The effect of the silicon content on the high temperature corrosion resistance of Fe-Si coatings applied by the thermal spray technique was studied. The coatings were applied using a double-layer system. The first layer was a Ni20Cr coating and the second was composed by the different Fe-Si coatings. The corrosion tests were carried out in a 80%V2O5-20%Na2SO4 corrosive mixture, for 500 hours at temperatures from 600 to 1000°C. The performance of each of the coatings varied as a function of the chemical composition, the physical characteristic and the temperature, Increasing the silicon content enhanced the corrosion resistance of the coating, Furthermore, the exposure of the coatings to the high temperature testing induced the densification by self-healing of the initial porosity of the coating. Even though the Si-based coatings significantly enhanced the corrosion resistance, sulfidation was observed. In the Ni20Cr coating and metal base the severity of this attack was also a function of the composition of the coating and the temperature of the test. Keywords: Silicon-based coatings, Fe-Si coatings, nickel-chromium coatings, vanadium compounds, high temperature corrosion, thermal spray.