Advanced coatings on the basis of Si(C)N precursors for protection of steel against oxidation

An effective and low-cost method for applying polysilazane-based barrier coatings on stainless steel is presented. Two different precursors in the system SiCN (ABSE) and SiN (PHPS) have been used for applications of polymeric and ceramic-like coating materials. With corresponding precursor solutions in toluene or ether, steel substrates were coated by means of a simple dip coating technique. The influence of different annealing atmospheres such as ambient air and nitrogen on the resulting coatings was determined. Therefore precursor-based powders and coatings were characterised by TGA, REM, TEM, GDOES and chemical composition measurements. Oxidation tests on coated samples were done in air at temperatures of 800–1000 °C. By measuring the weight gain and the oxidation depth, parabolic oxidation kinetics were determined. The precursor-based coatings protect stainless steel from oxidation up to 1000 °C.