Excellent Oxidation Behavior of the Spin-Coated SiCO Layers on the Austenitic Steel

Silicon oxycarbide (SiCO) coated AISI 301 steel was fabricated by pyrolysis of spin-coated three polysiloxane precursors (C1, C2, C3). In each of these precursors, the V3 polymer had a different molar mass (5 000, 10 000, 20 000 g/mol). The oxidation behavior of AISI 301 substrates covered with SiCO coatings was studied in air atmosphere under isothermal conditions at 900 degrees C for 100 h. It was determined that SiCO coated steel exhibits better performance (kp similar to 10(-13) g(2)cm-4s(-1)) than the uncoated AISI 301 steel (kp similar to 10(-12) g(2)cm(-4)s(-1)). This is due to the formation of dense and well-adherent to the substrate SiCO coatings. The molecular weight of the polymer did not affect the thickness or protective properties of the layers. An attempt was made to investigate the mechanism of SiCO layer oxidation by means of a marker experiment. The samples used in this experiment were examined via Scanning Electron Microscopy (SEM) and Raman spectroscopy that revealed inhibition of reactants transport.