A polyurea coating containing GO/MA@PFAN filler provides long-term shielding and passive performance to resist corrosion for N80 steel

The functionalization of graphite oxide (GO) by myristic acid (MA) enables stronger binding of fluoro-substituted polyaniline (PFAN) on the GO surface, improving hydrophobicity and compatibility with polyurea resin of fillers, resulting in uniform dispersion in coating. Electrochemical impedance spectroscopy (EIS) revealed that the impedance modulus of GO/MA@PFAN (GMPF) coating was greater than 10(10) Omegacm(2) (80 days, 3.5 wt.% NaCl solution). Simultaneously, the scratched GMPF coating retained extraordinarily high impedance (4.98 x 10(4) Omegacm(2), 72 h), which could be attributed to the outstanding passivation of PFAN. Furthermore, the |Z|(0.01 Hz) value of GMPF coating still reached 8.94 x 10(9) Omegacm(2) after being subjected to CO2-high temperature and high-pressure (HTHP) corrosion (90 degrees C, 2 MPa, 72 h, 3.5 wt.% NaCl solution). Herein, the proposed disposal can effectively improve the corrosion resistance of N80 steel under saline and CO2-HTHP corrosion environments and has broad application prospects in oil and gas well engineering.