A high-silicon anti-oxidation coating for carbon steel at high temperature

A high-silicon anti-oxidation coating for carbon steel at high temperature was prepared, which was mainly composed of high-silicon carbide, chromium and binder. The anti-oxidation performance of the coated and uncoated specimens were investigated from 900 °C to 1150 °C maintained for 60 and 120 min, respectively. Compared with the uncoated specimen, the high-silicon coating could enhance the anti-oxidation effect ~ 77% at 1000 °C for 60 min and 85% at 1050 °C for 120 min, respectively. Scanning electron microscope and Energy Dispersive Spectrometer, X-ray Diffraction and TG-DTA technology were used to investigate the protection mechanism of high-silicon coating. First, during high-temperature treatment, there was a big blister formed in the coating because of the chemical reactions of the compositions, which isolated the steel substrate from oxygen. Second, it was found that a series of materials (such as Fe2.35Si0.65O4, Fe2.45Si0.55O4, Fe2.95Si0.05O4 and FeCr2O4) were formed between coating and steel substrate. The formed effective phases to prevent the steel oxidation were ascribed to the solid sintering reaction. Thus, the oxygen reaction on the surface of carbon steel could be slowed or prevented. The high-silicon coating has low cost and easy handing, which is potentially to be used during the high-temperature heating treatment for carbon steel.