▎ 摘　　要

NOVELTY - A composite anti-corrosion coating comprises a bonding bottom layer, and a fluororesin layer, which is made of a fluororesin material filled with two-dimensional carbon material. The bottom layer and the fluororesin layer are prepared by electrostatic spraying. USE - The composite anti-corrosion coating is useful for corrosion protection of condensation-type flue gas waste heat recovery heat exchange device used in chemical equipment and marine equipment. ADVANTAGE - The coating has excellent heat-conducting property, self-cleaning property, surface mechanical property and cohesive force with matrix metal, and fully uses the characteristics of fluororesin and the two-dimensional carbon material, and can be prepared by a method, which is simple and easy to control, and can meet the requirement of the severe corrosion environment in flue gas waste heat recovery. Fluororesin has excellent chemical stability, thermal stability and hydrophobic property, and is filled with the two-dimensional carbon material, so that the permeation path of a corrosive medium is prolonged, the compactness and corrosion resistance of the coating are enhanced, and a bulk-phase heat-conducting network is constructed. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the composite anti-corrosion coating, which involves: (1) pretreating a substrate by removing an oxide film on a surface of a substrate, and then degreasing, cleaning and drying; (2) preparing the bonding bottom layer by spraying a bonding layer powder on a surface of a workpiece by electrostatic spraying at an electrostatic high voltage of 30-40 kV, an air pressure of 0.2-0.4 MPa, a distance between the workpiece and spray gun mouth of 150-300, and an angle between the workpiece and the spray gun mouth of 60-90°, placing in an oven, and maintaining the temperature at 380-400℃ for 10-30 minutes; and (3) preparing a fluororesin layer by preparing a fluororesin layer powder coating by (a) adding the two-dimensional carbon material to anhydrous ethanol, ultrasonically treating, then adding fluororesin powder, continuously performing ultrasonic treatment, mechanically stirring the mixed phase, and heating in a water bath at 50-7060°C until the mixed phase becomes a paste, transferring the whole mixed phase to a vacuum oven, drying for 12-24 hours, transferring the solid phase to a high-speed stirrer, and mechanically stirring at 5000-10000 rpm for 1-3 minutes, and (b) adding fluororesin powder to sodium-naphthalene complex solution, stirring, then adding absolute ethanol to the system to quench reaction, washing several times with warm water and absolute ethanol, then freeze-drying to obtain modified fluororesin powder, dispersing in anhydrous ethanol by continuously carrying out ultrasonic treatment, then adding two-dimensional carbon material to the mixed system to continue ultrasonic treatment, transferring the system to a water bath at 60-80°C, adding a silane coupling agent, continuously stirring to make the two-dimensional carbon material bond with the modified fluororesin, washing several times, and vacuum drying to obtain modified fluororesin/filler powder, placing in anhydrous ethanol, ultrasonically stirring, continuously drying under vacuum conditions, transferring the solid phase to a high-speed stirrer for mechanical stirring to obtain fluororesin powder, where the ratio of each component is such that the content of fluororesin is 64-97 vol.%, the content of modified fluororesin is 2.5-30 vol.%, and the content of two-dimensional carbon material is 0.5-6 vol.%, spraying and filling the fluororesin layer coating on the surface of the workpiece by electrostatic spraying.