Self-assembled (3-mercaptopropyl)trimethoxylsilane film modified with La2O3 nanoparticles for brass corrosion protection in NaCl solution

Self-assembled monolayers (SAMs) of 3-mercaptopropyltrimethoxysilane (PropS-SH) modified with La2O3 nanoparticles were investigated to evaluate the doping effect of La2O3 nanoparticles on PropS-SH silane film towards brass corrosion protection in NaCl solution. The results indicated that SAMs of PropS-SH modified with La2O3 nanoparticles presented improved barrier properties because La2O3 nanoparticles filled the holes of silane film, which in turn improved the density of silane film, thus enhanced the barrier properties of silane-metal interface. Further, part of La2O3 nanoparticles was transformed to lanthanum oxide hydroxide (LaOOH) by hydrolysis reaction, and the formed La compounds covered the cathode sites, giving rise to a blocking effect.