Polysilazane-derived SiON coating on stainless steel weld for corrosion resistance

In this study, SiON coatings were created using perhydropolysilazane (PHPS) on the weld region and the base stainless steel region with different microstructure and composition. The influences of the weld and base steel compositions and microstructures on coating formation, composition, microstructure, mechanical properties, and corrosion resistance are discussed. The SiON coatings show a higher N content and a lower O content on the base metal than on the weld metal. Salt spray tests show that the differences in mechanical properties and compositions on the weld and base steel substrates do not significantly affect the function of the corrosionprotective coatings. However, when the coating thickness is high, the corrosion resistance decreases. This study provides important guidance regarding the desirable SiON coating and thickness for best corrosion prevention.