A and B and load them onto the metal with SiO2 intermediate layer deposited by dipping, brushing, dripping, spin coating, etc. The loading times are 1 to 5 times, and place them in a constant temperature drying oven at 180°C for drying.

[0021] 6) The prepared metal material loaded with the composite component coating with SiO2 as the intermediate layer is placed in a muffle furnace, and the temperature is raised from 100°C to 280-340°C for 2-4 hours, then kept at a constant temperature of 280-340°C for 1-3 hours, and finally automatically cooled to room temperature for calcination. After cooling, a high temperature and high pressure water environment resistant composite coating with SiO2 as the intermediate layer is obtained.

[0022] The resin in component A is one or more silicone resins such as methyl silicone resin, epoxy silicone resin, phenyl silicone resin, etc.; The high temperature resistant resin powder in component A is polyphenylene sulfide (PPS) powder, polytetrafluoroethylene (PTFE) powder, ethylene tetrafluoroethylene copolymer (PFA) powder, etc.; The composite oxide powder of zirconium and cerium in component A is one of CexZr1-xO (x=0.5~0.8); The organic solvent in component A is one or more of toluene, xylene, methanol and ethanol.

[0023] The dispersion time of component A under magnetic stirring is 12 to 24 hours.

[0024] The isocyanate polymer substance of component B is one or more of the isocyanate trimer substances. The isocyanate dimer cyanate substances include hexamethylene diisocyanate dimer, toluene diisocyanate dimer, and isophorone diisocyanate dimer; the trimer substances include hexamethylene diisocyanate trimer, toluene diisocyanate trimer, and isophorone diisocyanate trimer.

[0025] The temperature for mixing components A and B is room temperature ~ 50°C.

[0026] Figure 1 This is a schematic diagram of the principles of related curing and sintering reactions, taking the resin as methylphenyl silicone resin, the high-temperature organic resin as polyphenylene sulfide, and the isocyanate as hexamethylene diisocyanate trimer as an example. Example 1

[0027] The Q235B low carbon steel substrate was ultrasonically degreased with anhydrous acetone for 30 min, rinsed with anhydrous ethanol, and then placed in a 60°C constant temperature drying oven for drying and set aside.

[0028] Preparation of precursor solution: Add 50 mL of anhydrous ethanol, 50 mL of 0.2 M sodium nitrate solution, 5 mL of tetraethyl silicate, and 1 M acetic acid solution to adjust the pH to about 5.0, stir at room temperature for 12 h, and set aside.

[0029] Add the prepared precursor solution into the three-electrode tank, use Q235B low-carbon steel substrate as the working electrode, Ag / AgCl as the reference electrode, platinum sheet as the counter electrode, control the potential at -3.0V, the deposition time is 100s, the deposition temperature is 30℃, rinse with deionized water and ethanol in turn, and then dry at 60℃. After cooling, Q235B low-carbon steel loaded with SiO2 film is obtained.

[0030] The traditional resin in component A is selected as methyl phenyl silicone resin, the high temperature heat-resistant resin is polyphenylene sulfide, and the composite metal oxide corrosion inhibitor is Ce 0.8 Zr 0.2 O, the organic solvent is xylene, the magnetic stirring temperature is 25°C, the stirring time is 12 hours, and the isocyanate substance in component B is hexamethylene diisocyanate.

[0031] Component A: weigh 6 g methyl phenyl silicone resin, 3 g polyphenylene sulfide, 0.5 g Ce 0.8 Zr 0.2 O, take 15 mL of organic solvent (xylene), stir magnetically for 12 hours and set aside; Component B: 5 mL of hexamethylene diisocyanate trimer.

[0032] Mix components A and B, stir at room temperature for 15 minutes and then apply by brush, cure at 180℃ for 2 hours, and sinter at 320℃ for 2 hours before testing.

[0033] Test results: It can remain corrosion-free for 14 days in a 3.5% NaCl solution at 120°C and a pressure of 0.15 MPa.

[0034] Figure 2 The SEM images of the high temperature and high pressure water environment resistant composite coating prepared in Example 1 are as follows; among them, at 500 times (part a) and 5000 times (part b), the coating surface is smooth and has no defects, indicating that its components have good compatibility after sintering. Example 2

[0035] The specific implementation steps are similar to those in Example 1, except that the conventional resin in component A is epoxy silicone resin, the high temperature heat-resistant resin is polytetrafluoroethylene, and the composite metal oxide corrosion inhibitor is Ce. 0.8 Zr 0.2 O, the organic solvent is xylene, the magnetic stirring temperature is 25°C, the stirring time is 12 hours, and the isocyanate substance in component B is hexamethylene diisocyanate.

[0036] Component A: weigh 6 g epoxy silicone resin, 3 g polytetrafluoroethylene, 0.5 g Ce 0.8 Zr 0.2 O, take 15 mL of organic solvent (xylene), stir magnetically for 12 hours and set aside; Component B: 5 mL of hexamethylene diisocyanate trimer.

[0037] Mix components A and B, stir at room temperature for 15 minutes and then apply by brush, cure at 180℃ for 2 hours, and sinter at 340℃ for 2 hours before testing.

