Enhanced corrosion protection performance using polysilazane-derived amorphous SiCN ceramic coating

In this work, a polymer-derived silicon carbonitride (SiCN) ceramic layer has been deposited on stainless steel 304 (SS304) to enhance the corrosion resistance of SS304 in a seawater environment. SS304 is dip-coated with a polysilazane solution followed by pyrolysis under argon environment at 800 °C to develop SiCN ceramic layer with a thickness of about 3 μm on SS304. Structural characterization of the prepared samples was performed using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Potentiodynamic polarization tests of SS304 and SiCN-coated SS304 were performed in 0.6 M NaCl solution. SiCN-coated SS304 showed very low corrosion current density of 4.2 × 10−10 A/cm2 whereas corrosion current density of uncoated SS304 was measured to be 1.52 × 10−7 A/cm2. Excellent corrosion resistance performance of SiCN-coated SS304 was observed as confirmed by electrochemical impedance spectroscopic (EIS) measurements. •Corrosion protection behavior of polymer-derived SiCN-coated SS304 has been investigated•Amorphous SiCN ceramic was synthesized by pyrolysis of a commercial polysilazane at 800 °C under agron•SiCN layer of thickness ~3 μm was coated on SS304 by dip-coating in polysilazane solution followed by pyrolysis step•SS304 showed icorr of ~10-7A/cm2 whereas for SiCN-coated SS304 icorr was significantly reduced to ~10-10 A/cm2•Pitting breakdown behavior was not observed in SiCN-coated SS304 as confirmed by Potentiodynamic Polarization test.