Corrosion and tribocorrosion mitigation of perhydropolysilazane-derived coatings on low carbon steel

Perhydropolysilazane (PHPS) is a polymer with [-SiH2-NH-](n) repeating units. By pyrolysis with PHPS as a precursor, highly adhesive and protective silicon oxynitride (SiON)-based coatings were synthesized. The formation of Si-O-Si bonds increased with pyrolysis temperature. Both the hardness and Young's modulus of the PHPS-derived coatings were enhanced at higher pyrolysis temperatures. The PHPS-derived coatings significantly enhanced the corrosion resistance of low carbon steel in a 0.6 M NaCl aqueous solution, especially for the coatings with the formation of extensive Si-O-Si bonds. The PHPS-derived coating at the pyrolysis temperature of 600 degrees C exhibited the best resistance to corrosion and tribocorrosion.