[0038] Test results: It can remain corrosion-free for 10 days in a 3.5% NaCl solution at 120°C and a pressure of 0.15 MPa. Example 3

[0039] The specific implementation steps are similar to those in Example 1, except that the conventional resin in component A is selected to be epoxy silicone resin, the high temperature heat-resistant resin is ethylene tetrafluoroethylene copolymer (PFA), and the composite metal oxide corrosion inhibitor is Ce. 0.8 Zr 0.2 O, the organic solvent is xylene, the magnetic stirring temperature is 25°C, the stirring time is 12 hours, and the isocyanate substance in component B is hexamethylene diisocyanate.

[0040] Component A: weigh 6 g epoxy silicone resin, 3 g ethylene tetrafluoroethylene copolymer, 0.5 g Ce 0.8 Zr 0.2 O, measure 15mL of organic solvent (xylene), stir magnetically for 12 hours and set aside; Component B: 5 mL of hexamethylene diisocyanate trimer.

[0041] Mix components A and B, stir at room temperature for 15 minutes and then apply by brush, cure at 180℃ for 2 hours, and sinter at 280℃ for 2 hours before testing.

[0042] Test results: It can remain corrosion-free for 15 days in a 3.5% NaCl solution at 120°C and a pressure of 0.15 MPa.

[0043] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a high temperature and high pressure water environment resistant composite coating, characterized in that: 1) Prepare component A: weigh 0.1-5 g silicone resin, 0.1-5 g high temperature resistant organic resin powder, 0.1-5 g zirconium and cerium composite oxide powder, and 5-50 mL organic solvent, and disperse them into a uniform suspension under magnetic stirring; Prepare component B: 0.5~5 mL of isocyanate polymer; The silicone resin in component A is one or more silicone resins such as methyl silicone resin, epoxy silicone resin, phenyl silicone resin, etc.; The high temperature resistant organic resin powder in component A is one or more of polyphenylene sulfide (PPS) powder, polytetrafluoroethylene (PTFE) powder and ethylene tetrafluoroethylene copolymer (PFA) powder; The composite oxide powder of zirconium and cerium in component A is Ce x Zr 1-x O, one of x=0.5~0.8; 2) Mix components A and B and load them onto the metal with SiO2 intermediate layer deposited by dipping, brushing, dripping or spin coating. The loading times are 1 to 5 times and then placed in a constant temperature drying oven at 180°C for drying. 3) The prepared metal material loaded with the composite component coating with SiO2 as the intermediate layer is placed in a muffle furnace, and calcined according to the procedure of heating from 100°C to 340°C for 2 to 4 hours, then maintaining a constant temperature of 340°C for 1 to 3 hours, and finally automatically cooling to room temperature. After cooling, a high temperature and high pressure water environment resistant composite coating with SiO2 as the intermediate layer is obtained.

2. The preparation method according to claim 1, characterized in that: Preparation of SiO2 pretreatment layer: 1) The metal substrate is ultrasonically degreased with anhydrous acetone for 10 to 30 minutes, rinsed with deionized water, rinsed with anhydrous ethanol, and then dried at a constant temperature of 60 to 100°C for use; 2) Preparation of the exogenous solution: add 50-100 mL of anhydrous ethanol, 50-100 mL of 0.2 M sodium nitrate solution, 1-10 mL of tetramethyl silicate or tetraethyl silicate, and 1 M acetic acid solution to adjust the pH to 2.0-5.0, stir at room temperature for 6-24 hours, and set aside; 3) Add the prepared precursor solution into the three-electrode tank, use the metal substrate as the working electrode, Ag / AgCl as the reference electrode, and the platinum sheet as the counter electrode. Control the potential at -1.0 to -3.0 V, the deposition time is 100s to 500s, and the deposition temperature is 30 to 60°C. After deposition, rinse with deionized water and ethanol in turn, and then dry at 40 to 100°C. After cooling, the metal loaded with SiO2 nanofilm is obtained.

3. The preparation method according to claim 1, characterized in that: The metal matrix includes low carbon steel, stainless steel, aluminum alloy and copper alloy.

4. The preparation method according to claim 1, characterized in that: The organic solvent in component A is one or more of toluene, xylene, methanol and ethanol.

5. The preparation method according to claim 1, characterized in that: The dispersion time of component A under magnetic stirring is 12 to 24 hours.

6. The preparation method according to claim 1, characterized in that: The isocyanate polymer substance of component B is one or more of the isocyanate trimer substances, and the isocyanate trimer cyanate substances include hexamethylene diisocyanate dimer, toluene diisocyanate dimer, and isophorone diisocyanate dimer; the trimer substances include hexamethylene diisocyanate trimer, toluene diisocyanate trimer, and isophorone diisocyanate trimer.

7. The preparation method according to claim 1, characterized in that: The temperature for mixing components A and B is room temperature ~ 50℃.

8. A high temperature and high pressure water environment resistant composite coating, characterized in that: The invention comprises the SiO2 layer according to claim 1, component A and component B of the composite coating.

9. The use of the high temperature and high pressure water environment resistant composite coating according to claim 7, characterized in that: The sintered and cured composite coating is used to protect metals in a water environment of 120-250°C and 0.15-10 MPa.

Images