▎ 摘　　要

NOVELTY - A micro-nano composite filler perfluoroalkoxy fluorocarbon resin (PFA) coating comprises high-temperature baked PFA as coating body, and titania-filled graphene oxide filler. The graphene oxide is 5-10 mu m long flake graphene oxide. The titania has diameter of 38-42 nm and thickness of 20-30 mu m. USE - Micro-nano composite filler perfluoroalkoxy fluorocarbon resin coating used for flue gas waste heat recovery and phase-change heat transfer. ADVANTAGE - The coating has good bonding force and anticorrosion performance, long service life and large coating contact angle, and solves the problem of high coating porosity and solvent volatilization after high-temperature baking. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the micro-nano composite filler PFA coating comprising: (A) adding nano-titania and silane coupling agent KH-550 to absolute ethanol at mass ratio of 1:15-30, stirring at 78 degrees C for 4-6 hours, centrifuging, washing with absolute ethanol multiple times, and vacuum drying at 60 degrees C for 13-17 hours; (B) adding graphene oxide, adding to N,N-dimethylacetamide at mass ratio of 1:2-1:3, sonicating for 1 hour to obtain homogeneous suspension, stirring at 105 degrees C for 5 hours, filtering, washing, and vacuum-drying at 60 degrees C for 24 hours to obtain graphene oxide-nano-titania complex; (C) adding to N,N-dimethylacetamide or acetone, sonicating for 30 minutes, adding organic dispersed emulsion of PFA powder, stirring, and ultrasonically dispersing for 1-2 hours to obtain 1-6 wt.% PFA emulsion with viscosity of 500-800 mPa.s; and (D) pretreating workpiece, spraying with PFA emulsion at pressure of 0.4-0.6 MPa, gradually heating to 370 degrees C for 30-50 minutes, sintering under 80 degrees C inert gas atmosphere having flow rate of 20-50 L/minute, and stop coating when coating thickness is 20-30 mu m.